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Sample records for energy helium-neon laser

  1. Unique method of treatment for exotropia applying low-energy helium-neon laser

    NASA Astrophysics Data System (ADS)

    Bessmertnaya, Valentina

    1995-01-01

    Orthoptic treatment for exotropia applying spheroprismatic correction and low-energy helium- neon laser stimulation possesses a series of advantages to the surgical treatment. Prismatic correction has been already applied for exotropia earlier and has proven to be quite effective treating the disease and its minor complications. But in more severe cases when exotropia is accompanied by hyperphoria exceeding 3 pr Dptr and cyclotropia, prismatic correction method is not helpful enough. To cure the most complicated cases of exotropia low-energy helium- neon laser was successfully used for the first time as the only means capable of eliminating hypertropia and cyclotropia. The novelty and high efficiency of the method enables ophthalmologists to approach concomitant squint not as an eye muscular deterioration but as physiological reaction of the visual analyzer to suppress diplopia. Thus the method eliminates the cause of squint.

  2. Low-energy helium-neon laser irradiation increases the motility of cultured human keratinocytes

    SciTech Connect

    Haas, A.F.; Isseroff, R.R.; Wheeland, R.G.; Rood, P.A.; Graves, P.J. )

    1990-06-01

    Helium-neon (HeNe) laser irradiation is known to stimulate wound healing. We investigated whether the biostimulatory effects of HeNe irradiation result from enhancement of keratinocyte proliferation or motility. HeNe effects on keratinocyte motility were evaluated by irradiating a wounded culture with 0.8 J/cm2 3 times over a 20-h period. At 20 h post-irradiation, videocinemicroscopy and sequential quantitative measurements of the leading edge were taken over a 6-h period. There was a significant difference in migration of the leading edge in irradiated wounds compared to non-irradiated wounded controls (12.0 microns/h vs 4.0 microns/h, p less than 0.0001). To determine if the increase in migration observed in irradiated cultures resulted from a proliferative effect of HeNe irradiation, subconfluent human keratinocyte cultures were irradiated with single or multiple doses of different fluences of HeNe irradiation (0.4 to 7.2 J/cm2) and evaluated 72 h post-irradiation. Irradiated and non-irradiated keratinocyte cultures grown on a microporous membrane surface were co-cultured with irradiated and non-irradiated fibroblasts to determine if HeNe irradiation induced a paracrine effect on keratinocyte proliferation. No significant increase in keratinocyte proliferation was demonstrated in any of these treatments. The biostimulatory effects of HeNe irradiation may now be extended to include enhancement of keratinocyte motility in vitro; this may contribute to the efficacy of HeNe irradiation in wound healing.

  3. [Treatment of lacrimal duct diseases using low energy helium-neon laser].

    PubMed

    Dushin, N V; Azibekian, A B; Ali Akhsan, M

    2002-01-01

    Treatment of diseases of the lacrimal duct remains a pressing problem in ophthalmology. These diseases are responsible for 71-85.4% diseases in capable people. Sixty patients with chronic dacryocystitis with partially retained patency of the lacrimal duct were treated by He-Ne low-frequency laser ULF-01 (output power 6.10 mcWt, laser beam wave length 0.632 nm). The patients received 3-5 min sessions twice a week, 5-8 sessions per course. Positive effect was attained in 56 patients: complete cessation of excessive lacrimal discharge in 38 patients and subjective improvement in 18. He-Ne laser exposure brings about a good antiinflammatory effect; in combination with antibiotic therapy it promotes rapid sanitization of the lacrimal duct, removes edema, and rapidly normalizes lacrimal discharge.

  4. Helium-neon laser irradiation stimulates migration and proliferation in melanocytes and induces repigmentation in segmental-type vitiligo.

    PubMed

    Yu, Hsin-Su; Wu, Chieh-Shan; Yu, Chia-Li; Kao, Ying-Hsien; Chiou, Min-Hsi

    2003-01-01

    Low-energy helium-neon lasers (632.8 nm) have been employed in a variety of clinical treatments including vitiligo management. Light-mediated reaction to low-energy laser irradiation is referred to as biostimulation rather than a thermal effect. This study sought to determine the theoretical basis and clinical evidence for the effectiveness of helium-neon lasers in treating vitiligo. Cultured keratinocytes and fibroblasts were irradiated with 0.5-1.5 J per cm2 helium-neon laser radiation. The effects of the helium-neon laser on melanocyte growth and proliferation were investigated. The results of this in vitro study revealed a significant increase in basic fibroblast growth factor release from both keratinocytes and fibroblasts and a significant increase in nerve growth factor release from keratinocytes. Medium from helium-neon laser irradiated keratinocytes stimulated [3H]thymidine uptake and proliferation of cultured melanocytes. Furthermore, melanocyte migration was enhanced either directly by helium-neon laser irradiation or indirectly by the medium derived from helium-neon laser treated keratinocytes. Thirty patients with segmental-type vitiligo on the head and/or neck were enrolled in this study. Helium-neon laser light was administered locally at 3.0 J per cm2 with point stimulation once or twice weekly. The percentage of repigmented area was used for clinical evaluation of effectiveness. After an average of 16 treatment sessions, initial repigmentation was noticed. Marked repigmentation (>50%) was observed in 60% of patients with successive treatments. Basic fibroblast growth factor is a putative melanocyte growth factor, whereas nerve growth factor is a paracrine factor for melanocyte survival in the skin. Both nerve growth factor and basic fibroblast growth factor stimulate melanocyte migration. It is reasonable to propose that helium-neon laser irradiation clearly stimulates melanocyte migration and proliferation and mitogen release for melanocyte growth

  5. Molecular Iodine Fluorescence Using a Green Helium-Neon Laser

    ERIC Educational Resources Information Center

    Williamson, J. Charles

    2011-01-01

    Excitation of molecular iodine vapor with a green (543.4 nm) helium-neon laser produces a fluorescence spectrum that is well suited for the upper-level undergraduate physical chemistry laboratory. Application of standard evaluation techniques to the spectrum yields ground electronic-state molecular parameters in good agreement with literature…

  6. Molecular Iodine Fluorescence Using a Green Helium-Neon Laser

    ERIC Educational Resources Information Center

    Williamson, J. Charles

    2011-01-01

    Excitation of molecular iodine vapor with a green (543.4 nm) helium-neon laser produces a fluorescence spectrum that is well suited for the upper-level undergraduate physical chemistry laboratory. Application of standard evaluation techniques to the spectrum yields ground electronic-state molecular parameters in good agreement with literature…

  7. Helium-neon laser improves skin repair in rabbits.

    PubMed

    Peccin, Maria Stella; Renno, Ana Claudia Muniz; de Oliveira, Flavia; Giusti, Paulo Ricardo; Ribeiro, Daniel Araki

    2012-12-01

    The purpose of this study was to evaluate the influence of helium-neon laser on skin injury in rabbits. For this purpose, 15 New Zealand rabbits underwent bilateral skin damage in leg. Helium-neon laser light, at a fluence of 6 J∕cm2 and wavelength of 632.8 nm, was applied on the left legs (laser group). The right leg lesions (control group) served as negative control. All sections were histopathologically analyzed using HE sections. The results showed little infiltration of inflammatory cells, with proliferation of fibroblasts forming a few fibrous connective tissue after 1 week post-injury. The lesion on the 3rd week was characterized by granulation tissue, which formed from proliferated fibrous connective tissue, congested blood vessels and mild mononuclear cell infiltration. On the 5th week, it was observed that debris material surrounded by a thick layer of connective tissue and dense collage, fibroblasts cells present in the dermis covered by a thick epidermal layer represented by keratinized epithelium. Taken together, our results suggest that helium-neon laser is able to improve skin repair in rabbits at early phases of recovery.

  8. Low-energy helium-neon laser induces locomotion of the immature melanoblasts and promotes melanogenesis of the more differentiated melanoblasts: recapitulation of vitiligo repigmentation in vitro.

    PubMed

    Lan, Cheng-Che E; Wu, Ching-Shuang; Chiou, Min-Hsi; Hsieh, Pei-Chen; Yu, Hsin-Su

    2006-09-01

    Helium-neon laser (He-Ne Laser, 632.8 nm) is a low-energy laser that has therapeutic efficacy on various clinical conditions. Our previous study has demonstrated efficacy of He-Ne laser on vitiligo, a disease characterized by skin depigmentation. To regain skin tone on vitiligo lesions, the process began by the migration of the immature melanoblasts (MBs) to the epidermis, which was followed by their functional development to produce melanin. In this study, we investigated the physiologic effects of He-Ne laser irradiation on two MB cell lines: the immature NCCmelb4 and the more differentiated NCCmelan5. The intricate interactions between MBs with their innate extracelluar matrix, fibronectin, were also addressed. Our results showed that He-Ne laser irradiation enhanced NCCmelb4 mobility via enhanced phosphorylated focal adhesion kinase expression and promoted melanogenesis in NCCmelan5. In addition, He-Ne laser decreased the affinity between NCCmelb4 and fibronectin, whereas the attachment of NCCmelan5 to fibronectin increased. The alpha5beta1 integrin expression on NCCmelb4 cells was enhanced by He-Ne laser. In conclusion, we have demonstrated that He-Ne laser induced different physiologic changes on MBs at different maturation stages and recapitulated the early events during vitiligo repigmentation process brought upon by He-Ne laser in vitro.

  9. Polarization of a Helium-Neon Laser.

    ERIC Educational Resources Information Center

    Jones, Edwin R.

    1996-01-01

    Describes an experiment that involves measuring the intensity of laser light passed by a linear polarizer. Discusses polarization effects, orthogonal polarizations, instrumentation, and further experiments. (JRH)

  10. Polarization of a Helium-Neon Laser.

    ERIC Educational Resources Information Center

    Jones, Edwin R.

    1996-01-01

    Describes an experiment that involves measuring the intensity of laser light passed by a linear polarizer. Discusses polarization effects, orthogonal polarizations, instrumentation, and further experiments. (JRH)

  11. Helium-neon laser treatment transforms fibroblasts into myofibroblasts.

    PubMed Central

    Pourreau-Schneider, N.; Ahmed, A.; Soudry, M.; Jacquemier, J.; Kopp, F.; Franquin, J. C.; Martin, P. M.

    1990-01-01

    The differentiation of myofibroblastic cells from normal human gingival fibroblasts in vitro has been established by transmission electron microscopy and quantitated by immunohistochemistry, using antigelsolin monoclonal antibodies. Untreated control cultures were compared to cultures exposed to Helium-Neon (He-Ne) laser irradiation. A direct and massive transformation of the cultured fibroblasts into myofibroblasts was observed as early as 24 hours after laser treatment, whereas control cultures were comprised of only resting fibroblasts and active fibroblasts. This in vitro induction of myofibroblasts may be analogous to that which occurs in vivo. Therefore we undertook a similar study using biopsies from gingival tissues after wisdom tooth extraction. Myofibroblasts were present in the connective tissue of laser-treated gums 48 hours after irradiation, but not in untreated contralateral control tissues. These data provide evidence that the primary biologic effect of the Helium-Neon laser on connective tissue is the rapid generation of myofibroblasts from fibroblasts. The induction of a phenotype with contractile properties may have clinical significance in the acceleration of the wound-healing process. Images Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:2372040

  12. Rapid healing of gingival incisions by the helium-neon diode laser.

    PubMed

    Neiburger, E J

    1999-01-01

    Fifty-eight extraction patients had one of two gingival flap incisions lased with a 1.4 mw helium-neon (670 nm) diode laser for 30 seconds (fluence = 0.34 J/cm2). Healing rates were evaluated clinically and photographically. Sixty-nine percent of the irradiated incisions healed faster than the control incisions. No significant difference in healing was noted when patients were compared by age, gender, race, and anatomic location of the incision. This study concludes that helium-neon diode lasers, at the previously mentioned energy level, increase the rate of gingival wound healing in 69 percent of patients, without any side effects. For the last 30 years, low-power lasers in dentistry have appeared to stimulate healing rates and increase the rate of repair of injured tissue. Helium-neon and similar lasers emit light in the red (600-700 nm) spectrums and produce energy densities (fluences) below 20 Joules/cm2. They have been studied in a variety of animal tissue culture and human evaluations to determine their ability to increase the rates of wound healing by biostimulation. Over the last three decades, researchers have found that ruby and gas helium-neon (low-power laser radiation) have a biostimulatory effect on living tissue. Studies show that under specific conditions, red spectrum laser light speeds the healing of wounds. Photons from the red light lasers, which include ruby lasers (694 nm), helium-neon gas lasers (632 nm), and helium-neon diode lasers (650-670 nm), appear to stimulate rapid epithelialization and fibroblast (collagen) proliferation in animal and human tissue cultures. Low-power lasers have been reported to reduce post-extraction pain and swelling and to increase rates of wound healing (including scar formation, phagocytosis) in cell culture, animal, and human clinical studies. The new, compact, and inexpensive (under $50) helium-neon diode lasers have produced similar effects. These FDA Class IIIa lasers have no hazards associated with them

  13. Low-energy helium-neon laser therapy induces repigmentation and improves the abnormalities of cutaneous microcirculation in segmental-type vitiligo lesions.

    PubMed

    Wu, Chieh-Shan; Hu, Stephen Chu-Sung; Lan, Cheng-Che E; Chen, Gwo-Shing; Chuo, Wen-Ho; Yu, Hsin-Su

    2008-04-01

    Segmental vitiligo (SV) is a special form of vitiligo occurring in a dermatomal distribution, and an abnormality involving the sympathetic nerves supplying the affected dermatome is known to underlie this disorder. Previously, we have shown that SV is associated with an abnormal increase in cutaneous blood flow and adrenoceptor responses in the affected areas. Since SV is resistant to conventional forms of therapy, its management represents a challenge for dermatologists. Low energy helium-neon lasers (He-Ne laser, wavelength 632.8 nm) have been employed as a therapeutic instrument in many clinical situations, including vitiligo management and repair of nerve injury. The purpose of this study was to evaluate the effectiveness and safety of He-Ne lasers in treating SV, and determine their effects on the repair of sympathetic nerve dysfunction. Forty patients with stable-stage SV on the head and/or neck were enrolled in this study. He-Ne laser irradiation was administered locally at 3.0 J/cm2 with point stimulation once or twice weekly. Cutaneous microcirculatory assessments in six SV patients were performed using a laser Doppler flowmeter. The sympathetic adrenoceptor response of cutaneous microcirculation was determined by measuring cutaneous blood flow before, during and after iontophoresis with sympathomimetic drugs (phenylephrine, clonidine and propranolol). All measurements of microcirculation obtained at SV lesions were simultaneously compared with contralateral normal skin, both before and after He-Ne laser treatment. After an average of 17 treatment sessions, initial repigmentation was noticed in the majority of patients. Marked repigmentation (> 50%) was observed in 60% of patients with successive treatments. Cutaneous blood flow was significantly higher at SV lesions compared with contralateral skin, but this was normalized after He-Ne laser treatment. In addition, the abnormal decrease in cutaneous blood flow in response to clonidine was improved by He

  14. Effect of helium-neon laser on musculoskeletal trigger points

    SciTech Connect

    Snyder-Mackler, L.; Bork, C.; Bourbon, B.; Trumbore, D.

    1986-07-01

    Cold lasers have been proposed recently as a therapeutic tool for treating a wide variety of pathological conditions, including wounds, arthritis, orthopedic problems, and pain. These proposed therapeutic effects largely have been unsubstantiated by research. A randomized, double blind study was undertaken to ascertain the effect of a helium-neon (He-Ne) laser on the resistance of areas of skin overlying musculoskeletal trigger points. These areas usually demonstrate decreased skin resistance when compared with the surrounding tissue. Thirty patients with musculoskeletal trigger points were assigned randomly to either an experimental or a placebo group. In addition to standard physical therapy, each patient received three 15-second applications of a He-Ne laser or placebo stimulation from an identical unit that did not emit a laser. The results of a two-way analysis of covariance with one repeated measure showed a statistically significant increase (p less than .007) in skin resistance. This increase in an abnormal skin resistance pattern may accompany the resolution of pathological conditions.

  15. Helium-neon laser therapy in the treatment of hydroxyapatite orbital implant exposure: A superior option.

    PubMed

    Xu, Qi-Hua; Zhao, Chen; Zhu, Jian-Gang; Chen, Mei-Juan; Liu, Qing-Huai

    2015-09-01

    The aim of the present study was to evaluate the efficacy of helium-neon laser therapy in the treatment of hydroxyapatite orbital implant exposure and compare the results with those of a combined drugs and surgery regimen. A total of 70 patients with hydroxyapatite orbital implant exposure in 70 eyes were randomly divided into two groups: Helium-neon laser therapy (group A) and drugs plus surgery (group B). Each group contained 35 patients. The healing rates and times of the conjunctival wound were recorded and compared following helium-neon laser treatment or the drugs plus surgery regimen. Changes in the hydroxyapatite orbital implant prior to and following helium-neon laser irradiation were analyzed. A similar animal study was conducted using 24 New Zealand white rabbits, which received orbital implants and were then received drug treatment or helium-neon therapy. In the human experiment, the rates for conjunctival wound healing were 97.14% in group A and 74.29% in group B, with a significant difference between the groups (χ(2)=5.71, P<0.05). Patients with mild exposure were healed after 7.22±2.11 days of helium-neon laser therapy and 14.33±3.20 days of drugs plus surgery. A statistically significant difference was found between the groups (t=8.97, P<0.05). Patients with moderate to severe exposure were healed after 18.19±2.12 days of helium-neon laser therapy and 31.25±4.21 days of drugs plus surgery. The difference between the groups was statistically significant (t=7.91, P<0.05). Enhanced magnetic resonance imaging showed that the helium-neon laser therapy significantly promoted vascularization of the hydroxyapatite orbital implant. These results, combined with pathological findings in animals, which showed that a helium-neon laser promoted vascularization and had anti-inflammatory effects, suggest that helium-neon laser irradiation is an effective method for treating hydroxyapatite orbital implant exposure, thereby avoiding secondary surgery.

  16. Helium-neon laser therapy in the treatment of hydroxyapatite orbital implant exposure: A superior option

    PubMed Central

    XU, QI-HUA; ZHAO, CHEN; ZHU, JIAN-GANG; CHEN, MEI-JUAN; LIU, QING-HUAI

    2015-01-01

    The aim of the present study was to evaluate the efficacy of helium-neon laser therapy in the treatment of hydroxyapatite orbital implant exposure and compare the results with those of a combined drugs and surgery regimen. A total of 70 patients with hydroxyapatite orbital implant exposure in 70 eyes were randomly divided into two groups: Helium-neon laser therapy (group A) and drugs plus surgery (group B). Each group contained 35 patients. The healing rates and times of the conjunctival wound were recorded and compared following helium-neon laser treatment or the drugs plus surgery regimen. Changes in the hydroxyapatite orbital implant prior to and following helium-neon laser irradiation were analyzed. A similar animal study was conducted using 24 New Zealand white rabbits, which received orbital implants and were then received drug treatment or helium-neon therapy. In the human experiment, the rates for conjunctival wound healing were 97.14% in group A and 74.29% in group B, with a significant difference between the groups (χ2=5.71, P<0.05). Patients with mild exposure were healed after 7.22±2.11 days of helium-neon laser therapy and 14.33±3.20 days of drugs plus surgery. A statistically significant difference was found between the groups (t=8.97, P<0.05). Patients with moderate to severe exposure were healed after 18.19±2.12 days of helium-neon laser therapy and 31.25±4.21 days of drugs plus surgery. The difference between the groups was statistically significant (t=7.91, P<0.05). Enhanced magnetic resonance imaging showed that the helium-neon laser therapy significantly promoted vascularization of the hydroxyapatite orbital implant. These results, combined with pathological findings in animals, which showed that a helium-neon laser promoted vascularization and had anti-inflammatory effects, suggest that helium-neon laser irradiation is an effective method for treating hydroxyapatite orbital implant exposure, thereby avoiding secondary surgery. PMID

  17. A UV laser by frequency doubling within the resonator of a helium-neon laser

    SciTech Connect

    Zhong Cantao; Li Xinzhang; Zhao Suitang; Wang Yichong

    1996-12-31

    An ultraviolet laser has been developed from the 632.8nm line of a helium-neon laser using internal frequency doubling method with a lithium iodate crystal. It generates continuous ultraviolet radiation at 316.4nm. By optimizing the optical components, a folded three-mirror resonator gave out UV radiation up to 1.5mW.

  18. Low-energy helium-neon laser induces melanocyte proliferation via interaction with type IV collagen: visible light as a therapeutic option for vitiligo.

    PubMed

    Lan, C-C E; Wu, C-S; Chiou, M-H; Chiang, T-Y; Yu, H-S

    2009-08-01

    The treatment of vitiligo remains a challenge for clinical dermatologists. We have previously shown that the helium-neon laser (He-Ne laser, 632.8 nm) is a therapeutic option for treatment of this depigmentary disorder. Addressing the intricate interactions between melanocytes, the most important cellular component in the repigmentation scheme of vitiligo, and their innate extracellular matrix collagen type IV, the current study aimed to elucidate the effects of the He-Ne laser on melanocytes. Cultured melanocytes were irradiated with the He-Ne laser. Relevant biological parameters including cell attachment, locomotion and growth were evaluated. In addition, the potentially involved molecular pathways were also determined. Our results show that in addition to suppressing mobility but increasing attachment to type IV collagen, the He-Ne laser stimulates melanocyte proliferation through enhanced alpha2beta1 integrin expression. The expression of phosphorylated cyclic-AMP response element binding protein (CREB), an important regulator of melanocyte growth, was also upregulated by He-Ne laser treatment. Using a specific mitochondrial uncoupling agent [carbonyl cyanide m-chlorophenyl-hydrazone (CCCP)], the proliferative effect of the He-Ne laser on melanocytes was abolished and suppression of melanocyte growth was noted. In summary, we have demonstrated that the He-Ne laser imparts a growth stimulatory effect on functional melanocytes via mitochondria-related pathways and proposed that other minor pathways including DNA damage may also be inflicted by laser treatment on irradiated cells. More importantly, we have completed the repigmentation scheme of vitiligo brought about by He-Ne laser light in vitro and provided a solid theoretical basis regarding how the He-Ne laser induces recovery of vitiligo in vivo.

  19. Photobiomodulation by helium neon and diode lasers in an excisional wound model: A single blinded trial.

    PubMed

    Dixit, Snehil; Maiya, Arun; Rao, Laxmi; Rao, M Arjun; Shastry, Barkur Ananthakrishna; Ramachandra, L

    2012-01-01

    Application of different kinds of lasers in clinical and experimental studies causes photobiomodulation that works at localized cellular and humoral level on various biological systems. Increased numbers of fibroblasts, myofibroblast, and degranulation of mast cells have been the observed benefits post-irradiation. Was to find out the effect of irradiation with energy densities of 3.38 J/cm(2), 8 J/cm(2), and 18 J/cm(2) on animal tissue (albino wistar rats) in an excisional wound model and to assess changes in biochemical (hydroxyproline) and histopathological levels in excisional wound model. The animals were divided into 4 groups, which were labeled as L1, diode laser (18 J/cm(2)), L2 Helium-neon (He-Ne, 8 J/cm(2)), L3 diode laser (3.38 J/cm(2)), and sham treatment for control was depicted by C, respectively. Histological and hydroxyproline analysis was performed on 7, 14, 21 days of post-wounding. One-way analysis of variance, ANOVA and Bonferroni's multiple comparison tests were done for tissue hydroxyproline levels. There was no significant increase in the hydroxyproline content (P < 0.005) when observed in study group and compared to controls. Whereas significant epithelizations was seen in group treated with He-Ne laser of intensity of 8 J/cm(2). The experimental observations suggest that low intensity helium-neon laser of 8 J/cm(2) intensity facilitated photo stimulation by tissue repair, but failed to show significant tissue hydroxyproline levels in excisional wound model.

  20. Photobiomodulation by helium neon and diode lasers in an excisional wound model: A single blinded trial

    PubMed Central

    Dixit, Snehil; Maiya, Arun; Rao, Laxmi; Rao, M. Arjun; Shastry, Barkur Ananthakrishna; Ramachandra, L.

    2012-01-01

    Background: Application of different kinds of lasers in clinical and experimental studies causes photobiomodulation that works at localized cellular and humoral level on various biological systems. Increased numbers of fibroblasts, myofibroblast, and degranulation of mast cells have been the observed benefits post-irradiation. Objective: Was to find out the effect of irradiation with energy densities of 3.38 J/cm2, 8 J/cm2, and 18 J/cm2 on animal tissue (albino wistar rats) in an excisional wound model and to assess changes in biochemical (hydroxyproline) and histopathological levels in excisional wound model. Materials and Methods: The animals were divided into 4 groups, which were labeled as L1, diode laser (18 J/cm2), L2 Helium-neon (He-Ne, 8 J/cm2), L3 diode laser (3.38 J/cm2), and sham treatment for control was depicted by C, respectively. Histological and hydroxyproline analysis was performed on 7, 14, 21 days of post-wounding. One-way analysis of variance, ANOVA and Bonferroni's multiple comparison tests were done for tissue hydroxyproline levels. Results: There was no significant increase in the hydroxyproline content (P < 0.005) when observed in study group and compared to controls. Whereas significant epithelizations was seen in group treated with He-Ne laser of intensity of 8 J/cm2. Conclusion: The experimental observations suggest that low intensity helium-neon laser of 8 J/cm2 intensity facilitated photo stimulation by tissue repair, but failed to show significant tissue hydroxyproline levels in excisional wound model. PMID:23326769

  1. Helium-neon laser improves bone repair in rabbits: comparison at two anatomic sites.

    PubMed

    Peccin, Maria Stella; de Oliveira, Flavia; Muniz Renno, Ana Claudia; Pacheco de Jesus, Gustavo Protasio; Pozzi, Renan; Gomes de Moura, Carolina Foot; Giusti, Paulo Ricardo; Ribeiro, Daniel Araki

    2013-07-01

    The purpose of this study was to evaluate the influence of helium-neon laser on bone repair of femur and tibia in rabbits. For this purpose, 15 New Zealand rabbits underwent bilateral bone damage (tibia and femur) using a spherical bur. Helium-neon laser light, at a fluency of 6 J∕cm(2) and wavelength of 632.8 nm was applied on the left legs (laser group). The right tibia or femur lesions (control group) served as negative control. All sections were histopathologically analyzed using HE sections and the morphometric data from bone tissue and hyaline cartilage were achieved. Histopathological analysis showed regular bone trabeculae covered by osteoblastic cells after 1 week in the group exposed to laser therapy from femur and tibia indistinctly. After 3 weeks, the laser group showed new bone formation coming from the bony walls in the femur and tibia as well. On the 5th week, well-defined trabecula undergoing remodeling process was detected for the most intense pattern in tibia only. Morphometric analysis revealed significant statistical differences (p < 0.05) in the bone tissue for the laser-exposed group on 1st and 3rd weeks. After 5th week, bone formation was increased to tibia only. Taken together, such findings suggest that helium-neon laser is able to improve bone repair in rabbits being the most pronounced effect in tibia.

  2. Does low-intensity helium-neon laser irradiation alter sensory nerve active potentials or distal latencies

    SciTech Connect

    Basford, J.R.; Daube, J.R.; Hallman, H.O.; Millard, T.L.; Moyer, S.K. )

    1990-01-01

    The effect of 1 mW helium neon continuous-wave (0.633 microns) laser irradiation on superficial radical sensory and median sensory nerve function was examined in a double-blind, controlled study involving 40 volunteers. No differences in action potential amplitudes, distal latencies, or forearm skin temperatures were found between the treated and control groups either at the time of irradiation or at subsequent evaluations 15 and 30 minutes later. As a result, we are unable to confirm reports that low-energy lasers of this power and wavelength alter nerve function.

  3. Helium-neon lasers for remote measurements of natural gas leaks

    NASA Astrophysics Data System (ADS)

    1983-09-01

    A Differential Absorption Lidar (DIAL) system that at a distance of 15 meters can remotely sense natura gas (methane) leaks was developed. The system uses two helium-neon lasers (each emitting a different wavelength), a receiver, and an indium antimonide (InSb) photodetector cooled to 77 K. It is demonstrated the system can defect methane leaks both from an underground gas distribution system, and from sanitary landfills.

  4. [Radioprotective effect of helium-neon laser radiation for fibroblast cells].

    PubMed

    Voskanian, K Sh; Mitsyn, G V; Gaevskiĭ, V N

    2007-01-01

    Effects of combined exposure to 633-nm laser waves and gamma-radiation, and laser waves and protons with the energy of 150 MeV on survivablilty of mice fibroblast cells C3H10T1/2 were compared. Cell suspension (1 - 5 x 10(5) cells/ml) was distributed in 2-ml plastic vials with 1 cm in diameter time interval between two exposures in a combination was no more than 60 s. immediately after exposure a required quantity of cells was inoculated in special vials for survivability assessment. Based on results of the experiment, preliminary and repeated laser treatment was favorable to survivability of fibroblast cells subjected to gamma- or proton irradiation (dose variation factor was within 1.3 to 2.2). Simultaneous exposure of C3H10T1/2 cells to the laser and proton beams also increased their survivability. The radioprotective effect of the helium-neon laser on fibroblasts earlier exposed to ionizing radiation is of chief interest, as most of the present-day radioprotectors are effective only if introduced into organism prior to exposure.

  5. Helium-neon laser preirradiation induces protection against UVC radiation in wild-type E. coli strain K12AB1157.

    PubMed

    Kohli, R; Gupta, P K; Dube, A

    2000-02-01

    We have observed that preirradiation with a helium-neon laser (632.8 nm) induces protection against UVC radiation in wild-type E. coli strain K12AB1157. The magnitude of protection was found to depend on the helium-neon laser irradiance, exposure time, and period of incubation between helium-neon laser exposure and subsequent UVC irradiation. The optimum values for dose, irradiance and interval between the two exposures were found to be 7 kJ/m(2), 100 W/m(2) and 1 h, respectively. The possible involvement of singlet oxygen in the helium-neon laser-induced protection is also discussed.

  6. Helium-neon laser in viability of random skin flap in rats.

    PubMed

    Pinfildi, Carlos E; Liebano, Richard E; Hochman, Bernardo S; Ferreira, Lydia M

    2005-07-01

    The purpose of this study was to determine the role of helium-neon (He-Ne) laser random skin flap viability in rats. Experimentally controlled randomized study. Forty-eight Wistar-EPM rats were used, weighed, and divided into 4 groups with 12 rats each. The random skin flap was performed measuring 10 x 4 cm, with a plastic sheet interposed between the flap and the donor site. The Group 1 (control) underwent sham irradiation with He-Ne laser. The Group 2 was submitted to laser irradiation, using the punctual contact technique on the skin flap surface. The Group 3 was submitted to laser irradiation surrounding the skin flap, and the Group 4 was submitted to laser irradiation both on the skin flap surface and around it. The experimental groups were submitted to He-Ne laser irradiation with 3 J/cm(2) energy density immediately after the surgery and for the four subsequent days. The percentage of necrotic area of the four groups was calculated at the 7th post-operative day, through a paper-template method. Group 1 reached an average necrotic area of 48.86%; Group 2, 38.67%; Group 3, 35.34%; and Group 4, 22.61%. After the statistic analysis, results showed that all experimental groups reached statistically significant values when compared to the control group, and Group 4 was the best one, when compared to all groups of this study (P<0.001). The He-Ne laser irradiation was efficient to increase random skin flap viability in rats. (c) 2005 Wiley-Liss, Inc.

  7. Effect of helium/neon laser irradiation on nerve growth factor synthesis and secretion in skeletal muscle cultures.

    PubMed

    Schwartz, Fidi; Brodie, Chaya; Appel, Elana; Kazimirsky, Gila; Shainberg, Asher

    2002-04-01

    Low energy laser irradiation therapy in medicine is widespread but the mechanisms are not fully understood. The aim of the present study was to elucidate the mechanism by which the light might induce therapeutic effects. Skeletal muscle cultures were chosen as a target for light irradiation and nerve growth factor (NGF) was the biochemical marker for analysis. It was found that there is a transient elevation of intracellular calcium in the myotubes immediately after irradiation (P<0.001). Preincubation of the myotubes with either the photosensitizers 5-amino-levulinic acid (5-ALA), or with hematoporphyrin (Hp) enhanced the elevation of cytosolic calcium (P<0.001) after helium/neon irradiation (633 nm) with an energy of 3 J/cm(2). In addition, helium/neon irradiation augmented the level of NGF mRNA fivefold and increased NGF release to the medium of the myotubes. Thus, it is speculated that transient changes in calcium caused by light can modulate NGF release from the myotubes and also affect the nerves innervating the muscle. The NGF is probably responsible for the beneficial effects of low-level light.

  8. Safe Helium--Neon Lasers Advance Understanding of Light

    ERIC Educational Resources Information Center

    Knowles, C. Harry

    1972-01-01

    Experimental data, Federal and State regulations, and user data are presented to assess the safety factors of low-power lasers. General safety precautions, basic laser theory, the place of the laser in the classroom, and some introductory exercises are also presented. (Author/TS)

  9. Safe Helium--Neon Lasers Advance Understanding of Light

    ERIC Educational Resources Information Center

    Knowles, C. Harry

    1972-01-01

    Experimental data, Federal and State regulations, and user data are presented to assess the safety factors of low-power lasers. General safety precautions, basic laser theory, the place of the laser in the classroom, and some introductory exercises are also presented. (Author/TS)

  10. Helium-neon laser: thermal high-resolution recording.

    PubMed

    Carlson, C O; Stone, E; Bernstein, H L; Tomita, W K; Myers, W C

    1966-12-23

    Scan-line recording by means of a moving laser spot has been achieved on metallic and organic thin films Recording rates of the order of one million spots per second were obtained with a laser beam power of 38 milliwatts at the recording surface. Typical recorded line widths were of the order of 2 microns.

  11. Chicago sky blue and a helium neon laser abolish endothelium dependent relaxation in vivo in the microcirculation

    SciTech Connect

    Nishimura, H.; Nelson, G.H.; Rosenblum, W.I. )

    1989-12-01

    Chicago sky blue, also known as Niagara sky blue, is a vital dye that can successfully be used as an intravascular energy absorbing target for the light from a helium-neon (HeNe) laser. The result of this light/dye interaction is endothelium damage which can be controlled by adjusting the duration of the laser exposure and the amount of dye injected intravenously. The endothelial damage probably is the result of the heat generated by the dyes absorption of energy at the interface between plasma and endothelium. The most minimal damage resulted in selective loss of the dilation normally produced by acetylcholine and bradykinin, two endothelium dependent dilators. The dilation produced by sodium nitroprusside, a dilator acting directly on vascular smooth muscle, was preserved. More severe injury (i.e. more prolonged exposure to light and/or more dye), resulted in local platelet aggregation at the site of laser impact.

  12. Chicago sky blue and a helium neon laser abolish endothelium dependent relaxation in vivo in the microcirculation.

    PubMed

    Nishimura, H; Nelson, G H; Rosenblum, W I

    1989-12-01

    Chicago sky blue, also known as Niagara sky blue, is a vital dye that can successfully be used as an intravascular energy absorbing target for the light from a helium-neon (HeNe) laser. The result of this light/dye interaction is endothelium damage which can be controlled by adjusting the duration of the laser exposure and the amount of dye injected intravenously. The endothelial damage probably is the result of the heat generated by the dyes absorption of energy at the interface between plasma and endothelium. The most minimal damage resulted in selective loss of the dilation normally produced by acetylcholine and bradykinin, two endothelium dependent dilators. The dilation produced by sodium nitroprusside, a dilator acting directly on vascular smooth muscle, was preserved. More severe injury (i.e. more prolonged exposure to light and/or more dye, resulted in local platelet aggregation at the site of laser impact.

  13. Effect of helium-neon laser irradiation on peripheral sensory nerve latency

    SciTech Connect

    Snyder-Mackler, L.; Bork, C.E.

    1988-02-01

    The purpose of this randomized, double-blind study was to determine the effect of a helium-neon (He-Ne) laser on latency of peripheral sensory nerve. Forty healthy subjects with no history of right upper extremity pathological conditions were assigned to either a Laser or a Placebo Group. Six 1-cm2 blocks along a 12-cm segment of the subjects' right superficial radial nerve received 20-second applications of either the He-Ne laser or a placebo. We assessed differences between pretest and posttest latencies with t tests for correlated and independent samples. The Laser Group showed a statistically significant increase in latency that corresponded to a decrease in sensory nerve conduction velocity. Short-duration He-Ne laser application significantly increased the distal latency of the superficial radial nerve. This finding provides information about the mechanism of the reported pain-relieving effect of the He-Ne laser.

  14. Infrared transmission at the 3.39 micron helium-neon laser wavelength in liquid-core quartz fibers

    NASA Technical Reports Server (NTRS)

    Majumdar, A. K.; Hinkley, E. D.; Menzies, R. T.

    1979-01-01

    Infrared transmission at the 3.39 micron helium-neon laser wavelength has been measured in a tetrachloroethylene-filled fused-quartz fiber. The loss measurements were taken for three different settings of laser light intensity using a series of neutral density filters. The average value of transmission loss at this wavelength was found to be 56 dB/km.

  15. Molecular iodine fluorescence spectra generated with helium-neon lasers for spectrometer calibration.

    PubMed

    Williamson, J Charles

    2010-12-01

    Gas-phase molecular iodine laser-induced fluorescence (LIF) spectra were recorded out to 815 nm at 1 cm(-1) resolution using green, yellow, and red helium-neon (HeNe) lasers as excitation sources. Nine previously unreported I(2) B←X absorption transitions accessed by these lasers were identified, and specific rovibronic transition assignments were made for two hundred LIF peaks--more than sixty per laser. These I(2) LIF peaks can be used to calibrate the vacuum wavenumber coordinate of spectrometers to better than 0.1 cm(-1) accuracy. In particular, green HeNe excitation of the I(2) R(106) 28-0 transition leads to strong fluorescence well suited for calibration, with a rotational doublet spacing of 15 cm(-1) and a doublet-to-doublet spacing of 190 cm(-1). Calibration by HeNe I(2) LIF may be an especially valuable technique for Raman spectroscopy applications.

  16. PHOTO-STIMULATORY EFFECT OF LOW ENERGY HELIUM-NEON LASER IRRADIATION ON EXCISIONAL DIABETIC WOUND HEALING DYNAMICS IN WISTAR RATS

    PubMed Central

    Maiya, Arun G; Kumar, Pramod; Nayak, Shivanand

    2009-01-01

    Background: Generally, the significances of laser photo stimulation are now accepted, but the laser light facilitates wound healing and tissue repair remains poorly understood. Aims: We have examined the hypothesis that the laser photo stimulation can enhance the collagen production in diabetic wounds using the excision wound model in the Wistar rat model. Methods: The circular wounds were created on the dorsum of the back of the animals. The animals were divided into two groups. The study group (N = 24) wound was treated with 632.8 nm He-Ne laser at a dose of 3-9 J/cm2 for 5 days a week until the wounds healed completely. The control group was sham irradiated. Result: A significant increase in the hydroxyproline content and reduction in the wound size were observed in the study group. The pro-healing actions seem to be due to increased collagen deposition as well as better alignment and maturation. Conclusion: The biochemical analysis and clinical observation suggested that 3-6 J/cm2 laser photo stimulation facilitates the tissue repair process by accelerating collagen production in diabetic wound healing. PMID:20101331

  17. Solid-state ring laser gyro behaving like its helium-neon counterpart at low rotation rates.

    PubMed

    Schwartz, Sylvain; Gutty, François; Feugnet, Gilles; Loil, Eric; Pocholle, Jean-Paul

    2009-12-15

    Nonlinear couplings induced by crystal diffusion and spatial inhomogeneities of the gain have been suppressed over a broad range of angular velocities in a solid-state ring laser gyro by vibrating the gain crystal at 168 kHz and 0.4 microm along the laser cavity axis. This device behaves in the same way as a typical helium-neon ring laser gyro, with a zone of frequency lock-in (or dead band) resulting from the backscattering of light on the cavity mirrors. Furthermore, it is shown that the level of angular random-walk noise in the presence of mechanical dithering depends only on the quality of the cavity mirrors, as is the case with typical helium-neon ring laser gyros.

  18. Effect of helium-neon laser on fast excitatory postsynaptic potential of neurons in the isolated rat superior cervical ganglia

    NASA Astrophysics Data System (ADS)

    Mo, Hua; He, Ping; Mo, Ning

    2004-08-01

    The aim of this study is to further measure the effect of 632.8-nm helium-neon laser on fast excitatory postsynaptic potential (f-EPSP) of postganglionic neurons in isolated rat superior cervical ganglia by means of intracellular recording techniques. The neurons with f-EPSP were irradiated by different power densities (1-5 mW/cm2) laser. Irradiated by the 2-mW/cm2 laser, the amplitude of the f-EPSP could augment (P<0.05, paired t test) and even cause action potential at the end of the first 1-2 minutes, the f-EPSP could descend and last for 3-8 minutes. But the amplitude of the f-EPSP of neurons irradiated by the 5-mW/cm2 laser could depress for the irradiating periods. The results show that: 1) the variation of the amplitude of f-EPSP caused by laser is power density-dependent and time-dependent; 2) there exist the second-order phases in the interaction of the helium-neon laser with neurons. These findings may provide certain evidence in explanation of the mechanisms of clinical helium-neon laser therapy.

  19. Helium-neon laser irradiation stimulates cell proliferation through photostimulatory effects in mitochondria.

    PubMed

    Hu, Wan-Ping; Wang, Jeh-Jeng; Yu, Chia-Li; Lan, Cheng-Che E; Chen, Gow-Shing; Yu, Hsin-Su

    2007-08-01

    Previous reports have shown that cellular functions could be influenced by visual light (400-700 nm). Recent evidence indicates that cellular proliferation could be triggered by the interaction of a helium-neon laser (He-Ne laser, 632.8 nm) with the mitochondrial photoacceptor-cytochrome c oxidase. Our previous studies demonstrated that He-Ne irradiation induced an increase in cell proliferation, but not migration, in the melanoma cell line A2058 cell. The aim of this study was to investigate the underlying mechanisms involved in photostimulatory effects induced by an He-Ne laser. Using the A2058 cell as a model for cell proliferation, the photobiologic effects induced by an He-Ne laser were studied. He-Ne irradiation immediately induced an increase in mitochondrial membrane potential (delta psi(mt)), ATP, and cAMP via enhanced cytochrome c oxidase activity and promoted phosphorylation of Jun N-terminal kinase (JNK)/activator protein-1 (AP-1) expressions. He-Ne irradiation-induced A2058 cell proliferation was significantly abrogated by the addition of delta psi(mt) and JNK inhibitors. Moreover, treatment with an He-Ne laser resulted in delayed effects on IL-8 and transforming growth factor-beta1 release from A2058 cells. These results suggest that He-Ne irradiation elicits photostimulatory effects in mitochondria processes, which involve JNK/AP-1 activation and enhanced growth factor release, and ultimately lead to A2058 cell proliferation.

  20. Effect of low-level helium-neon laser therapy on histological and ultrastructural features of immobilized rabbit articular cartilage.

    PubMed

    Bayat, Mohammad; Ansari, Enayatallah; Gholami, Narges; Bayat, Aghdas

    2007-05-25

    The present study investigates whether low-level helium-neon laser therapy can increase histological parameters of immobilized articular cartilage in rabbits or not. Twenty five rabbits were divided into three groups: the experiment group, which received low-level helium-neon laser therapy with 13J/cm(2) three times a week after immobilization of their right knees; the control group which did not receive laser therapy after immobilization of their knees; and the normal group which received neither immobilization nor laser therapy. Histological and electron microscopic examinations were performed at 4 and 7 weeks after immobilization. Depth of the chondrocyte filopodia in four-week immobilized experiment group, and depth of articular cartilage in seven-week immobilized experiment group were significantly higher than those of relevant control groups (exact Fisher test, p=0.001; student's t-test, p=0.031, respectively). The surfaces of articular cartilages of the experiment group were relatively smooth, while those of the control group were unsmooth. It is therefore concluded that low-level helium-neon laser therapy had significantly increased the depth of the chondrocyte filopodia in four-week immobilized femoral articular cartilage and the depth of articular cartilage in seven-week immobilized knee in comparison with control immobilized articular cartilage.

  1. [The application of helium-neon laser radiation for the combined treatment of the patients with atrophic rhinitis].

    PubMed

    Sharipov, R A; Sharipova, E R

    2012-01-01

    The objective of the present study was to improve the efficacy of the treatment of the patients presenting with atrophic rhinitis (ozena) of the upper respiratory tract by the application of helium-neon laser radiation. A total of 120 patients aged from 15 to 53 years were treated based at the Department of Otorhinolaryngology, G.G. Kuvatov Republican Clinical Hospital, Ufa. All these patients underwent routine clinical, roentgenological, microbiological, and rheographic examination. The method for the treatment of atrophic rhinitis is described; it includes the application of helium-neon laser radiation in combination with the administration of the purified preparation of liquid polyvalent Klebsiella bacteriophage. The positive results of the treatment by the proposed method were documented in 90% of the patients.

  2. Effect of low-power helium-neon laser irradiation on 13-week immobilized articular cartilage of rabbits.

    PubMed

    Bayat, Mohammad; Ansari, Anayatallah; Hekmat, Hossien

    2004-09-01

    Influence of low-power (632.8 nm, Helium-Neon, 13 J/cm2, three times a week) laser on 13-week immobilized articular cartilage was examined with rabbits knee model. Number of chondrocytes and depth of articular cartilage of experimental group were significantly higher than those of sham irradiated group. Surface morphology of sham-irradiated group had rough prominences, fibrillation and lacunae but surface morphology of experimental group had more similarities to control group than to sham irradiated group. There were marked differences between ultrastructure features of control group and experimental group in comparison with sham irradiated group. Low-power Helium-Neon laser irradiation on 13-week immobilized knee joints of rabbits neutrilized adverse effects of immobilization on articular cartilage.

  3. Effect of helium-neon and infrared laser irradiation on wound healing in rabbits

    SciTech Connect

    Braverman, B.; McCarthy, R.J.; Ivankovich, A.D.; Forde, D.E.; Overfield, M.; Bapna, M.S.

    1989-01-01

    We examined the biostimulating effects of helium-neon laser radiation (HeNe; 632.8 nm), pulsed infrared laser radiation (IR; 904 nm), and the two combined on skin wound healing in New Zealand white rabbits. Seventy-two rabbits received either (1) no exposure, (2) 1.65 J/cm2 HeNe, (3) 8.25 J/cm2 pulsed IR, or (4) both HeNe and IR together to one of two dorsal full-thickness skin wounds, daily, for 21 days. Wound areas were measured photographically at periodic intervals. Tissue samples were analyzed for tensile strength, and histology was done to measure epidermal thickness and cross-sectional collagen area. Significant differences were found in the tensile strength of all laser-treated groups (both the irradiated and nonirradiated lesion) compared to group 1. No differences were found in the rate of wound healing or collagen area. Epidermal growth was greater in the HeNe-lased area compared to unexposed tissue, but the difference was not significant. Thus, laser irradiation at 632.8 nm and 904 nm alone or in combination increased tensile strength during wound healing and may have released tissue factors into the systemic circulation that increased tensile strength on the opposite side as well.

  4. In vitro synthesis of prostaglandin E2 by synovial tissue after helium-neon laser radiation in rheumatoid arthritis.

    PubMed

    Barberis, G; Gamron, S; Acevedo, G; Cadile, I; Juri, H; Campana, V; Castel, A; Onetti, C M; Palma, J A

    1996-08-01

    This paper reports the effect of helium-neon laser radiation (power of 5 mW and 632.8 nm wave length) on the synthesis of PGE2 in vitro in synovial tissue of biopsy samples of knee joints in patients with chronic rheumatoid arthritis stages II or III. Twelve patients were studied. Each patient received 15 applications of He-Ne laser. Eleven points for He-Ne laser applications were selected in one of the affected knees. The energy density used was 8 J/cm2 per application point. The He-Ne laser therapy reduced the synthesis of PGE2. The analysis of the data revealed a statistically significant difference between the levels of the synthesis of PGE2 before treatment (17.69 +/- 2.65 ng mg-1 of dry tissue h-1) and after treatment (13.85 +/- 2.73 ng mg-1 of dry tissue h-1), with p < 0.01 comparing mean values. This was also accompanied by relief of pain (91.6%), and a favorable subjective report from the patient. We conclude that PGE2 is a quantifiable parameter that could explain what causes pain relief in patients with rheumatoid arthritis that are treated with He-Ne laser.

  5. Helium-neon laser radiation effect on fish embryos and larvae

    NASA Astrophysics Data System (ADS)

    Uzdensky, Anatoly B.

    1994-09-01

    Helium-neon laser irradiation (HNLI) is an effective biostimulating agent but its influence on embryonal processes is almost unknown. We have studied fish embryos and larvae development, viability, and growth after HNLI of fish eggs at different stages. With this aim carp, grass carp, sturgeon, and stellared sturgeon eggs were incubated in Petri plates or in fish-breeding apparatuses and were irradiated in situ with different exposures. Then we studied hutchling percentage, larvae survival and growth dynamics, and morphological anomalies percentage. HNLI effect depended on irradiation exposures and intensity, embryonal stages, and fish species. Laser eggs irradiation essentially affected larvae viability and growth in the postembryonal phase. For example, HNLI of sturgeon spawn at cleavage stage or grass carp at organogenesis decreased larvae survival rate. On the contrary HNLI at gastrulation or embryonal motorics stages markedly increased larvae survival rate and decreased the morphological anomalies percentage. We determined most effective irradiation regimes depending of fish species which may be used in practical fish-breeding.

  6. Effect of helium-neon laser irradiation on hair follicle growth cycle of Swiss albino mice.

    PubMed

    Shukla, S; Sahu, K; Verma, Y; Rao, K D; Dube, A; Gupta, P K

    2010-01-01

    We report the results of a study carried out to investigate the effect of helium-neon (He-Ne) laser (632.8 nm) irradiation on the hair follicle growth cycle of testosterone-treated and untreated mice. Both histology and optical coherence tomography (OCT) were used for the measurement of hair follicle length and the relative percentage of hair follicles in different growth phases. A positive correlation (R = 0.96) was observed for the lengths of hair follicles measured by both methods. Further, the ratios of the lengths of hair follicles in the anagen and catagen phases obtained by both methods were nearly the same. However, the length of the hair follicles measured by both methods differed by a factor of 1.6, with histology showing smaller lengths. He-Ne laser irradiation (at approximately 1 J/cm(2)) of the skin of both the control and the testosterone-treated mice was observed to lead to a significant increase (p < 0.05) in % anagen, indicating stimulation of hair growth. The study also demonstrates that OCT can be used to monitor the hair follicle growth cycle, and thus hair follicle disorders or treatment efficacy during alopecia.

  7. The effect of low-level helium-neon laser on oral wound healing

    PubMed Central

    Sardari, Farimah; Ahrari, Farzaneh

    2016-01-01

    Background: The effectiveness of low power lasers on incisional wound healing, because of conflicting results of previous studies, is uncertain. Therefore, the aim of this study was to evaluate the effects of low-level helium-neon (He-Ne) laser irradiation on wound healing in rat's oral mucosa. Materials and Methods: Sixty-four standardized incisions were carried out on the buccal mucosa of 32 male Wistar divided into four groups of eight animals each. Each rat received two incisions on the opposite sides of the buccal mucosa by a steel scalpel. On the right side (test side), a He-Ne laser (632 nm) was employed on the incision for 40 s. Laser radiation was used just in 1st day, 1st and 2nd day, 1st and 3rd day, and continuous 3 days in groups of A, B, C, and D of rats, respectively. The left side (control side) did not receive any laser. Histological processing and hematoxylin and eosin staining were done on tissue samples after 5 days. Wilcoxon and Kruskal-Wallis tests were used for statistical analysis. Results: Histological analysis showed that the tissue healing after continuous 3 days on the laser irradiated side was better than the control side, but there was no difference between the two sides in each groups (P > 0.05). Conclusion: This study showed that He-Ne laser had no beneficial effects on incisional oral wound healing particularly in 5 days after laser therapy. Future research in the field of laser effects on oral wound healing in human is recommended. PMID:26962312

  8. [Low-intensity helium-neon laser in the treatment of patients after endonasal dacryocystorhinostomy].

    PubMed

    Beloglazov, V G; At'kova, E L; Nurieva, S M; Khvedelidze, E P

    2004-01-01

    Described in the paper is an efficiency study of using, postoperatively, the low-intensity helium-neon laser (LIHNL) in patients with obstruction of the lacrimal tracts. Eighty patients were examined after endonasal dacryocystorhinostomy. They were shared between 2 groups with respect to a postoperative course: group 1--experimental, 40 patients, and group 2--control, 40 patients. The experimental patients received, apart from the traditional postoperative therapy, a course of LIHNL therapy. The controls received only the traditional postoperative treatment. The efficiency of postoperative treatment was evaluated by clinical, instrumental and laboratory examination methods. The study denoted that the use of LIHNL in the early postoperative period after endonasal dacryocystorhinostomy had a pronounced anti-inflammatory effect, speeded up the wound healing, prevented the growth of granulation tissues and the merging of the shaped lacrimal-sac fistula with the nasal cavity. LIHNL contributed to a complete recovery of the functional activity of the nasal mucous tunic. Thus, the LIHNL therapy essentially facilitates the postoperative management of patients, cuts the rehabilitation period and enhances the treatment results.

  9. Effects of helium-neon laser on the mucopolysaccharide induction in experimental osteoarthritic cartilage.

    PubMed

    Lin, Y-S; Huang, M-H; Chai, C-Y

    2006-04-01

    To investigate the effects of mucopolysaccharide induction after treatment by low power laser for experimental osteoarthritis (OA). Seventy-two rats with three different degrees of papain induced OA over right knee joints were collected for helium-neon (He-Ne) laser treatment. The severity of induced arthritis was measured by 99mTc bone scan and classified into three groups (I-III) by their radioactivity ratios (right to left knee joints). The rats in each group were further divided into study subgroups (Is, IIs, and IIIs) and control subgroups (Ic, IIc, and IIIc) randomly. The arthritic knees in study subgroups received He-Ne laser treatment, and those in controls received sham laser treatment. The changes of arthritic severity after treatment and follow-up 2 months later were measured. The histopathological changes were evaluated through light microscope after disarticulation of sections (H.E. stain), and the changes of mucopolysaccharide density in cartilage matrix were measured by Optimas scanner analyzer after Alcian blue (AB) stain. The densities of mucopolysaccharide induced after treatment in arthritic cartilage were compared and correlated with their histopathological changes. The density of mucopolysaccharide rose at the initial stage of induced arthritis, and decreased progressively in later stages. The densities of mucopolysaccharide in treated rats increased upon complete laser treatment more than those of the controls, which is closely related with the improvement in histopathological findings, but conversely with the changes in arthritic severity. He-Ne laser treatment will enhance the biosynthesis of arthritic cartilage, and results in the improvement of arthritic histopathological changes.

  10. Increase in the ADP/ATP exchange in rat liver mitochondria irradiated in vitro by helium-neon laser

    SciTech Connect

    Passarella, S.; Ostuni, A.; Atlante, A.; Quagliariello, E.

    1988-10-31

    To gain some insight into the mechanism of cell photostimulation by laser light, measurements were made of the rate of ADP/ATP exchange in mitochondria irradiated with the low power continuous wave Helium Neon laser (energy dose 5 Joules/cm2). To do this a method has been developed to continuously monitor ATP efflux from phosphorylating mitochondria caused by externally added ADP, by photometrically following the NADP+ reduction which occurs in the presence of glucose, hexokinase, glucose-6-phosphate dehydrogenase and effluxed ATP. The NADP+ reduction rate shows hyperbolic dependence on ADP concentration (Km and Vmax values 8.5 +/- 0.87 microM and 20.7 +/- 0.49 nmoles NADP+ reduced/min x mg mitochondrial protein, respectively), and proves to measure the activity of the ADP/ATP translocator as shown by inhibition experiments using atracyloside, powerful inhibitor of this carrier. Irradiation was found to enhance the rate of ADP/ATP antiport, with externally added ADP ranging between 5 and 100 microM. As a result of experiments carried out with mitochondria loaded with either ATP or ADP, the increase in the activity of the ADP/ATP translocator is here proposed to depend on the increase in the electrochemical proton gradient which occurs owing to irradiation of mitochondria.

  11. Effects of helium-neon laser on levels of stress protein and arthritic histopathology in experimental osteoarthritis.

    PubMed

    Lin, Yueh-Shuang; Huang, Mao-Hsiung; Chai, Chee-Yin; Yang, Rei-Cheng

    2004-10-01

    To investigate the effect of low-power laser therapy on levels of stress proteins (SPs) in experimental arthritis and their relation to the bioeffects on arthritic cartilage repair. A total of 42 rats with similar degrees of induced arthritis evaluated by means of bone scan were divided randomly into two groups. In the treated group, 21 rats received helium-neon laser treatment; in the control group, 21 rats received sham laser treatment. The changes in chondrocytes of SPs were measured by electrophoresis of proteins extracted from chondrocytes of arthritic cartilage at various time periods. The histopathologic changes and the presence of SP of arthritic cartilage were identified by hematoxylin and eosin stain and by immunostains of SP72 antibody individually from frozen sections of arthritic cartilage. SP density increased markedly in rats after laser treatment and was closely related to the repair of arthritic cartilage. Furthermore, the pathohistology of arthritic cartilage improved significantly with the decline of SP levels in the follow-up period. Helium-neon (632 nm) low-power laser can enhance SP production in arthritic chondrocytes. The extragenic production of SP is well correlated with the therapeutic effect of low-power laser in preserving chondrocytes and the repair of arthritic cartilage in rats.

  12. Helium-neon laser irradiation of cryopreserved ram sperm enhances cytochrome c oxidase activity and ATP levels improving semen quality.

    PubMed

    Iaffaldano, N; Paventi, G; Pizzuto, R; Di Iorio, M; Bailey, J L; Manchisi, A; Passarella, S

    2016-08-01

    This study examines whether and how helium-neon laser irradiation (at fluences of 3.96-9 J/cm(2)) of cryopreserved ram sperm helps improve semen quality. Pools (n = 7) of cryopreserved ram sperm were divided into four aliquots and subjected to the treatments: no irradiation (control) or irradiation with three different energy doses. After treatment, the thawed sperm samples were compared in terms of viability, mass and progressive sperm motility, osmotic resistance, as well as DNA and acrosome integrity. In response to irradiation at 6.12 J/cm(2), mass sperm motility, progressive motility and viability increased (P < 0.05), with no significant changes observed in the other investigated properties. In parallel, an increase (P < 0.05) in ATP content was detected in the 6.12 J/cm(2)-irradiated semen samples. Because mitochondria are the main cell photoreceptors with a major role played by cytochrome c oxidase (COX), the COX reaction was monitored using cytochrome c as a substrate in both control and irradiated samples. Laser treatment resulted in a general increase in COX affinity for its substrate as well as an increase in COX activity (Vmax values), the highest activity obtained for sperm samples irradiated at 6.12 J/cm(2) (P < 0.05). Interestingly, in these irradiated sperm samples, COX activity and ATP contents were positively correlated, and, more importantly, they also showed positive correlation with motility, suggesting that the improved sperm quality observed was related to mitochondria-laser light interactions. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Low-level laser therapy with helium-neon laser improved viability of osteoporotic bone marrow-derived mesenchymal stem cells from ovariectomy-induced osteoporotic rats

    NASA Astrophysics Data System (ADS)

    Fallahnezhad, Somaye; Piryaei, Abbas; Tabeie, Faraj; Nazarian, Hamid; Darbandi, Hasan; Amini, Abdoldllah; Mostafavinia, Ataroalsadat; Ghorishi, Seyed Kamran; Jalalifirouzkouhi, Ali; Bayat, Mohammad

    2016-09-01

    The purpose of this study was to evaluate the influences of helium-neon (He-Ne) and infrared (IR) lasers on the viability and proliferation rate of healthy and ovariectomy-induced osteoporotic (OVX) bone marrow mesenchymal stem cells (BMMSCs) in vitro. MSCs harvested from the BM of healthy and OVX rats were culture expanded. He-Ne and IR lasers were applied three times at energy densities of 0.6, 1.2, and 2.4 J/cm2 for BMMSCs. BMMSCs viability and proliferation rate were evaluated by MTT assay on days 2, 4, 6, 14, and 21. The results showed that healthy BMMSCs responded optimally to 0.6 J/cm2 using an IR laser after three times of laser radiation. Moreover, it was found that OVX-BMMSCs responded optimally to 0.6 J/cm2 with He-Ne laser and one-time laser radiation. It is concluded that the low-level laser therapy (LLLT) effect depends on the physiological state of the BMMSCs, type of the laser, wavelength, and number of laser sessions. The biostimulation efficiency of LLLT also depends on the delivered energy density. LLLT can enhance the viability and proliferation rate of healthy and especially osteoporotic autologous BMMSCs, which could be very useful in regenerative medicine.

  14. Sensing earth's rotation with a helium-neon ring laser operating at 1.15  μm.

    PubMed

    Ulrich Schreiber, K; Thirkettle, Robert J; Hurst, Robert B; Follman, David; Cole, Garrett D; Aspelmeyer, Markus; Wells, Jon-Paul R

    2015-04-15

    We report on the operation of a 2.56  m2 helium-neon based ring laser interferometer at a wavelength of 1.152276 μm using crystalline coated intracavity supermirrors. This work represents the first implementation of crystalline coatings in an active laser system and expands the core application area of these low-thermal-noise cavity end mirrors to inertial sensing systems. Stable gyroscopic behavior can only be obtained with the addition of helium to the gain medium as this quenches the 1.152502 μm (2s4→2p7) transition of the neon doublet which otherwise gives rise to mode competition. For the first time at this wavelength, the ring laser is observed to readily unlock on the bias provided by the earth's rotation alone, yielding a Sagnac frequency of approximately 59 Hz.

  15. [Efficiency of a combination of haloaerosols and helium-neon laser in the multimodality treatment of patients with bronchial asthma].

    PubMed

    Faradzheva, N A

    2007-01-01

    A hundred and thirty-eight patients with infection-dependent bronchial asthma, including 73 with moderate persistent asthma and 65 with severe persistent one, were examined. Four modes of a combination of traditional (drug) therapy (DT) and untraditional (halotherapy (HT) and endobronchial helium-neon laser irradiation (ELI) one were used. The efficiency of the treatment performed was evaluated, by determining the time course of clinical symptoms of the disease on the basis of scores of their magnitude and the patients' condition. The findings indicated that in moderate persistent asthma, both HT and ELI in combination with DT exerted an equal therapeutic effect, which provided a good and excellent condition in 83.3% of cases. In severe persistent asthma, such a condition was achieved in 93.75% of cases only when multimodality treatment involving DT, HT, and ELI had been performed.

  16. Frequency stabilisation of multimode helium-neon lasers in laser Doppler flowmetry.

    PubMed

    Deblén, H; Oberg, P A

    1991-09-01

    Low-frequency noise in laser Doppler recordings can be generated because of thermal instabilities in the gas laser cavity. Mode partition noise can be eliminated by thermal stabilisation of the laser cavity. The paper describes a method for closed loop temperature control of the laser cavity. The method uses orthogonal properties of longitudinal laser modes for the temperature control. The signal-to-noise ratio is considerably improved by the procedure. It is recommended that all gas laser equipped Doppler instruments used for precision blood flow studies should be equipped with stabilised laser sources.

  17. The effects of topical tripeptide copper complex and helium-neon laser on wound healing in rabbits.

    PubMed

    Gul, Nihal Y; Topal, Ayse; Cangul, I Taci; Yanik, Kemal

    2008-02-01

    The aim of this study was to compare the clinical and histopathological effects of tripeptide copper complex (TCC) and two different doses of laser application (helium-neon laser, 1 and 3 J cm(-2)) on wound healing with untreated control wounds. Experimental wounds were created on a total of 24 New Zealand white rabbits and topical TCC or laser was applied for 28 days. The wounds were observed daily, and planimetry was performed on days 7, 14, 21 and 28 to measure the unhealed wound area and percentage of total wound healing. Biopsies were taken weekly to evaluate the inflammatory response and the level of neovascularization. The median time for the first observable granulation tissue was shorter (P < 0.05) in the low and high dose laser groups than in the control group (3 and 2.66 vs. 4.5 days), but was not different between the TCC and control groups (4.16 vs. 4.5 days). Filling of the open wound to skin level with granulation tissue was faster (P < 0.05) in the TCC and high dose laser groups than in the control group (14 and 16 vs. 25 days), but was not different between the low dose laser and control groups (23 vs. 25 days). The average time for healing was shorter (P < 0.05) in the TCC and high dose laser groups (29.8 and 30.2 vs. 34.6 days), but was not different between the low dose laser and control groups (33.8 vs. 34.6 days). Histopathologically, wound healing was characterized by a decrease in the neutrophil counts and an increase in neovascularization. The TCC and high dose laser groups had greater neutrophil and vessel counts than in the control group, suggesting a more beneficial effect for wound healing.

  18. High-power helium-neon laser irradiation inhibits the growth of traumatic scars in vitro and in vivo.

    PubMed

    Shu, Bin; Ni, Guo-Xin; Zhang, Lian-Yang; Li, Xiang-Ping; Jiang, Wan-Ling; Zhang, Li-Qun

    2013-05-01

    This study explored the inhibitory effect of the high-power helium-neon (He-Ne) laser on the growth of scars post trauma. For the in vitro study, human wound fibroblasts were exposed to the high-power He-Ne laser for 30 min, once per day with different power densities (10, 50, 100, and 150 mW/cm(2)). After 3 days of repeated irradiation with the He-Ne laser, fibroblast proliferation and collagen synthesis were evaluated. For in vivo evaluation, a wounded animal model of hypertrophic scar formation was established. At postoperative day 21, the high-power He-Ne laser irradiation (output power 120 mW, 6 mm in diameter, 30 min each session, every other day) was performed on 20 scars. At postoperative day 35, the hydroxyproline content, apoptosis rate, PCNA protein expression and FADD mRNA level were assessed. The in vitro study showed that the irradiation group that received the power densities of 100 and 150 mW/cm(2) showed decreases in the cell proliferation index, increases in the percentage of cells in the G0/G1 phase, and decreases in collagen synthesis and type I procollagen gene expression. In the in vivo animal studies, regions exposed to He-Ne irradiation showed a significant decrease in scar thickness as well as decreases in hydroxyproline levels and PCNA protein expression. Results from the in vitro and in vivo studies suggest that repeated irradiation with a He-Ne laser at certain power densities inhibits fibroblast proliferation and collagen synthesis, thereby inhibits the growth of hypertrophic scars.

  19. Direction sensitive laser velocimeter. [determining the direction of particles using a helium-neon laser

    NASA Technical Reports Server (NTRS)

    Franke, J. M. (Inventor)

    1981-01-01

    A laser velocimeter is described which determines the direction of movement of particles. A laser produces a transmitted beam that illuminates the volume under investigation. The backscattered light is divided into two equal intensity beams. A first part of a sample of the transmitted beam is mixed with one of the two equal intensity beams and applied to a first photodetector. A second part of the sample is phase shifted by 90 deg, mixed with the other of the two equal intensity beams and applied to a second photodetector. The output of the first photodetector is phase shifted by 90 deg and then multiplied with the output of the second photodetector to produce a signal indicative of direction of movement.

  20. Helium-neon laser irradiation enhances DNA synthesis in a human neuroblastoma cell line

    NASA Astrophysics Data System (ADS)

    Condon, Michael R.; Gump, Frank; Wu, Wen-hsien

    1993-07-01

    To gain further insight into the mechanism of cell photostimulation by laser light ((lambda) equals 632.8 nm), DNA synthesis was measured in the human neuroblastoma cell line BE(2)-C. Cells were irradiated at high density to establish the characteristics of cellular energy into S- phase in response to laser stimulation. BE(2)-C cells after release from a quiescent, growth arrested state exhibited increased incorporation of isotope 12 hours after replating at subconfluent density in the presence of 2.5% fetal bovine serum (FBS) and [3H] thymidine. In contrast, cells replated under the same conditions, but stimulated with 15% FBS exhibited a time lag of approximately 16 hours in apparent DNA synthesis. These results were not corroborated by flow cytometry. Laser irradiation did not affect the fraction of cells entering S-phase. It therefore appears that the stimulatory effect of He-Ne laser irradiation on BE(2)-C cells is to enhance DNA synthesis while not altering the G1-S transition rate.

  1. Effectiveness of helium-neon laser irradiation on viability and cytotoxicity of diabetic-wounded fibroblast cells.

    PubMed

    Houreld, N N; Abrahamse, H

    2007-12-01

    This study investigated the effectiveness of helium-neon (He-Ne) laser irradiation at increasing intervals on diabetic-induced wounded human skin fibroblast cells (WS1) at a morphological, cellular, and molecular level. The controversies over light therapy can be explained by the differing exposure regimens and models used. No therapeutic window for dosimetry and mechanism of action has been determined at the level of individual cell types, particularly in diabetic cells in vitro. WS1 cells were used to simulate an in vitro wounded diabetic model. The effect of the frequency of He-Ne irradiation (632.8 nm) at a fluence of 5 J/cm(2) was determined by analysis of cell morphology, viability, cytotoxicity, and DNA damage. Cells were irradiated using three different protocols: they were irradiated at 30 min only; irradiated twice, at 30 min and at 24 h; or irradiated twice, at 30 min and at 72 h post-wound induction. A single exposure to 5 J/cm(2) 30 min post-wound induction increased cellular damage. Irradiation of cells at 30 min and at 24 h post-wound induction decreased cellular viability, cytotoxicity, and DNA damage. However, complete wound closure as well as an increase in viability and a decrease in cytotoxicity and DNA damage occurs when cells were irradiated at 30 min and at 72 h post-wound induction. Wounded diabetic WS1 cells irradiated to 5 J/cm(2) showed increased cellular repair when irradiated with adequate time between irradiations, allowing time for cellular response mechanisms to take effect. Therefore, the irradiation interval was shown to play an important role in wound healing in vitro and should be taken into account.

  2. Effect of helium-neon laser on fast excitatory postsynaptic potential (f-EPSP) of neurons in the isolated rat superior cervical ganglia

    NASA Astrophysics Data System (ADS)

    Hua, Mo; Ping, He; Ning, Mo

    2002-06-01

    Single electrical stimulation of the cervical sympathetic trunk elicits in the ganglion cells an excitatory postsynaptic potential (EPSP) or multiple EPSPs of varying latencies, among which a fast excitatory postsynaptic potential (f-EPSP) is the main type of ganglionic transmission in the sympathetic neurons. In previous work, we studied the effects of Helium-Neon laser with wavelength 632.8 nm on membrane conductance of neurons with stable f- EPSP in isolated rat superior cervical ganglia. The aim of this study is to further measure the effect of Helium-Neon Laser with wavelength 632.8 nm on fast excitatory postsynaptic potential of postganglionic neurons in the isolated rate superior cervical ganglia by means of intracellular recording techniques. The neurons with fast excitatory postsynaptic potential were irradiated by different power densities (1 and 5 mW/cm2), pulse frequency of 1 Hz laser. Irradiated by the 2 mW/cm2 laser, the amplitude of the f-EPSP could augment (P<0.05) and even caused action potential (AP) at the end of the first 1-2 minute, the F-EPSP could descend and lasted for 3- 8 minutes later.

  3. Helium-neon laser-induced respiratory burst of phagocytic cells

    SciTech Connect

    Karu, T.I.; Ryabykh, T.P.; Fedoseyeva, G.E.; Puchkova, N.I. )

    1989-01-01

    The effect of He-Ne laser radiation (lambda = 632.8 nm, I = 6.8 W/m2, irradiation time from 5 to 50 sec) on kinetics of spontaneous and Candida ablicans-stimulated chemiluminescence of mouse spleen cells was studied. It was found that laser radiation caused significant enhancement (180-250%) both of spontaneous chemiluminescence and Candida-induced chemiluminescence. The effective dose interval ranges from 100 to 300 J/m2, with a maximum at 200 J/m2. This finding shows that He-Ne laser irradiation can induce the respiratory burst (generation of reactive oxygen species having bactericidal activity) of phagocytic cells.

  4. [Experience in irradiating with helium-neon lasers to treat patients with relapsing aphthous stomatitis].

    PubMed

    Prikuls, V F

    2000-01-01

    Seventy-five patients with relapsing aphthous stomatitis (41 with the fibrinous form, 25 with glandular form, and 9 with necrotic form) were treated using He-Ne laser and a photosensitizer. A good therapeutic effect was attained.

  5. Helium-neon and nitrogen laser irradiation accelerates the phagocytic activity of human monocytes.

    PubMed

    Hemvani, Nanda; Chitnis, Dhananjay Sadashiv; Bhagwanani, Nijram Satramdas

    2005-12-01

    Intracellular survival of mycobacteria within monocytes is a crucial stage in the pathogenesis of tuberculosis. The aim was to check intracellular survival of Mycobacterium fortuitum within the human monocytes exposed to He-Ne and nitrogen laser irradiation. Tuberculosis remains one of the most important infectious diseases for developing countries. Low-level laser therapy (LLLT) has been tried to treat tubercular cavitory lung disease with encouraging results. The in vitro photobiological effect of low level laser radiation on the intracellular mycobacteria needs to be evaluated before we could go for large clinical trials. The aliquots of human monocytes from peripheral blood of healthy volunteers and tuberculosis cases were exposed to He-Ne or nitrogen laser beam. The non-irradiated monocytes from the same source served as controls. The monocytes were then challenged with M. fortuitum, and surviving mycobacteria within monocytes were subjected to viable counts. Enhanced killing of mycobacterial cells was seen among monocytes exposed to He-Ne and nitrogen laser irradiation. He-Ne and nitrogen laser irradiation activates the monocytes to increase intracellular killing of mycobacteria.

  6. Treatment of TMJDS with helium-neon laser beam irradiation on the acupoints

    NASA Astrophysics Data System (ADS)

    Li, Ping

    1993-03-01

    Through He-NE laser stimulation of acupuncture points, we treated and observed 50 cases of Temporomandibular Joint Dysfunction Syndrome (TMJDS). The results proved that this treatment was very effective for relieving the patient's pain. In cases which had structural disturbances and organic damage such as limitation of mouth-opening and joint clink, there was less improvement of symptoms and no relief for joint clink.

  7. Biological effects of helium-neon laser irradiation on normal and wounded human skin fibroblasts.

    PubMed

    Hawkins, D; Abrahamse, H

    2005-06-01

    This study aimed to investigate a number of structural, cellular, and molecular responses to heliumneon (632.8 nm) laser irradiation following a single dose of 0.5, 2.5, 5, or 10 J/cm2 on normal and wounded human skin fibroblasts. Low-level laser therapy (LLLT) is a form of phototherapy, involving the application of low-power monochromatic and coherent light to injuries and lesions to stimulate healing. 1 This therapy has been successfully used for pain attenuation and to induce wound healing in nonhealing defects. Changes in normal and wounded fibroblast cell morphology were evaluated by light microscopy. Cellular parameters evaluated cell proliferation, cell viability, and cytotoxicity while molecular parameters assessed the extent of DNA damage. The results clearly demonstrate that LLLT has an effect on normal and wounded(3) human skin fibroblasts. The parameters showed that doses of 0.5, 2.5, 5, and 10 J/cm2 were sufficient to produce measurable changes in fibroblast cells. A dose of 10 J/cm2 appeared to produce a significant amount of cellular and molecular damage, which could be an important consideration for other therapies, such as photodynamic therapy.

  8. Relationship between cardiovascular system response and adrenocortical glucocorticoid function on exposure to diffuse, low-intensity helium-neon laser emission

    NASA Astrophysics Data System (ADS)

    Ushkova, I. N.; Pokrovskaya, L. A.; Stepanov, G. S.; Suvorov, I. M.; Kogan, M. Y.; Grishina, Y. F.

    1984-06-01

    The effect of light from a low intensity helium neon laser on the formation of a series of adaptive processes in the body is investigated. The study is carried out on 32 chinchilla rabbits, weighing from two to two point five kilograms. The right eyes of the creatures were subjected to diffuse laser radiation, for 30 days, 14 minutes per day, under conditions of low illumination. Controls are rabbits under the same conditions, but not exposed to laser radiation. In order to isolate the early glucocorticoid response to the treatment, the hydrocortisone content of the blood is determined which permitted judgment on presence of a functional cumulation effect. The body developed an adaptive/compensatory reaction to the laser radiation so that hydrocortisone levels and the system's hemodynamics and nervous system returned to normal.

  9. The role of laser fluence in cell viability, proliferation, and membrane integrity of wounded human skin fibroblasts following helium-neon laser irradiation.

    PubMed

    Hawkins, Denise H; Abrahamse, Heidi

    2006-01-01

    In medicine, lasers have been used predominantly for applications, which are broadly termed low level laser therapy (LLLT), phototherapy or photobiomodulation. This study aimed to establish cellular responses to Helium-Neon (632.8 nm) laser irradiation using different laser fluences (0.5, 2.5, 5, 10, and 16 J/cm(2)) with a single exposure on 2 consecutive days on normal and wounded human skin fibroblasts. Changes in normal and wounded fibroblast cell morphology were evaluated by light microscopy. Changes following laser irradiation were evaluated by assessing the mitochondrial activity using adenosine triphosphate (ATP) luminescence, cell proliferation using neutral red and an alkaline phosphatase (ALP) activity assay, membrane integrity using lactate dehydrogenase (LDH), and percentage cytotoxicity and DNA damage using the Comet assay. Morphologically, wounded cells exposed to 5 J/cm(2) migrate rapidly across the wound margin indicating a stimulatory or positive influence of phototherapy. A dose of 5 J/cm(2) has a stimulatory influence on wounded fibroblasts with an increase in cell proliferation and cell viability without adversely increasing the amount of cellular and molecular damage. Higher doses (10 and 16 J/cm(2)) were characterized by a decrease in cell viability and cell proliferation with a significant amount of damage to the cell membrane and DNA. Results show that 5 J/cm(2) stimulates mitochondrial activity, which leads to normalization of cell function and ultimately stimulates cell proliferation and migration of wounded fibroblasts to accelerate wound closure. Laser irradiation can modify cellular processes in a dose or fluence (J/cm(2)) dependent manner.

  10. Helium-Neon Laser Irradiation Promotes the Proliferation and Migration of Human Epidermal Stem Cells In Vitro: Proposed Mechanism for Enhanced Wound Re-epithelialization

    PubMed Central

    Liao, Xuan; Xie, Guang-Hui; Cheng, Biao; Li, Sheng-Hong; Xie, Shan; Xiao, Li-Ling; Fu, Xiao-Bing

    2014-01-01

    Abstract Objective: The present study was conducted to investigate the effects of helium-neon (He-Ne) laser irradiation on the proliferation, migration, and differentiation of cultured human epidermal stem cells (ESCs). Background data: A He-Ne laser with a wavelength of 632.8 nm is known to have photobiological effects, and is widely used for accelerating wound healing; however, the cellular mechanisms involved have not been completely understood. Methods: The ESCs were prepared from human foreskin, and irradiated by using He-Ne laser at 632.8 nm with 2 J/cm2. The ESC proliferation, migration, and differentiation were examined by using XTT assay, scratch assay, and flow cytometry technology, respectively. The phosphorylation of extracellular signal-regulated kinases (ERK) was analyzed by using Western blotting. Results: He-Ne laser irradiation markedly promoted cell proliferation and migration accompanied by an increase in the phosphorylation of ERK, but did not significantly influence cell differentiation. Conclusion: Our data indicated that photostimulation with a He-Ne laser resulted in a significant increase in human ESC proliferation and migration in vitro, which might contribute, at least partially, to accelerated wound re-epithelialization by low-level laser therapy. PMID:24661127

  11. Induction of primitive pigment cell differentiation by visible light (helium-neon laser): a photoacceptor-specific response not replicable by UVB irradiation.

    PubMed

    Lan, Cheng-Che E; Wu, Shi-Bei; Wu, Ching-Shuang; Shen, Yi-Chun; Chiang, Tzu-Ying; Wei, Yau-Huei; Yu, Hsin-Su

    2012-03-01

    Solar lights encompass ultraviolet (UV), visible, and infrared spectrum. Most previous studies focused on the harmful UV effects, and the biologic effects of lights at other spectrums remained unclear. Recently, lights at visible region have been used for regenerative purposes. Using the process of vitiligo repigmentation as a research model, we focused on elucidating the pro-differentiation effects induced by visible light. We first showed that helium-neon (He-Ne) laser (632.8 nm) irradiation stimulated differentiation of primitive pigment cells, an effect not replicable by UVB treatment even at high and damaging doses. In addition, significant increases of mitochondrial DNA copy number and the regulatory genes for mitochondrial biogenesis were induced by He-Ne laser irradiation. Mechanistically, we demonstrated that He-Ne laser initiated mitochondrial retrograde signaling via a Ca(2+)-dependent cascade. The impact on cytochrome c oxidase within the mitochondria is responsible for the efficacy of He-Ne laser in promoting melanoblast differentiation. Taken together, we propose that visible lights from the sun provide important environmental cues for the relatively quiescent stem or primitive cells to differentiate. In addition, our results also indicate that visible light may be used for regenerative medical purposes involving stem cells.

  12. Development and evaluation of fiber optic probe-based helium-neon low-level laser therapy system for tissue regeneration--an in vivo experimental study.

    PubMed

    Prabhu, Vijendra; Rao, Satish B S; Rao, Nageshwara B; Aithal, Kiran B; Kumar, Pramod; Mahato, Krishna K

    2010-01-01

    We report the design and development of an optical fiber probe-based Helium-Neon (He-Ne) low-level laser therapy system for tissue regeneration. Full thickness excision wounds on Swiss albino mice of diameter 15 mm were exposed to various laser doses of 1, 2, 3, 4, 6, 8 and 10 J cm(-2) of the system with appropriate controls, and 2 J cm(-2) showing optimum healing was selected. The treatment schedule for applying the selected laser dose was also standardized by irradiating the wounds at different postwounding times (0, 24 and 48 h). The tissue regeneration potential was evaluated by monitoring the progression of wound contraction and mean wound healing time along with the hydroxyproline and glucosamine estimation on wound ground tissues. The wounds exposed to 2 J cm(-2) immediately after wounding showed considerable contraction on days 5, 9, 12, 14, 16 and 19 of postirradiation compared with the controls and other treatment schedules, showing significant (P < 0.001) decrease in the healing time. A significant increase in hydroxyproline and glucosamine levels was observed for the 2 J cm(-2) irradiation group compared with the controls and other treatment groups. In conclusion, the wounds treated with 2 J cm(-2) immediately after the wounding show better healing compared with the controls.

  13. Relative blood velocity measurement in individual microvessels using the self-mixing effect in a fiber-coupled helium-neon laser.

    PubMed

    Ren, T; Nuttall, A L; Miller, J M

    1995-03-01

    A system has been developed for the measurement of relative blood velocity in micro-vessels by using the self-mixing effect of a laser. A helium-neon laser was coupled to a single-mode optical fiber and the pulled fiber tip (approximately 30 microns diameter) was positioned on a single microvessel. The backscattered Doppler-shifted laser light from moving red blood cells enters the laser cavity and modulates the laser output by influencing internal laser parameters. The signal of the laser output intensity change was produced using a fiber-coupled photodiode and processed by a signal processor. This processor yields an output signal proportional to the first moment of the power spectral density, i.e., the mean frequency of the Doppler shift, corresponding to the blood flow velocity on an arbitrary instrument scale. Results of the in vitro experiment demonstrated that the current method can detect moving particles in fluid and moving red blood cells in a small plastic tube. Data from the in vivo study showed that this system is capable of measuring relative blood velocity in arterioles and venules and can easily follow the cardiac cycle up to 360 beats/min. Primary data suggest that, in addition to high sensitivity, good spatial and temporal resolution, and convenience of use, the self-mixing technique may have an even greater capacity for analysis of blood flow in microvessels than explored in this study, since information on the absolute velocity and velocity distribution of red blood cells is available in self-mixing signal. Further study on its hematocrit dependence and particle bias effect is needed.

  14. A randomized double-blind clinical trial on the effectiveness of helium-neon laser in the prevention of pain, swelling and trismus after removal of impacted third molars.

    PubMed

    Carrillo, J S; Calatayud, J; Manso, F J; Barberia, E; Martinez, J M; Donado, M

    1990-02-01

    The effect of helium-neon (He-Ne) laser on the prevention of pain, swelling and trismus following the removal of an impacted third molar was studied in 100 patients randomly allocated to receive He-Ne laser, ibuprofen or placebo in a prospective double-blind parallel clinical trial. Trismus was significantly reduced in the He-Ne laser and ibuprofen treatment groups. Pain was significantly less in the ibuprofen group with regard to He-Ne laser and placebo groups. Swelling was the same in the three treatment groups.

  15. Evaluation effect of low level Helium-Neon laser and Iranian propolis extract on Collagen Type I gene expression by human gingival fibroblasts: an in vitro study.

    PubMed

    Eslami, Hosein; Motahari, Paria; Safari, Ebrahim; Seyyedi, Maryam

    2017-06-30

    production of collagen by fibroblast cells is a key component in wound healing. Several studies have shown that low level laser therapy (LLLT) and propolis extract stimulate collagen Type I production. The aim of this study is to evaluation the combined effect of LLL helium neon (632.8 nm) and Iranian propolis extract on collagen Type I gene expression by human gingival fibroblasts (HGF3-PI 53). Human gingival fibroblasts after culturing divided into six experimental groups: G1-control group, which received no irradiation and propolis extract, G2-irradiated at1.5 J/cm(2), G3-irradiated at 0.15 J/cm(2), G4-recived extract of propolis, G5- combined extract of propolis and 1.5 J/cm(2) laser irradiation and G6- combined extract of propolis and 0.15 J/cm(2) laser irradiation. The experiments were conducted in triplicate. After 24 hour, the total RNA was extracted and cDNA synthesis was performed. Type I collagen mRNA expression was determined with real time PCR. The obtained results illustrated a statistically significant difference between G3 (0.15 J/cm(2)) and G1 (control group) in levels of collagen Type I messenger RNA (mRNA) expression (p<0.05). The irradiated cells showed a 1.4 times increase in mRNA expression of the collagen Type I gene. Expression of this gene decreases in other groups that this difference was statistically significant. LLLT in different dosage and propolis extract may result in decreased or increased collagen type I gene expression. However this effect should be investigated in clinical studies.

  16. In vitro effects of helium-neon laser irradiation on human blood: blood viscosity and deformability of erythrocytes.

    PubMed

    Mi, Xian-Qiang; Chen, Ji-Yao; Liang, Zi-Jun; Zhou, Lu-Wei

    2004-12-01

    The purpose of this study was to investigate the in vitro effects of He-Ne laser irradiation on some rheological factors of human blood, such as blood viscosity, erythrocyte deformability, and sedimentation rate. The intravascular irradiation of low power laser has been applied in pre-clinical and clinical to treat various pathological processes. However, the mechanism is not fully understood so far. Especially the interaction and related mechanism between the laser and blood are unclear. In this work, by measuring the change of the main rheological factors after laser irradiation, the interaction and mechanism were explored. A30-mW He-Ne laser was used for irradiation with a 4-5-mm-diameter beam spot on blood samples, with a fluence rate of about 150 mW/cm.(2) The irradiation time was 60 min, so the total dose of irradiation was 540 J/cm.(2) The pathological samples of blood were obtained from patients (volunteers), and each sample was divided into two tubes for irradiation and control. The blood viscosity, erythrocyte deformability, and sedimentation rate were measured after laser irradiation and compared with un-irradiated control. The blood samples with poor erythrocyte deformability were prepared by adding Ca(2+) to the normal erythrocytes of a healthy person for investigating the laser effect on erythrocyte deformability further. Laser irradiation reduced the erythrocyte sedimentation rate of blood samples, which had a hyper-sedimentation rate originally. The blood viscosity of samples in hyper-values was lowered by laser irradiation in all shear rates measured (10-110 S(-1)), with a relative variation of approximately 10%. The deformability of erythrocytes from pathological samples and Ca(2+)-treated samples was improved after laser irradiation. The positive effects of laser irradiation on improving the rheological properties of blood were demonstrated in vitro.

  17. Flow cytometric immunofluorescence and DNA analysis: Using a 1.5 mW helium-neon laser (544 nm)

    SciTech Connect

    Hudson, J.C.; Porcelli, R.T.; Russell, T.R.

    1995-10-01

    We evaluate a 1.5 mW HeNe laser (544 nm) for use on an EPICS{reg_sign} Elite with a 76 {mu}m Sortsense flow cell. The two applications chosen were immunofluorescence and DNA analysis. We measured the fluorescence threshhold of phycoerytherin calibration beads to be approximately 336 MESF. Cell analysis with a HeNe laser and Argon laser correlated well for the CD4{sup PE}, CD56{sup PE}, CD19{sup PE} conjugates, with correlation coefficients of 0.98, 0.99, 0.94, respectively. The % positive and mean channel fluorescence were comparable to the results obtained with a 15 mW Argon laser. In addition, a three-color configuration PE yielded excellent results. Cell analysis of CD4{sup PE}, CD3{sup ECD} and CD19{sup Cy-Chrome} with the HeNe laser and Argon laser correlated well with correlation coefficients of 0.96, 0.95, and 0.92, respectively. The histograms showed good separation between the negative cells, the dimly staining cells and the brightly staining cells. Propidium Iodide was chosen for DNA analysis. Full CV values for whole blood DNA fluorescence using the green laser were good at 2.6%. These data indicate the low power 544 nm laser is sufficient to do immunophenotyping and DNA analysis. Results may be explained by higher quantum efficiency and lower background fluorescence. The wavelength of the 544 nm laser is much closer to the excitation peaks of PI, PE, and the tandem dyes ECD and Cy-Chrome. Also, the Raman scattering of water for the 544 nm laser has a longer wavelength maximum than the emission peaks of PI, PE, and ECD. The major advantages of this laser for the research laboratory are small size, no cooling fan, low power requirements and low cost. 16 refs., 5 figs., 3 tabs.

  18. Effect of low intensity helium-neon (HeNe) laser irradiation on experimental paracoccidioidomycotic wound healing dynamics.

    PubMed

    Ferreira, Maria Carolina; Gameiro, Jacy; Nagib, Patrícia Resende Alo; Brito, Vânia Nieto; Vasconcellos, Elza da Costa Cruz; Verinaud, Liana

    2009-01-01

    The effect of HeNe laser on the extracellular matrix deposition, chemokine expression and angiogenesis in experimental paracoccidioidomycotic lesions was investigated. At days 7, 8 and 9 postinfection the wound of each animal was treated with a 632.8 nm HeNe laser at a dose of 3 J cm(-2). At day 10 postinfection, the wounds were examined by using histologic and immunohistochemical methods. Results revealed that laser-treated lesions were lesser extensive than untreated ones, and composed mainly by macrophages and lymphocytes. High IL-1beta expression was shown in the untreated group whereas in laser-treated animals the expression was scarce. On the other hand, the expression of CXCL-10 was found to be reduced in untreated animals and quite intensive and well distributed in the laser-treated ones. Also, untreated lesions presented vascular endothelial growth factor (VEGF) in a small area near the center of the lesion and high immunoreactivity for hypoxia-inducible factor-1 (HIF-1), whereas laser-treated lesions expressed VEGF surrounding blood vessels and little immunoreactivity for HIF-1. Laser-treated lesions presented much more reticular fibers and collagen deposition when compared with the untreated lesion. Our results show that laser was efficient in minimizing the local effects observed in paracoccidioidomycosis and can be an efficient tool in the treatment of this infection, accelerating the healing process.

  19. Poor penetration of infra-red and helium neon low power laser light into the dermal tissue.

    PubMed

    Kolari, P J; Airaksinen, O

    1993-01-01

    The skin transmittance for low power laser light was studied in vitro. The penetration of both He-Ne and infra-red lasers was observed for only a few millimeters. The most important absorption was observed at the depth level of 0.4 and 0.5 mm. These results suggested that the dermal vascular plexus barrier seemed to decrease the penetration at that level. This finding should mean that the laser therapy did not have really direct effects on the deep tissues. However, the effects can be mediated by many different pathways.

  20. Control of transverse mode pattern in a helium neon laser using the cat’s eye cavity

    NASA Astrophysics Data System (ADS)

    Xu, Zhiguang; Zhang, Shulian; Du, Wenhua; Liang, Dong; Li, Yan

    2006-05-01

    This paper introduces an innovative method to control and select transverse mode pattern in a He-Ne laser. The cat's eye cavity is established by using a cat's eye reflector as the reflecting mirror. Laser transverse mode pattern varies continuously when the distance between the convex lens and the concave mirror is changed, which form the cat's eye reflector. By Newton-Cotes method, the numerical solution of two-dimensional diffraction integral equation in the cat's eye cavity is obtained, the laser operating modes under various parameters are analyzed, and the eigenvalue ηmn and diffraction power loss corresponding with every transverse mode are calculated. The parameters assuring fundamental transverse mode output are figured out, which match the experiment results well. Therefore, a new convenient real-time means for the control and selection of the laser transverse mode is realized.

  1. Effects of helium-neon laser irradiation and local anesthetics on potassium channels in pond snail neurons.

    PubMed

    Ignatov, Yu D; Vislobokov, A I; Vlasov, T D; Kolpakova, M E; Mel'nikov, K N; Petrishchev, I N

    2005-10-01

    Intracellular dialysis and membrane voltage clamping were used to show that He-Ne laser irradiation of a pond snail neuron at a dose of 0.7 x 10(-4) J (power density 1.5 x 10(2) W/m2) increases the amplitude of the potential-dependent slow potassium current, while a dose of 0.7 x 10(-3) J decreases this current. Bupivacaine suppresses the potassium current. Combined application of laser irradiation at a dose of 0.7 x 10(-3) J increased the blocking effect of 10 microM bupivacaine on the slow potassium current, while an irradiation dose of 0.7 x 10(-4) J weakened the effect of bupivacaine.

  2. Combined Effect of Low-Intensity Helium-Neon Laser and X-Ray Radiation on in Vivo Cellular Response of the Whole Blood and Lymphoid Organs in Mice.

    PubMed

    Zaichkina, S I; Dyukina, A R; Rozanova, O M; Romanchenko, S P; Sirota, N P; Kuznetsova, E A; Simonova, N B; Sorokina, S S; Zakrzhevskaya, D T; Yusupov, V I; Bagratishvili, V N

    2016-09-01

    We studied the effect of exposure to helium-neon laser (dose range 0.16-50 mJ/cm(2)) on activation of natural protection reserve in mice using the adaptive response test. DNA comets method revealed a protective response manifested in DNA damage level in whole blood leukocytes of mice and in lymphoid organs by the thymus and spleen weight index; preexposure to laser did not induce the adaptive response. ROS level in the whole blood was assessed by the level of zymosan-induced luminol chemiluminescence. In mice subjected to adaptive laser irradiation in doses of 0.16-5 mJ/cm(2) followed by X-ray irradiation in a dose of 1.5 Gy, the activation index calculated as the ratio of induced to spontaneous area of luminescence was by 1.4 times lower than that in non-irradiated animals, which attested to reduced ROSgeneration reserve capacity of neutrophils.

  3. Low-level laser therapy with helium-neon laser improved viability of osteoporotic bone marrow-derived mesenchymal stem cells from ovariectomy-induced osteoporotic rats.

    PubMed

    Fallahnezhad, Somaye; Piryaei, Abbas; Tabeie, Faraj; Nazarian, Hamid; Darbandi, Hasan; Amini, Abdoldllah; Mostafavinia, Ataroalsadat; Ghorishi, Seyed Kamran; Jalalifirouzkouhi, Ali; Bayat, Mohammad

    2016-09-01

    The purpose of this study was to evaluate the influences of helium–neon (He–Ne) and infrared (IR) lasers on the viability and proliferation rate of healthy and ovariectomy-induced osteoporotic (OVX) bone marrow mesenchymal stem cells (BMMSCs) in vitro. MSCs harvested from the BM of healthy and OVX rats were culture expanded. He–Ne and IR lasers were applied three times at energy densities of 0.6, 1.2, and 2.4??J/cm2 for BMMSCs. BMMSCs viability and proliferation rate were evaluated by MTT assay on days 2, 4, 6, 14, and 21. The results showed that healthy BMMSCs responded optimally to 0.6??J/cm2 using an IR laser after three times of laser radiation. Moreover, it was found that OVX-BMMSCs responded optimally to 0.6??J/cm2 with He–Ne laser and one-time laser radiation. It is concluded that the low-level laser therapy (LLLT) effect depends on the physiological state of the BMMSCs, type of the laser, wavelength, and number of laser sessions. The biostimulation efficiency of LLLT also depends on the delivered energy density. LLLT can enhance the viability and proliferation rate of healthy and especially osteoporotic autologous BMMSCs, which could be very useful in regenerative medicine.

  4. Formation of long-lived reactive species of blood serum proteins induced by low-intensity irradiation of helium-neon laser and their involvement in the generation of reactive oxygen species.

    PubMed

    Ivanov, Vladimir E; Usacheva, Anna M; Chernikov, Anatoly V; Bruskov, Vadim I; Gudkov, Sergey V

    2017-09-14

    It was demonstrated that low-intensity radiation of helium-neon (He-Ne) laser at 632.8nm, which leads to the transition of oxygen to a singlet state, causes the formation of reactive oxygen species (ROS) - hydrogen peroxide, hydroxyl and superoxide (hydroperoxide) radicals - in aqueous solutions. The oxygen effect - dependence of hydrogen peroxide formation on the concentration of molecular oxygen - was shown, and the participation of singlet oxygen, hydroxyl radicals and superoxide (hydroperoxide) radicals in this process was testified. Laser radiation-induced ROS in solutions of blood serum proteins, bovine serum albumin and bovine gamma-globulin, cause the formation of long-lived reactive protein species (LRPS) with a half-life of about 4h. The generation of LRPS caused by laser irradiation results in prolonged several-hour generation of ROS - hydrogen peroxide, hydroxyl and superoxide radicals. As affected by LRPS, coupled radical reactions lead to conversion of dissolved molecular oxygen to hydrogen peroxide. Irradiation with light sources away from the oxygen absorption band is not attended by formation of ROS and LRPS. A consideration is provided for the possible molecular mechanisms of ROS formation under the influence of He-Ne laser irradiation, the role of proteins in their generation and the biological significance of these processes. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Effect of single-dose low-level helium-neon laser irradiation on orthodontic pain: a split-mouth single-blind placebo-controlled randomized clinical trial.

    PubMed

    Sobouti, Farhad; Khatami, Maziar; Chiniforush, Nasim; Rakhshan, Vahid; Shariati, Mahsa

    2015-01-01

    Pain is the most common complication of orthodontic treatment. Low-level laser therapy (LLLT) has been suggested as a new analgesic treatment free of the adverse effects of analgesic medications. However, it is not studied thoroughly, and the available studies are quite controversial. Moreover, helium neon (He-Ne) laser has not been assessed before. This split-mouth placebo-controlled randomized clinical trial was performed on 16 male and 14 female orthodontic patients requiring bilateral upper canine retraction. The study was performed at a private clinic in Sari, Iran, in 2014. It was single blind: patients, orthodontist, and personnel were blinded of the allocations, but the laser operator (periodontist) was not blinded. Once canine retractor was activated, a randomly selected maxillary quarter received a single dose of He-Ne laser irradiation (632.8 nm, 10 mw, 6 j/cm(2) density). The other quarter served as the placebo side, treated by the same device but powered off. In the first, second, fourth, and seventh days, blinded patients rated their pain sensed on each side at home using visual analog scale (VAS) questionnaires. There was no harm identified during or after the study. Pain changes were analyzed using two- and one-way repeated-measures ANOVA, Bonferroni, and t-test (α = 0.01, β > 0.99). This trial was not registered. It was self-funded by the authors. Sixteen males and 11 females remained in the study (aged 12-21). Average pain scores sensed in all 4 intervals on control and laser sides were 4.06 ± 2.85 and 2.35 ± 1.77, respectively (t-test P < 0.0001). One-way ANOVA showed significant pain declines over time, in each group (P < 0.0001). Two-way ANOVA showed significant effects for LLLT (P < 0.0001) and time (P = <0.0001). Single-dose He-Ne laser therapy might reduce orthodontic pain caused by retracting maxillary canines.

  6. Effect of low-power radiation (helium/neon) upon submandibulary glands.

    PubMed

    Plavnik, Luis M; De Crosa, Marta E; Malberti, Alicia I

    2003-08-01

    The aim of this work was to study the effect of low-power laser radiation on guinea pig salivary glands. Low-power laser radiation changes some cellular functions. The effect on salivary glands has not been sufficiently studied. One hundred and forty-four male guinea pigs (150 +/- 30 g body weight) were used. The animals were divided into two groups: control group (fed animals and those undergoing 2, 4, 8, 10, and 12 h of fasting) and experimental group (irradiated). Both the right and left submandibular glands were later irradiated with helium-neon laser at 7-mW power, with a 0.75-mm spot, under continuous pulse for 2 min in a one-session exposure; a 11.2 J/cm(2) energy density was applied. Then, the irradiated animals were fed, or underwent 2, 4, 8, 10 and 12 h of fasting. Samples of submandibular glands were taken with a punch (5 mm diameter) and were used for optic and transmission electron microscopy studies. The structural observations showed that the irradiation effect was progressive; and showed a trophic stimulant effect at 2 h following irradiation, with vasodilatation, vascular congestion, perivascular infiltrate, and a necrotic picture of glandular parenchyma at longer times. The ultrastructural observations showed alterations of rough endoplasmic reticulum. We propose that low-power laser radiation with the doses applied in this study disturbs protein synthesis and secretion of guinea pig submandibulary glands.

  7. [Modulating effect of helium-neon laser radiation on the state of antioxidant and hydroxylation systems of quail liver under X-ray irradiation and chemical intoxication].

    PubMed

    Iakimenko, I L; Tsarenko, T M; Sidorik, E P

    2004-01-01

    Red laser light (lambda = 633 nm) in a dose of 9.5 mJ/cm2 defends quail's embryo from X-ray irradiation (8.5 Gr). It is expressed in the 1.9 times decrease of embryo mortality on early term of incubation and 1.6 times increase of hatch in a group of embryos, which were affected by X-rays and laser radiation compared with an embryo, irradiated only by X-rays. Repeated laser irradiation of adult quails (dose 21 J) after CCl4-intoxication led to normalization of hydroxylation and antioxidant systems functions.

  8. Improvement of the antifungal activity of Litsea cubeba vapor by using a helium-neon (He-Ne) laser against Aspergillus flavus on brown rice snack bars.

    PubMed

    Suhem, Kitiya; Matan, Narumol; Matan, Nirundorn; Danworaphong, Sorasak; Aewsiri, Tanong

    2015-12-23

    The aim of this study was to improve the antifungal activity of the volatile Litsea cubeba essential oil and its main components (citral and limonene) on brown rice snack bars by applying He-Ne laser treatment. Different volumes (50-200 μL) of L. cubeba, citral or limonene were absorbed into a filter paper and placed inside an oven (18 L). Ten brown rice snack bars (2 cm wide × 4 cm long × 0.5 cm deep) were put in an oven and heated at 180 °C for 20 min. The shelf-life of the treated snack bars at 30 °C was assessed and sensory testing was carried out to investigate their consumer acceptability. A count of total phenolic content (TPC) and Fourier transform infrared spectroscopy (FTIR) on the properties of essential oil, citral, and limonene before and after the laser treatment was studied for possible modes of action. It was found that the laser treatment improved the antifungal activity of the examined volatile L. cubeba and citral with Aspergillus flavus inhibition by 80% in comparison with those of the control not treated with the laser. L. cubeba vapor at 100 μL with the laser treatment was found to completely inhibit the growth of natural molds on the snack bars for at least 25 days; however, without essential oil vapor and laser treatment, naturally contaminating mold was observed in 3 days. Results from the sensory tests showed that the panelists were unable to detect flavor and aroma differences between essential oil treatment and the control. Laser treatment caused an increase in TPC of citral oil whereas the TPC in limonene showed a decrease after the laser treatment. These situations could result from the changing peak of the aliphatic hydrocarbons that was revealed by the FTIR spectra.

  9. [Ultrastructural changes of neutrophilic granulocytes in dilated cardiomyopathy and their dynamics after blood irradiation with Helium-Neon laser in vitro].

    PubMed

    Khomeriki, S G; Morozov, I A

    1998-01-01

    Venous blood from 10 patients with dilated cardiomyopathy was irradiated with a laser in vitro. The control group consisted of 20 healthy donors. The neutrophil granulocytes were separated at gradient centrifugation. Alterations of neutrophils manifested with an increase of specific cytoplasmic granules number, thickening of submembrane actin, cell configuration changes with a relative increase of their surface. Laser irradiation of the blood resulted in destruction of the altered (less resistant) cells while morphometric parameters of the remaining cells approaches those of donor cells. Thus, low-intensity laser irradiation results in the renewal of the neutrophil population in patients with dilated cardiomyopathy and normalization of structural-functional changes in the circulating neutrophil population.

  10. Influence of helium-neon laser irradiation on seed germination in vitro and physico-biochemical characters in seedlings of brinjal (Solanum melongena L.) var. Mattu Gulla.

    PubMed

    Muthusamy, Annamalai; Kudwa, Prathibha P; Prabhu, Vijendra; Mahato, Krishna K; Babu, Vidhu Sankar; Rao, Mattu Radhakrishna; Gopinath, Puthiya Mandyat; Satyamoorthy, Kapaettu

    2012-01-01

    In the present study, the seeds of brinjal (Solanum melongena L.) var. Mattu Gulla were irradiated with single exposure of He-Ne laser at different doses of 5-40 J cm(-2) and germinated aseptically. Thirty day old seedlings were harvested and the germination, growth, physiological and biochemical parameters were estimated and compared with un-irradiated control seedlings. A significant enhancement in growth characters were noted with respect to length, fresh and dry weight of shoots and roots. In addition, chlorophyll (a and b), carotenoid content, anthocyanin and amylases (α and β) activities were found to be altered. Significant alterations in percentage of seed germination (P < 0.001) and time to 50% germination (P < 0.001) were observed in the irradiated seeds compared with the un-irradiated controls. In conclusion, the results of the present study demonstrated that low dose (5-30 J cm(-2) ) of He-Ne laser irradiation enhanced the germination process and altered growth, by positively influencing physiological and biochemical parameters of the brinjal seedlings compared with un-irradiated control under in vitro conditions. © 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology.

  11. First principles study of inert-gas (helium, neon, and argon) interactions with hydrogen in tungsten

    NASA Astrophysics Data System (ADS)

    Kong, Xiang-Shan; Hou, Jie; Li, Xiang-Yan; Wu, Xuebang; Liu, C. S.; Chen, Jun-Ling; Luo, G.-N.

    2017-04-01

    We have systematically evaluated binding energies of hydrogen with inert-gas (helium, neon, and argon) defects, including interstitial clusters and vacancy-inert-gas complexes, and their stable configurations using first-principles calculations. Our calculations show that these inert-gas defects have large positive binding energies with hydrogen, 0.4-1.1 eV, 0.7-1.0 eV, and 0.6-0.8 eV for helium, neon, and argon, respectively. This indicates that these inert-gas defects can act as traps for hydrogen in tungsten, and impede or interrupt the diffusion of hydrogen in tungsten, which supports the discussion on the influence of inert-gas on hydrogen retention in recent experimental literature. The interaction between these inert-gas defects and hydrogen can be understood by the attractive interaction due to the distortion of the lattice structure induced by inert-gas defects, the intrinsic repulsive interaction between inert-gas atoms and hydrogen, and the hydrogen-hydrogen repelling in tungsten lattice.

  12. A First Test of a New Analyte.193 Laser Ablation System: In-Situ Helium, Neon and Argon Compositions of Chondrule Zones and Surrounding Matrix in NWA 801 CR2 Chondrite

    NASA Astrophysics Data System (ADS)

    Das, J. P.; Meshik, A. P.; Pravdivtseva, O. V.; Hohenberg, C. M.

    2011-03-01

    A new excimer laser is attached to the noble gas mass spectrometer at St Louis Noble Gas Laboratory. This abstract discuss the first test with this new set up and report primary results obtained during this test for the chondrules of NWA 801 CR2 chondrite.

  13. [In vivo measurement of the distribution of the refractive index of the human lens using a Scheimpflug photo of the anterior eye segment and a helium-neon laser beam].

    PubMed

    Roth, E H; Kluxen, G

    1990-01-01

    The distribution of the refractive index of the human lens in vivo is measured by taking a Scheimpflug photograph of the anterior segment while simultaneously passing a HeNe laser beam through these structures. The refractive index can be evaluated simply by using the Snellens formula for refraction on the course of the beam after reevaluating the Scheimpflug photograph for distortion. It is possible to perform this measurement during accommodation and in the relaxed lens.

  14. [Age-related peculiarities of thymus reaction to the exposure to helium-neon laser and injured muscle alloplasty with the muscle tissue from the animals of the same age].

    PubMed

    Bulyakova, N V; Azarova, V S

    2015-01-01

    Histological, cytological and morphometric changes in the thymus of 1 month-old, adult (3-4 months-old) and old (24-30 months-old) rats (24 animals in each group) were studied during muscle regeneration after the alloplasty of the injured area with the muscle tissue from the animal of the same age. Muscles of the donor or recipient were subjected to the course of preliminary irradiation with He-Ne laser (dose: 4.5-5.4 J/cm2 for each extremity; total dose of 9.0-10.8 J/cm2 per animal). It was shown that the exposure of gastrocnemius muscles that were prepared for the operation to He-Ne laser radiation decreased morpho-functional activity of the thymus in young, adult and old recipient rats the before surgery. This was demonstrated by its weaker reaction to the allograft during the early time intervals after surgery. The observed effect was more pronounced with the increasing age of an animal.

  15. Intermolecular dispersion interactions of normal alkanes with rare gas atoms: van der Waals complexes of n-pentane with helium, neon, and argon

    NASA Astrophysics Data System (ADS)

    Balabin, Roman M.

    2008-09-01

    Interaction energies of normal pentane with three rare gas atoms (helium, neon, and argon) were calculated using ab initio methods: the second-order Møller-Plesset (MP2), the fourth-order Møller-Plesset (MP4), and coupled cluster with single and double substitutions with noniterative triple excitation (CCSD(T)) levels of theory. Dunning's correlation consistent basis sets up to aug-cc-pVQZ were applied. Eight profiles (246 points for each rare gas atom) of potential energy surface (PES) of all-trans (anti-anti) conformation of n-pentane were scanned. Optimal distances for complex formation were found. MP2 interaction energies at the basis set limit were evaluated by three different methods (Feller's, Helgaker's, and Martin's). The MP2 interaction energy at the basis set limit for a global minimum of n-pentane complex with argon was more than 400 cm -1, so formation of a stable complex (at least at low temperature) can be expected. A comparison with previously published data on propane complexes with rare gas atoms (both computational and experimental) was done. The MP4 level of theory was found to be sufficient for a description of C 5H 12 complexes with helium, neon, and argon.

  16. Low-energy laser treatment of rheumatic diseases: a long-term study

    NASA Astrophysics Data System (ADS)

    Antipa, Ciprian; Moldoveanu, Vladimir; Rusca, Nicolae; Bruckner, Ion I.; Podoleanu, Adrian Gh.; Stanciulescu, Viorica

    1995-05-01

    We tried to establish the efficiency of low energy (power) lasers (LEL), in various inflammatory and noninflammatory rheumatic diseases during five years. We treated 514 patients with osteoarthrosis, 326 patients with nonarticular rheumatism and 82 patients with inflammatory rheumatism, in four different ways: only with Galium-Aluminum-Arsenide (GaAs) infrared lasers; both GaAs lasers and Helium neon (HeNe) lasers; with placebo laser; with classical anti-inflammatory therapy. The results were analyzed using local objective improvements and the score obtained from a pain scale before and after the treatments. We also note some preliminary results obtained by the computer analysis of the evocated potentials after laser irradiation. We conclude that LEL (especially HeNe with GaAs) is obviously more efficient than placebo laser therapy and also had better or at least similar results, in most of the cases, than classical anti-inflammatory therapy.

  17. Electron Excitation Coefficients in Helium, Neon, Oxygen and Methane at High E/N

    SciTech Connect

    Nikitovic, Zeljka D.

    2006-12-01

    Swarm analysis is performed by comparing experimental and calculated transport coefficients. Comparisons are repeated until a satisfactory agreement is achieved after modifications of the cross sections. We have made an analysis of our excitation coefficient data for neon and methane by using detailed Monte Carlo simulation scheme. In this work we also present experimental electron excitation coefficients for other gases: helium, neon and oxygen. We used a drift tube technique to measure the absolute emission intensities in low current self sustained Townsend type discharges.

  18. Helium, neon and argon diffraction from Ru(0001).

    PubMed

    Minniti, M; Díaz, C; Fernández Cuñado, J L; Politano, A; Maccariello, D; Martín, F; Farías, D; Miranda, R

    2012-09-05

    We present an experimental and theoretical study of He, Ne and Ar diffraction from the Ru(0001) surface. Close-coupling calculations were performed to estimate the corrugation function and the potential well depth in the atom-surface interaction in all three cases. DFT (density functional theory) calculations, including van der Waals dispersion forces, were used to validate the close-coupling results and to further analyze the experimental results. Our DFT calculations indicate that, in the incident energy range 20-150 meV, anticorrugating effects are present in the case of He and Ar diffraction, whereas normal corrugation is observed with Ne beams.

  19. The effects of helium-neon light therapy on healing of partial osteotomy of the tibia in streptozotocin induced diabetic rats.

    PubMed

    Abdi, Shabnam; Bayat, Mohammad; Javadieh, Farshad; Mohsenifar, Zhaleh; Rezaie, Fatemesadat; Bayat, Maryam

    2009-12-01

    The effect of light therapy (LT) on surgically created partial osteotomy in streptozotocin (STZ)-induced diabetic rats was examined. LT has been shown to enhance bone repair in healthy human and animal models. Forty male rats were divided into groups 1 to 5. Diabetes was induced in rats of groups 1, 2, and 3 using an intraperitoneal injection of STZ. All diabetic rats were maintained for 30 days after STZ injection. Under general anesthesia and sterile conditions, a partial transversal standardized osteotomy was made in the mid-portion of the right tibia. The defects in groups 2, 3, and 5 were treated using a helium-neon (He-Ne) laser (632.8 nm, 10 mW, circular beam shape). Groups 1 and 4 were diabetic placebo and normal placebo groups, respectively. A dose of 369.4 J/cm2 for groups 2 and 5 and a dose of 66.8 J/cm2 for group 3 were applied three times a week. Six weeks after surgery, the right tibia was collected. The specimen was subjected to a three-point bending test. LT with 369.4 J/cm2 energy density resulted in significantly greater bending stiffness in group 5 (41.8+/-5.2) than in groups 1 (18.5+/-4.1), 2 (17.7+/-1.6), and 3 (11.5+/-4) (least significant difference (LSD) test, p<0.01, p<0.001, and p<0.001, respectively). LT with 369.4 J/cm2 energy density resulted in a significantly higher stress load in group 5 (10+/-0.4) than in groups 1 (4.9+/-1.5), 2 (5.7+/-0.52), and 3 (3.9+/-1.1) (LSD test, p<0.01, p<0.01, p<0.001, respectively). LT with a He-Ne laser in STZ-induced diabetic rats did not enhance bone repair of a partial transversal standardized osteotomy.

  20. On the origins of trapped helium, neon and argon isotopic variations in meteorites. I - Gas-rich meteorites, lunar soil and breccia. II - Carbonaceous meteorites.

    NASA Technical Reports Server (NTRS)

    Black, D. C.

    1972-01-01

    Data are presented from stepwise heating experiments and total extractions on five meteorites: Kapoeta, Fayetteville, Holman Island, Cee Vee, and Pultusk. These data reveal the presence of four isotopically distinct trapped neon components. A comparison of trapped neon with trapped helium and argon in bulk analyses indicates the existence of correlated helium, neon and argon isotopic structures. Component B is attributed primarily to direct implantation of rare gas ions by the present day solar wind. Component C is identified with directly implanted low energy (1-10 Mev/n) solar flare rare gases. Component D is associated with rare gas ions implanted in meteoritic material by the primitive, pre-main sequence, solar wind. A fourth component, observed only in Kapoeta and the lunar fines and breccia, is tentatively attributed to parent body 'atmospheric' ions implanted in surface material by a solar wind induced electric field.

  1. On the origins of trapped helium, neon and argon isotopic variations in meteorites. I - Gas-rich meteorites, lunar soil and breccia. II - Carbonaceous meteorites.

    NASA Technical Reports Server (NTRS)

    Black, D. C.

    1972-01-01

    Data are presented from stepwise heating experiments and total extractions on five meteorites: Kapoeta, Fayetteville, Holman Island, Cee Vee, and Pultusk. These data reveal the presence of four isotopically distinct trapped neon components. A comparison of trapped neon with trapped helium and argon in bulk analyses indicates the existence of correlated helium, neon and argon isotopic structures. Component B is attributed primarily to direct implantation of rare gas ions by the present day solar wind. Component C is identified with directly implanted low energy (1-10 Mev/n) solar flare rare gases. Component D is associated with rare gas ions implanted in meteoritic material by the primitive, pre-main sequence, solar wind. A fourth component, observed only in Kapoeta and the lunar fines and breccia, is tentatively attributed to parent body 'atmospheric' ions implanted in surface material by a solar wind induced electric field.

  2. Some Student Experiments with a Laser.

    ERIC Educational Resources Information Center

    Young, P. A.

    1989-01-01

    Described are three experiments on the photometric, Gaussian, and image-forming properties of a helium-neon gas laser. Details of the experimental method and typical calculations with diagrams and graphs are provided. (YP)

  3. Just How Bright Is a Laser?

    ERIC Educational Resources Information Center

    Van Baak, David A.

    1995-01-01

    Attempts to quantify the subjective sensation of brightness of the spot projected by a helium-neon laser and compares this with conventional sources of light. Provides an exercise in using the blackbody radiation formulas. (JRH)

  4. Some Student Experiments with a Laser.

    ERIC Educational Resources Information Center

    Young, P. A.

    1989-01-01

    Described are three experiments on the photometric, Gaussian, and image-forming properties of a helium-neon gas laser. Details of the experimental method and typical calculations with diagrams and graphs are provided. (YP)

  5. Just How Bright Is a Laser?

    ERIC Educational Resources Information Center

    Van Baak, David A.

    1995-01-01

    Attempts to quantify the subjective sensation of brightness of the spot projected by a helium-neon laser and compares this with conventional sources of light. Provides an exercise in using the blackbody radiation formulas. (JRH)

  6. Stabilized Lasers and Precision Measurements.

    ERIC Educational Resources Information Center

    Hall, J. L.

    1978-01-01

    Traces the development of stabilized lasers from the Massachusetts Institute of Technology passive-stabilization experiments of the early 1960s up through the current epoch of highly stabilized helium-neon and carbon dioxide and continuous wave dye lasers. (Author/HM)

  7. Stabilized Lasers and Precision Measurements.

    ERIC Educational Resources Information Center

    Hall, J. L.

    1978-01-01

    Traces the development of stabilized lasers from the Massachusetts Institute of Technology passive-stabilization experiments of the early 1960s up through the current epoch of highly stabilized helium-neon and carbon dioxide and continuous wave dye lasers. (Author/HM)

  8. Light noble gas chemistry: Structures, stabilities, and bonding of helium, neon and argon compounds

    SciTech Connect

    Frenking, G. ); Koch, W. ); Reichel, F. ); Cremer, D. )

    1990-05-23

    Theoretically determined geometries are reported for the light noble gas ions Ng{sub 2}C{sup 2+}, Ng{sub 2}N{sup 2+}, Ng{sub 2}O{sup 2+}, NgCCNg{sup 2+}, NgCCH{sup +}, NgCN{sup +}, and NgNC{sup +} (Ng = He, Ne, Ar) at the MP2/6-31G(d,p) level of theory. In a few cases, optimizations were carried out at CASSCF/6-31G(d,p). The thermodynamic stability of the Ng compounds is investigated at MP4(SDTQ)/6-311G(2df,2pd) for Ng = He, Ne and at MP4(SDTQ)/6-311G(d,p) for Ng = Ar. The structures and stabilities of the molecules are discussed in terms of donor-acceptor interactions between Ng and the respective fragment cation, by using molecular orbital arguments and utilizing the analysis of the electron density distribution and its associated Laplace field. Generally, there is an increase in Ng,X binding interactions of a noble gas molecule NgX with increasing atomic size of Ng. In some cases the Ne,X stabilization energies are slightly smaller than the corresponding He,X values because of repulsive p-{pi} interactions in the neon compounds. The argon molecules are in all cases significantly stronger bound.

  9. Laser Mode Structure Experiments for Undergraduate Laboratories.

    ERIC Educational Resources Information Center

    Phillips, Richard A.; Gehrz, Robert D.

    Experiments dealing with laser mode structure are presented which are suitable for an upper division undergraduate laboratory. The theory of cavity modes is summarized. The mode structure of the radiation from a helium-neon laser is measured by using a photodiode detector and spectrum analyzer to detect intermode beating. Off-axial modes can be…

  10. Laser Mode Structure Experiments for Undergraduate Laboratories.

    ERIC Educational Resources Information Center

    Phillips, Richard A.; Gehrz, Robert D.

    Experiments dealing with laser mode structure are presented which are suitable for an upper division undergraduate laboratory. The theory of cavity modes is summarized. The mode structure of the radiation from a helium-neon laser is measured by using a photodiode detector and spectrum analyzer to detect intermode beating. Off-axial modes can be…

  11. Laser communication system for controlling several functions at a location remote to the laser

    NASA Technical Reports Server (NTRS)

    Burcher, E. E.; Rowland, C. W.; Sinclair, A. R. (Inventor)

    1973-01-01

    A multichannel laser remote control system is described. The system is used in areas where radio frequency, acoustic, and hardware control systems are unsatisfactory or prohibited and where line of sight is unobstructed. A modulated continuous wave helium-neon laser is used as the transmitter and a 360 degree light collector serves as the antenna at the receiver.

  12. Closed-Cycle Rare-Gas Electrical-Discharge Laser

    DTIC Science & Technology

    1977-04-01

    Shtyrkov and E. V. Subbes, "Characteristics of Pulsed Laser Action in Helium-Neon and Helium-Argon Mixtures," Optics and Spectroscopy 21, 143 (August 1966...34Etude du Deplacement des Raies Laser Infrarouges du Xenon sous l’Influence de la Pression," Phys. Lett. 33A, 398 (November 1970). 89. L. A. Newman

  13. Laser measuring system accurately locates point coordinates on photograph

    NASA Technical Reports Server (NTRS)

    Doede, J. H.; Lindenmeyer, C. W.; Vonderohe, R. H.

    1966-01-01

    Laser activated ultraprecision ranging apparatus interfaced with a computer determines point coordinates on a photograph. A helium-neon gas CW laser provides collimated light for a null balancing optical system. This system has no mechanical connection between the ranging apparatus and the photograph.

  14. Generation of high-quality electron beams from a laser-based advanced accelerator

    NASA Astrophysics Data System (ADS)

    Ahmed, M. M. Elsied; Nasr, A. M. Hafz; Li, Song; Mohammad, Mirzaie; Thomas, Sokollik; Zhang, Jie

    2015-06-01

    At Shanghai Jiao Tong University (SJTU) we have established a research laboratory for advanced acceleration research based on high-power lasers and plasma technologies. In a primary experiment based on the laser wakefield acceleration (LWFA) scheme, multi-hundred MeV electron beams of reasonable quality are generated using 20-40 TW, 30 femtosecond laser pulses interacting independently with helium, neon, nitrogen and argon gas jet targets. The laser-plasma interaction conditions are optimized for stabilizing the electron beam generation from each type of gas. The electron beam pointing angle stability and divergence angle as well as the energy spectra from each gas jet are measured and compared. Supported by 973 National Basic Research Program of China (2013CBA01504) and Natural Science Foundation of China NSFC (11121504, 11334013, 11175119, 11374209)

  15. Laser Hazards Bibliography - November 1980.

    DTIC Science & Technology

    1980-11-01

    eye, the skin, laser safety, laser propagation in the atmosphere, and laser measurements . DD) FOR" 143 ,ornOM orF..ov.,so ,- /_ onwL D M 73...128 VI. Atmospheric Attenuation of Laser Beams .................. 151 VI I. Measurements ...Martins Press (1967). 32. Feigen, L., et al., A method for detecting and measuring frequency of surface vibrations using a helium-neon laser, Rev Sci Instr

  16. PHYSICAL EFFECTS OCCURRING DURING GENERATION AND AMPLIFICATION OF LASER RADIATION: Kinetic model of the active medium of an XeCl laser pumped by an electron beam

    NASA Astrophysics Data System (ADS)

    Boĭchenko, A. M.; Derzhiev, V. I.; Zhidkov, A. G.; Yakovlenko, Sergei I.

    1989-02-01

    Kinetic models of active media of an XeCl laser are developed for the case when these media are diluted by various buffer gases (helium, neon, argon) and the laser is pumped by an electron beam. The results of the calculations are in satisfactory agreement with experimental data.

  17. Percutaneous delivery of low-level laser energy reverses histamine-induced spasm in atherosclerotic Yucatan microswine.

    PubMed

    Gal, D; Chokshi, S K; Mosseri, M; Clarke, R H; Isner, J M

    1992-02-01

    Previous in vitro experiments performed in our laboratory have shown that low-level laser energy may produce prompt reduction in isometric tension of vascular smooth muscle. The present study was designed to extend these previous in vitro findings to an in vivo model and thereby investigate the hypothesis that laser light delivered percutaneously in vivo could successfully reverse arterial spasm. Spasm defined as greater than 50% reversible reduction in luminal diameter persisting for greater than or equal to 5 minutes was successfully provoked by injection of histamine (100-400 micrograms/kg) in 13 arteries among 10 atherosclerotic Yucatan microswine; the magnitude of histamine-induced vasoconstriction was then documented angiographically by repeated injections of contrast media for as long as 30 minutes (controls). After return of angiographic luminal diameter to baseline, spasm was reproduced with a second injection of histamine into the same artery. Representative wavelengths generated by ultraviolet (UV), visible, and infrared lasers were then delivered percutaneously via conventional fiberoptics to the site of spasm, and angiographic assessment was repeated for as long as 30 minutes (treatment trial). In three arteries treated with UV (351 nm) light from an excimer laser, angiographic luminal diameter narrowing decreased from 100% to 23.9%, 50.0% to 9.3%, and 76.0% to 42.3%, respectively. The magnitude of laser-induced increase in luminal diameter was 50.2 +/- 22.7%, which was significantly greater than the magnitude of relaxation observed spontaneously during the control trials (10.9 +/- 9.8%, p = 0.02). Visible light from a helium-neon (632 nm) laser accomplished complete reversal of histamine-induced spasm in two of four arteries; in the remaining two arteries, luminal diameter narrowing percentages were reduced from 57.0% to 20.0% and from 76.5% to 30.8%, respectively. The magnitude of helium-neon laser-induced relaxation (55.8 +/- 17.9%) was again

  18. Endodontic applications of short pulsed FR Nd:YAG dental laser: treatment of dystrophic calcification: a clinical trial report

    NASA Astrophysics Data System (ADS)

    Gregg, Robert H., II

    1992-06-01

    Formation of dystrophic calcification deposits within the root canal of a tooth, have historically been difficult clinical endodontic complications. Presently, removal of such tissue, mineralized through the deposition of calcareous materials in a root canal (a 'calcified canal'), remains resistant to conventional endodontic techniques. The subsequent treatment primarily involves undesirable surgical procedures and/or loss of the tooth. Described in this clinical trial is a technique using free running (RF) pulsed, Nd:YAG laser energy to ablate hard calcified tissue which obstructed mechanical access of the root canal and root apex--a technique employed after conventional endodontic methods failed. This paper discusses the 'plasma' effect, 'spallation', canal illumination and transillumination using the helium-neon (HeNe) aiming beam. A free running pulsed, FR Nd:YAG dental laser was successfully used at 20 pulses per second and 1.75 watts to photovaporize and photodisrupt enough calcified tissue obstruction, to allow a conventional endodontic file to pass the canal blockage, and access the root apex. This clinical trial achieved the immediate, short term objective of endodontic hard tissue removal via photovaporization and photodisruption. The pulsed FR Nd:YAG dental laser used as described in this clinical report appears to be a very safe and very effective technique; offers a treatment alternative to traditional therapy that suggests high patient acceptance; and is significantly less stressful for the doctor and staff than traditional treatment options. Long-term, controlled scientific and clinical studies are necessary to establish the safety and efficacy of both the helium-neon energy for visualization and the low- watt pulsed FR Nd:YAG energy for photovaporization and photodisruption of hard calcified tissue within the root canal. Research is especially needed to understand the effects of low- watt, pulsed FR, Nd:YAG laser on the activity of osteoclasts and

  19. Low-level laser therapy in chemo- and radiation-induced mucositis: results of multicenter phase III studies

    NASA Astrophysics Data System (ADS)

    Bensadoun, Rene-Jean

    2001-04-01

    Low of middle energy irradiation with helium-neon laser (LLLT) appears to be a simple atraumatic technique for the prevention and treatment of mucositis of various origins. Preliminary findings obtained by Ciais et al prompted randomized multi-center, double-blind trials to evaluate LLLT for the prevention of a acute chemo- and radiation- induced stomatitis. Irradiation by LLLT corresponds to local application of a high photon density monochromatic light source. Activation of epithelial healing on LLL-treated surfaces, the most commonly recognized effect, has been confirmed by numerous in vitro studies, and is a function of cell type, wavelength, and energy dose. The mechanism of action at a molecular and enzymatic level is currently being studied (detoxification of free-radicals).

  20. Effect of buffer gases on broadening of the Iodine-127 resonance absorption line at a 633-nm He-Ne laser wavelength

    SciTech Connect

    Kireev, S.V.; Shnyrev, S.L.; Zaspa, Yu.P.

    1995-04-01

    Collisional broadening coefficients are measured for iodine-127 resonance absorption lines in several rare cases of atmospheric air and CO{sub 2}. The results obtained are used to determine the optimum pressure of a gaseous mixture in a measuring cell for detecting iodine-127 by a helium-neon (633 nm) laser-induced fluorescence technique of monitoring iodine in atmospheric air.

  1. Helium, neon, and argon composition of the solar wind as recorded in gold and other Genesis collector materials

    NASA Astrophysics Data System (ADS)

    Pepin, Robert O.; Schlutter, Dennis J.; Becker, Richard H.; Reisenfeld, Daniel B.

    2012-07-01

    We report compositions and fluxes of light noble gases in the solar wind (SW), extracted by stepped pyrolysis and amalgamation from gold collector materials carried on the Genesis Solar Wind Sample Return Mission. Results are compared with data from other laboratories on SW-He, Ne and Ar distributions implanted in Genesis aluminum, carbon, and silicon collectors and extracted by laser ablation. Corrections for mass-dependent losses (“backscatter”) of impinging SW ions due to scattering from the collector material are substantially larger for gold than for these lower atomic weight targets. We assess such losses by SRIM simulation calculations of SW backscatter from gold which are applied to the measurements to recover the composition of the incident SW. Averaged results of integrated stepped pyrolysis and single-step amalgamation measurements, with 1σ errors, are as follows: for SW-Ne and Ar isotope ratios (3He/4He was not measured), 20Ne/22Ne = 14.001 ± 0.042, 21Ne/22Ne = 0.03361 ± 0.00018, 36Ar/38Ar = 5.501 ± 0.014; for SW element ratios, 4He/20Ne = 641 ± 15, 20Ne/36Ar = 51.6 ± 0.5; and for SW fluxes in atoms cm-2 s-1 at the Genesis L1 station, 4He = 1.14 ± 0.04 × 107, 20Ne = 1.80 ± 0.06 × 104, 36Ar = 3.58 ± 0.11 × 102. Except for the 21Ne/22Ne and 20Ne/36Ar ratios, these values are in reasonable accord (within ∼1-3σ) with measurements on different collector materials reported by one or both of two other Genesis noble gas research groups. We further find, in three stepped pyrolysis experiments on gold foil, that He, Ne and Ar are released at increasing temperatures without elemental fractionation, in contrast to a pyrolytic extraction of a single non-gold collector (Al) where the release patterns point to mass-dependent thermal diffusion. The pyrolyzed gold foils exhibit enhancements, relative to sample totals, in 20Ne/22Ne and 21Ne/22Ne ratios evolved at low temperatures. The absence of elemental fractionation in pyrolytic release from gold

  2. Laser treatment for skin disease

    NASA Astrophysics Data System (ADS)

    Bloznelyte-Plesniene, Laima; Cepulis, Vytautas; Ponomarev, Igor V.

    1996-12-01

    The correct selection of patients is the most difficult part of the laser treatment. Since 1985 the total number of patients treated by us using different laser systems was 1544. High power lasers: Nd:YAG and CO2 lasers were used by us for surgical treatment. Low power lasers: Helium-Neon, Copper vapor, gold vapor and dye lasers were applied by us to PDT or to treatment of port wine hemangiomas. this paper reports our efforts in selecting the patients with different skin lesions for the treatment with different laser systems.

  3. Laser plasmadynamic energy conversion

    NASA Technical Reports Server (NTRS)

    Shimada, K.

    1976-01-01

    The generation of electrons ions by interacting an intense laser beam with cesium vapor is considered. Theoretical calculation shows that the conversion efficiency is as high as 40 percent if the entire photon energy is utilized in ionizing the cesium vapor that is generated initially by the incoming laser beam. An output voltage is expected to be generated across two electrodes, one of which is the liquid cesium, by keeping the other electrode at a different work function. Evaluation of the laser plasmadynamic (LPD) converter was performed using pulsed ruby and Nd-glass lasers. Although the results obtained to date indicate an efficiency smaller than that of theoretical predictions, an unoptimized LPD converter did demonstrate the capability of converting laser energy at large power levels. The limitations in the performance may by due to converter geometry, the types of lasers used, and other limitations inherent to the cesium plasma.

  4. Laser energy conversion

    NASA Technical Reports Server (NTRS)

    Billman, K. W.

    1975-01-01

    Laser radiation could possibly provide a feasible approach for the transmission of energy between stations and vehicles in space and on earth. The transmitted energy could be used for the operational requirements of the receiving space station, lunar base, or spacecraft. In addition, laser energy could also be employed to provide power for the propulsion of vehicles in space. The present status of development regarding the various technological areas involved in an implementation of these objectives is examined, taking into account the possibility of further advances needed to satisfy the technical requirements. Attention is given to laser-induced chemistry for converting the radiation energy into chemical energy. Other subjects considered are related to photovoltaics, optical diodes, thermo-electronics, laser rockets, and photon engines.

  5. Laser energy conversion

    NASA Technical Reports Server (NTRS)

    Jalufka, N. W.

    1989-01-01

    The conversion of laser energy to other, more useful, forms is an important element of any space power transmission system employing lasers. In general the user, at the receiving sight, will require the energy in a form other than laser radiation. In particular, conversion to rocket power and electricity are considered to be two major areas where one must consider various conversion techniques. Three systems (photovoltaic cells, MHD generators, and gas turbines) have been identified as the laser-to-electricity conversion systems that appear to meet most of the criteria for a space-based system. The laser thruster also shows considerable promise as a space propulsion system. At this time one cannot predict which of the three laser-to-electric converters will be best suited to particular mission needs. All three systems have some particular advantages, as well as disadvantages. It would be prudent to continue research on all three systems, as well as the laser rocket thruster. Research on novel energy conversion systems, such as the optical rectenna and the reverse free-electron laser, should continue due to their potential for high payoff.

  6. Laser energy conversion

    NASA Astrophysics Data System (ADS)

    Jalufka, N. W.

    1989-07-01

    The conversion of laser energy to other, more useful, forms is an important element of any space power transmission system employing lasers. In general the user, at the receiving sight, will require the energy in a form other than laser radiation. In particular, conversion to rocket power and electricity are considered to be two major areas where one must consider various conversion techniques. Three systems (photovoltaic cells, MHD generators, and gas turbines) have been identified as the laser-to-electricity conversion systems that appear to meet most of the criteria for a space-based system. The laser thruster also shows considerable promise as a space propulsion system. At this time one cannot predict which of the three laser-to-electric converters will be best suited to particular mission needs. All three systems have some particular advantages, as well as disadvantages. It would be prudent to continue research on all three systems, as well as the laser rocket thruster. Research on novel energy conversion systems, such as the optical rectenna and the reverse free-electron laser, should continue due to their potential for high payoff.

  7. Balloon borne laser transceiver

    NASA Technical Reports Server (NTRS)

    Wischnia, H. F.

    1974-01-01

    A balloon borne laser transceiver (BBLT) which was carried to an altitude of 80,000 feet, was used to measure the turbulence effect of the atmosphere in daylight on laser beams going both up and down through the intervening atmosphere. The principles of operation of the BBLT are discussed. The instrument must acquire an up-going argon laser beam, lock onto it, and transmit back to the ground observatory a helium-neon laser beam. Questions of system operation for the down-going and the up-going beam are considered along with a servo system analysis.

  8. Responses of astrocytes in culture after low dose laser irradiation

    SciTech Connect

    Yew, D.T.; Zheng, D.R.; Au, C.; Li, W.W. )

    1990-03-01

    The effect of Helium-Neon low dose laser on astrocytes was investigated in cultures of isolated astrocytes from albino neonatal rats. The laser appeared to inhibit the growth of astrocytes as exemplified by the smaller sizes of the cells and the decreased leucine uptake in each cell after treatment. Temporary decrease in the number of mitoses was also observed, but this trend was reversed soon after. Electron microscopic studies revealed an increase in buddings from cell bodies and processes (branches) after irradiation.

  9. Low power laser irradiation does not affect the generation of signals in a sensory receptor

    SciTech Connect

    Lundeberg, T.; Zhou, J.

    1989-01-01

    The effect of low power Helium-Neon (He-Ne) and Gallium-Arsenide (Ga-As) laser on the slowly adapting crustacean stretch receptor was studied. The results showed that low power laser irradiation did not affect the membrane potential of the stretch receptor. These results are discussed in relation to the use of low power laser irradiation on the skin overlaying acupuncture points in treatment of pain syndrome.

  10. Investigation of the stability of the emission wavelength of a laser with an external neon absorption cell

    SciTech Connect

    Kapralov, V.P.; Privalov, V.E.; Chulyaeva, E.G.

    1980-08-01

    The optical heterodyne method was used to determine the absolute wavelength of a commercial LG-149-1 helium--neon laser. Measurements were carried out using apparatus containing a laser stabilized by the saturated absorption in /sup 127/I, which acted as the reference source. The iodine laser wavelength was determined interferrometrically by comparison with the wavelength of the orange line of /sup 86/Kr.

  11. A parametric study of the copper chloride laser

    NASA Technical Reports Server (NTRS)

    Nerheim, N. M.

    1977-01-01

    A parametric study of the double-pulsed copper chloride laser is reported. The effects of a wide range of variables on the laser energy density and on three characteristic time intervals (the minimum, maximum, and optimum delay time) between the two electrical-discharge pulses were studied. The geometric variables investigated included a tube diameter of 2.3 to 40 mm and a tube length of 3 to 60 cm. Three buffer gases, helium, neon, and argon, were studied over the pressure range 0.5-50 torr, and the tube temperature was varied from 270 to 500 C. The energy density and voltage of both the dissociation and pumping pulse were varied independently from less than 1 mJ/cu cm at 8.5 kV to over 500 mJ/cu cm at 20 kV. The optimum conditions for maximum laser energy density were found to be with 20 torr neon in a 10-mm by 30-cm tube at 400 C. The maximum energy density obtained was 22 microjoules/cu cm.

  12. How to detect the Chandler and the annual wobble of the Earth with a large ring laser gyroscope.

    PubMed

    Schreiber, K U; Klügel, T; Wells, J-P R; Hurst, R B; Gebauer, A

    2011-10-21

    We demonstrate a 16 m(2) helium-neon ring laser gyroscope with sufficient sensitivity and stability to directly detect the Chandler wobble of the rotating Earth. The successful detection of both the Chandler and the annual wobble is verified by comparing the time series of the ring laser measurements against the "C04 series" of Earth rotation data from the International Earth Rotation and Reference System Service.

  13. How to Detect the Chandler and the Annual Wobble of the Earth with a Large Ring Laser Gyroscope

    NASA Astrophysics Data System (ADS)

    Schreiber, K. U.; Klügel, T.; Wells, J.-P. R.; Hurst, R. B.; Gebauer, A.

    2011-10-01

    We demonstrate a 16m2 helium-neon ring laser gyroscope with sufficient sensitivity and stability to directly detect the Chandler wobble of the rotating Earth. The successful detection of both the Chandler and the annual wobble is verified by comparing the time series of the ring laser measurements against the “C04 series” of Earth rotation data from the International Earth Rotation and Reference System Service.

  14. Action of low-energy monochromatic coherent light on the stability of retinal lysosomes

    NASA Astrophysics Data System (ADS)

    Metelitsina, Irina P.; Leus, N. F.

    1995-05-01

    The data had been obtained during the experiment in vitro by irradiation of solubilized lysosomal enzymes, retinal homogenates and native lysosomes enabled us to conclude that the laser beam ((lambda) equals 632.8 nm, power density from 0.1 to 15.0 mWt/cm2) acts on the level of membranous structures of lysosomes. During irradiation of rabbits eyes in vitro with an unfocused laser beam (power density on the cornea aur face from 0.01 to 15.0 mWt/cm2 was shown, that low-energy, ranged from 0.01 to 1.0 mWt/cm2 promotes stabilization of lysosomal membranes. Irradiation with laser beam of 8.0 mWt/cm2 and more power induces destabilization of lysosomal membranes. We have also shown that vitamins A and E effecting membranotropic on lysosomes may be corrected by low-energy radiation of helium-neon laser. It is substantiated experimentally that the stabilizing effect of vitamin E may be intensified in case of the combined action of laser radiation on lysosomes. The labilizing effect of vitamin A on membranes of organelles, as was studied, may be weakened by application of laser radiation of low intensities.

  15. GASP: A computer code for calculating the thermodynamic and transport properties for ten fluids: Parahydrogen, helium, neon, methane, nitrogen, carbon monoxide, oxygen, fluorine, argon, and carbon dioxide. [enthalpy, entropy, thermal conductivity, and specific heat

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Baron, A. K.; Peller, I. C.

    1975-01-01

    A FORTRAN IV subprogram called GASP is discussed which calculates the thermodynamic and transport properties for 10 pure fluids: parahydrogen, helium, neon, methane, nitrogen, carbon monoxide, oxygen, fluorine, argon, and carbon dioxide. The pressure range is generally from 0.1 to 400 atmospheres (to 100 atm for helium and to 1000 atm for hydrogen). The temperature ranges are from the triple point to 300 K for neon; to 500 K for carbon monoxide, oxygen, and fluorine; to 600 K for methane and nitrogen; to 1000 K for argon and carbon dioxide; to 2000 K for hydrogen; and from 6 to 500 K for helium. GASP accepts any two of pressure, temperature and density as input conditions along with pressure, and either entropy or enthalpy. The properties available in any combination as output include temperature, density, pressure, entropy, enthalpy, specific heats, sonic velocity, viscosity, thermal conductivity, and surface tension. The subprogram design is modular so that the user can choose only those subroutines necessary to the calculations.

  16. [Influence of low-intensity laser radiation on the formation of liquid crystalline structures in a solution of glycoproteins].

    PubMed

    Skopinov, S A; Iakovleva, S V; Denisova, E A; Vazina, A A; Zheleznaia, L A

    1989-01-01

    Liquid-crystalline structure formation in glycoprotein solutions irradiated by helium-neon laser in the presence of hydrogen peroxide was observed by both polarizing microscopy and spectrophotometry. High molecular weight (2.10(6) Da) and heavily glycosylated (about 80%) glycoprotein was isolated from the mucus layer of pig small intestine. Remarkable changes of both optic parameters of the solutions and the morphology of liquid-crystalline structures were detected in irradiated samples compared to the non-irradiated ones.

  17. HIGH ENERGY CRYSTALLINE LASER MATERIALS.

    DTIC Science & Technology

    The object of this research is to obtain improved laser materials for high energy lasers. During the third quarter of this contract, the study of... energy transfer from Cr to Nd in GdAlO3 and YAlG continued. In order to study the Nd fluorescence arising via transfer from Cr, the material was excited

  18. Compact, high energy gas laser

    DOEpatents

    Rockwood, Stephen D.; Stapleton, Robert E.; Stratton, Thomas F.

    1976-08-03

    An electrically pumped gas laser amplifier unit having a disc-like configuration in which light propagation is radially outward from the axis rather than along the axis. The input optical energy is distributed over a much smaller area than the output optical energy, i.e., the amplified beam, while still preserving the simplicity of parallel electrodes for pumping the laser medium. The system may thus be driven by a comparatively low optical energy input, while at the same time, owing to the large output area, large energies may be extracted while maintaining the energy per unit area below the threshold of gas breakdown.

  19. A linewidth-narrowed and frequency-stabilized dye laser for application in laser cooling of molecules.

    PubMed

    Dai, D P; Xia, Y; Yin, Y N; Yang, X X; Fang, Y F; Li, X J; Yin, J P

    2014-11-17

    We demonstrate a robust and versatile solution for locking the continuous-wave dye laser for applications in laser cooling of molecules which need linewidth-narrowed and frequency-stabilized lasers. The dye laser is first stabilized with respect to a reference cavity by Pound-Drever-Hall (PDH) technique which results in a single frequency with the linewidth 200 kHz and short-term stabilization, by stabilizing the length of the reference cavity to a stabilized helium-neon laser we simultaneously transfer the ± 2 MHz absolute frequency stability of the helium-neon laser to the dye laser with long-term stabilization. This allows the dye laser to be frequency chirped with the maximum 60 GHz scan range while its frequency remains locked. It also offers the advantages of locking at arbitrary dye laser frequencies, having a larger locking capture range and frequency scanning range to be implemented via software. This laser has been developed for the purpose of laser cooling a molecular magnesium fluoride beam.

  20. Inducing myoblast re-entry into the cell cycle: a potential mechanism for laser-enhanced skeletal muscle regeneration

    NASA Astrophysics Data System (ADS)

    Liu, T.; Fang, Y.; Zhang, C. P.; Chen, P.; Wang, C. Z.; Kang, H. X.; Shen, B. J.; Liang, J.; Fu, X. B.

    2014-09-01

    This study investigated the effect of low-level laser irradiation (LLLI) on the cell cycle and proliferative activity of cultured myoblasts, and sought to elucidate the possible cellular mechanism by which LLLI promotes the regeneration of skeletal muscle in vivo. Primary myoblasts isolated from rat hindlegs were irradiated with helium-neon laser light at different energy densities. Distributions of cell-cycle subpopulations and the expression of cell-cycle regulatory proteins in myoblasts were assessed using flow cytometric analysis and western blot assay. It was found that laser irradiation stimulated cell-cycle entry; induced the expression of cyclin A and cyclin D; and increased cell proliferation index and bromodeoxyuridine incorporation as compared to the unirradiated control cells, indicating LLLI augmented the number of proliferative myoblasts in the S phase and G2/M phase of the cell cycle. These results suggest that LLLI at certain fluxes and wavelengths could activate quiescent myoblasts, leading to cell division and facilitating new myofiber formation. This could contribute to the improvement of skeletal muscle regeneration following trauma and myopathic diseases.

  1. Bacteria in supragingival plaque samples can be killed by low-power laser light in the presence of a photosensitizer.

    PubMed

    Wilson, M; Burns, T; Pratten, J; Pearson, G J

    1995-05-01

    The purpose of this study was to determine whether bacteria in supragingival plaque samples could be killed by low-power laser light in the presence of a suitable photosensitizer. Plaque samples were obtained from 10 volunteers, treated with either toluidine blue O (TBO) or aluminum disulphonated phthalocyanine (AlPcS2), and then exposed to light from a helium/neon (HeNe) or gallium aluminium arsenide (GaAs) laser respectively. Following irradiation, substantial reductions were achieved in the total anaerobic count as well as in the number of viable streptococci and actinomyces present in the samples. In the absence of laser light, the sensitizers themselves had little effect on the viability of the bacteria in the plaque samples. The HeNe/TBO combination appeared to be more effective than the GaAs/AlPcS2 combination, achieving log10 reductions of 2.95, 5.40 and 3.34 in the total anaerobic count, streptococci and actinomyces respectively with a light energy dose of 1.31 J. If effective in vivo, lethal photosensitization may be useful as a means of eliminating plaque bacteria from a carious lesion prior to its restoration.

  2. Photovoltaic conversion of laser energy

    NASA Technical Reports Server (NTRS)

    Stirn, R. J.

    1976-01-01

    The Schottky barrier photovoltaic converter is suggested as an alternative to the p/n junction photovoltaic devices for the conversion of laser energy to electrical energy. The structure, current, output, and voltage output of the Schottky device are summarized. The more advanced concepts of the multilayer Schottky barrier cell and the AMOS solar cell are briefly considered.

  3. Thermo electronic laser energy conversion

    NASA Technical Reports Server (NTRS)

    Hansen, L. K.; Rasor, N. S.

    1976-01-01

    The thermo electronic laser energy converter (TELEC) is described and compared to the Waymouth converter and the conventional thermionic converter. The electrical output characteristics and efficiency of TELEC operation are calculated for a variety of design variables. Calculations and results are briefly outlined. It is shown that the TELEC concept can potentially convert 25 to 50 percent of incident laser radiation into electric power at high power densities and high waste heat rejection temperatures.

  4. Sensitisation of Candida albicans to killing by low-power laser light.

    PubMed

    Wilson, M; Mia, N

    1993-09-01

    The purpose of this study was to determine whether Candida albicans, and other Candida spp. responsible for HIV-associated candidosis, could be sensitised to killing by low-power laser light. Suspensions of C. albicans were treated with a number of potential photosensitisers, exposed to laser light from a Helium/Neon (HeNe) or Gallium aluminium arsenide (GaAs) laser for 120 s and survivors enumerated. Toluidine blue O (TBO), thionin and crystal violet were able to sensitise the yeast to killing by light from the HeNe laser (energy dose = 876 mJ at a density of 66.36 J/cm2), the kills achieved being 6.8 x 10(6) cfu/ml, 3.1 x 10(6) cfu/ml and 1.3 x 10(6) cfu/ml respectively. TBO was also able to sensitise several other Candida spp. to killing by HeNe laser light. Dihaematoporphyrin ester was not an effective photosensitiser under the conditions employed. Methylene blue, but not aluminium disulphonated phthalocyanine, was able to sensitise C. albicans to killing by light from the GaAs laser (energy dose 1.32 J at a density of 2.04 J/cm2). The viability of the yeast was not affected by exposure to laser light in the absence of the photosensitisers. As killing of dye-sensitised C. albicans, and other Candida spp., could be achieved by exposure to low-power laser light for short periods of time, this approach merits further investigation as a potential therapeutic modality for HIV-associated candidosis.

  5. Sensitized action of low-level laser radiation mechanism

    NASA Astrophysics Data System (ADS)

    Chichuk, Tatyana V.; Stranadko, Eugeny P.; Lubchenko, G. N.; Podgornaya, E. V.; Pozdnyakova, E. E.; Klebanov, Gennady I.

    1999-12-01

    The goal of this work is to study the laser-induced photosensitized oxidation of lipids of the artificial (lyposomes) and cell's (erythrocytes, leukocytes) membranes and human blood lipoproteins. As a exogenous photosensitizers we are used hematoporphyrin derivatives (HPD) and sulfonated phthalocyanine aluminum (Pc). Irradiation was performed by helium-neon laser (632.8 nm). It was found out the increasing of the products of lipid oxidation in the suspensions of a lyposomes, human blood apo-(beta) -lipoproteins, erythrocytes and leucocytes. Accumulation of the lipid oxidation products depend on as irradiation dose as HPD or Pc concentrations. Interaction of photosensitizers with the lyposomes, lipoproteins and erythrocytes was investigated.

  6. Soft-tissue injuries from sports activities and traffic accidents--treatment with low-level laser therapy: a multicenter double-blind placebo-controlled clinical study on 132 patients

    NASA Astrophysics Data System (ADS)

    Simunovic, Zlatko; Trobonjaca, Tatjana

    2000-06-01

    The aim of current multicenter clinical study was to assess the efficacy of low energy-level laser therapy (LLLT) in the treatment of soft tissue injuries compared to the placebo and classical phyiotherapeutic procedures. This clinical study was conducted in two centers located in Locarno, Switzerland and Opatija, Croatia. Two types of irradiation techniques were used: (1) direct, skin contact technique for treatment of trigger points where IR diode laser 830 nm continuous wave was applied; and (2) scanning technique for irradiation of larger surface area with use of Helium Neon laser 632.8 nm combined with IR diode laser 904 nm pulsed wave. Results were evaluated according to clinical parameters like: hematoma, swelling, heat, pan and loss of function. The findings were statistically analyzed via chi- square test. Results have demonstrated that the recovery process was accelerated in 85 percent of patients treated with LLLT compared to the control group of patients. The results and advantages obtained proved once again the efficacy of LLLT as a new and successful way to treat soft tissue injuries.

  7. EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Thermally induced optical damage to barium-sodium niobate crystals

    NASA Astrophysics Data System (ADS)

    Baryshev, S. A.; Goncharova, I. F.; Konvisar, P. G.; Kuznetsov, V. A.

    1990-06-01

    Thermally induced optical damage (TIOD) was observed in undoped barium-sodium niobate (BSN) crystals as a result of changes in their temperature. This damage was deduced from the behavior of YAG:Nd3+ laser radiation when a BSN crystal was inserted in the resonator and also using a helium-neon laser probe beam. The experimental results were satisfactorily explained by the familiar pyroelectric model of TIOD and, in the crystals studied, an inhomogeneity of the conductivity rather than an inhomogeneity of the pyroelectric constant played the main role.

  8. Laser speckle tracking for monitoring and analysis of retinal photocoagulation

    NASA Astrophysics Data System (ADS)

    Seifert, Eric; Bliedtner, Katharina; Brinkmann, Ralf

    2014-02-01

    Laser coagulation of the retina is an established treatment for several retinal diseases. The absorbed laser energy and thus the induced thermal damage varies with the transmittance and scattering properties of the anterior eye media and with the pigmentation of the fundus. The temperature plays the most important role in the coagulation process. An established approach to measure a mean retinal temperature rise is optoacoustics, however it provides limited information on the coagulation. Phase sensitive OCT potentially offers a three dimensional temporally resolved temperature distribution but is very sensitive to slightest movements which are clinically hard to avoid. We develop an optical technique able to monitor and quantify thermally and coagulation induced tissue movements (expansions and contractions) and changes in the tissue structure by dynamic laser speckle analysis (LSA) offering a 2D map of the affected area. A frequency doubled Nd:YAG laser (532nm) is used for photocoagulation. Enucleated porcine eyes are used as targets. The spot is 100μm. A Helium Neon laser (HeNe) is used for illumination. The backscattered light of a HeNe is captured with a camera and the speckle pattern is analyzed. A Q-switched Nd:YLF laser is used for simultaneous temperature measurements with the optoacoustic approach. Radial tissue movements in the micrometer regime have been observed. The signals evaluation by optical flow algorithms and generalized differences tuned out to be able to distinguish between regions with and without immediate cell damage. Both approaches have shown a sensitivity of 93% and a specificity above 99% at their optimal threshold.

  9. Second NASA Conference on Laser Energy Conversion

    NASA Technical Reports Server (NTRS)

    Billman, K. W. (Editor)

    1976-01-01

    The possible transmission of high power laser beams over long distances and their conversion to thrust, electricity, or other useful forms of energy is considered. Specific topics discussed include: laser induced chemistry; developments in photovoltaics, including modification of the Schottky barrier devices and generation of high voltage emf'sby laser radiation of piezoelectric ceramics; the thermo electronic laser energy converter and the laser plasmadynamics converters; harmonic conversion of infrared laser radiation in molecular gases; and photon engines.

  10. Laser energy converted into electric power

    NASA Technical Reports Server (NTRS)

    Shimada, K.

    1973-01-01

    Apparatus verifies concepts of converting laser energy directly into electric energy. Mirror, placed in beam and inclined at angle to it, directs small amount of incident radiation to monitor which establishes precise power levels and other beam characteristics. Second mirror and condensing lens direct bulk of laser energy into laser plasmadynamic converter.

  11. Geochemical prospecting for oil and gas by remote laser spectrometry of methane in the air at ground level

    SciTech Connect

    Biryulin, V.P.; Golubev, O.A.; Mironov, O.A.; Popov, A.I.; Nazarov, I.M.; Fridman, Sh.D.

    1981-06-01

    A method is described for detecting the methane aureole in the air at ground level; the measuring device is a system based on a three-wave helium-neon laser. By the example of measurements in an existing oil and gas field it is shown that the gas aureole of methane can be detected; encouraging conclusions are drawn concerning the effectiveness of the laser-surveying method. Methods are described for improving the effectiveness of detection of methane anomalies by the laser method.

  12. Possibility of using laser-fibre optics as a fire detection system

    NASA Astrophysics Data System (ADS)

    Chow, W. K.; Wan, Eric T. K.; Cheung, K. P.

    1997-05-01

    Optical fibres together with a helium-neon laser is proposed to be used as a new fire detection system. This has been Investigated experimentally and reported in this paper. Results on the coupling loss, bending loss, extinction loss of the fibres due to smoke and refraction loss through hot air shimmer are described. Comparison with the performance of common optical and ionization detectors is made. Experimental results indicate that the optical signal would be significantly changed when there is smoke. Hence it is highly probable that a new fire detection system can be designed using laser-fibre optics.

  13. State of some peripheral organs during laser puncture correction of ovarian functional deficiency

    NASA Astrophysics Data System (ADS)

    Vylegzhanina, T. A.; Kuznetsova, Tatiana I.; Maneeva, O.; Ryzhkovskaya, E. L.; Yemelianova, A.

    2001-01-01

    The findings from studies on structural and functional parameters of the adrenal, thyroid, and pineal glands in conditions of ovarian hypofunction and after its correction by laser puncture are presented. An experimentally induced hypofunction of the ovaries was shown to be accompanied by a decreased hormonal synthesis in the cortical fascicular zone. The epiphysis showed ultra structural signs of increased functional activity. Application of a helium-neon laser to biologically active points of the ovarian reflexogenic zone induced normalization of the ovarian cycle, potentiating of the adrenal functional state, and a decreased thyroid hormone production and abolished the activatory effect of the dark regime on the functional state of the pineal gland.

  14. Interaction of a He-Ne laser light with the moist surface zone of porous material

    NASA Astrophysics Data System (ADS)

    Rozniakowski, Kazimierz; Wojtatowicz, Tomasz W.; Drobnik, Antoni; Jeske, I.

    1995-03-01

    The light scattered from the `rough' surface of a porous body illuminated by a narrow laser beam is carrying the information on geometrical micro structure of this surface. It is possible that the water vapor and water droplets in pores will cause changes in scattered light too. The aim of this paper is to present the results of the experimental investigations of the intensity of a helium-neon laser light reflected by a porous and moist gypsum slurry surface. Experiments show that the scattered light intensity increases with the decrease of the moisture content in porous material.

  15. High Energy 2-Micron Laser Developments

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Trieu, Bo C.; Petros, Mulugeta; Bai, Yingxin; Petzar, Paul J.; Koch, Grady J.; Singh, Upendra N.; Kavaya, Michael J.

    2007-01-01

    A master oscillator power amplifier, high energy Q-switched 2-micron laser system has been recently demonstrated. The laser and amplifiers are all designed in side-pumped rod configuration, pumped by back-cooled conductive packaged GaAlAs diode laser arrays. This 2-micron laser system provides nearly transform limited beam quality.

  16. High Energy Laser Diagnostic Sensors

    NASA Astrophysics Data System (ADS)

    Luke, James R.; Goddard, Douglas N.; Lewis, Jay; Thomas, David

    2010-10-01

    Recent advancements in high energy laser (HEL) sources have outpaced diagnostic tools capable of accurately quantifying system performance. Diagnostic tools are needed that allow system developers to measure the parameters that define HEL effectiveness. The two critical parameters for quantifying HEL effectiveness are the irradiance on target and resultant rise in target temperature. Off-board sensing has its limitations, including unpredictable changes in the reflectivity of the target, smoke and outgassing, and atmospheric distortion. On-board sensors overcome the limitations of off-board techniques but must survive high irradiance levels and extreme temperatures. We have developed sensors for on-target diagnostics of high energy laser beams and for the measurement of the thermal response of the target. The conformal sensors consist of an array of quantum dot photodetectors and resistive temperature detectors. The sensor arrays are lithographically fabricated on flexible substrates and can be attached to a variety of laser targets. We have developed a nanoparticle adhesive process that provides good thermal contact with the target and that ensures the sensor remains attached to the target for as long as the target survives. We have calibrated the temperature and irradiance sensors and demonstrated them in a HEL environment.

  17. Continuous-Integration Laser Energy Lidar Monitor

    NASA Technical Reports Server (NTRS)

    Karsh, Jeremy

    2011-01-01

    This circuit design implements an integrator intended to allow digitization of the energy output of a pulsed laser, or the energy of a received pulse of laser light. It integrates the output of a detector upon which the laser light is incident. The integration is performed constantly, either by means of an active integrator, or by passive components.

  18. Computer-controlled system for frequency stabilization of He-Ne laser radiation with the use of a thin absorbing layer

    NASA Astrophysics Data System (ADS)

    Jankiewicz, Zdzislaw; Rutyna, K.

    1995-03-01

    In this paper the requirements for single-frequency helium-neon lasers are characterized. The system of single-frequency He-Ne laser is presented with the thin-layer CWA selector operating with the stabilization of power output. In the stabilization loop the computer has been applied, co-working with the specially made for this purpose digital system of piezoceramics control. The principle of operation of computer stabilization loop of the power of single-frequency laser is described, as well as some results of investigations.

  19. Fiber Laser Front Ends for High Energy, Short Pulse Lasers

    SciTech Connect

    Dawson, J; Messerly, M; Phan, H; Siders, C; Beach, R; Barty, C

    2007-06-21

    We are developing a fiber laser system for short pulse (1-10ps), high energy ({approx}1kJ) glass laser systems. Fiber lasers are ideal for these systems as they are highly reliable and enable long term stable operation.

  20. Endodontic applications of a short pulsed FR Nd:YAG dental laser: photovaporization of extruded pulpal tissue following traumatic fractures of two maxillary central incisors--a clinical trial repor

    NASA Astrophysics Data System (ADS)

    Gregg, Robert H., II

    1992-06-01

    Historically, many techniques have been attempted in the search for a satisfactory and consistent treatment of inflamed, painful, hyperemic pulpal tissue. Present techniques attempting to achieve profound local anesthesia in such tissue, have not been satisfactory. Local anesthesia techniques acceptable to the patient with painful hyperemic pulpal tissue, has eluded previous technology. The subsequent treatment of hyperemic tissue without sufficient anesthesia primarily involves undesirable invasive mechanical/surgical procedures. Described in this clinical trial is a technique using free running (FR) pulsed, Nd:YAG laser energy to ablate soft tooth pulpal tissue--a technique employed after conventional endodontic methods failed. A free running pulsed, FR Nd:YAG dental laser was successfully used at 20 pulses per second and 1.25 watts to photovaporize endodontic pulpal tissue (pulpectomy) to allow a conventional endodontic file to extirpate the remaining soft tissue remnants and access the root apex. Also described in this paper is the 'hot-tip' effect of contact fiber laser surgery. This clinical trial achieved the immediate, short term objective of endodontic soft tissue removal via photovaporization, without pain reported by the patient. The pulsed FR Nd:YAG dental laser used as described in this clinical report appears to be a very safe and very effective technique; offers a treatment alternative to traditional therapy that suggests high patient acceptance; and is significantly less stressful for the doctor and staff than traditional treatment options. Long-term, controlled scientific and clinical studies are necessary to establish the safety and efficacy of both the helium-neon energy for visualization and the low-watt pulsed FR Nd:YAG energy for photovaporization of soft endodontic pulpal tissue within the root canal. Research is especially needed to understand the effects of a low-watt, pulsed FR, Nd:YAG laser on the activity of osteoclasts and odontoclasts

  1. Control of light backscattering in blood during intravenous laser irradiation

    NASA Astrophysics Data System (ADS)

    Melnik, Ivan S.; Popov, V. D.; Rusina, Tatyana V.; Dets, Sergiy M.

    1997-02-01

    One of the most important problems in modern laser medicine is the determination of system response on laser treatment. Reaction of living system is significant during many kinds of laser procedures like surgery, therapy and biostimulation. Our study was aimed to optimize laser exposure using feed-back fiber system for intravenous laser irradiation of blood (ILIB). This system consisted of helium-neon laser (633 nm, 5 mW) with coupled fiber unit, photodetector and PC interface. Photodetector signals produced due to light backscattering were storaged and processed during all blood irradiation procedure. Significant time-dependent variations were observed within 9-15 min after beginning of treatment procedure and were correlated with number of trials, stage and character of disease. The designed feed-back system allows us to register a human blood response on laser irradiation to achieve better cure effect.

  2. Laser Scheimpflug videography.

    PubMed

    Huebscher, H J; Möller, D E; Seiler, T

    1996-01-01

    Conventional Scheimpflug photography uses slits with a constant width of 80 microns. This parameter limits the resolution as sharp contours are imaged with a basic uncertainty. In order to reduce this basic uncertainty we developed an illumination slit with a width of 20 microns and less, using a green helium-neon laser (543 nm). With this slit, much sharper imaging of ocular contours can be achieved. Since this illumination is coupled to on-line videographic detection of the Scheimpflug image, any adjustment of the target is done under visual control at the monitor. Using this device, the slope of a densitogram of contrasted contours (for example the corneal surfaces) is steeper, which guarantees a more accurate detection of corneal thickness and curvature.

  3. The influence of intravenous laser irradiation of blood on some metabolic and functional parameters in intact rabbits and experimental cerebral ischaemia

    NASA Astrophysics Data System (ADS)

    Nechipurenko, N.; Vasilevskaya, L.; Musienko, J.; Maslova, G.

    2007-07-01

    It has been studied the intravenous laser irradiation of blood (ILIB) influence with helium-neon laser (HNL) of 630 nm wavelength on some of lipid peroxidation (LPO) and antioxidant system (AOS) findings, aside-base status (ABS) and blood oxygen transport (BOT), state of dermal microhaemodynamics (MGD) in the intact rabbits and after modeling of local ischemia of brain (LIB). Depending on conditions of organism functioning (norm or brain ischaemia) ILIB has resulted in stimulating or normalizing effects on the whole metabolic and microhaemocirculation processes which had been studied during our investigation. It is discussed the mechanisms of pathogenetic directivity of ILIB influence in cerebral ischaemia

  4. The irradiation of rabbit sperm cells with He-Ne laser prevents their in vitro liquid storage dependent damage.

    PubMed

    Iaffaldano, Nicolaia; Rosato, Maria Pina; Paventi, Gianluca; Pizzuto, Roberto; Gambacorta, Mario; Manchisi, Angelo; Passarella, Salvatore

    2010-05-01

    The aim of the study was to investigate the effects of different energy doses of helium-neon (He-Ne) laser irradiation on both mitochondrial bioenergetics functions and functional quality of rabbit spermatozoa during 48 h of in vitro liquid storage at 15 degrees C. 11 rabbit semen pools were each divided into four aliquots: three of them were irradiated with He-Ne laser with different energy doses (3.96, 6.12 and 9.00 J/cm(2)) being the last control kept under the same experimental conditions without irradiation. Sperm motility, viability and acrosome integrity were monitored together with cytochrome c oxidase (COX) activity and the cell energy charge (EC) at 0, 24 and 48 h of storage. Irradiated samples stored for 24 and 48 h better maintained motility (P < 0.01), acrosome integrity (P < 0.01) and viability (P < 0.05) with respect to the control, particularly with the energy dose of 6.12 J/cm(2) that showed the most intense biostimulative effect. COX activity and EC were immediately increased by irradiation particularly in the treatments 6.12 and 9.00 J/cm(2) (P < 0.05), that maintained their levels higher with respect to the control after 48 h of storage (P < 0.01). COX activity of rabbit sperm cells was positively correlated with EC (P < 0.05), viability (P < 0.01) and acrosome integrity (P < 0.05) parameters. These results indicate that the effects of He-Ne laser irradiation on sperm cells are mediated through the stimulation of the sperm mitochondrial respiratory chain and that this effect plays a significant role in the augmentation of the rabbit sperm cells' capability to survive during liquid storage conditions.

  5. Energy conversion in laser propulsion: III

    NASA Astrophysics Data System (ADS)

    Larson, Carl W.; Mead, Franklin B., Jr.; Kalliomaa, Wayne M.

    2002-09-01

    Conversion of pulses of CO2 laser energy (18 microsecond pulses) to propellant kinetic energy was studied in a Myrabo Laser Lightcraft (MLL) operating with laser heated STP air and laser ablated delrin propellants. The MLL incorporates an inverted parabolic reflector that focuses laser energy into a toroidal volume where it is absorbed by a unit of propellant mass that subsequently expands in the geometry of the plug nozzle aerospike. With Delrin propellant, measurements of the coupling coefficients and the ablated mass as a function of laser pulse energy showed that the efficiency of conversion of laser energy to propellant kinetic energy was approximately 54%. With STP air, direct experimental measurement efficiency was not possible because the propellant mass associated with measured coupling coefficients was not known. Thermodynamics predicted that the upper limit of the efficiency of conversion of the internal energy of laser heated air to jet kinetic energy, (alpha) , is approximately 0.30 for EQUILIBRIUM expansion to 1 bar pressure. For FROZEN expansion (alpha) approximately 0.27. These upper limit efficiencies are nearly independent of the initial specific energy from 1 to 110 MJ/kg. With heating of air at its Mach 5 stagnation density (5.9 kg/m3 as compared to STP air density of 1.18 kg/m3) these efficiencies increase to about 0.55 (equilibrium) and 0.45 (frozen). Optimum blowdown from 1.18 kg/m3 to 1 bar occurs with expansion ratios approximately 1.5 to 4 as internal energy increases from 1 to 100 MJ/kg. Optimum expansion from the higher density state requires larger expansion ratios, 8 to 32. Expansion of laser ablated Delrin propellant appears to convert the absorbed laser energy more efficiently to jet kinetic energy because the effective density of the ablated gaseous Delrin is significantly greater than that of STP air.

  6. Energy conversion in laser propulsion III

    NASA Astrophysics Data System (ADS)

    Larson, C. William; Mead, Franklin B.; Kalliomaa, Wayne M.

    2003-05-01

    Conversion of pulses of CO2 laser energy (18 microsecond pulses) to propellant kinetic energy was studied in a Myrabo Laser Lightcraft (MLL) operating with laser heated STP air and laser ablated delrin propellants. The MLL incorporates an inverted parabolic reflector that focuses laser energy into a toroidal volume where it is absorbed by a unit of propellant mass that subsequently expands in the geometry of the plug nozzle aerospike. With Delrin propellant, measurements of the coupling coefficients and the ablated mass as a function of laser pulse energy showed that the efficiency of conversion of laser energy to propellant kinetic energy was ~ 54%. With STP air, direct experimental measurement of efficiency was not possible because the propellant mass associated with measured coupling coefficients was not known. Thermodynamics predicted that the upper limit of the efficiency of conversion of the internal energy of laser heated air to jet kinetic energy, α, is ~ 0.30 for EQUILIBRIUM expansion to 1 bar pressure. For FROZEN expansion α ~ 0.27. These upper limit efficiencies are nearly independent of the initial specific energy from 1 to 110 MJ/kg. With heating of air at its Mach 5 stagnation density (5.9 kg/m3 as compared to STP air density of 1.18 kg/m3) these efficiencies increase to about 0.55 (equilibrium) and 0.45 (frozen). Optimum blowdown from 1.18 kg/m3 to 1 bar occurs with expansion ratios ~ 1.5 to 4 as internal energy increases from 1 to 100 MJ/kg. Optimum expansion from the higher density state requires larger expansion ratios, 8 to 32. Expansion of laser ablated Delrin propellant appears to convert the absorbed laser energy more efficiently to jet kinetic energy because the effective density of the ablated gaseous Delrin is significantly greater than that of STP air.

  7. High Energy Laser Techniques In Industrial Measurements

    NASA Astrophysics Data System (ADS)

    Erdelyi, Laszlo; Fagan, William F.

    1984-03-01

    High energy lasers are used for industrial measurements in connection with additional instrumentations. The most advanced system for this purposes is the Image Derotator. This system in combination with high energy laser systems is a powerful engeneering and scientific tool in the field of holographic interferometry and speckle photography. Traditional measurements complete the application range of the Image Derotator.

  8. Cross Sections for Ionization of Rare Gas Excimers by Electron Impact and Atomic and Molecular Processes in Excimer Lasers.

    DTIC Science & Technology

    1980-03-01

    Theoretical cross sections for ionization of msetastable excimers - helium , neon, argon, krypton and zenon - and of metastable mercury are presented...AO-A086 698 GEORGIA INST OF TECH ATLANTA SCHOOL. OF PHYSICS FB20/5 CROSS SECTION1S FOR IONIZATION OF RARE GAS EXCIMERS By ELECTRON -- ETC(O) MAR 80 M...in Excimer Lasers. - -- 7 AUT 4OR(u) 8. CONTRACT OR GRANT NUMBER-) M. Raymond Flannery aW K. J./McCann . I F33615-78-C-20 128 9 PERFORMING

  9. Apparatus for advancing a wellbore using high power laser energy

    DOEpatents

    Zediker, Mark S.; Land, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Koblick, Yeshaya; Moxley, Joel F.

    2014-09-02

    Delivering high power laser energy to form a borehole deep into the earth using laser energy. Down hole laser tools, laser systems and laser delivery techniques for advancement, workover and completion activities. A laser bottom hole assembly (LBHA) for the delivery of high power laser energy to the surfaces of a borehole, which assembly may have laser optics, a fluid path for debris removal and a mechanical means to remove earth.

  10. Study of laser energy standard and establishment of calibration device

    NASA Astrophysics Data System (ADS)

    Xia, Ming; Gao, Jianqiang; Xia, Junwen; Yin, Dejin; Li, Tiecheng; Zhang, Dong

    2016-10-01

    This paper studied the standard laser energy meter. A self calibration of the thermoelectric type standard laser energy meter is developed, which is provided with a suitable electric heater. It can be used to simulate and replace the equivalent thermal effect, and to realize the absolute measurement of the laser energy. Because the standard laser energy meter can bulk absorb laser radiation, it can bear higher laser energy density. The material absorption spectrum of the standard laser energy meter is relatively flat from the ultraviolet to the infrared, so it can be used for the measurement of laser energy at any wavelength. In addition, an electric calibration instrument is developed. The electric calibration instrument can be directly displayed or synchronous display by the digital frequency meter. The laser energy calibration device is composed of standard laser energy meter, pulsed laser source, monitoring system, digital multi meter and complete set of electric calibration system. Laser energy calibration device uses split beam detection method. The laser is divided into two beams by means of a wedge shaped optical beam splitter. A laser energy meter is used to monitor the change of the reflected light to reduce the influence of the output laser energy stability of the pulsed laser source, thereby improving the uncertainty of the calibration result. The sensitivity, correction factor and indication error of the laser energy meter can be calibrated by using the standard laser energy meter and the under calibrated laser energy meter to measure the transmission laser beam.

  11. Effects of low-power laser irradiation (LPLI) at different wavelengths and doses on oxidative stress and fibrogenesis parameters in an animal model of wound healing.

    PubMed

    Silveira, Paulo Cesar Lock; Silva, Luciano A; Freitas, Tiago P; Latini, Alexandra; Pinho, Ricardo A

    2011-01-01

    Gallium-arsenide (GaAs) and helium-neon (HeNe) lasers are the most commonly used low-energy lasers in physiotherapy for promoting wound healing and pain modulation. The aim of this study was investigate the effect of low-power laser irradiation (LPLI) at different wavelengths and doses on oxidative stress and fibrogenesis parameters in an animal model of wound healing. The animals were randomly divided into five groups (n=6): Controls (skin injured animals without local or systemic treatment), skin injury treated with HeNe 1 J/cm(2) (two seg); skin injury treated with HeNe 3 J/cm(2) (six seg); skin injury treated with GaAs 1 J/cm(2) (three seg); skin injury treated with GaAs 3 J/cm(2) (nine seg). A single circular wound measuring 8 mm in diameter was surgically created on the back of the animal. The rats were irradiated at 2, 12, 24, 48, 72, 96, and 120 h after skin injury. The parameters, namely hydroxyproline content, activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and lipid (TBARS) and protein oxidation (carbonyl groups) measurements were assessed. In addition, wound size regression was also analyzed. The results showed an improvement in the wound healing reflected by the reduction in wound size and increased collagen synthesis. Moreover, a significant reduction in TBARS levels, carbonyl content, and SOD and CAT activities were observed after laser irradiation, particularly with the treatments HeNe laser 1 and 3 J/cm(2) dose and GaAs 3 J/cm(2) dose. The data strongly indicate that LPLI therapy is efficient in accelerating the skin wound healing process after wounding, probably by reducing the inflammatory phase and inducing collagen synthesis.

  12. High energy chemical laser system

    DOEpatents

    Gregg, D.W.; Pearson, R.K.

    1975-12-23

    A high energy chemical laser system is described wherein explosive gaseous mixtures of a reducing agent providing hydrogen isotopes and interhalogen compounds are uniformly ignited by means of an electrical discharge, flash- photolysis or an electron beam. The resulting chemical explosion pumps a lasing chemical species, hydrogen fluoride or deuterium fluoride which is formed in the chemical reaction. The generated lasing pulse has light frequencies in the 3- micron range. Suitable interhalogen compounds include bromine trifluoride (BrF$sub 3$), bromine pentafluoride (BrF$sub 5$), chlorine monofluoride (ClF), chlorine trifluoride (ClF$sub 3$), chlorine pentafluoride (ClF$sub 5$), iodine pentafluoride (IF$sub 5$), and iodine heptafluoride (IF$sub 7$); and suitable reducing agents include hydrogen (H$sub 2$), hydrocarbons such as methane (CH$sub 4$), deuterium (D$sub 2$), and diborane (B$sub 2$H$sub 6$), as well as combinations of the gaseous compound and/or molecular mixtures of the reducing agent.

  13. Scientific applications for high-energy lasers

    SciTech Connect

    Lee, R.W.

    1994-03-01

    The convergence of numerous factors makes the time ripe for the development of a community of researchers to use the high-energy laser for scientific investigations. This document attempts to outline the steps necessary to access high-energy laser systems and create a realistic plan to implement usage. Since an academic/scientific user community does not exist in the USA to any viable extent, we include information on present capabilities at the Nova laser. This will briefly cover laser performance and diagnostics and a sampling of some current experimental projects. Further, to make the future possibilities clearer, we will describe the proposed next- generation high-energy laser, named for its inertial fusion confinement (ICF) goal, the multi-megaJoule, 500-teraWatt National Facility, or NIF.

  14. Conversion of laser energy to gas kinetic energy

    NASA Technical Reports Server (NTRS)

    Caledonia, G. E.

    1976-01-01

    Techniques for the gas phase absorption of laser radiation for ultimate conversion to gas kinetic energy are discussed. Particular emphasis is placed on absorption by the vibration rotation bands of diatomic molecules at high pressures. This high pressure absorption appears to offer efficient conversion of laser energy to gas translational energy. Bleaching and chemical effects are minimized and the variation of the total absorption coefficient with temperature is minimal.

  15. Evaluating the effect of low-level laser therapy on healing of tentomized Achilles tendon in streptozotocin-induced diabetic rats by light microscopical and gene expression examinations.

    PubMed

    Aliodoust, Morteza; Bayat, Mohammad; Jalili, Mohammad Reza; Sharifian, Zainalabedin; Dadpay, Masoomeh; Akbari, Mohammad; Bayat, Mehrnoush; Khoshvaghti, Amir; Bayat, Homa

    2014-07-01

    Tendon healing is impaired in individuals diagnosed with diabetes mellitus (DM). According to research, there is considerable improvement in the healing of surgically tenotomized Achilles tendons following low-level laser therapy (LLLT) in non-diabetic, healthy animals. This study uses light microscopic (LM) and semi-quantitative reverse transcription PCR (RT-PCR) analyses to evaluate the ability of LLLT in healing Achilles tendons from streptozotocin-induced diabetic (STZ-D) rats. A total of 88 rats were randomly divided into two groups, non-diabetic and diabetic. DM was induced in the rats by injections of STZ. The right Achilles tendons of all rats were tenotomized 1 month after administration of STZ. Laser-treated rats were treated with a helium-neon (He-Ne) laser that had a 632.8-nm wavelength and 7.2-mW average power. Experimental group rats received a daily dose of 0.014 J (energy density, 2.9 J/cm(2)). Control rats did not receive LLLT. Animals were sacrificed on days 5, 10, and 15 post-operatively for semi-quantitative LM and semi-quantitative RT-PCR examinations of transforming growth factor-beta1 (TGF-β1) gene expression. The chi-square test showed that LLLT significantly reduced inflammation in non-diabetic rats compared with their non-diabetic controls (p = 0.02). LLLT significantly decreased inflammation in diabetic rats on days 5 (p = 0.03) and 10 (p = 0.02) compared to the corresponding control diabetic rats. According to the student's t test, LLLT significantly increased TGF-β1 gene expression in healthy (p = 0.000) and diabetic (p = 0.000) rats compared to their relevant controls. The He-Ne laser was effective in altering the inflammatory reaction and increasing TGF-β1 gene production.

  16. Low-power-laser therapy used in tendon damage

    NASA Astrophysics Data System (ADS)

    Strupinska, Ewa

    1996-03-01

    The following paper covers evaluation of low-power laser therapy results in chronic Achilles tendon damage and external Epicondylalia (tennis elbow). Fifty patients with Achilles damage (18 women and 32 men, age average 30, 24 plus or minus 10, 39 years) and fifty patients having external Epicondyalgiae (31 women and 19 men, age average 44, 36 plus or minus 10, 88 years) have been examined. The patients were irradiated by semiconductor infrared laser wavelength 904 nm separately or together with helium-neon laser wavelength 632.8 nm. The results of therapy have been based on the patient's interviews and examinations of patients as well as on the Laitinen pain questionnaire. The results prove analgesic effects in usage of low- power laser radiation therapy can be obtained.

  17. Study on energy loss compensation of back scattering conical cavity high-energy laser energy meter

    NASA Astrophysics Data System (ADS)

    Yu, Xun; Wang, Hui; Shang, Xiao-yan; Nie, Liang; Liu, Bao-yuan

    2009-05-01

    Because absolute quantity thermal laser energy meter based on conical cavity has some features, for example, wide wavelength adaptation range, high laser damage threshold value, extensive measuring energy range and so on, it is often used as the standard of high-energy laser energy meter, and is used extensively in the domain of high energy laser measurement. But, laser energy will lose because of back scattering of conical absorption cavity. So, only after the loss is compensated and amended, exact measurement of laser energy can be achieved. Aiming at energy loss compensation problem of conical cavity high-energy laser energy meter, we firstly, according to speckle statistics optical theory, analyze the back scattering of the conical absorption cavity in condition of uniform distribution laser incident on diffuse reflection surface, and secondly, we aim at high power laser's output facula shape: round, based on optical principles of interaction of the conical cavity inner face and the incident laser and utilize complexfication Simpson numerical method, the mathematical models of optical power density distribution at open-end of conical cavity and back scattering gross power are established. On this basis, the measured result is compensated and amended. The back scattering energy loss is about 0.5% to 2.5%.High-energy laser energy measuring accuracy is improved effectively.

  18. A survey of laser and selected optical systems for remote measurement of pollutant gas concentrations

    NASA Technical Reports Server (NTRS)

    Grant, W. B.; Menzies, R. T.

    1983-01-01

    Applications of the Differential Absorption Lidar (DIAL) technique to the remote sensing of pollutant gases are surveyed. In the DIAl technique, the differential absorption of two laser beams reflected back to a receiver from a target determines the concentration of the gas being studied. The types of instruments available are considered in detail: dye lidar (to measure nitrogen dioxide, sulfur dioxide, and ozone); carbon dioxide laser (for ozone, ethylene, ammonia, and hydrazine), helium-neon laser (for methane); hydrogen fluoride laser (for HF); and tunable diode laser (for nitric oxide and carbon monoxide). DIAL instruments are compared with other optical remote sensors such as Fourier-transform infrared spectrometers, correlation spectrometers (COSPEC and GASPEC), and grating spectrometers; and criteria for the selection of an appropriate gas measuring system are suggested. Laser and other optical remote sensors are found to be cost effective in many cases, despite the fact that they are more costly than point-monitoring systems.

  19. A survey of laser and selected optical systems for remote measurement of pollutant gas concentrations

    NASA Technical Reports Server (NTRS)

    Grant, W. B.; Menzies, R. T.

    1983-01-01

    Applications of the Differential Absorption Lidar (DIAL) technique to the remote sensing of pollutant gases are surveyed. In the DIAl technique, the differential absorption of two laser beams reflected back to a receiver from a target determines the concentration of the gas being studied. The types of instruments available are considered in detail: dye lidar (to measure nitrogen dioxide, sulfur dioxide, and ozone); carbon dioxide laser (for ozone, ethylene, ammonia, and hydrazine), helium-neon laser (for methane); hydrogen fluoride laser (for HF); and tunable diode laser (for nitric oxide and carbon monoxide). DIAL instruments are compared with other optical remote sensors such as Fourier-transform infrared spectrometers, correlation spectrometers (COSPEC and GASPEC), and grating spectrometers; and criteria for the selection of an appropriate gas measuring system are suggested. Laser and other optical remote sensors are found to be cost effective in many cases, despite the fact that they are more costly than point-monitoring systems.

  20. Conversion of blackbody radiation into laser energy

    NASA Astrophysics Data System (ADS)

    McInville, R. M.; Hassan, H. A.

    1982-06-01

    By employing detailed kinetic models, three concepts which utilize a blackbody cavity for the conversion of solar energy into laser energy using a CO2 lasant are analyzed and compared. In the first, the blackbody radiation is used to excite flowing CO2 directly. The second and third employ a mixing laser concept with CO and N2 being the donor gases. The CO is optically pumped while thermal heating excites the N2. Blackbody temperatures ranging from 1500 deg K - 2500 deg K are considered. Based on calculated laser power output per unit flow rate of CO2, it appears that the N2-CO2 mixing laser is the most attractive system.

  1. Status of thermoelectronic laser energy conversion, TELEC

    NASA Technical Reports Server (NTRS)

    Britt, E. J.

    1982-01-01

    A concept known as a thermo-electronic laser energy converter (TELEC), was studied as a method of converting a 10.6 micron CO2 laser beam into electric power. The calculated characteristics of a TELEC seem to be well matched to the requirements of a spacecraft laser energy conversion system. The TELEC is a high power density plasma device which absorbs an intense laser beam by inverse bremsstrahlung with the plasma electrons. In the TELEC process, electromagnetic radiation is absorbed directly in the plasma electrons producing a high electron temperature. The energetic electrons diffuse out of the plasma striking two electrodes which are in contact with the plasma at the boundaries. These two electrodes have different areas: the larger one is designated as the collector, the smaller one is designated as the emitter. The smaller electrode functions as an electron emitter provide continuity of the current. Waste heat is rejected from the collector electrode. An experiment was carried out with a high power laser using a cesium vapor TELEC cell with 30 cm active length. Laser supported plasma were produced in the TELEC device during a number of laser runs over a period of several days. Electric power from the TELEC was observed with currents in the range of several amperes and output potentials of less than 1 volt.

  2. High energy laser demonstrators for defense applications

    NASA Astrophysics Data System (ADS)

    Jung, M.; Riesbeck, Th.; Schmitz, J.; Baumgärtel, Th.; Ludewigt, K.; Graf, A.

    2017-01-01

    Rheinmetall Waffe Munition has worked since 30 years in the area of High Energy Laser (HEL) for defence applications, starting from pulsed CO2 to pulsed glass rods lasers. In the last decade Rheinmetall Waffe Munition changed to diode pumped solid state laser (DPSSL) technology and has successfully developed, realised and tested a variety of versatile HEL weapon demonstrators for air- and ground defence scenarios like countering rocket, artillery, mortar, missile (RAMM), unmanned aerial systems (UAS) and unexploded ordnances clearing. By employing beam superimposing technology and a modular laser weapon concept, the total optical power has been successively increased. Stationary weapon platforms, military vehicles and naval platforms have been equipped with high energy laser effectors. The contribution gives a summary of the most recent development stages of Rheinmetalls HEL weapon program. In addition to the stationary 30 kW laser weapon demonstrator, we present vehicle based HEL demonstrators: the 5 kW class Mobile HEL Effector Track V, the 20 kW class Mobile HEL Effector Wheel XX and the 50 kW class Mobile HEL Effector Container L and the latest 10 kW HEL effector integrated in the naval weapon platform MLG 27. We describe the capabilities of these demonstrators against different potential targets. Furthermore, we will show the capability of the 30 kW stationary Laser Weapon Demonstrator integrated into an existing ground based air defence system to defeat saturated attacks of RAMM and UAS targets.

  3. Status of thermoelectronic laser energy conversion, TELEC

    NASA Technical Reports Server (NTRS)

    Britt, E. J.

    1982-01-01

    A concept known as a thermo-electronic laser energy converter (TELEC), was studied as a method of converting a 10.6 micron CO2 laser beam into electric power. The calculated characteristics of a TELEC seem to be well matched to the requirements of a spacecraft laser energy conversion system. The TELEC is a high power density plasma device which absorbs an intense laser beam by inverse bremsstrahlung with the plasma electrons. In the TELEC process, electromagnetic radiation is absorbed directly in the plasma electrons producing a high electron temperature. The energetic electrons diffuse out of the plasma striking two electrodes which are in contact with the plasma at the boundaries. These two electrodes have different areas: the larger one is designated as the collector, the smaller one is designated as the emitter. The smaller electrode functions as an electron emitter provide continuity of the current. Waste heat is rejected from the collector electrode. An experiment was carried out with a high power laser using a cesium vapor TELEC cell with 30 cm active length. Laser supported plasma were produced in the TELEC device during a number of laser runs over a period of several days. Electric power from the TELEC was observed with currents in the range of several amperes and output potentials of less than 1 volt.

  4. Laser source for dimensional metrology: investigation of an iodine stabilized system based on narrow linewidth 633 nm DBR diode

    NASA Astrophysics Data System (ADS)

    Rerucha, Simon; Yacoot, Andrew; Pham, Tuan M.; Cizek, Martin; Hucl, Vaclav; Lazar, Josef; Cip, Ondrej

    2017-04-01

    We demonstrated that an iodine stabilized distributed Bragg reflector (DBR) diode based laser system lasing at a wavelength in close proximity to λ =633 nm could be used as an alternative laser source to the helium-neon lasers in both scientific and industrial metrology. This yields additional advantages besides the optical frequency stability and coherence: inherent traceability, wider optical frequency tuning range, higher output power and high frequency modulation capability. We experimentally investigated the characteristics of the laser source in two major steps: first using a wavelength meter referenced to a frequency comb controlled with a hydrogen maser and then on an interferometric optical bench testbed where we compared the performance of the laser system with that of a traditional frequency stabilized He–Ne laser. The results indicate that DBR diode laser system provides a good laser source for applications in dimensional (nano)metrology, especially in conjunction with novel interferometric detection methods exploiting high frequency modulation or multiaxis measurement systems.

  5. [Adoptive laser immunotherapy and photodynamic therapy in ORL oncology].

    PubMed

    Antoniv, V F; Dmitriev, A A; Daĭkhes, N A; Ivanov, A V; Davudov, Kh Sh; Perekosova, Iu V; Laptev, V P

    1990-01-01

    Present-day developments in oncological applications of laser therapy are adaptive laser immunotherapy (ALIT) and photodynamic therapy (PDT). ALIT (helium-neon laser) was used in 35 ENT-cancer patients to irradiate immunocompetent leukocytes isolated from blood in an Amino cell separator. The use of ALIT in the combined treatment of our patients improved their health condition. Cytological, immunochemical and immunological examinations of blood revealed an increased count of activated lymphocytes, normalization of acute-phase proteins, stimulation of cell-mediated immunity and nonspecific resistance. The pharmacokinetics and photodynamic activity of porphyrin compounds in mice with inoculated tumors were investigated. Experimental observations demonstrated that the application of photodynamic therapy of hematoporphyrins in ENT-oncology seems very promising.

  6. High Energy Laser for Space Debris Removal

    SciTech Connect

    Barty, C; Caird, J; Erlandson, A; Beach, R; Rubenchik, A

    2009-10-30

    The National Ignition Facility (NIF) and Photon Science Directorate at Lawrence Livermore National Laboratory (LLNL) has substantial relevant experience in the construction of high energy lasers, and more recently in the development of advanced high average power solid state lasers. We are currently developing new concepts for advanced solid state laser drivers for the Laser Inertial Fusion Energy (LIFE) application, and other high average power laser applications that could become central technologies for use in space debris removal. The debris population most readily addressed by our laser technology is that of 0.1-10 cm sized debris in low earth orbit (LEO). In this application, a ground based laser system would engage an orbiting target and slow it down by ablating material from its surface which leads to reentry into the atmosphere, as proposed by NASA's ORION Project. The ORION concept of operations (CONOPS) is also described in general terms by Phipps. Key aspects of this approach include the need for high irradiance on target, 10{sup 8} to 10{sup 9} W/cm{sup 2}, which favors short (i.e., picoseconds to nanoseconds) laser pulse durations and high energy per pulse ({approx} > 10 kJ). Due to the target's orbital velocity, the potential duration of engagement is only of order 100 seconds, so a high pulse repetition rate is also essential. The laser technology needed for this application did not exist when ORION was first proposed, but today, a unique combination of emerging technologies could create a path to enable deployment in the near future. Our concepts for the laser system architecture are an extension of what was developed for the National Ignition Facility (NIF), combined with high repetition rate laser technology developed for Inertial Fusion Energy (IFE), and heat capacity laser technology developed for military applications. The 'front-end' seed pulse generator would be fiber-optics based, and would generate a temporally, and spectrally tailored

  7. Digital Communication System Based on Polarization Self-Modulation in Lasers

    NASA Astrophysics Data System (ADS)

    Tabarin, V. A.; Ikonnikov, V. P.; Shatalov, A. N.

    2014-09-01

    Polarization self-modulation in lasers can be used to create instruments for generating optical pulses at very high repetition rates without using high-speed electronics. Self-oscillation is observed when part of the output of a laser is returned to the laser after a 90° polarization change. A practical scheme based on polarization self-modulation in a 3.39-μm helium-neon laser is proposed for pulsed code data transmission with an yttrium-iron garnet magnetooptical Q-switch. Highly efficient transmission of digital signals is implemented with a repetition rate of 75 MHz, equivalent to half the free spectral range of the laser.

  8. Stability of short, single-mode erbium-doped fiber lasers.

    PubMed

    Svalgaard, M; Gilbert, S L

    1997-07-20

    We conducted a detailed study of the stability of short, erbium-doped fiber lasers fabricated with two UV-induced Bragg gratings written into the doped fiber. We find that the relative intensity noise of single-longitudinal-mode fiber grating lasers is approximately 3 orders of magnitude lower than that of a single-frequency 1.523-mum helium-neon laser. The frequency noise spectrum contains few resonances, none of which exceeds 0.6 kHz/Hz(1/2) rms; the integrated rms frequency noise from 50 Hz to 63 kHz is 36 kHz. We also demonstrate a simple method for monitoring the laser power and number of oscillating modes during laser fabrication.

  9. HIGH ENERGY CRYSTALLINE LASER MATERIALS.

    DTIC Science & Technology

    decay rates. Transfer of energy to neodymium from chromium and gadolinium in GdAlO3 and from chromium in Y3Al5G12 (YA1G) is described. Improvements in...Hamiltonian which couples two impurity ions, determining the phonon-assisted energy transfer between the ions. (Author)

  10. High-energy laser plasma diagnostic system

    NASA Astrophysics Data System (ADS)

    Zhao, Mingjun M.; Aye, Tin M.; Fruehauf, Norbert; Savant, Gajendra D.; Erwin, Daniel A.; Smoot, Brayton E.; Loose, Richard W.

    2000-07-01

    This paper describes the development of a non-contact diagnosis system for analyzing the plasma density profile, temperature profile, and ionic species of a high energy laser-generated plasma. The system was developed by Physical Optics Corporation in cooperation with the U.S. Army Space and Missile Defense Command, High Energy Laser Systems Test Facility at White Sands Missile Range, New Mexico. The non- contact diagnostic system consists of three subsystems: an optical fiber-based interferometer, a plasma spectrometer, and a genetic algorithm-based fringe-image processor. In the interferometer subsystem, the transmitter and the receiver are each packaged as a compact module. A narrow notch filter rejects strong plasma light, passing only the laser probing beam, which carries the plasma density information. The plasma spectrum signal is collected by an optical fiber head, which is connected to a compact spectrometer. Real- time genetic algorithm-based data processing/display permits instantaneous analysis of the plasma characteristics. The research effort included design and fabrication of a vacuum chamber, and high-energy laser plasma generation. Compactness, real-time operation, and ease of use make the laser plasma diagnosis system well suited for dual use applications such as diagnosis of electric arc and other industrial plasmas.

  11. Atmospheric applications of high-energy lasers

    NASA Astrophysics Data System (ADS)

    Cook, Joung R.

    2005-03-01

    It has been over forty years since the invention of the laser, which has inspired the imagination of scientists and science fiction writers alike. Many ideas have been realized, many still remain as dreams, and new ones are still being conceived. The High Energy Laser (HEL) has been associated with weapon applications during the past three decades. Much of the same technology can be directly applied to power beaming, laser propulsion, and other potential remote energy and power transfer applications. Economically, these application areas are becoming increasingly more viable. This paper reviews the evolutionarey history of the HEL device technologies. It points out the basic system components and layouts with associated key technologies that drive the effectiveness and efficiency of the system level performance. It describes the fundamental properties and wavelength dependencies of atmospheric propagation that in turn have become the prescription for wavelength properties that are desired from the device.

  12. Initiation of insensitive explosives by laser energy

    NASA Technical Reports Server (NTRS)

    Menichelli, V. J.; Yang, L. C.

    1972-01-01

    Instantaneous longitudinal detonations were observed in confined columns of pentaerythritol tetranitrate (PETN), cyclotrimethylene trinitramine (RDX), and tetryl when these materials were pulsed with light energy from a focused Q-switch ruby laser. The laser energy ranged from 0.5 to 4.2 J with a pulse width of 25 ns. Enhancement of the ignition mechanism is hypothesized when a 100-nm (1000-A) thick aluminum film is vacuum-deposited on the explosive side of the window. Upon irradiation from the laser, a shock is generated at the aluminum explosive interface. Steady state detonations can be reached in less than 0.5 microseconds with less than 10% variation in detonation velocity for PETN and RDX.

  13. Conversion of laser energy to gas kinetic energy

    NASA Technical Reports Server (NTRS)

    Caledonia, G. E.

    1977-01-01

    Techniques for the gas-phase absorption of laser energy with ultimate conversion to heat or directed kinetic energy are reviewed. It is shown that the efficiency of resonance absorption by the vibration/rotation bands of the working gas can be enhanced by operating at sufficiently high pressures so that the linewidths of the absorbing transition exceed the line spacing. Within this limit, the gas can absorb continuously over the full spectral region of the band, and bleaching can be minimized since the manifold of molecular vibrational levels can simultaneously absorb the laser radiation.

  14. Conversion of laser energy to gas kinetic energy

    NASA Technical Reports Server (NTRS)

    Caledonia, G. E.

    1977-01-01

    Techniques for the gas-phase absorption of laser energy with ultimate conversion to heat or directed kinetic energy are reviewed. It is shown that the efficiency of resonance absorption by the vibration/rotation bands of the working gas can be enhanced by operating at sufficiently high pressures so that the linewidths of the absorbing transition exceed the line spacing. Within this limit, the gas can absorb continuously over the full spectral region of the band, and bleaching can be minimized since the manifold of molecular vibrational levels can simultaneously absorb the laser radiation.

  15. Applications for Energy Recovering Free Electron Lasers

    SciTech Connect

    George Neil

    2007-08-01

    The availability of high-power, high-brilliance sources of tunable photons from energy-recovered Free Electron Lasers is opening up whole new fields of application of accelerators in industry. This talk will review some of the ideas that are already being put into production, and some of the newer ideas that are still under development.

  16. Stored energy in pulsed dye laser ampifiers

    SciTech Connect

    Hnilo, A.A.; Martinez, O.E.; Quel, E.J.

    1986-01-01

    A new, more complete geometrical description of amplified spontaneous emission is included in the usual numerical models for dye laser amplifiers. A strong discrepancy with previous models is found for the low input signal regime and when evaluating the stored energy. The model was thoroughly tested experimentally.

  17. Combined effects of low-level laser therapy and human bone marrow mesenchymal stem cell conditioned medium on viability of human dermal fibroblasts cultured in a high-glucose medium.

    PubMed

    Hendudari, Farzane; Piryaei, Abbas; Hassani, Seyedeh-Nafiseh; Darbandi, Hasan; Bayat, Mohammad

    2016-05-01

    Low-level laser therapy (LLLT) exhibited biostimulatory effects on fibroblasts viability. Secretomes can be administered to culture mediums by using bone marrow mesenchymal stem cells conditioned medium (BM-MSCs CM). This study investigated the combined effects of LLLT and human bone marrow mesenchymal stem cell conditioned medium (hBM-MSCs CM) on the cellular viability of human dermal fibroblasts (HDFs), which was cultured in a high-glucose (HG) concentration medium. The HDFs were cultured either in a concentration of physiologic (normal) glucose (NG; 5.5 mM/l) or in HG media (15 mM/l) for 4 days. LLLT was performed with a continuous-wave helium-neon laser (632.8 nm, power density of 0.00185 W/cm(2) and energy densities of 0.5, 1, and 2 J/cm(2)). About 10% of hBM-MSCs CM was added to the HG HDF culture medium. The viability of HDFs was evaluated using dimethylthiazol-diphenyltetrazolium bromide (MTT) assay. A significantly higher cell viability was observed when laser of either 0.5 or 1 J/cm(2) was used to treat HG HDFs, compared to the control groups. The cellular viability of HG-treated HDFs was significantly lower compared to the LLLT + HG HDFs, hBM-MSCs CM-treated HG HDFs, and LLLT + hBM-MSCs CM-treated HG HDFs. In conclusion, hBM-MSCs CM or LLLT alone increased the survival of HG HDFs cells. However, the combination of hBM-MSCs CM and LLLT improved these results in comparison to the conditioned medium.

  18. High-Energy Petawatt Capability for the Omega Laser

    SciTech Connect

    Waxer, L.J.; Maywar, D.N.; Kelly, J.H.; Kessler, T.J.; Kruschwitz, B.E.; Loucks, S.J.; McCrory, R.L.; Meyerhofer, D.D.; Morse, S.F.B.; Stoeckl, C.; Zuegel, J.D.

    2005-07-25

    The 60-beam Omega laser system at the University of Rochester's Laboratory for Laser Energetics (LLE) has been a workhorse on the frontier of laser fusion and high-energy-density physics for more than a decade. LLE scientists are currently extending the performance of this unique, direct-drive laser system by adding high-energy petawatt capabilities.

  19. Laser system for natural gas detection. Phase 1: Laboratory feasibility studies

    NASA Technical Reports Server (NTRS)

    Grant, W. B.; Hinkley, E. D., Jr.

    1982-01-01

    This project demonstrated the feasibility of using laser remote sensing technology as a tool for leak survey work in natural gas distribution systems. A laboratory device was assembled using a pair of helium neon (HeNe) lasers to measure methane. One HeNe laser emits radiation at a wavelength of 3.3922 micrometers, which corresponds to a strong absorption feature of methane, while the other emits radiation at a wavelength of 3.3911 micrometers, which corresponds to a weak absorption by methane. As a particular area is scanned for leaks, the laser is pointed at convenient topographic targets within its operating range, about 25 m. A portion of the backscattered radiation is collected by a receiver and focused onto an indium antimonide (InSb) photodetector, cooled to 77K. Methane concentrations were determined from the differential absorption at the two wavelengths for the backscattered radiation.

  20. Semiconductor Laser Diode Pumps for Inertial Fusion Energy Lasers

    SciTech Connect

    Deri, R J

    2011-01-03

    Solid-state lasers have been demonstrated as attractive drivers for inertial confinement fusion on the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) and at the Omega Facility at the Laboratory for Laser Energetics (LLE) in Rochester, NY. For power plant applications, these lasers must be pumped by semiconductor diode lasers to achieve the required laser system efficiency, repetition rate, and lifetime. Inertial fusion energy (IFE) power plants will require approximately 40-to-80 GW of peak pump power, and must operate efficiently and with high system availability for decades. These considerations lead to requirements on the efficiency, price, and production capacity of the semiconductor pump sources. This document provides a brief summary of these requirements, and how they can be met by a natural evolution of the current semiconductor laser industry. The detailed technical requirements described in this document flow down from a laser ampl9ifier design described elsewhere. In brief, laser amplifiers comprising multiple Nd:glass gain slabs are face-pumped by two planar diode arrays, each delivering 30 to 40 MW of peak power at 872 nm during a {approx} 200 {micro}s quasi-CW (QCW) pulse with a repetition rate in the range of 10 to 20 Hz. The baseline design of the diode array employs a 2D mosaic of submodules to facilitate manufacturing. As a baseline, they envision that each submodule is an array of vertically stacked, 1 cm wide, edge-emitting diode bars, an industry standard form factor. These stacks are mounted on a common backplane providing cooling and current drive. Stacks are conductively cooled to the backplane, to minimize both diode package cost and the number of fluid interconnects for improved reliability. While the baseline assessment in this document is based on edge-emitting devices, the amplifier design does not preclude future use of surface emitting diodes, which may offer appreciable future cost reductions and

  1. Phase conjugation of high energy lasers.

    SciTech Connect

    Bliss, David E; Valley, Michael T.; Atherton, Briggs W.; Bigman, Verle Howard; Boye, Lydia Ann; Broyles, Robin Scott; Kimmel, Mark W.; Law, Ryan J.; Yoder, James R.

    2013-01-01

    In this report we explore claims that phase conjugation of high energy lasers by stimulated Brillouin scattering (SBS) can compensate optical aberrations associated with severely distorted laser amplifier media and aberrations induced by the atmosphere. The SBS media tested was a gas cell pressurized up to 300 psi with SF6 or Xe or both. The laser was a 10 Hz, 3J, Q-switched Nd:YAG with 25 ns wide pulses. Atmospheric aberrations were created with space heaters, helium jets and phase plates designed with a Kolmogorov turbulence spectrum characterized by a Fried parameter, ro , ranging from 0.6 6.0 mm. Phase conjugate tests in the laboratory were conducted without amplification. For the strongest aberrations, D/ro ~ 20, created by combining the space heaters with the phase plate, the Strehl ratio was degraded by a factor of ~50. Phase conjugation in SF6 restored the peak focusable intensity to about 30% of the original laser. Phase conjugate tests at the outdoor laser range were conducted with laser amplifiers providing gain in combination with the SBS cell. A large 600,000 BTU kerosene space heater was used to create turbulence along the beam path. An atmospheric structure factor of Cn2 = 5x10-13 m2/3 caused the illumination beam to expand to a diameter 250mm and overfill the receiver. The phase conjugate amplified return could successfully be targeted back onto glints 5mm in diameter. Use of a lenslet arrays to lower the peak focusable intensity in the SBS cell failed to produce a useful phase conjugate beam; The Strehl ratio was degraded with multiple random lobes instead of a single focus. I will review literature results which show how multiple beams can be coherently combined by SBS when a confocal reflecting geometry is used to focus the laser in the SBS cell.

  2. Laser energy deposition in crossing shock interaction

    NASA Astrophysics Data System (ADS)

    Yan, H.; Knight, D.; Elliott, G.

    A combined computational and experimental study was performed to investigate the effect of a single laser energy pulse on the transition from a Mach Reflection (MR) to a Regular Reflection (RR) in the Dual Solution Domain (DSD). The freestream Mach number is 3.45 and two oblique shock waves are formed by two symmetric 22° wedges. These conditions correspond to a point midway within the DSD wherein either an MR or an RR is possible. A steady MR was first obtained experimentally and numerically, then a single laser pulse was deposited above the horizontal center plane. The experiment showed that the Mach stem height decreased to 30% of its original height due to the interaction with the thermal spot generated by the laser pulse and then returned to its original height by 300μs. That the Mach stem returned to its original height was most likely due to freestream turbulence in the wind tunnel. The numerical simulation successfully predicted the reverse transition from a stable MR to a stable RR and the stable RR persisted across the span. This study showed the capability of a laser energy pulse to control the reverse transition of MR → RR within the Dual Solution Domain.

  3. High energy photocathodes for laser fusion diagnostics.

    PubMed

    Halvorson, C; Houck, T; Macphee, A; Opachich, Y P; Lahowe, D; Copsey, B

    2010-10-01

    Laser fusion experiments at the National Ignition Facility require time-resolved x-ray images of the ignition target self-emission. The photon energies are expected to be greater than 10 keV. Photoemission quantum yield measurement data and photoelectron energy spectrum data are presently unavailable in this photon energy range, but are essential in the design of x-ray imaging diagnostics. We developed an apparatus to measure the quantum efficiency of primary and secondary photoelectron emission and to estimate the energy spectrum of the secondary photoelectrons. The apparatus has been tested using photon energies less than 10 keV to allow comparisons with prior work. A method for preparing photocathodes with geometrically enhanced photoefficiency has been developed.

  4. Pulse switching for high energy lasers

    NASA Technical Reports Server (NTRS)

    Laudenslager, J. B.; Pacala, T. J. (Inventor)

    1981-01-01

    A saturable inductor switch for compressing the width and sharpening the rise time of high voltage pulses from a relatively slow rise time, high voltage generator to an electric discharge gas laser (EDGL) also provides a capability for efficient energy transfer from a high impedance primary source to an intermediate low impedance laser discharge network. The switch is positioned with respect to a capacitive storage device, such as a coaxial cable, so that when a charge build-up in the storage device reaches a predetermined level, saturation of the switch inductor releases or switches energy stored in the capactive storage device to the EDGL. Cascaded saturable inductor switches for providing output pulses having rise times of less than ten nanoseconds and a technique for magnetically biasing the saturable inductor switch are disclosed.

  5. Research of the conical cavity high-energy laser energy meter energy loss compensation technique

    NASA Astrophysics Data System (ADS)

    Yu, Xun; Li, Qian; Nie, Liang; Shang, Xiaoyan; Liu, Baoyuan

    2008-09-01

    Because absolute quantity thermal laser energy meter based on conical cavity has some features, for example, wavelength adaptation range is wide and laser damage threshold value is high. It is used for the standard of the high-energy laser energy meter and extensively in the domain of the high energy laser measurement. However, laser energy will lose because of the heat exchange and the back scattering of the conical absorption cavity. Therefore, only after compensating and amending the loss, the exact measurement of the laser energy can be achieved. Aimed to the energy loss compensation problem of the conical cavity high-energy laser energy meter, firstly, according to the heat transfer theory, this paper analyzes the heat energy loss of the conical cavity due to the heat emission, the heat convection and the heat exchange, and construct the mathematical model of the heat energy loss, based on which measuring result is curved fit using the least squares technique, and is compensated and amended utilizing the fitting curve, whose measurement repetitiveness is 0.7%, from which we can know that measuring repetitiveness is increased consumedly. Secondly, according to the optics principles of reciprocity of the conical cavity inner face and the incident laser and utilizing complexification Simpson numerical method, the mathematical model of conical cavity jaw opening optical power density distribution and back scattering gross power is established, based on which measuring result is compensated and amended, the back scattering energy loss is about 0.5% to 2.5%, high-energy laser energy measuring accuracy is improved availably.

  6. Path toward a high-energy solid-state laser

    NASA Astrophysics Data System (ADS)

    Wood, Gary L.; Merkle, Larry D.; Dubinskii, Mark; Zandi, Bahram

    2004-04-01

    Lasers have come a long way since the first demonstration by Maiman of a ruby crystal laser in 1960. Lasers are used as scientific tools as well as for a wide variety of applications for both commercial industry and the military. Today lasers come in all types, shapes and sizes depending on their application. The solid-state laser has some distinct advantages in that it can be rugged, compact, and self contained, making it reliable over long periods of time. With the advent of diode laser pumping a ten times increase in overall laser efficiency has been realized. This significant event, and others, is changing the way solid-state lasers are applied and allows new possibilities. One of those new areas of exploration is the high energy laser. Solid-state lasers for welding are already developed and yield energies in the 0.5 to 6 kilojoule range. These lasers are at the forefront of what is possible in terms of high energy solid-state lasers. It is possible to achieve energies of greater than 100 kJ. These sorts of energies would allow applications, in addition to welding, such as directed energy weapons, extremely remote sensing, power transfer, propulsion, biological and chemical agent neutralization and unexploded and mine neutralization. This article will review these new advances in solid-state lasers and the different paths toward achieving a high energy laser. The advantages and challenges of each approach will be highlighted.

  7. Phosphate glass useful in high energy lasers

    DOEpatents

    Hayden, Y.T.; Payne, S.A.; Hayden, J.S.; Campbell, J.H.; Aston, M.K.; Elder, M.L.

    1996-06-11

    In a high energy laser system utilizing phosphate laser glass components to amplify the laser beam, the laser system requires a generated laser beam having an emission bandwidth of less than 26 nm and the laser glass components consist essentially of (on an oxide composition basis) in mole percent: P{sub 2}O{sub 5}, 50--75; Al{sub 2}O{sub 3}, {gt}0--10; K{sub 2}O, {gt}0--30; MgO, 0--30; CaO, 0--30; Li{sub 2}O, 0--20; Na{sub 2}O, 0--20; Rb{sub 2}O, 0--20; Cs{sub 2}O, 0--20; BeO, 0--20; SrO, 0--20; BaO, 0--20; ZnO, 0--20; PbO, 0--20; B{sub 2}O{sub 3}, 0--10; Y{sub 2}O{sub 3}, 0--10; La{sub 2}O{sub 3}, 0--8; Ln{sub 2}O{sub 3}, 0.01--8; wherein the sum of MgO and CaO is >0--30; the sum of Li{sub 2}O, Na{sub 2}O, Rb{sub 2}O, and Cs{sub 2}O is 0--20; the sum of BeO, SrO, BaO, ZnO, and PbO is 0--20; the sum of B{sub 2}O{sub 3} and Y{sub 2}O{sub 3} is 0--10; and Ln{sub 2}O{sub 3} represents the sum of the oxides of active lasing lanthanides of atomic number 58--71. 21 figs.

  8. Phosphate glass useful in high energy lasers

    DOEpatents

    Hayden, Yuiko T.; Payne, Stephen A.; Hayden, Joseph S.; Campbell, John H.; Aston, Mary Kay; Elder, Melanie L.

    1996-01-01

    In a high energy laser system utilizing phosphate laser glass components to amplify the laser beam, the laser system requires a generated laser beam having an emission bandwidth of less than 26 nm and the laser glass components consist essentially of (on an oxide composition basis) in mole percent: P{sub 2}O{sub 5}, 50--75; Al{sub 2}O{sub 3}, {gt}0--10; K{sub 2}O, {gt}0--30; MgO, 0--30; CaO, 0--30; Li{sub 2}O, 0--20; Na{sub 2}O, 0--20; Rb{sub 2}O, 0--20; Cs{sub 2}O, 0--20; BeO, 0--20; SrO, 0--20; BaO, 0--20; ZnO, 0--20; PbO, 0--20; B{sub 2}O{sub 3}, 0--10; Y{sub 2}O{sub 3}, 0--10; La{sub 2}O{sub 3}, 0--8; Ln{sub 2}O{sub 3}, 0.01--8; wherein the sum of MgO and CaO is >0--30; the sum of Li{sub 2}O, Na{sub 2}O, Rb{sub 2}O, and Cs{sub 2}O is 0--20; the sum of BeO, SrO, BaO, ZnO, and PbO is 0--20; the sum of B{sub 2}O{sub 3} and Y{sub 2}O{sub 3} is 0--10; and Ln{sub 2}O{sub 3} represents the sum of the oxides of active lasing lanthanides of atomic number 58--71. 21 figs.

  9. Treatment of 65 patients with cholelithiasis by He-Ne laser acupoint irradiation

    NASA Astrophysics Data System (ADS)

    Hu, Yong-Jun

    1993-03-01

    The treatment of 65 patients with cholelithiasis by low power helium-neon laser irradiation on acu-points was studied. The results show that 51 of them started to discharge the gallstones within the duration of 6 to 15 laser irradiations, and 11 patients after more than 15 treatments. Two patients (3.1%) were fully cured, 42 (64.6%) markedly effective, 18 (27.7%) effective, and 3 (4.6%) failed. The total effective rate was 95.4%. By chemical analysis, the discharged gallstones were identified as calcium bilirubinate or mixed stones. Patients with stones smaller than 1 cm in diameter or stones made of calcium bilirubinate were more effectively treated than others. The He-Ne laser seems to be a useful treatment for some patients with cholelithiasis without surgical operation.

  10. A novel laser wavelength meter based on the measurement of synthetic wavelength

    NASA Astrophysics Data System (ADS)

    Yan, Liping; Chen, Benyong; Yang, Wanfu; Wei, Ruofei; Zhao, Siwei

    2010-11-01

    The accuracy of the current wavelength meter using optical interferometry is limited by the numbers of fringe counted. To solve this problem, a novel laser wavelength meter based on the measurement of synthetic wavelength is proposed. The unknown wavelength is obtained by measuring the value of synthetic wavelength produced by the unknown and reference wavelengths, and half of this value corresponds to 2π variation of the phase difference between the interference signals of the unknown and reference wavelengths. The optical configuration of the wavelength meter is designed and the measurement principle is analyzed theoretically. To verify its feasibility, three helium-neon lasers' wavelengths were determined experimentally, and a relative uncertainty on the unknown wavelength of the order of 10-8 was realized. Accuracy analysis shows that this wavelength meter has the advantage of high accuracy when the unknown wavelength is around the standard laser wavelength recommended by CIPM.

  11. Sensitization of oral bacteria to killing by low-power laser radiation.

    PubMed

    Wilson, M; Dobson, J; Harvey, W

    1992-08-01

    Twenty-seven compounds were screened for their ability to sensitize Streptococcus sanguis to killing by light from a 7.3-mW Helium/Neon (HeNe) laser. Bacteria were mixed with various concentrations of the test compounds, spread over the surfaces of agar plates, and then exposed to light from the HeNe laser for various time periods. The plates were then incubated and examined for zones of inhibition. Those compounds found to be effective photosensitizers were then tested against Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, and Fusobacterium nucleatum. Toluidine blue O, azure B chloride, and methylene blue at concentrations of 0.005% (wt/vol) were effective photosensitizers of all four species, enabling killing of bacteria following exposure to laser light for only 30 s.

  12. Laser biostimulation (Ne-He and Ga-As) effects as compared to the conventional therapy in several pelvic inflammatory diseases

    NASA Astrophysics Data System (ADS)

    Antipa, Ciprian; Dona, Dumitru; Podoleanu, Adrian Gh.; Crisan, Nicolae; Constantinescu, Camelia

    1993-05-01

    We studied the effects of the very low-power Gallium-Arsenic infrared semiconductor laser and low-power Helium-Neon laser irradiation, single or in combination, compared to the placebo and conventional therapy on the recovery of 118 female patients from our hospital with the diagnosis of chronic pelvic inflammatory disorders. Laser biostimulation therapy proved to be significantly more efficient as compared with placebo or conventional therapy. The most efficient of all kinds of irradiations was the combination between He-Ne and Ga-As (laserpuncture and scanning). After laser treatments we didn't find any significant local genital changes both at the bimanual examination (except provoked pain), and at the echographical examination. Soft and very low-power laser therapy can be a useful alternative to the conventional treatments for pelvic inflammatory diseases.

  13. Conversion of laser energy to gas kinetic energy

    NASA Technical Reports Server (NTRS)

    Caledonia, G. E.

    1975-01-01

    Techniques for the gas phase absorption of laser radiation for conversion to gas kinetic energy are discussed. Absorption by inverse Bremsstrahlung, in which laser energy is converted at a gas kinetic rate in a spectrally continuous process, is briefly described, and absorption by molecular vibrational rotation bands is discussed at length. High pressure absorption is proposed as a means of minimizing gas bleaching and dissociation, the major disadvantages of the molecular absorption process. A band model is presented for predicting the molecular absorption spectra in the high pressure absorption region and is applied to the CO molecule. Use of a rare gas seeded with Fe(CO)5 for converting vibrational modes to translation modes is described.

  14. Staging Laser Plasma Accelerators for Increased Beam Energy

    SciTech Connect

    Panasenko, D.; Shu, A. J.; Schroeder, C. B.; Gonsalves, A. J.; Nakamura, K.; Matlis, N. H.; Cormier-Michel, E.; Plateau, G.; Lin, C.; Toth, C.; Geddes, C. G. R.; Esarey, E.; Leemans, W. P.

    2009-01-22

    Staging laser plasma accelerators is an efficient way of mitigating laser pump depletion in laser driven accelerators and necessary for reaching high energies with compact laser systems. The concept of staging includes coupling of additional laser energy and transporting the electron beam from one accelerating module to another. Due to laser damage threshold constraints, in-coupling laser energy with conventional optics requires distances between the accelerating modules of the order of 10 m, resulting in decreased average accelerating gradient and complicated e-beam transport. In this paper we use basic scaling laws to show that the total length of future laser plasma accelerators will be determined by staging technology. We also propose using a liquid jet plasma mirror for in-coupling the laser beam and show that it has the potential to reduce distance between stages to the cm-scale.

  15. Staging laser plasma accelerators for increased beam energy

    SciTech Connect

    Panasenko, Dmitriy; Shu, Anthony; Schroeder, Carl; Gonsalves, Anthony; Nakamura, Kei; Matlis, Nicholas; Cormier-Michel, Estelle; Plateau, Guillaume; Lin, Chen; Toth, Csaba; Geddes, Cameron; Esarey, Eric; Leemans, Wim

    2008-09-29

    Staging laser plasma accelerators is an efficient way of mitigating laser pump depletion in laser driven accelerators and necessary for reaching high energies with compact laser systems. The concept of staging includes coupling of additional laser energy and transporting the electron beam from one accelerating module to another. Due to laser damage threshold constraints, in-coupling laser energy with conventional optics requires distances between the accelerating modules of the order of 10m, resulting in decreased average accelerating gradient and complicated e-beam transport. In this paper we use basic scaling laws to show that the total length of future laser plasma accelerators will be determined by staging technology. We also propose using a liquid jet plasma mirror for in-coupling the laser beam and show that it has the potential to reduce distance between stages to the cm-scale.

  16. Stabilizing laser energy density on a target during pulsed laser deposition of thin films

    DOEpatents

    Dowden, Paul C.; Jia, Quanxi

    2016-05-31

    A process for stabilizing laser energy density on a target surface during pulsed laser deposition of thin films controls the focused laser spot on the target. The process involves imaging an image-aperture positioned in the beamline. This eliminates changes in the beam dimensions of the laser. A continuously variable attenuator located in between the output of the laser and the imaged image-aperture adjusts the energy to a desired level by running the laser in a "constant voltage" mode. The process provides reproducibility and controllability for deposition of electronic thin films by pulsed laser deposition.

  17. Tactical laser weapons and other directed-energy weapons

    NASA Astrophysics Data System (ADS)

    Wang, Rongrui

    1993-07-01

    This paper briefly introduces the current development status of three directed-energy weapons: laser weapons, radio frequency/microwave weapons, and charged-particle-beam weapons. Among them, the tactical laser weapon may be the first to find application.

  18. Study of a carbon dioxide ring laser gyroscope

    NASA Astrophysics Data System (ADS)

    Dennis, M. L.; Diels, J.-C.; Mohebi, M.

    1992-04-01

    We have experimentally investigated a basic ring laser gyroscope (RLG) with carbon dioxide gain, and studied the prospects of developing a practical CO2 RLG. Rotation sensing was demonstrated on a number of transitions in the 9.4 μm and 10.4 μm vibration-rotation bands. Gyro response is discussed with regard to lock-in, bias, homogeneous broadening effects, and high power operation. We show that such a system may offer important advantages over standard helium-neon RLGs, including reduced quantum limit and backscattering. The prospects and possible approaches for developing a practical high power CO2 RLG are discussed, and a method of eliminating cross-saturation at high pressure is proposed and analyzed.

  19. Study of a carbon dioxide ring laser gyroscope

    NASA Astrophysics Data System (ADS)

    Dennis, M. L.; Diels, J.-C.; Mohebi, M.

    1992-04-01

    We have experimentally investigated a basic ring laser gyroscope (RLG) with carbon dioxide gain, and studied the prospects of developing a practical CO2 RLG. Rotation sensing was demonstrated on a number of transitions in the 9.4 microns and 10.4 microns vibration-rotation bands. Gyro response is discussed with regard to lock-in, bias, homogeneous broadening effects, and high power operation. We show that such a system may offer important advantages over standard helium-neon RLGs, including reduced quantum limit and backscattering. The prospects and possible approaches for developing a practical high power CO2 RLG are discussed, and a method of eliminating cross-saturation at high pressure is proposed and analyzed.

  20. Performance calculation and simulation system of high energy laser weapon

    NASA Astrophysics Data System (ADS)

    Wang, Pei; Liu, Min; Su, Yu; Zhang, Ke

    2014-12-01

    High energy laser weapons are ready for some of today's most challenging military applications. Based on the analysis of the main tactical/technical index and combating process of high energy laser weapon, a performance calculation and simulation system of high energy laser weapon was established. Firstly, the index decomposition and workflow of high energy laser weapon was proposed. The entire system was composed of six parts, including classical target, platform of laser weapon, detect sensor, tracking and pointing control, laser atmosphere propagation and damage assessment module. Then, the index calculation modules were designed. Finally, anti-missile interception simulation was performed. The system can provide reference and basis for the analysis and evaluation of high energy laser weapon efficiency.

  1. Evaluation of probe lasers employed in optical diagnostics for phase transformation of thin films during excimer laser crystallization

    NASA Astrophysics Data System (ADS)

    Kuo, Chil-Chyuan

    2008-06-01

    The stability and reliability of probe laser is an important factor affecting the inspection of the phase transformation process of Si thin films during excimer laser crystallization using in-situ time-resolved optical measurements. The changes in 2D intensity profile, peak power density, and beam wander of the commonly used helium-neon (He-Ne) and diode laser are investigated experimentally. It is found that the peak power density of He-Ne laser is higher than that of diode laser, while the total power of He-Ne laser is lower than that of diode laser. Although the instability in the peak power density of He-Ne laser will increase with increasing the operation time, the beam stability of He-Ne laser is better than that of diode laser. For long-time operation (>24 h) of optical measurements, the diode laser is a good candidate of probe laser. Conversely, the diode laser is suitable for the short-time operation (<24 h) of optical measurements because the beam-wander is higher than that of He-Ne laser.

  2. Space electric power design study. [laser energy conversion

    NASA Technical Reports Server (NTRS)

    Martini, W. R.

    1976-01-01

    The conversion of laser energy to electrical energy is discussed. Heat engines in which the laser heats the gas inside the engine through a window as well as heat engines in which the gas is heated by a thermal energy storage reservoir which has been heated by laser radiation are both evaluated, as well as the necessary energy storage, transmission and conversion components needed for a full system. Preliminary system concepts are presented and a recommended development program is outlined. It appears possible that a free displacer Stirling engine operating directly a linear electric generator can convert 65% of the incident laser energy into electricity.

  3. Advanced solar energy conversion. [solar pumped gas lasers

    NASA Technical Reports Server (NTRS)

    Lee, J. H.

    1981-01-01

    An atomic iodine laser, a candidate for the direct solar pumped lasers, was successfully excited with a 4 kW beam from a xenon arc solar simulator, thus proving the feasibility of the concept. The experimental set up and the laser output as functions of operating conditions are presented. The preliminary results of the iodine laser amplifier pumped with the HCP array to which a Q switch for giant pulse production was coupled are included. Two invention disclosures - a laser driven magnetohydrodynamic generator for conversion of laser energy to electricity and solar pumped gas lasers - are also included.

  4. Controlling the Motion of Electronic Wavepackets Using Cycle-Sculpted Two-Color Laser Fields

    NASA Astrophysics Data System (ADS)

    Kitzler, M.; Xie, X.; Roither, S.; Kartashov, D.; Baltuška, A.

    We use cycle-sculpted two-color waveforms to drive electronic wavepackets generated by strong-field ionization from helium, neon, and argon gas atoms and analyze their momentum spectra measured by electron-ion coincidence momentum spectroscopy. Varying the relative phase of the two colors allows to sculpt the ionizing field and hence to control the emission times and motion of the wavepackets on an attosecond timescale. Using semiclassical calculations, we investigate the influence of the ionic Coulomb field onto the motion of emitted electronic wavepackets. We further show that the measured electron momentum spectra contain interference patterns created by pairs of electron wavepackets that are released within a single laser-field cycle. We experimentally distinguish these subcycle interference structures from above-threshold ionization (ATI) peaks and argue that they can be used to extract the subcycle phase evolution of the laser-driven complex bound-state wavefunction.

  5. Cryogenic monocrystalline silicon Fabry-Perot cavity for the stabilization of laser frequency

    NASA Technical Reports Server (NTRS)

    Richard, J.-P.; Hamilton, J. J.

    1991-01-01

    A 1.6 kg silicon monocrystal was used to make a Fabry-Perot optical cavity operated at cryogenic temperatures. High-resolution thermal expansion measurements were made as the silicon cooled to 4.2 K, in order to characterize the cavity as a length reference standard. A helium-neon laser was then locked to a transmission resonance at liquid-helium temperatures, and the laser frequency tracked the cavity resonance with error fluctuations at the level of 10 Hz/sq rt Hz in the bandwidth dc to 1 Hz. Implications of the combined set of data, thermal expansion plus frequency-tracking fluctuations, for using such a system as a frequency standard are discussed.

  6. Sensitization of periodontopathogenic bacteria to killing by light from a low-power laser.

    PubMed

    Wilson, M; Dobson, J; Sarkar, S

    1993-06-01

    Cultures of Porphyromonas gingivalis, Fusobacterium nucleatum and Actinobacillus actinomycetemcomitans were treated with a range of photosensitizers and then exposed to light from a 7.3 mW helium/neon laser for up to 80 s. Toluidine blue O (25 micrograms/ml) and methylene blue (25 micrograms/ml) were effective lethal photosensitizers of all 3 target organisms, enabling substantial light dose-related reductions in viable counts. Dihaematoporphyrin ester and aluminium disulphonated phthalocyanine were lethal photosensitizers only of P. gingivalis. In the absence of a photosensitizer, exposure to laser light had no significant effect on the viability of the cultures. If such low doses of light (22 J/cm2) are effective at killing bacteria in vivo, the technique may be useful as a means of eliminating periodontopathogenic bacteria from diseased sites.

  7. Recent progresses in He-Ne lasers stabilized to (I-127)2

    SciTech Connect

    Bertinetto, F.; Cordiale, P.; Fontana, S.; Picotto, G.B.

    1985-06-01

    The stabilization of a He-Ne (helium-neon) laser to hyperfine structure (HFS) components of the P(48)11-3 transition of (I-127)2 at 612 nm observed in an external iodine cell, may give a frequency reproducibility of + or - 5 kHz or + or - 1 x 10 to the -11th nu and a stability of 1.4 x 10 to the -13th nu for an observation time tau = 100 s. From He-3-Ne-22 lasers stabilized to HFS components of (I-127)2 observed in an intracavity cell, both at 612 and 640 nm wavelengths, a reproducibility of + or - 2 x 10 to the -10th nu can be expected. Common and convenient operating conditions have been found at both wavelengths. 12 references.

  8. High Energy 2-micron Laser Developments

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Trieu, Bo C.; Petros, Mulugeta; Bai, Yingxin; Petzar, Paul J.; Koch, Grady J.; Singh, Upendra N.; Kavaya, Michael J.

    2007-01-01

    This viewgraph presentation shows the development of 2-micron solid state lasers. The topics covered include: 1) Overview 2-micron solid state lasers; 2) Modeling and population inversion measurement; 3) Side pump oscillator; and 4) One Joule 2-m Laser.

  9. Future scientific applications for high-energy lasers

    SciTech Connect

    Lee, R.W.

    1994-08-01

    This report discusses future applications for high-energy lasers in the areas of astrophysics and space physics; hydrodynamics; material properties; plasma physics; radiation sources; and radiative properties.

  10. High Energy Laser Systems Test Facility (HELSTF) Enhanced Laser and Range Operations. Environmental Assessment

    DTIC Science & Technology

    2005-06-16

    energy technologies for the DoD, other government agencies, industry, and academia. HELSTF represents a national investment of approximately $800 million...in high energy laser technology . As a result of the existing laser technologies and supporting infrastructure, which have an established record of...successful and innovative laser testing, research, and development, HELSTF is an important national asset to support continued laser technologies . It is

  11. Scanning laser measure of optical quality of the cultured crystalline lens.

    PubMed

    Weerheim, J A; Sivak, J G

    1992-01-01

    An apparatus has been designed to automate the laser measuring technique and make it possible to monitor lens refractive function (spherical aberration) as well as change in lens transmittance during lens culture. A scanning laser beam (helium-neon) is used so that a number of beams pass through different spots on the lens to determine lens spherical aberration compared over time. Each refracted beam, received by two video cameras (X and Y directions), is digitized. The system first locates the optical centre of the lens by determining the beam position providing the least deflection for both the X and Y directions. The beam is then moved in predetermined steps on either side of the centre, and focal lengths are determined relative to the optic axis for each position. A measure of beam scatter is noted from post-refraction pixel excitation for each beam position. Improvements to the scanning laser system have led to greater accuracy and speed as well as to improved culture cells. Accuracy was increased by using high resolution (1 micron) stepping motors to move the scanning helium-neon laser. A new alignment process involving the superposition of the incident beam reflected on itself ensures that the incident beam is perpendicular to the lens equatorial axis. Scanning speed has been improved through a variety of hardware and software changes. Scanning time for a lens, including locating the optical centre and measuring focal length for 20 lens positions along the X and Y directions, takes about 60 seconds. Long-term studies on the degradation of lens optical performance frequency yield diffuse beams of very low intensity.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Correction of biochemical and functional disorders in brain ischaemia with laser therapy

    NASA Astrophysics Data System (ADS)

    Musienko, Julia I.; Nechipurenko, Natalia I.; Vasilevskaya, Ludmila A.

    2005-08-01

    Application of intravenous laser irradiation of blood (ILIB) is considered to be the most effective method of laser therapy and its application is expedient pathogenetically in the ischemic disturbances. The aim of this study is to investigate ILIB influence with red helium-neon laser (HNL) with 630 nm wavelength and different powers on blood oxygen transport (BOT), cerebral and dermal microhaemodynamics (MGD), hydro-ion balance in normal rabbits and after modeling of local ischemia of brain (LIB). Experimental cerebral ischemia is characterized by development of BOT disturbance, ionic disbalance and edema in the ischemic brain region. Microcirculation disturbances with worsening of the cerebral and dermal MHD were revealed. ILIB with HNL radiation of 2.5 and 4.5 mW powers provokes dehydratation of brain structure alone with the K+, Na+ concentration decreasing and hemoglobin-oxygen affinity increasing in intact group of animals. There was not revealed marked changes of cerebral MHD condition here. Using of ILIB in rabbits after LIB contributes for improving function of BOT, normalizing of water content in all cerebral structures compared to operated animals. Preventive ILIB provoked improvement of speckl-optical parameters and marked protective effect on microhaemodynamics processes in superficial brain structures. HNL radiation with 1.0 mW power results in worsening of oxygen transport, cerebral and skin MHD, hydro-ion homeostasis in animals with LIB modeling. Thus, laser haemotherapy contributes for improving of hydro-ion status, blood oxygen transport and cerebral microcirculation in brain ischemia, what allows considering that helium-neon radiation with the pointed regimen is substantiated pathogenetically in brain ischaemia.

  13. Induratio penis plastica (IPP) and laser: a review

    NASA Astrophysics Data System (ADS)

    Longo, Leonardo; Mancini, S.; Postiglione, M. G.

    2002-10-01

    The first employments of Laser therapy for I.P.P. came from back to more than twenty years ago. At the beginning it was employed only in the acute forms as analgesic laser laser was used also as anti-inflammatory following the doses of Low Level Laser Therapy. Than the science tried to use the laser effect remodelling phase of the scars, to make the fibrosis regrade in the chronic forms. Tunable laser in small optical fiber was used for ablation of calcified zones with very good results. For the slight forms were used diode laser 660 and 904 nm, alone ir coupling with CO2 laser with large spot. At first some Author used helium-Neon laser 632. Some of these lasers were combined wtih microiontophoresis and ultrasounds therapy in teh same treatment. Now we use 810 nm surgical diode laser in almost all induratio forms. The immediate results and follow up will be discussed. Thanks to these results we could conclude that IPP laser therapy can be effective in most of the clinic forms. Although the used procedure is subject to improvement.

  14. CO2 LASERS IN HIGH ENERGY PHYSICS.

    SciTech Connect

    POGORELSKY,I.V.

    2001-12-03

    Several proof-of-principle laser accelerator experiments turned a long-wavelength of a CO{sub 2} laser to advantage. Ongoing advancement to multi-terawatt femtosecond CO{sub 2} lasers opens new venues for next-generation laser acceleration research.

  15. Chromatism compensation of the PETAL multipetawatt high-energy laser.

    PubMed

    Néauport, J; Blanchot, N; Rouyer, C; Sauteret, C

    2007-03-20

    High-energy petawatt lasers use series of spatial filters in their amplification section. The refractive lenses employed introduce longitudinal chromatism that can spatially and temporally distort the ultrafast laser beam after focusing. To ensure optimum performances of petawatt laser facilities, these distortions need to be corrected. Several solutions using reflective, refractive, or diffractive optical components can be addressed. We give herein a review of these various possibilities with their application to the PETAL (Petawatt Aquitaine Laser at the Laser Integration Line facility) laser beamline and show that diffractive-based corrections appear to be the most promising.

  16. Laser-Plasma Interactions in High-Energy Density Plasmas

    SciTech Connect

    Constantin, C G; Baldis, H A; Schneider, M B; Hinkel, D E; Langdon, A B; Seka, W; Bahr, R; Depierreaux, S

    2005-08-24

    Laser-plasma interactions (LPI) have been studied experimentally in high-temperature, high-energy density plasmas. The studies have been performed using the Omega laser at the Laboratory for Laser Energetics (LLE), Rochester, NY. Up to 10 TW of power was incident upon reduced-scale hohlraums, distributed in three laser beam cones. The hot hohlraums fill quickly with plasma. Late in the laser pulse, most of the laser energy is deposited at the laser entrance hole, where most of the LPI takes place. Due to the high electron temperature, the stimulated Raman scattering (SRS) spectrum extends well beyond {omega}{sub 0}/2, due to the Bohm-Gross shift. This high-temperature, high-energy density regime provides a unique opportunity to study LPI beyond inertial confinement fusion (ICF) conditions.

  17. Mathematical modeling of a photovoltaic-laser energy converter for iodine laser radiation

    NASA Technical Reports Server (NTRS)

    Walker, Gilbert H.; Heinbockel, John H.

    1987-01-01

    Space-based laser power systems will require converters to change laser radiation into electricity. Vertical junction photovoltaic converters are promising devices for this use. A promising laser for the laser power station is the t-C4F9I laser which emits radiation at a wavelength of 1.315 microns. This paper describes the results of mathematical modeling of a photovoltaic-laser energy converter for use with this laser. The material for this photovoltaic converter is Ga(53)In(47)As which has a bandgap energy of 0.94 eV, slightly below the energy of the laser photons (0.943 eV). Results of a study optimizing the converter parameters are presented. Calculated efficiency for a 1000 vertical junction converter is 42.5 percent at a power density of 1 x 10 to the 3d power w/sq cm.

  18. Parametric study of laser photovoltaic energy converters

    NASA Technical Reports Server (NTRS)

    Walker, G. H.; Heinbockel, J. H.

    1987-01-01

    Photovoltaic converters are of interest for converting laser power to electrical power in a space-based laser power system. This paper describes a model for photovoltaic laser converters and the application of this model to a neodymium laser silicon photovoltaic converter system. A parametric study which defines the sensitivity of the photovoltaic parameters is described. An optimized silicon photovoltaic converter has an efficiency greater than 50 percent for 1000 W/sq cm of neodymium laser radiation.

  19. Phosphate glass useful in high energy lasers

    DOEpatents

    Hayden, Yuiko T.; Guesto-Barnak, Donna

    1992-01-01

    A low-or no-silica, low- or no-alkali phosphate glass useful as a laser amplifier in a multiple pass, high energy laser system having a high thermal conductivity, K.sub.90.degree. C. >0.85 W/mK, a low coefficient of thermal expansion, .alpha..sub.20.degree.-300.degree. C. <80.times.10.sup.-7 /.degree.C., low emission cross section, .sigma.<2.5.times.10.sup.-20 cm.sup.2, and a high fluorescence lifetime, .tau.>325 .mu.secs at 3 wt. % Nd doping, consisting essentially of (on an oxide composition basis): wherein Ln.sub.2 O.sub.3 is the sum of lanthanide oxides; .SIGMA.R.sub.2 O is <5, R being Li, Na, K, Cs, and Rb; the sum of Al.sub.2 O.sub.3 and MgO is <24 unless .SIGMA.R.sub.2 O is 0, then the sum of Al.sub.2 O.sub.3 and MgO is <42; and the ratio of MgO to B.sub.2 O.sub.3 is 0.48-4.20.

  20. Preliminary results on the conversion of laser energy into electricity

    NASA Technical Reports Server (NTRS)

    Thompson, R. W.; Manista, E. J.; Alger, D. L.

    1978-01-01

    A preliminary experiment was performed to investigate conversion of 10.6 micron laser energy to electrical energy via a laser-sustained argon plasma. Short-circuit currents of 0.7 A were measured between a thoriated-tungsten emitter and collector electrodes immersed in the laser-sustained argon plasma. Open-circuit voltages of about 1.5 V were inferred from the current-voltage load characteristics. The dominant mechanism of laser energy conversion is uncertain at this time. Much higher output powers appear possible.

  1. Preliminary results on the conversion of laser energy into electricity

    NASA Technical Reports Server (NTRS)

    Thompson, R. W.; Manista, E. J.; Alger, D. L.

    1978-01-01

    A preliminary experiment was performed to investigate conversion of 10.6 micron laser energy to electrical energy via a laser-sustained argon plasma. Short-circuit currents of 0.7 A were measured between a thoriated-tungsten emitter and collector electrodes immersed in the laser-sustained argon plasma. Open-circuit voltages of about 1.5 V were inferred from the current-voltage load characteristics. The dominant mechanism of laser energy conversion is uncertain at this time. Much higher output powers appear possible.

  2. Pulsed neodymium-YAG laser trabeculotomy: energy requirements and replicability.

    PubMed Central

    Dutton, G N; Allan, D; Cameron, S A

    1989-01-01

    Short pulsed laser trabeculotomy has been shown to reduce intraocular pressure in patients with primary open angle glaucoma. This study seeks to determine the energy levels required to produce a fistula into the canal of Schlemm for four different Q-switched neodymium-YAG lasers. The laser was fired at fixed human trabecular meshwork specimens at a range of energy settings for each laser and the characteristics and replicability of the lesions produced were analysed. Energy levels between 3 and 5 mJ were sufficient to produce fistulae into the canal of Schlemm with an approximately 50% success rate for each instrument. Images PMID:2706207

  3. Problems of cosmic laser energy supply to users on Earth

    NASA Astrophysics Data System (ADS)

    Kuzyakov, Boris A.; Batenin, Vyatcheslav M.; Klimovskii, Ivan I.; Konev, Yuri B.

    1999-01-01

    The global cosmic systems may be used for solution of problems of the Earth supply with energy in the nearest future. Such system can involve several cosmic platforms on the polar or heliostationary orbits. The present paper deals with prospects for using 3 types of the high power IR lasers for the cosmic power systems. The first laser type is a laser optically pumped by thermal radiation; it uses an intermediate 'black body' radiator heated by solar radiation and offers substantial and important advantages. The second laser type is a CO2 laser with radio frequency pumping. We can use several 33 X 30000 W lasers in one module for approximately 1 MW cosmic laser system. The module of 320 X 320 m2 solar cells is needed for such laser system energy supply. The third laser type is a CO2 gas-dynamic laser. The numerical studies of carbon dioxide laser that is pumped by solar-thermal heating were made, and the output laser power approximately 1 MW was calculated. The parameters studies were conducted for this laser conception.

  4. The brain-derived neurotrophic factor, nerve growth factor, neurotrophin-3, and induced nitric oxide synthase expressions after low-level laser therapy in an axonotmesis experimental model.

    PubMed

    Gomes, Lessandra Esper Abdala; Dalmarco, Eduardo Monguilhott; André, Edison Sanfelice

    2012-11-01

    A robust body of evidence has shown that low-level laser therapy (LLLT) improves peripheral nerve regeneration. However, the biochemical background triggered in this process is not yet fully understood. The purpose of this study was to evaluate the mRNA expression of neurotrophic factors (brain-derived neurotrophic factor [BDNF], nerve growth factor [NGF], and neurotrophin-3, [NT-3]) and also an inflammatory marker (induced nitric oxide synthase [iNOS]) in an axonotmesis experimental model after low-level laser therapy. Thirty-six adult male Wistar rats (250-350 g) were subjected to right sciatic nerve crush injury, and 24 h later, the animals in the three different experimental groups (n=18) were irradiated on a daily basis with helium-neon laser (collimated HeNe laser, continuous emission, wavelength: 632.8 nm, power density: 0.5 mW/cm(2), irradiation time: 20 sec, energy density: 10 J/cm(2)) during 7, 14, and 21 consecutive days, respectively. The control group (n=18) underwent the same procedures, but with the equipment turned off. At the end of the experiments, animals were killed with an overdose of anesthesia to remove samples from the sciatic nerve lesion epicenter to determine the mRNA expression of BDNF, NGF, NT-3 and iNOS enzyme. Comparisons between groups showed that HeNe laser increased the mRNA expression of both BDNF and NGF factors after 14 days of LLLT, with peak expression at the 21st day. Increase in NT-3 mRNA expression was not observed. In addition, HeNe laser produced iNOS expression reduction, which played an important role in the inflammatory process. The reported data could have a relevant practical value because LLLT is a noninvasive procedure, and have revealed significant increase in neurotrophic factor expressions and inflammatory process reduction, opening the possibility of using LLLT as an important aid to nerve regeneration process.

  5. High energy conversion efficiency in laser-proton acceleration by controlling laser-energy deposition onto thin foil targets

    NASA Astrophysics Data System (ADS)

    Brenner, C. M.; Robinson, A. P. L.; Markey, K.; Scott, R. H. H.; Gray, R. J.; Rosinski, M.; Deppert, O.; Badziak, J.; Batani, D.; Davies, J. R.; Hassan, S. M.; Lancaster, K. L.; Li, K.; Musgrave, I. O.; Norreys, P. A.; Pasley, J.; Roth, M.; Schlenvoigt, H.-P.; Spindloe, C.; Tatarakis, M.; Winstone, T.; Wolowski, J.; Wyatt, D.; McKenna, P.; Neely, D.

    2014-02-01

    An all-optical approach to laser-proton acceleration enhancement is investigated using the simplest of target designs to demonstrate application-relevant levels of energy conversion efficiency between laser and protons. Controlled deposition of laser energy, in the form of a double-pulse temporal envelope, is investigated in combination with thin foil targets in which recirculation of laser-accelerated electrons can lead to optimal conditions for coupling laser drive energy into the proton beam. This approach is shown to deliver a substantial enhancement in the coupling of laser energy to 5-30 MeV protons, compared to single pulse irradiation, reaching a record high 15% conversion efficiency with a temporal separation of 1 ps between the two pulses and a 5 μm-thick Au foil. A 1D simulation code is used to support and explain the origin of the observation of an optimum pulse separation of ˜1 ps.

  6. High Average Power, High Energy Short Pulse Fiber Laser System

    SciTech Connect

    Messerly, M J

    2007-11-13

    Recently continuous wave fiber laser systems with output powers in excess of 500W with good beam quality have been demonstrated [1]. High energy, ultrafast, chirped pulsed fiber laser systems have achieved record output energies of 1mJ [2]. However, these high-energy systems have not been scaled beyond a few watts of average output power. Fiber laser systems are attractive for many applications because they offer the promise of high efficiency, compact, robust systems that are turn key. Applications such as cutting, drilling and materials processing, front end systems for high energy pulsed lasers (such as petawatts) and laser based sources of high spatial coherence, high flux x-rays all require high energy short pulses and two of the three of these applications also require high average power. The challenge in creating a high energy chirped pulse fiber laser system is to find a way to scale the output energy while avoiding nonlinear effects and maintaining good beam quality in the amplifier fiber. To this end, our 3-year LDRD program sought to demonstrate a high energy, high average power fiber laser system. This work included exploring designs of large mode area optical fiber amplifiers for high energy systems as well as understanding the issues associated chirped pulse amplification in optical fiber amplifier systems.

  7. Phase Conjugation Scaling for High Energy Lasers.

    DTIC Science & Technology

    1985-05-30

    ultimate output power (-105W) of the laser system. Our object is to demonstrate phase-conjugation of an available pulsed or cw CO2 10.6 micron lasers ...with or without guiding, has never been reported. Pilot SBB experiments with higher powers from an available pulsed CO2 laser without guiding were...L required to obtain stimulated Brillouin backscattering (-1 to 10 m for our 50 W, CO2 laser ). The dielectric wall or "cladding" which surrounds the

  8. High energy efficient solid state laser sources

    NASA Technical Reports Server (NTRS)

    Byer, Robert L.

    1987-01-01

    Investigations continue of diode-laser-pumped solid-state laser oscillators and nonlinear processes using them as sources. Diode laser array pumped Nd:YAG and Nd:glass lasers have been demonstrated. Theoretical studies of non-planar oscillators have been advanced, producing new designs which should be more resistant to feedback and offer better frequency stability. A monolithic, singly resonant Optical Parametric Oscillator in MgO:LiNbO3 has been operated.

  9. Determinants of holmium:yttrium-aluminum-garnet laser time and energy during ureteroscopic laser lithotripsy.

    PubMed

    Molina, Wilson R; Marchini, Giovanni S; Pompeo, Alexandre; Sehrt, David; Kim, Fernando J; Monga, Manoj

    2014-04-01

    To evaluate the association of preoperative noncontrast computed tomography stone characteristics, laser settings, and stone composition with cumulative holmium:yttrium-aluminum-garnet (Ho:YAG) laser time/energy. We retrospectively reviewed patients who underwent semirigid/flexible ureteroscopy and Ho:YAG laser lithotripsy (200 or 365 μm laser fiber; 0.8-1.0 J energy; and 8-10 Hz rate) at 2 tertiary care centers (April 2010-May 2012). Studied parameters were as follows: patient's characteristics; stone characteristics (location, burden, hardness, and composition); total laser time and energy; and surgical outcomes. One hundred patients met our inclusion criteria. Mean stone size was 1.01 ± 0.42 cm and volume 0.33 ± 0.04 cm(3). Mean stone radiodensity was 990 ± 296 HU, and Hounsfield units density 13.8 ± 6.0 HU/mm. All patients were considered stone free. Stone size and volume had a significant positive correlation with laser energy (R = 0.516, P <.001; R = 0.621, P <.001) and laser time (R = 0.477, P <.001; R = 0.567, P <.001). When controlling for stone size, only the correlation between HU and laser time was significant (R = 0.262, P = .011). In the multivariate analysis, with exception of stone composition (P = .103), all parameters significantly increased laser energy (R(2) = 0.524). Multivariate analysis revealed a positive significant association of laser time with stone volume (P <.001) and Hounsfield units density (P <.001; R(2) = 0.512). In multivariate analysis for laser energy, only calcium phosphate stones required less energy to fragment compared with uric acid stones. No significant differences were found in the multivariate laser time model. Ho:YAG laser cumulative energy and total time are significantly affected by stone dimensions, hardness location, fiber size, and power. Kidney location, laser fiber size, and laser power have more influence on the final laser energy than on the total laser time. Calcium phosphate stones require less laser

  10. [Effects of laser radiation on the periodontium. An animal model approach. Effects of usual radiation dosage].

    PubMed

    Noguerol Rodriguez, B; Alandez Chamorro, J; Cañizares Garcia, J; Campos Muñoz, A; Sicilia Felechosa, A

    1989-05-01

    Twenty four albino mice of forty days old were selected. Twelve forty days old albino mice were irradiated with a Helium-Neon laser source, dose of 10.50566 Jul/cm2. They were divided in two groups according to time of animal sacrifice (immediately after irradiation and ten days after). As control were used twelve mice using the same time as the experimental groups, but without radiation. T.E.M. ultrathin sections showed alteration only in the conjunctiva and in the bone tissues, but not in the epithelial tissue. The bone showed two osteocyte population according to their response to irradiation. The first population showed characteristic comparable with the controls, and the second showed alterations suggestive of a degenerative process. The connective tissue also showed two fibroblasts populations, the first showed signs of a big synthesizing activity, and the second, degenerative signs. The first fibroblast population appeared in the animals sacrificed immediately after irradiation.

  11. Sensitization of oral bacteria in biofilms to killing by light from a low-power laser.

    PubMed

    Dobson, J; Wilson, M

    1992-11-01

    Biofilms of Streptococcus sanguis, Porphyromonas gingivalis, Fusobacterium nucleatum and Actinobacillus actinomycetemcomitans were prepared on the surfaces of agar plates and a number of compounds were screened for their ability to sensitize bacteria in these biofilms to killing by light from a 7.3 mW Helium/Neon (He/Ne) laser. Toluidine blue O and methylene blue enabled detectable killing of all four target organisms after exposure to He/Ne light for 30 s. Aluminium disulphonated phthalocyanine, haematoporphyrin HCl and haematoporphyrin ester were effective photosensitizers of only some of the target organisms. These findings suggest that lethal photosensitization may be an effective means of eliminating periodontopathogenic bacteria from dental plaque.

  12. Rapid laser induced energy transfer in atomic systems

    NASA Technical Reports Server (NTRS)

    Harris, S. E.; Young, J. F.

    1978-01-01

    Analytical and experimental studies of the rapid transfer of stored populations from metastable states to selected target states of a different species are reported. Both laser-induced or laser-switched collision and laser-induced two-photon spontaneous emission are described. It is shown that the laser-induced collision method is particularly useful in the visible and UV spectral regions. It has applications in photochemistry, gas-phase kinetics, and in high-power, high-energy gas-phase lasers. The anti-Stokes source is useful in the VUV and soft X-ray spectral regions.

  13. High-power lasers for directed-energy applications.

    PubMed

    Sprangle, Phillip; Hafizi, Bahman; Ting, Antonio; Fischer, Richard

    2015-11-01

    In this article, we review and discuss the research programs at the Naval Research Laboratory (NRL) on high-power lasers for directed-energy (DE) applications in the atmosphere. Physical processes affecting propagation include absorption/scattering, turbulence, and thermal blooming. The power levels needed for DE applications require combining a number of lasers. In atmospheric turbulence, there is a maximum intensity that can be placed on a target that is independent of the initial beam spot size and laser beam quality. By combining a number of kW-class fiber lasers, scientists at the NRL have successfully demonstrated high-power laser propagation in a turbulent atmosphere and wireless recharging. In the NRL experiments, four incoherently combined fiber lasers having a total power of 5 kW were propagated to a target 3.2 km away. These successful high-power experiments in a realistic atmosphere formed the basis of the Navy's Laser Weapon System. We compare the propagation characteristics of coherently and incoherently combined beams without adaptive optics. There is little difference in the energy on target between coherently and incoherently combined laser beams for multi-km propagation ranges and moderate to high levels of turbulence. Unlike incoherent combining, coherent combining places severe constraints on the individual lasers. These include the requirement of narrow power spectral linewidths in order to have long coherence times as well as polarization alignment of all the lasers. These requirements are extremely difficult for high-power lasers.

  14. Fabrication of photovoltaic laser energy converterby MBE

    NASA Technical Reports Server (NTRS)

    Lu, Hamilton; Wang, Scott; Chan, W. S.

    1993-01-01

    A laser-energy converter, fabricated by molecular beam epitaxy (MBE), was developed. This converter is a stack of vertical p-n junctions connected in series by low-resistivity, lattice matched CoSi2 layers to achieve a high conversion efficiency. Special high-temperature electron-beam (e-beam) sources were developed especially for the MBE growth of the junctions and CoSi2 layers. Making use of the small (greater than 1.2 percent) lattice mismatch between CoSi2 and Si layers, high-quality and pinhole-free epilayers were achieved, providing a capability of fabricating all the junctions and connecting layers as a single growth process with one pumpdown. Well-defined multiple p-n junctions connected by CoSi2 layers were accomplished by employing a low growth temperature (greater than 700 C) and a low growth rate (less than 0.5 microns/hour). Producing negligible interdiffusion, the low growth temperature and rate also produced negligible pinholes in the CoSi2 layers. For the first time, a stack of three p-n junctions connected by two 10(exp -5) Ohm-cm CoSi2 layers was achieved, meeting the high conversion efficiency requirement. This process can now be optimized for high growth rate to form a practical converter with 10 p-n junctions in the stack.

  15. High energy efficient solid state laser sources

    NASA Technical Reports Server (NTRS)

    Byer, Robert L.

    1987-01-01

    Diode-laser-pumped solid-state laser oscillators and nonlinear processes were investigated. A new generation on nonplanar oscillator was fabricated, and it is anticipated that passive linewidths will be pushed to the kilohertz regime. A number of diode-pumped laser transitions were demonstrated in the rod configuration. Second-harmonic conversion efficiencies as high as 15% are routinely obtained in a servo-locked external resonant doubling crystal at 15 mW cw input power levels at 1064 nm.

  16. Phase-Shifted Laser Feedback Interferometry

    NASA Technical Reports Server (NTRS)

    Ovryn, Benjie

    1999-01-01

    Phase-shifted, laser feedback interferometry is a new diagnostic tool developed at the NASA Lewis Research Center under the Advanced Technology Development (ATD) Program directed by NASA Headquarters Microgravity Research Division. It combines the principles of phase-shifting interferometry (PSI) and laser-feedback interferometry (LFI) to produce an instrument that can quantify both optical path length changes and sample reflectivity variations. In a homogenous medium, the optical path length between two points is the product of the index of refraction and the geometric distance between the two points. LFI differs from other forms of interferometry by using the laser as both the source and the phase detector. In LFI, coherent feedback of the incident light either reflected directly from a surface or reflected after transmission through a region of interest will modulate the output intensity of the laser. The combination of PSI and LFI has produced a robust instrument, based on a low-power helium-neon (HeNe) gas laser, with a high dynamic range that can be used to measure either static or oscillatory changes of the optical path length. Small changes in optical path length are limited by the fraction of a fringe that can be measured; we can measure nonoscillatory changes with a root mean square (rms) error of the wavelength/1000 without averaging.

  17. Applications analysis of high energy lasers

    NASA Technical Reports Server (NTRS)

    Arno, R. D.; Mackay, J. S.; Nishioka, K.

    1972-01-01

    An analysis and comparison of laser technology with competing technologies were made to determine possible laser applications. The analysis was undertaken as follows: (1) possible applications were listed and categorized; (2) required components were enumerated and the characteristics of these components were extrapolated; (3) complete system characteristics were calculated parametrically for selected applications using the postulated component characteristics; and (4) where possible and appropriate, comparisons were made with competing systems. It was found that any large scale replacement of existing systems and methods by lasers requires many technological advances in laser and associated systems. However, several applications appear feasible, such as low orbit drag make-up, orbit changing, communications, and illumination applications.

  18. Measurements of Laser Absorption and Ion Energy in Femtosecond Laser-Cluster Interaction

    NASA Astrophysics Data System (ADS)

    Lin, Jing-Quan; Zhang, Jie; Li, Ying-Jun; Chen, Li-Ming; Lü, Tie-Zheng; Teng, Hao; Man, Bao-Yuan; Zhao, Li-Zeng

    2001-02-01

    Laser absorption is measured in Xe, Ar and He clusters irradiated by 5 mJ laser pulses in 150 fs. The measurements show that the absorption efficiency strongly depends on the backing pressure of the gas jets, the laser pulse duration and the atomic number Z of the working gas. The laser absorption for Xe clusters is found to be as high as 45% at a backing pressure of 20 atm and a laser intensity of 1×1015 W/cm2. Significant numbers of ions with energies up to 100 keV are detected from Xe cluster explosion. The variation trend of the average ion energy at different backing pressures is consistent with that of the laser energy absorption.

  19. High energy XeBr electric discharge laser

    DOEpatents

    Sze, R.C.; Scott, P.B.

    A high energy XeBr laser for producing coherent radiation at 282 nm is disclosed. The XeBr laser utilizes an electric discharge as the excitation source to minimize formation of molecular ions thereby minimizing absorption of laser radiation by the active medium. Additionally, HBr, is used as the halogen donor which undergoes harpooning reactions with Xe/sub M/ to form XeBr.

  20. High-energy transversely pumped alkali vapor laser

    NASA Astrophysics Data System (ADS)

    Zweiback, J.; Komashko, A.

    2011-03-01

    We report on the results from our transversely pumped alkali laser. This system uses an Alexandrite laser to pump a stainless steel laser head. The system uses methane and helium as buffer gasses. Using rubidium, the system produced up to 40 mJ of output energy when pumped with 63 mJ. Slope efficiency was 75%. Using potassium as the lasing species the system produced 32 mJ and a 53% slope efficiency.

  1. High energy XeBr electric discharge laser

    DOEpatents

    Sze, Robert C.; Scott, Peter B.

    1981-01-01

    A high energy XeBr laser for producing coherent radiation at 282 nm. The XeBr laser utilizes an electric discharge as the excitation source to minimize formation of molecular ions thereby minimizing absorption of laser radiation by the active medium. Additionally, HBr is used as the halogen donor which undergoes harpooning reactions with Xe.sub.M * to form XeBr*.

  2. Phosphate glass useful in high energy lasers

    DOEpatents

    Hayden, Y.T.; Guesto-Barnak, D.

    1992-12-22

    Disclosed is a low-or no-silica, low- or no-alkali phosphate glass useful as a laser amplifier in a multiple pass, high energy laser system having a high thermal conductivity, K[sub 90 C] >0.85 W/mK, a low coefficient of thermal expansion, [alpha][sub 20-300 C] <80[times]10[sup [minus]7]/C, low emission cross section, [sigma]<2.5[times]10[sup [minus]20] cm[sup 2], and a high fluorescence lifetime, [tau]>325 [mu]secs at 3 wt. % Nd doping, consisting essentially of (on an oxide composition basis): (Mole %) P[sub 2]O[sub 5], (52-72); Al[sub 2]O[sub 3], (0-<20); B[sub 2]O[sub 3], (>0-25); ZnO, (0-31); Li[sub 2]O, (0-5); K[sub 2]O, (0-5); Na[sub 2]O, (0-5); Cs[sub 2]O, (0-5); Rb[sub 2]O, (0-5); MgO, (>0-<30); CaO, (0-20); BaO, (0-20); SrO, (0-<20); Sb[sub 2]O[sub 3], (0-<1); As[sub 2]O[sub 3], (0-<1); Nb[sub 2]O[sub 5], (0-<1); Ln[sub 2]O[sub 3], (up to 6.5); PbO, (0-<5); and SiO[sub 2], (0-3); wherein Ln[sub 2]O[sub 3] is the sum of lanthanide oxides; [Sigma]R[sub 2]O is <5, R being Li, Na, K, Cs, and Rb; the sum of Al[sub 2]O[sub 3] and MgO is <24 unless [Sigma]R[sub 2]O is 0, then the sum of Al[sub 2]O[sub 3] and MgO is <42; and the ratio of MgO to B[sub 2]O[sub 3] is 0.48-4.20. 7 figs.

  3. High-energy krypton fluoride lasers for inertial fusion.

    PubMed

    Obenschain, Stephen; Lehmberg, Robert; Kehne, David; Hegeler, Frank; Wolford, Matthew; Sethian, John; Weaver, James; Karasik, Max

    2015-11-01

    Laser fusion researchers have realized since the 1970s that the deep UV light from excimer lasers would be an advantage as a driver for robust high-performance capsule implosions for inertial confinement fusion (ICF). Most of this research has centered on the krypton-fluoride (KrF) laser. In this article we review the advantages of the KrF laser for direct-drive ICF, the history of high-energy KrF laser development, and the present state of the art and describe a development path to the performance needed for laser fusion and its energy application. We include descriptions of the architecture and performance of the multi-kilojoule Nike KrF laser-target facility and the 700 J Electra high-repetition-rate KrF laser that were developed at the U.S. Naval Research Laboratory. Nike and Electra are the most advanced KrF lasers for inertial fusion research and energy applications.

  4. Open-ended projects in undergraduate optics and lasers courses

    NASA Astrophysics Data System (ADS)

    Hoyt, Chad

    This talk will describe the format and experience of undergraduate Lasers and Optics courses at Bethel University. The courses, which include a rigorous lecture portion, are built on open-ended research projects that have a novel aspect. They begin with four weeks of small student groups rotating between several standard laser and optics laboratory exercises. These may include, for example, alignment and characterization of a helium neon laser and measurements with a Michelson interferometer or a scanning Fabry-Pérot optical cavity. During the following seven weeks of the course, student groups (2-4 people) choose and pursue research questions in the lab. Their work culminates in a group manuscript typeset in and a twenty-minute presentation to the class. Projects in the spring, 2014 Optics course included experiments with ultracold lithium atoms in a magneto-optical trap, optical tweezers, digital holography and adaptive optics. Projects in the spring, 2015 Lasers course included ultrafast optics with a mode-locked erbium fiber laser, quantum optics, surface plasmon lasers (led by Nathan Lindquist) and a low-cost, near-infrared spectrometer. Several of these projects are related to larger scale, funded research in the physics department. The format and experience in Lasers and Optics is representative of other upper-level courses at Bethel, including Fluid Mechanics and Computer Methods. A physics education research group from the University of Colorado evaluated the spring, 2015 Lasers course. They focused on student experimental attitudes and measurements of student project ownership.

  5. Influence Of Low Intensity Laser Therapy On Diabetic Polyneuropathy

    NASA Astrophysics Data System (ADS)

    Abdel-Raoof, N. A.; Elnhas, N. G.; Elsayed, I. M.

    2011-09-01

    Diabetic peripheral neuropathy is a consequence of diabetes-mediated impairment of blood flow, and resultant hypoxia of nerves that may develop within 10 years of the onset of diabetes in 40-50% of people with type 1 or type 2 diabetes. Low Intensity Laser Therapy (LILT) has been advocated for the treatment of chronic pain disorders as blood flow is an important determinant for pain relief. Comparing the effect of Helium-Neon Laser therapy versus Infrared laser therapy on blood vessels diameter and flow as well as level of sensation for neuropathy. Twenty diabetic patients suffering from neuropathy were enrolled in the study with age 45-55 years. They were assigned randomly into two equal groups in number; Group A underwent an application of He-Neon laser while Group B underwent an application of Infrared laser. Both groups received laser for 2 months. Blood flow velocity, and blood vessel diameter were investigated by using duplex Doppler ultrasound and peripheral neuropathy parameters were investigated by Semmes-Weinstein monofilament assessment. The results revealed that He-Neon laser as well as Infrared laser groups showed significant improvement in blood flow velocity, blood vessel diameter & neuropathy tested parameters after treatment but there was no significance difference between the two types of LILT. LILT is a safe, non-invasive and drug free method for improving blood flow & sensation in patients suffering from diabetic polyneuropathy in addition to preventing one of the most threatening microvascular complications of diabetes.

  6. Effect of nonablative laser energy on joint capsular properties

    NASA Astrophysics Data System (ADS)

    Hayashi, Kei; Markel, Mark D.; Thabit, George, III; Bogdanske, John J.; Thielke, Robert J.

    1995-05-01

    Recent scientific studies evaluating laser energy for tissue welding and thermokeratoplasty have demonstrated that the application of laser energy at non-ablative levels can alter collagen's structural and biochemical properties. The application of non-ablative laser to the human shoulder joint capsule in patients with glenohumeral instability has been found to enhance stability of the joint. Based on the collective findings of these studies, we hypothesized that thermal modification of dense collagenous tissues such as joint capsule, ligament, and tendon can be achieved by applying non-ablative laser energy. The purpose of this study was to evaluate the effect of laser energy at non-ablative levels on joint capsular mechanical properties in an in vitro rabbit model. Twelve mature New Zealand white rabbits, ranging from 3.73 to 5.33 kg (4.49 +/- 0.44; mean +/- SD), were used for this experiment. Animals were euthanized and two 5 mm X 20 mm specimens were collected from the medial and lateral portion of the femoropatellar joint of each rabbit under a dissecting microscope; therefore four specimens were collected from each rabbit (right medial, right lateral, left medial, left lateral). Specimens were divided into four groups using a randomized block design; a control group and 3 laser power settings (5 watts (5 W), 10 watts (10 W), 15 watts (15 W)). Laser energy was applied using the Ho:YAG laser in four transverse passes across the tissue at a velocity of 2 mm/sec and distance from the tip of the handpiece to the synovial surface of the specimen set at 1.5 mm in a 37 degree(s)C tissue bath of lactated Ringer's solution. Forty-eight specimens (n equals 12) were mechanically tested to determine single cycle structural properties (stiffness) and viscoelastic properties (% relaxation) before and after laser treatment. Shrinkage of the tissue and the loads required to return specimens to their original length were recorded after laser treatment. The application of laser

  7. ND:GLASS LASER DESIGN FOR LASER ICF FISSION ENERGY (LIFE)

    SciTech Connect

    Caird, J A; Agrawal, V; Bayramian, A; Beach, R; Britten, J; Chen, D; Cross, R; Ebbers, C; Erlandson, A; Feit, M; Freitas, B; Ghosh, C; Haefner, C; Homoelle, D; Ladran, T; Latkowski, J; Molander, W; Murray, J; Rubenchik, S; Schaffers, K; Siders, C W; Stappaerts, E; Sutton, S; Telford, S; Trenholme, J; Barty, C J

    2008-10-28

    We have developed preliminary conceptual laser system designs for the Laser ICF (Inertial Confinement Fusion) Fission Energy (LIFE) application. Our approach leverages experience in high-energy Nd:glass laser technology developed for the National Ignition Facility (NIF), along with high-energy-class diode-pumped solid-state laser (HEC-DPSSL) technology developed for the DOE's High Average Power Laser (HAPL) Program and embodied in LLNL's Mercury laser system. We present laser system designs suitable for both indirect-drive, hot spot ignition and indirect-drive, fast ignition targets. Main amplifiers for both systems use laser-diode-pumped Nd:glass slabs oriented at Brewster's angle, as in NIF, but the slabs are much thinner to allow for cooling by high-velocity helium gas as in the Mercury laser system. We also describe a plan to mass-produce pump-diode lasers to bring diode costs down to the order of $0.01 per Watt of peak output power, as needed to make the LIFE application economically attractive.

  8. A High Energy 2-microns Laser for Multiple Lidar Applications

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Singh, Upendra N.; Barnes, James C.; Barnes, Norman P.; Petros, Mulugeta

    2000-01-01

    Solid-state 2-microns laser has been receiving considerable interest because of its eye-safe property and efficient diode pump operation, It has potential for multiple lidar applications to detect water vapor. carbon dioxide and winds. In this paper, we describe a 2-microns double pulsed Ho:Tm:YLF laser and end-pumped amplifier system. A comprehensive theoretical model has been developed to aid the design and optimization of the laser performance. In a single Q-switched pulse operation the residual energy stored in the Tm atoms will be wasted. However, in a double pulses operation mode, the residual energy stored in the Tm atoms will repopulate the Ho atoms that were depleted by the extraction of the first Q-switched pulse. Thus. the Tin sensitized Ho:YLF laser provides a unique advantage in applications that require double pulse operation, such as Differential Absorption Lidar (DIAL). A total output energy of 146 mJ per pulse pair under Q-switch operation is achieved with as high as 4.8% optical to optical efficiency. Compared to a single pulse laser, 70% higher laser efficiency is realized. To obtain high energy while maintaining the high beam quality, a master-oscillator-power-amplifier 2-microns system is designed. We developed an end-pumped Ho:Tm:YLF disk amplifier. This amplifier uses two diode arrays as pump source. A non-imaging lens duct is used to couple the radiation from the laser diode arrays to the laser disk. Preliminary result shows that the efficiency of this laser can be as high as 3%, a factor of three increases over side-pump configuration. This high energy, highly efficient and high beam quality laser is a promising candidate for use in an efficient, multiple lidar applications.

  9. A High Energy 2-microns Laser for Multiple Lidar Applications

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Singh, Upendra N.; Barnes, James C.; Barnes, Norman P.; Petros, Mulugeta

    2000-01-01

    Solid-state 2-microns laser has been receiving considerable interest because of its eye-safe property and efficient diode pump operation, It has potential for multiple lidar applications to detect water vapor. carbon dioxide and winds. In this paper, we describe a 2-microns double pulsed Ho:Tm:YLF laser and end-pumped amplifier system. A comprehensive theoretical model has been developed to aid the design and optimization of the laser performance. In a single Q-switched pulse operation the residual energy stored in the Tm atoms will be wasted. However, in a double pulses operation mode, the residual energy stored in the Tm atoms will repopulate the Ho atoms that were depleted by the extraction of the first Q-switched pulse. Thus. the Tin sensitized Ho:YLF laser provides a unique advantage in applications that require double pulse operation, such as Differential Absorption Lidar (DIAL). A total output energy of 146 mJ per pulse pair under Q-switch operation is achieved with as high as 4.8% optical to optical efficiency. Compared to a single pulse laser, 70% higher laser efficiency is realized. To obtain high energy while maintaining the high beam quality, a master-oscillator-power-amplifier 2-microns system is designed. We developed an end-pumped Ho:Tm:YLF disk amplifier. This amplifier uses two diode arrays as pump source. A non-imaging lens duct is used to couple the radiation from the laser diode arrays to the laser disk. Preliminary result shows that the efficiency of this laser can be as high as 3%, a factor of three increases over side-pump configuration. This high energy, highly efficient and high beam quality laser is a promising candidate for use in an efficient, multiple lidar applications.

  10. High energy KrCl electric discharge laser

    DOEpatents

    Sze, R.C.; Scott, P.B.

    A high energy KrCl laser is presented for producing coherent radiation at 222 nm. Output energies on the order of 100 mJ per pulse are produced utilizing a discharge excitation source to minimize formation of molecular ions, thereby minimizing absorption of laser radiation by the active medium. Additionally, HCl is used as a halogen donor which undergoes a harpooning reaction with metastable Kr/sub M/ to form KrCl.

  11. Laser Energy Transmission to a Disaster Data Collection Helicopter

    NASA Astrophysics Data System (ADS)

    Takeda, Kazuya; Kawashima, Nobuki

    We developed a laser energy transmission system for a disaster data collection helicopter. A demonstration test-flight was successfully done in a large indoor arena at Kobe. The laser energy transmission system (max output power : 580 W/cw) was tracking on a helicopter for a long-time flight at a distance of 30 m. This test flight shows the possibility of tools for a collecting data of a natural disaster and a nuclear power plant disaster.

  12. High energy KrCl electric discharge laser

    DOEpatents

    Sze, Robert C.; Scott, Peter B.

    1981-01-01

    A high energy KrCl laser for producing coherent radiation at 222 nm. Output energies on the order of 100 mJ per pulse are produced utilizing a discharge excitation source to minimize formation of molecular ions, thereby minimizing absorption of laser radiation by the active medium. Additionally, HCl is used as a halogen donor which undergoes a harpooning reaction with metastable Kr.sub.M * to form KrCl.

  13. Laser safety research and modeling for high-energy laser systems

    NASA Astrophysics Data System (ADS)

    Smith, Peter A.; Montes de Oca, Cecilia I.; Kennedy, Paul K.; Keppler, Kenneth S.

    2002-06-01

    The Department of Defense has an increasing number of high-energy laser weapons programs with the potential to mature in the not too distant future. However, as laser systems with increasingly higher energies are developed, the difficulty of the laser safety problem increases proportionally, and presents unique safety challenges. The hazard distance for the direct beam can be in the order of thousands of miles, and radiation reflected from the target may also be hazardous over long distances. This paper details the Air Force Research Laboratory/Optical Radiation Branch (AFRL/HEDO) High-Energy Laser (HEL) safety program, which has been developed to support DOD HEL programs by providing critical capability and knowledge with respect to laser safety. The overall aim of the program is to develop and demonstrate technologies that permit safe testing, deployment and use of high-energy laser weapons. The program spans the range of applicable technologies, including evaluation of the biological effects of high-energy laser systems, development and validation of laser hazard assessment tools, and development of appropriate eye protection for those at risk.

  14. High-Energy Passive Mode-Locking of Fiber Lasers.

    PubMed

    Ding, Edwin; Renninger, William H; Wise, Frank W; Grelu, Philippe; Shlizerman, Eli; Kutz, J Nathan

    2012-01-01

    Mode-locking refers to the generation of ultrashort optical pulses in laser systems. A comprehensive study of achieving high-energy pulses in a ring cavity fiber laser that is passively mode-locked by a series of waveplates and a polarizer is presented in this paper. Specifically, it is shown that the multipulsing instability can be circumvented in favor of bifurcating to higher-energy single pulses by appropriately adjusting the group velocity dispersion in the fiber and the waveplate/polarizer settings in the saturable absorber. The findings may be used as practical guidelines for designing high-power lasers since the theoretical model relates directly to the experimental settings.

  15. Traveling-wave laser-produced-plasma energy source for photoionization laser pumping and lasers incorporating said

    DOEpatents

    Sher, Mark H.; Macklin, John J.; Harris, Stephen E.

    1989-09-26

    A traveling-wave, laser-produced-plasma, energy source used to obtain single-pass gain saturation of a photoionization pumped laser. A cylindrical lens is used to focus a pump laser beam to a long line on a target. Grooves are cut in the target to present a surface near normal to the incident beam and to reduce the area, and hence increase the intensity and efficiency, of plasma formation.

  16. Efficient energy conversion from laser to proton beam in a laser-foil interaction

    SciTech Connect

    Takahashi, K.; Kawata, S.; Satoh, D.; Barada, D.; Ma, Y. Y.; Kong, Q.; Wang, P. X.

    2010-09-15

    Demonstrated is a remarkable improvement on the energy conversion efficiency from laser to protons in a laser-foil interaction by particle simulations. The total laser-proton energy conversion efficiency becomes 16.7%, although a conventional plane foil target serves a rather low efficiency. In our previous study we found that Al multihole thin-foil target was efficient for the energy conversion from laser to protons [Y. Nodera and S. Kawata, Phys. Rev. E 78, 046401 (2008)], and the energy conversion efficiency was 9.3%. In our 2.5-dimensional particle-in-cell simulations the Al multihole structure is also employed, and the parameters of the Al multihole wing width and length are optimized in the paper. The present results clarify the roles of the target Al hole width and depth in the laser-proton energy conversion. The main physical reason for the enhancement of the conversion efficiency is a reduction of the laser reflection at the target surface area. The optimized multihole foil target provides a remarkable increase in the laser-proton energy conversion efficiency as shown above.

  17. Efficiency enhancement using electron energy detuning in a laser seeded free electron laser amplifier

    SciTech Connect

    Wang, X. J.; Watanabe, T.; Shen, Y.; Li, R. K.; Murphy, J. B.; Tsang, T.; Freund, H. P.

    2007-10-29

    We report the experimental characterization of efficiency enhancement in a single-pass seeded free-electron laser (FEL) where the electron energy is detuned from resonance. Experiments show a doubling of the efficiency for beam energies above the resonant energy. Measurements of the FEL spectra versus energy detuning shows that the wavelength is governed by the seed laser. The variation in the gain length with beam energy was also observed. Good agreement is found between the experiment and numerical simulations using the MEDUSA simulation code.

  18. Measuring Energy Scaling of Laser Driven Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Williams, Jackson; Goyon, Clement; Mariscal, Derek; Pollock, Brad; Patankar, Siddharth; Moody, John

    2016-10-01

    Laser-driven magnetic fields are of interest in particle confinement, fast ignition, and ICF platforms as an alternative to pulsed power systems to achieve many times higher fields. A comprehensive model describing the mechanism responsible for creating and maintaining magnetic fields from laser-driven coils has not yet been established. Understanding the scaling of key experimental parameters such as spatial and temporal uniformity and duration are necessary to implement coil targets in practical applications yet these measurements prove difficult due to the highly transient nature of the fields. We report on direct voltage measurements of laser-driven coil targets in which the laser energy spans more than four orders of magnitude. Results suggest that at low energies, laser-driven coils can be modeled as an electric circuit; however, at higher energies plasma effects dominate and a simple circuit treatment is insufficient to describe all observed phenomenon. The favorable scaling with laser power and pulse duration, observed in the present study and others at kilojoule energies, has positive implications for sustained, large magnetic fields for applications on the NIF. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  19. Laser interaction based on resonance saturation (LIBORS): an alternative to inverse bremsstrahlung for coupling laser energy into a plasma.

    PubMed

    Measures, R M; Drewell, N; Cardinal, P

    1979-06-01

    Resonance saturation represents an efficient and rapid method of coupling laser energy into a gaseous medium. In the case of a plasma superelastic collision quenching of the laser maintained resonance state population effectively converts the laser beam energy into translational energy of the free electrons. Subsequently, ionization of the laser pumped species rapidly ensues as a result of both the elevated electron temperature and the effective reduction of the ionization energy for those atoms maintained in the resonance state by the laser radiation. This method of coupling laser energy into a plasma has several advantages over inverse bremsstrahlung and could therefore be applicable to several areas of current interest including plasma channel formation for transportation of electron and ion beams, x-ray laser development, laser fusion, negative ion beam production, and the conversion of laser energy to electricity.

  20. The National Ignition Facility High-Energy Ultraviolet Laser System

    SciTech Connect

    Moses, E I

    2003-09-15

    The National Ignition Facility (NIF), currently under construction at the Lawrence Livermore National Laboratory, is a stadium-sized facility containing a 192-beam, 1 .&Megajoule, 500-Terawatt, ultraviolet laser system together with a 10-meter diameter target chamber with room for nearly 100 experimental diagnostics. When completed, NIF will be the world's largest and most energetic laser experimental system, providing an international center to study inertial confinement fusion and the physics of matter at extreme energy densities and pressures. NIF's 192 energetic laser beams will compress fusion targets to conditions required for thermonuclear burn, liberating more energy than required to initiate the fusion reactions. Other NIF experiments will allow the study of physical processes at temperatures approaching 10{sup 8} K and 10{sup 11} Bar, conditions that exist naturally only in the interior of stars, planets and in nuclear weapons. NIF is now entering the first phases of its laser commissioning program. The first four beams of the NIF laser system have generated 106 kilojoules of infrared light and over 10 kJ at the third harmonic (351 nm). NIF's target experimental systems are also being installed in preparation for experiments to begin in late 2003. This paper provides a detailed look the NIF laser systems, the significant laser and optical systems breakthroughs that were developed, the results of recent laser commissioning shots, and plans for commissioning diagnostics for experiments on NIF.

  1. Optical properties of barcode symbols for laser scanning

    NASA Astrophysics Data System (ADS)

    Quinn, Anna M.; Eastman, Jay M.

    1991-02-01

    Not all bar code symbols are alike. This paper will discuss the characteristics of bar code symbols which can make or break a bar code laser scanner''s performance in a specific application. These characteristics can be broken down into three catergories: Substrates " inks" ( inks toners dyes etc. ) and the light source used to read the symbol. The characteristics of the substrate can be further separated into three groups: the medium used the scattering properties of the the medium and overlaminates. Intrinsic properties of the medium can include " paper noise" resulting from the grain of paper metal grain or a retro-reflective background. Scattering characteristics cover angular distribution of the scattered light absolute scatter levels from the substrate internal scatter and specularly reflected light. Overlaminates contribute their own assets and liabilities in successfully choosing a scanner that will perform for all your needs. The inks used and the light source utilized work in conjunction with each other in determining the performance of a laser scanner. The spectral characteristics and composition of the ink determine which light source the scanner must employ to be used to successfully interpret the symbol. The three common light sources available in laser bar code scanners are helium-neon lasers visible laser diodes and infra-red laser diodes. Experimental data will be presented illustrating the optical properties discussedIbove.

  2. Laser speckle imaging of atherosclerotic plaques through optical fiber bundles

    PubMed Central

    Nadkarni, Seemantini K.; Bouma, Brett E.; Yelin, Dvir; Gulati, Amneet; Tearney, Guillermo J.

    2009-01-01

    Laser speckle imaging (LSI), a new technique that measures an index of plaque viscoelasticity, has been investigated recently to characterize atherosclerotic plaques. These prior studies demonstrated the diagnostic potential of LSI for detecting high-risk plaques and were conducted ex vivo. To conduct intracoronary LSI in vivo, the laser speckle pattern must be transmitted from the coronary wall to the image detector in the presence of cardiac motion. Small-diameter, flexible optical fiber bundles, similar to those used in coronary angioscopy, may be incorporated into an intravascular catheter for this purpose. A key challenge is that laser speckle is influenced by inter-fiber leakage of light, which may be exacerbated during bundle motion. In this study, we tested the capability of optical fiber bundles to transmit laser speckle patterns obtained from atherosclerotic plaques and evaluated the influence of motion on the diagnostic accuracy of fiber bundle-based LSI. Time-varying helium-neon laser speckle images of aortic plaques were obtained while cyclically moving the flexible length of the bundle to mimic coronary motion. Our results show that leached fiber bundles may reliably transmit laser speckle images in the presence of cardiac motion, providing a viable option to conduct intracoronary LSI. PMID:19021396

  3. High-energy lasers by using distributed reflection: A concept

    NASA Technical Reports Server (NTRS)

    Saffren, M. M.

    1975-01-01

    Lasers may be made with higher energy photons than heretofore possible. It has been proposed that vacuum ultraviolet lasing can be obtained by bombarding superfluid helium with electron beam, while coupling acoustic energy into helium to set up standing waves in fluid.

  4. Acoustical problems in high energy pulsed E-beams lasers

    NASA Technical Reports Server (NTRS)

    Horton, T. E.; Wylie, K. F.

    1976-01-01

    During the pulsing of high energy, CO2, electron beam lasers, a significant fraction of input energy ultimately appears as acoustical disturbances. The magnitudes of these disturbances were quantified by computer analysis. Acoustical and shock impedance data are presented on materials (Rayleigh type) which show promise in controlling acoustical disturbance in E-beam systems.

  5. Energy transfer between laser filaments in liquid methanol.

    PubMed

    Strycker, B D; Springer, M; Trendafilova, C; Hua, X; Zhi, M; Kolomenskii, A A; Schroeder, H; Strohaber, J; Schuessler, H A; Kattawar, G W; Sokolov, A V

    2012-01-01

    We demonstrate energy exchange between two filament-forming femtosecond laser beams in liquid methanol. Our results are consistent with those of previous works documenting coupling between filaments in air; in addition, we identify an unreported phenomenon in which the direction of energy exchange oscillates at increments in the relative pulse delay equal to an optical period (2.6 fs). Energy transfer from one filament to another may be used in remote sensing and spectroscopic applications utilizing femtosecond laser filaments in water and air.

  6. Field experiment of laser energy transmission and laser to electric conversion

    SciTech Connect

    Yugami, H.; Kanamori, Y.; Arashi, H.; Niino, M.; Moro, A.; Eguchi, K.; Okada, Y.; Endo, A.

    1997-12-31

    In this paper, the authors report the result of the field experiment of laser power transmission over 500m using different laser systems, i.e., CO{sub 2}, YAG, etc. The efficiency of energy transmission for long time period under various meteorological conditions was measured. They have observed large and long time scale fluctuation of beam pointing. It is found that the position of laser beam at the receiving site is correlated with the temperature difference between laser path height and ground. The laser to electricity conversion experiment has been performed using GaAs, c-Si, tandem-type a-Si, and CuInSe{sub 2} (CIS) solar cells. Finally, they briefly introduce the proposal on the space experiment of laser power transmission at Japanese Experiment Module (JEM) on the international space station.

  7. The FIDIAS project: Development of a Micromegas TPC for the detection of low-energy heavy ions

    NASA Astrophysics Data System (ADS)

    Iguaz, Francisco José; Panebianco, Stefano; Axiotis, Michael; Druillole, Frédéric; Fanourakis, George; Geralis, Theodoros; Giomataris, Ioannis; Harissopulos, Sotirios; Lagoyannis, Anastasios; Papaevangelou, Thomas

    2014-01-01

    Time Projection Chambers are widely used since many years for tracking and identification of charged particles in high energy physics. We present here a new R&D project, called FIDIAS, meant to investigate the feasibility of a Micromegas TPC for low energy heavy ions detection. In this framework, a TPC prototype based on Micromegas bulk technique has been extensively tested with spontaneous fission source. A deep analysis of the experimental results has been realized leading to a full characterization of the prototype in terms of gain, energy resolution and track reconstruction as a function of three working gas: helium, neon and argon. The encouraging results have also been compared to simulations, showing the Micromegas TPC is a very well suited detector for the detection of heavy ions in nuclear reactions at low energy.

  8. Effect of mass and density of ambient gas on the interaction of laser-blow-off plasma plumes propagating in close proximity

    SciTech Connect

    Kumar, Bhupesh; Singh, R. K.; Kumar, Ajai

    2016-04-15

    The effects of mass and pressure of ambient gas on the propagation dynamics of two laser-blow-off plasma plumes created in close proximity are investigated. A time gated fast imaging technique is used for recording the images of the laterally colliding plumes under different experimental conditions. Pressure is varied from 0.1 to 3 mbar in three ambient, i.e., helium, neon, and argon. Emphasis is given on the nature of shock-shock interaction under different ambient conditions. It has been observed that the shock-velocity, shape, strength, and their interactions are strongly dependent on the mass and density of the ambient gases. The role of the interacting shocks and their subsequent reflections on the formation and geometrical shape of the interaction region in different ambient conditions is briefly described.

  9. Effect of mass and density of ambient gas on the interaction of laser-blow-off plasma plumes propagating in close proximity

    NASA Astrophysics Data System (ADS)

    Kumar, Bhupesh; Singh, R. K.; Kumar, Ajai

    2016-04-01

    The effects of mass and pressure of ambient gas on the propagation dynamics of two laser-blow-off plasma plumes created in close proximity are investigated. A time gated fast imaging technique is used for recording the images of the laterally colliding plumes under different experimental conditions. Pressure is varied from 0.1 to 3 mbar in three ambient, i.e., helium, neon, and argon. Emphasis is given on the nature of shock-shock interaction under different ambient conditions. It has been observed that the shock-velocity, shape, strength, and their interactions are strongly dependent on the mass and density of the ambient gases. The role of the interacting shocks and their subsequent reflections on the formation and geometrical shape of the interaction region in different ambient conditions is briefly described.

  10. Spectroscopic properties, energy transfer dynamics, and laser performance of thulium-holmium doped laser systems

    NASA Astrophysics Data System (ADS)

    Kalisky, Yehoshua Y.; Rotman, Stanley R.; Boulon, Georges; Pedrini, Christian; Brenier, Alain

    1994-07-01

    Spectroscopic studies using laser induced fluorescence and numerical modelling of energy transfer and back transfer mechanism are reported in Er:Tm:Ho:YLF, Cr:Tm:Ho:YAG and Cr:Tm:YAG laser crystals at various temperatures (10 K - 300 K). Direct energy transfer from Tm3+ excited states to Ho3+ 5I7 emitting level was observed and analyzed both in YAG and YLF. Further analysis of Cr3+ and Tm3+ time-dependent emission curves indicate a strong correlation of chromium- thulium pairs. Pulsed operation of holmium laser at high temperature will be presented.

  11. High energy efficient solid state laser sources

    NASA Technical Reports Server (NTRS)

    Byer, Robert L.

    1989-01-01

    Recent progress in the development of highly efficient coherent optical sources was reviewed. This work has focused on nonlinear frequency conversion of the highly coherent output of the non-planar ring laser oscillators developed earlier in the program, and includes high efficiency second harmonic generation and the operation of optical parametric oscillators for wavelength diversity and tunability.

  12. High energy efficient solid state laser sources

    NASA Technical Reports Server (NTRS)

    Byer, Robert L.

    1988-01-01

    Recent progress in the development of highly efficient coherent optical sources is reviewed. This work focusses on nonlinear frequency conversion of the highly coherent output of the Non-Planar Ring Laser Oscillators developed earlier in the program, and includes high efficiency second harmonic generation and the operation of optical parametric oscillators for wavelength diversity and tunability.

  13. Laser energy density, structure and properties of pulsed-laser deposited zinc oxide films

    NASA Astrophysics Data System (ADS)

    Tsoutsouva, M. G.; Panagopoulos, C. N.; Kompitsas, M.

    2011-05-01

    Zinc oxide thin films were deposited on soda lime glass substrates by pulsed laser deposition in an oxygen-reactive atmosphere at 20 Pa and a constant substrate temperature at 300 °C. A pulsed KrF excimer laser, operated at 248 nm with pulse duration 10 ns, was used to ablate the ceramic zinc oxide target. The structure, the optical and electrical properties of the as-deposited films were studied in dependence of the laser energy density in the 1.2-2.8 J/cm 2 range, with the aid of X-ray Diffraction, Atomic Force Microscope, Transmission Spectroscopy techniques, and the Van der Pauw method, respectively. The results indicated that the structural and optical properties of the zinc oxide films were improved by increasing the laser energy density of the ablating laser. The surface roughness of the zinc oxide film increased with the decrease of laser energy density and both the optical bang gap and the electrical resistivity of the film were significantly affected by the laser energy density.

  14. Research of the temperature measurement of high-energy laser energy meter and energy loss compensation technique

    NASA Astrophysics Data System (ADS)

    Yu, Xun; Wang, Hui; Wu, Ji'an; Wang, Fang; Li, Qian

    2009-11-01

    The energy measurement of high energy laser is converts incident laser energy into heat energy, calculates energy utilizing absorber temperature rise, thus the energy value can be gained. Temperature measurement of high-energy laser energy meter and energy loss compensation during the course of the measurement were studied here. Firstly, temperature-resistance characteristics of resistance wire was analyzed, which was winded on exterior surface of the absorbing cavity of high-energy laser energy meter and used in temperature measurement. Least square method was used to process experiment data and a compensation model was established to calibrate the relationship of temperature vs. resistance. Experiment proved that, error between resistance wire and Pt100 is less than 0.01Ω and temperature error is less than 0.02°C. This greatly improves accuracy of the high energy meter measurement result. Secondly, aimed to the compensation of laser energy loss caused by absorbing cavity's heat exchange, the heat energy loss of absorbing cavity, resulted from thermal radiation, heat convection and heat conduction was analyzed based on heat transfer theory. Its mathematics model was established. Least square method was used to fit a curve of experiment data in order to compensate energy loss. Repetitiveness of measurement is 0.7%, which is highly improved.

  15. Technical challenges for the future of high energy lasers

    SciTech Connect

    LaFortune, K N; Hurd, R L; Fochs, S N; Rotter, M D; Pax, P H; Combs, R L; Olivier, S S; Brase, J M; Yamamoto, R M

    2007-01-10

    The Solid-State, Heat-Capacity Laser (SSHCL) program at Lawrence Livermore National Laboratory is a multi-generation laser development effort scalable to the megawatt power levels with current performance approaching 100 kilowatts. This program is one of many designed to harness the power of lasers for use as directed energy weapons. There are many hurdles common to all of these programs that must be overcome to make the technology viable. There will be a in-depth discussion of the general issues facing state-of-the-art high energy lasers and paths to their resolution. Despite the relative simplicity of the SSHCL design, many challenges have been uncovered in the implementation of this particular system. An overview of these and their resolution are discussed. The overall system design of the SSHCL, technological strengths and weaknesses, and most recent experimental results will be presented.

  16. Technical challenges for the future of high energy lasers

    NASA Astrophysics Data System (ADS)

    LaFortune, K. N.; Hurd, R. L.; Fochs, S. N.; Rotter, M. D.; Pax, P. H.; Combs, R. L.; Olivier, S. S.; Brase, J. M.; Yamamoto, R. M.

    2007-02-01

    The Solid-State, Heat-Capacity Laser (SSHCL) program at Lawrence Livermore National Laboratory is a multi-generation laser development effort scalable to the megawatt power levels with current performance approaching 100 kilowatts. This program is one of many designed to harness the power of lasers for use as directed energy weapons. There are many hurdles common to all of these programs that must be overcome to make the technology viable. There will be a in-depth discussion of the general issues facing state-of-the-art high energy lasers and paths to their resolution. Despite the relative simplicity of the SSHCL design, many challenges have been uncovered in the implementation of this particular system. An overview of these and their resolution are discussed. The overall system design of the SSHCL, technological strengths and weaknesses, and most recent experimental results will be presented.

  17. Effects of CO2 laser energy on dentin permeability.

    PubMed

    Pashley, E L; Horner, J A; Liu, M; Kim, S; Pashley, D H

    1992-06-01

    The effect of a CO2 laser on the structure and permeability of smear layer-covered human dentin was evaluated in vitro. Three different energy levels were used (11, 113, and 566 J/cm2). The lowest exposure to the laser energy increased dentin permeability, measured as a hydraulic conductance, due to partial measured as a hydraulic conductance, due to partial loss of the superficial smear layer and smear plugs. The intermediate energy level also increased dentin permeability by crater formation, making the dentin thinner. The lack of uniform glazing of the surface of the crater, leaving its surface porous and in communication with the underlying dentinal tubules also contributed to the increase in dentin permeability seen with the intermediate laser energy. The highest laser energy produced complete glazing of the crater surfaces and sealed the dentinal tubules beneath the crater. However, it also completely removed the smear layer in a halo zone about 100-microns wide around each crater which increased the permeability of the pericrater dentin at the same time it decreased the permeability of the dentin within the crater. The combined use of scanning electron microscopy and permeability measurements provides important complementary information that is essential in evaluating the effects of lasers on dentin.

  18. Free electron lasers for transmission of energy in space

    NASA Technical Reports Server (NTRS)

    Segall, S. B.; Hiddleston, H. R.; Catella, G. C.

    1981-01-01

    A one-dimensional resonant-particle model of a free electron laser (FEL) is used to calculate laser gain and conversion efficiency of electron energy to photon energy. The optical beam profile for a resonant optical cavity is included in the model as an axial variation of laser intensity. The electron beam profile is matched to the optical beam profile and modeled as an axial variation of current density. Effective energy spread due to beam emittance is included. Accelerators appropriate for a space-based FEL oscillator are reviewed. Constraints on the concentric optical resonator and on systems required for space operation are described. An example is given of a space-based FEL that would produce 1.7 MW of average output power at 0.5 micrometer wavelength with over 50% conversion efficiency of electrical energy to laser energy. It would utilize a 10 m-long amplifier centered in a 200 m-long optical cavity. A 3-amp, 65 meV electrostatic accelerator would provide the electron beam and recover the beam after it passes through the amplifier. Three to five shuttle flights would be needed to place the laser in orbit.

  19. LASERS: Pulse-periodic iodine photodissociation laser with a high output energy

    NASA Astrophysics Data System (ADS)

    Abashev, R. T.; Kamrukov, A. S.; Kozlov, N. P.; Korolenko, V. G.; Ovchinnikov, P. A.; Protasov, Yu S.; Rychkov, M. L.; Telenkov, I. I.

    1991-05-01

    A description is given of a pulse-periodic iodine laser pumped by high-power nonmagnetic plasma-dynamic flashlamps and incorporating a thermal closed circulation system for the active medium (n-C4F9I-C6F14 mixture) based on a condensation-evaporation cycle. An investigation was made of the energy balance and the output characteristics of the laser under single-pulse and pulse-periodic conditions at a repetition frequency of 17-50 mHz. The laser output energy was ~ 0.5 kJ, the pulse duration was 35-40 μs, the angular divergence was ~ 0.56 mrad, and the efficiency in terms of the electrical energy deposited in the pumping system was ~ 1 %. Stimulated emission during the complete laser pulse was achieved at the frequency of the unperturbed F' = 3 →F = 4 electronic transition in the hyperfine structure of the iodine atom.

  20. Influence of laser energy on the electron temperature of a laser-induced Mg plasma

    NASA Astrophysics Data System (ADS)

    Asamoah, Emmanuel; Hongbing, Yao

    2017-01-01

    The magnesium plasma induced by a 1064-nm Q-switched Nd:YAG laser in atmospheric air was investigated. The evolution of the plasma was studied by acquiring spectral images at different laser energies and delay times. We observed that the intensities of the spectral lines decrease with larger delay times. The electron temperature was determined using the Boltzmann plot method. At a delay time of 100 ns and laser energy of 350 mJ, the electron temperature attained their highest value at 10164 K and then decreases slowly up to 8833.6 K at 500 ns. We found that the electron temperature of the magnesium plasma increases rapidly with increasing laser energy.

  1. INTERACTION OF LASER RADIATION WITH MATTER. LASER PLASMA: Mechanism of high-energy electron production in a laser plasma

    NASA Astrophysics Data System (ADS)

    Belyaev, V. S.

    2004-01-01

    A mechanism of high-energy electron production in the interaction of high-intensity short laser pulses with a solid target is proposed and analysed. The theoretical dependences of fast-electron kinetic energy on the parameters of laser radiation and target material are given. The effect of ionisation of the target material is considered. The generation of ultrastrong magnetic fields in the laser plasma is shown to play the key part in the formation, transfer, and acceleration of electron beams. This results in the production of vortex electric fields accelerating electrons. The theoretical dependences yield well-proved limits for the electron energy and are in good agreement with the results of experiments performed on high-intensity laser setups, including the results obtained with participation of the author.

  2. RECENT LASER ACCIDENTS AT DEPARTMENT OF ENERGY LABORATORIES

    SciTech Connect

    ODOM, CONNON R.

    2007-02-02

    Recent laser accidents and incidents at research laboratories across the Department of Energy complex are reviewed in this paper. Factors that contributed to the accidents are examined. Conclusions drawn from the accident reports are summarized and compared. Control measures that could have been implemented to prevent the accidents will be summarized and compared. Recommendations for improving laser safety programs are outlined and progress toward achieving them are summarized.

  3. Impact of Fast Ignition on Laser Fusion Energy Development

    NASA Astrophysics Data System (ADS)

    Mirna, Kunioki

    2016-10-01

    Reviewed are the early history of Japanese laser fusion research and the recent achievement of fast ignition research at Institute of Laser Engineering (ILE), Osaka University. After the achievement of high density compression at Osaka University, LLE of University Rochester, and LLNL, the critical issue of Inertial Fusion Energy (IFE) research became the formation of hot spark in a compressed plasma. In this lecture, the history of the fast ignition research will be reviewed and future prospects are presented.

  4. Energy Absorption Structure of Laser Supported Detonation Wave

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Yamaguchi, Toshikazu; Hatai, Keigo; Komurasaki, Kimiya; Arakawa, Yoshihiro

    2010-05-01

    In Repetitive Pulsed (RP) laser propulsion, when the high energy laser beam is focused in the thruster, Laser Supported Detonation (LSD) wave is generated. This LSD wave converts the laser energy to the enthalpy of the blast wave, which will then apply impulse to the wall of the thruster. Therefore, the energy absorption structure and sustaining condition of LSD wave are important to be understood, which was still not clear though some visualized experiments have been conducted by Ushio et al. before. In this paper, 2-wavelength Mach-Zehnder interferometry is brought to investigate the electron density distribution of LSD area. At the same time, the temperature of the laser induced plasma is measured by an emission spectroscopy experiment, and calculated based on the assumption of local thermal equilibrium. The results show that in LSD, the electron density has a peak (as high as 2×1024[m-3]) behind the shock wave. The irradiated laser can be entirely absorbed before reaching the position of this peak. As a result, a new peak is always generating in front of the old one and this propagating has the same velocity as that of the blast wave. In this way, high heating ratio is sustained right after the shock front. However, as the laser pulse energy becomes lower, the propagating peak cannot catch up with the blast wave anymore, which leads to a termination of the LSD wave. From this study, it is found that for sustaining the LSD wave, a sufficiently thin laser absorption layer is necessary.

  5. Interaction of repetitively pulsed high energy laser radiation with matter

    NASA Astrophysics Data System (ADS)

    Hugenschmidt, M.

    1986-05-01

    Laser target interaction processes and methods of improving the overall energy balance are discussed. This can be achieved with high repetition rate pulsed lasers even for initially highly reflecting materials, such as metals. Experiments were performed using a pulsed CO2 laser at mean powers up to 2 KW and repetition rates up to 100 Hz. The rates of temperature rise of aluminum for example are increased by more than a factor of 3 as compared to cw-radiation of comparable power density. Similar improvements are found for the overall absorptivities, that are increased by more than an order of magnitude.

  6. High-energy Nd:glass laser for oncology

    NASA Astrophysics Data System (ADS)

    Boutchenkov, Vyatcheslav A.; Utenkov, Boris I.; Zaitsev, V. K.; Bayanov, Valentin I.; Serebryakov, Victor A.

    1991-07-01

    The use of high energy solid state lasers for the treatment of human skin neoplasia was based on the experiments and clinic studies by Helsper and Goldman (1964), McGuff (1966). The heat of precise local volume is emitted due to the pulse laser radiation. The thermal effect results in the superficial necrosis of tissues with their integrity destruction, vascular repture accompanied by bloodstoke in some cases and by capillary embolism in others. Obvious tumour destruction is note only in case of high density irradiation. General tumour destruction depends on biological neoplasia features as well as the laser type.

  7. Diode-pumped solid state laser for inertial fusion energy

    SciTech Connect

    Payne, S.A.; Krupke, W.F.; Orth, C.D.

    1994-11-01

    The authors evaluate the prospect for development of a diode-pumped solid-state-laser driver in an inertial fusion energy power plant. Using a computer code, they predict that their 1 GWe design will offer electricity at 8.6 cents/kW {center_dot} hr with the laser operating at 8.6% efficiency and the recycled power level at 31%. The results of their initial subscale experimental testbed of a diode-pumped solid state laser are encouraging, demonstrating good efficiencies and robustness.

  8. Pulsed delivery of laser energy in experimental thermal retinal photocoagulation

    NASA Astrophysics Data System (ADS)

    Pankratov, Michail M.

    1990-06-01

    Retinal lesions produced with a pulsed laser beam of 1-20 kHz frequency and 10-100% duty cycle were compared with lesions produced with a continuous wave (cw) laser of the same peak power and total energy. Photocoagulation was applied to the retina of three black pigmented rabbits using krypton red laser (647.1 nm) equipped with an acousto-optical modulator to convert cw laser emission to a pulsating beam. An optical fiber fed the laser beam into an optical system delivering a collimated beam of predetermined divergence; the animal's eye focused this beam to a 50-pm spot on the retina. Peak power was kept constant at 0.2 W, and energy was kept constant at 20 mJ. After 7 months the animals were sacrificed and retinal tissue examined by light microscopy. The central section of each lesion was identified and photographed. For lesions with the same energy per pulse and the same pulse duration, the most influential factor, in the frequency range of 1-20 kHz, appeared to be the duty cycle: the smaller the duty cycle, the smaller the lesion, and vice versa. In other words, the shorter the time interval between consecutive pulses, the larger were the pulsed laser lesions.

  9. Improvements to the FLASH Laser Energy Deposition Package

    NASA Astrophysics Data System (ADS)

    Flocke, Norbert; Bachan, J.; Couch, S.; Daley, C.; Dubey, A.; Fatenejad, M.; Graziani, C.; Lamb, Don; Lee, Dongwook; Scopatz, A.; Tzeferacos, P.; Weide, K.

    2012-10-01

    FLASH is an open source, compressible, spatially-adaptive, radiation magnetohydrodynamics code that is currently used at a number of institutions for simulating laser-driven HEDP experiments. FLASH uses ray-tracing to model laser energy deposition via the inverse-Bremsstrahlung process on an Eulerian block-structured mesh. We describe recent improvements to the laser ray-tracing package in FLASH which have led to increased accuracy and performance. A ``3D-in-2D'' ray-trace model has been developed which transports rays in three-dimensions when FLASH is configured to run in 2D cylindrical geometry. Several options have been added which allow users greater flexibility in choosing the initial ray placement. These options can be used to reduce the number of rays needed to accurately represent the energy deposition. Several models have been added to FLASH for smoothing the deposited laser energy to reduce numerical noise. The laser package has also been modified to use threading and mesh-replication for parallelization to improve computational performance. Finally, we will present the results of FLASH simulations that use these improvements and compare results using different laser options.

  10. Low Energy Laser Biostimulation: New Prospects For Medical Applications

    NASA Astrophysics Data System (ADS)

    Castel, John C.; Abergel, R. Patrick; Willner, Robert E.; Baumann, James G.

    1987-03-01

    The therapeutic benefits of light-energy is not a new concept to the modern world. Documented applications from ancient times tell of the therapeutic effects of ordinary sun-light to treat such common ailments as painful body joints, wounds, compound fractures and tetanus. The discovery of laser light in the 1960's, opened up new prospects for the medical use of light. Laser light differs from other forms of electromagnetic spectrum in that a single wavelength rather than a spectrum of wavelengths is emitted. Since the early 1970's, low-energy laser radiation has been reported to enhance wound healing rates, reduce edema, and relieve musculoskeletal pain. There is no detectable thermal effect of this laser on the tissue being treated. The effects are considered to occur as a result of photochemical, non thermal effects of the laser beam. Photons are absorbed by the tissue being treated and, in turn, produce positive therapeutic effects such as reduction of pain and edema. Pre-clinical and clinical evaluations are, presently, underway to document the safety and efficacy of low energy laser therapy, which represents a significant advance in the non-invasive treatment of pain.

  11. Aspects of High-Energy Laser Theory.

    DTIC Science & Technology

    1981-10-31

    Intensity correlations in a two-mode laser oscillating on two coupled transitions have been studied by means of the Fokker - Planck equation . It as shown...dependent phenomena. This paper field. A master equation for the photon distribu- answers this question partly. II. TIME-DEPENDENT FOKKER - PLANCK EQUATION ...Note that Eq. (7) has the formal structure of a -I Fokker - Planck equation and is the desired equa- [1 +B (nt *n +2 Pn, n2) tion that will form the

  12. High energy mode locked fiber oscillators for high contrast, high energy petawatt laser seed sources

    SciTech Connect

    Dawson, J W; Messerly, M J; An, J; Kim, D; Barty, C J

    2006-06-15

    In a high-energy petawatt laser beam line the ASE pulse contrast is directly related to the total laser gain. Thus a more energetic input pulse will result in increased pulse contrast at the target. We have developed a mode-locked fiber laser with high quality pulses and energies exceeding 25nJ. We believe this 25nJ result is scalable to higher energies. This oscillator has no intra-cavity dispersion compensation, which yields an extremely simple, and elegant laser configuration. We will discuss the design of this laser, our most recent results and characterization of all the key parameters relevant to it use as a seed laser. Our oscillator is a ring cavity mode-locked fiber laser [1]. These lasers operate in a self-similar pulse propagation regime characterized by a spectrum that is almost square. This mode was found theoretically [2] to occur only in the positive dispersion regime. Further increasing positive dispersion should lead to increasing pulse energy [2]. We established that the positive dispersion required for high-energy operation was approximately that of 2m of fiber. To this end, we constructed a laser cavity similar to [1], but with no gratings and only 2m of fiber, which we cladding pumped in order to ensure sufficient pump power was available to achieve mode-locked operation. A schematic of the laser is shown in figure 1 below. This laser produced low noise 25nJ pulses with a broad self similar spectrum (figure 2) and pulses that could be de-chirped to <100fs (figure 3). Pulse contrast is important in peta-watt laser systems. A major contributor to pulse contrast is amplified spontaneous emission (ASE), which is proportional to the gain in the laser chain. As the oscillator strength is increased, the required gain to reach 1PW pulses is decreased, reducing ASE and improving pulse contrast. We believe these lasers can be scaled in a stable fashion to pulse energies as high as 100nJ and have in fact seen 60nJ briefly in our lab, which is work still

  13. Fiber Laser Front Ends for High-Energy Short Pulse Lasers

    SciTech Connect

    Dawson, J W; Liao, Z M; Mitchell, S; Messerly, M; Beach, R; Jovanovic, I; Brown, C; Payne, S A; Barty, C J

    2005-01-18

    We are developing an all fiber laser system optimized for providing input pulses for short pulse (1-10ps), high energy ({approx}1kJ) glass laser systems. Fiber lasers are ideal solutions for these systems as they are highly reliable and once constructed they can be operated with ease. Furthermore, they offer an additional benefit of significantly reduced footprint. In most labs containing equivalent bulk laser systems, the system occupies two 4'x8' tables and would consist of 10's if not a 100 of optics which would need to be individually aligned and maintained. The design requirements for this application are very different those commonly seen in fiber lasers. High energy lasers often have low repetition rates (as low as one pulse every few hours) and thus high average power and efficiency are of little practical value. What is of high value is pulse energy, high signal to noise ratio (expressed as pre-pulse contrast), good beam quality, consistent output parameters and timing. Our system focuses on maximizing these parameters sometimes at the expense of efficient operation or average power. Our prototype system consists of a mode-locked fiber laser, a compressed pulse fiber amplifier, a ''pulse cleaner'', a chirped fiber Bragg grating, pulse selectors, a transport fiber system and a large flattened mode fiber amplifier. In our talk we will review the system in detail and present theoretical and experimental studies of critical components. We will also present experimental results from the integrated system.

  14. Indications for laser therapy in diverse models of periodontitis

    NASA Astrophysics Data System (ADS)

    Kunin, Anatoly A.; Erina, Stanislava V.; Sokolova, Irina A.; Pankova, Svetlana N.; Ippolitov, Yu. A.; Lepechina, L. I.; Malinovskaya, L. A.; Chitrina, L. L.

    1996-11-01

    Parodontal diseases have an immunological pathogenic mechanism leading to various manifestations and can not be referred to as a common inflammation. The home and foreign research points at active and immunological reaction with the following distraction surrounding tissues of the tooth. Histochemical and biochemical examinations show metabolic disturbances of parodontal tissues. A total sample size of 604 people suffering from average height of chronic generalized parodontitis was examined in the survey. Immunological and histochemical tests were taken before and after a course of laser therapy with the use of helium-neon laser 'YAGODA', an inhibitory and stimulating dosage irradiations and anti-inflammatory dosage irradiations with infrared laser 'UZOR'. We selected a group of patients with the decreased local immunological status on the ground of immunological tests. Histochemical tests shaped the next group with the passive and active forms of parodontitis pathology. The tests data resulted in a method of laser therapy. The investigations confirm that the chronic generalized parodontitis has a shift in tissue immunity of the oral cavity and cell-bound metabolic disturbance of gum epithelium. It is expedient to use the anti-inflammatory dosage irradiations with infrared laser 'UZOR' to correct immunity, and in case of and active process to realize the DNA and RNA synthesis by means of increasing the irradiation with the apparatus 'YAGODA'. The irradiation decreases in case of a passive process.

  15. Radiant energy absorption studies for laser propulsion. [gas dynamics

    NASA Technical Reports Server (NTRS)

    Caledonia, G. E.; Wu, P. K. S.; Pirri, A. N.

    1975-01-01

    A study of the energy absorption mechanisms and fluid dynamic considerations for efficient conversion of high power laser radiation into a high velocity flow is presented. The objectives of the study are: (1) to determine the most effective absorption mechanisms for converting laser radiation into translational energy, and (2) to examine the requirements for transfer of the absorbed energy into a steady flow which is stable to disturbances in the absorption zone. A review of inverse Bremsstrahlung, molecular and particulate absorption mechanisms is considered and the steady flow and stability considerations for conversion of the laser power to a high velocity flow in a nozzle configuration is calculated. A quasi-one-dimensional flow through a nozzle was formulated under the assumptions of perfect gas.

  16. Germanate glass as a window for high energy laser systems

    NASA Astrophysics Data System (ADS)

    Bayya, Shyam S.; Chin, Geoffrey D.; Sanghera, Jasbinder S.; Aggarwal, Ishwar D.

    2006-11-01

    A modified Barium Gallo-Germanate glass has been developed as an exit window for high energy lasers operating in the mid-infrared wavelength region. All the physical properties, for application as a window for high energy laser systems have been measured. Absorption loss and thermo-optic coefficient were identified as key in developing the Barium Gallo-Germanate glass for high energy laser applications. A purification method was developed to reduce the absorption loss of the glass from 6x10-2 cm-1 to 2x10-3 cm-1 at 3.8 μm. Manufacturability in large size windows has been demonstrated with the fabrication of an 18” diameter prototype window. Modified Barium Gallo-Germanate glasses have also been developed with lower thermo-optic coefficient resulting in lower optical path distortion.

  17. Interface module for transverse energy input to dye laser modules

    DOEpatents

    English, Jr., Ronald E.; Johnson, Steve A.

    1994-01-01

    An interface module (10) for transverse energy input to dye laser modules is provided particularly for the purpose of delivering enhancing transverse energy beams (36) in the form of illumination bar (54) to the lasing zone (18) of a dye laser device, in particular to a dye laser amplifier (12). The preferred interface module (10) includes an optical fiber array (30) having a plurality of optical fibers (38) arrayed in a co-planar fashion with their distal ends (44) receiving coherent laser energy from an enhancing laser source (46), and their proximal ends (4) delivered into a relay structure (3). The proximal ends (42) of the optical fibers (38) are arrayed so as to be coplanar and to be aimed generally at a common point. The transverse energy beam array (36) delivered from the optical fiber array (30) is acted upon by an optical element array (34) to produce an illumination bar (54) which has a cross section in the form of a elongated rectangle at the position of the lasing window (18). The illumination bar (54) is selected to have substantially uniform intensity throughout.

  18. Interface module for transverse energy input to dye laser modules

    DOEpatents

    English, R.E. Jr.; Johnson, S.A.

    1994-10-11

    An interface module for transverse energy input to dye laser modules is provided particularly for the purpose of delivering enhancing transverse energy beams in the form of illumination bar to the lasing zone of a dye laser device, in particular to a dye laser amplifier. The preferred interface module includes an optical fiber array having a plurality of optical fibers arrayed in a co-planar fashion with their distal ends receiving coherent laser energy from an enhancing laser source, and their proximal ends delivered into a relay structure. The proximal ends of the optical fibers are arrayed so as to be coplanar and to be aimed generally at a common point. The transverse energy beam array delivered from the optical fiber array is acted upon by an optical element array to produce an illumination bar which has a cross section in the form of a elongated rectangle at the position of the lasing window. The illumination bar is selected to have substantially uniform intensity throughout. 5 figs.

  19. Laser-based profile and energy monitor for H beams

    SciTech Connect

    Connolly,R.; Alessi, J.; Bellavia, S.; Dawson, C.; Degen, C.; Meng, W.; Raparia, D.; Russo, T.; Tsoupas, N.

    2008-09-29

    A beam profile and energy monitor for H{sup -} beams based on laser photoneutralization was built at Brookhaven National Laboratory (BNL)* for use on the High Intensity Neutrino Source (HMS) at Fermilab. An H{sup -} ion has a first ionization potential of 0.75eV and can be neutralized by light from a Nd:YAG laser ({lambda}=1064nm). To measure beam profiles, a narrow laser beam is stepped across the ion beam, removing electrons from the portion of the H{sup -} beam intercepted by the laser. These electrons are channeled into a Faraday cup by a curved axial magnetic field. To measure the energy distribution of the electrons, the laser position is fixed and the voltage on a screen in front of the Faraday cup is raised in small steps. We present a model which reproduces the measured energy spectrum from calculated beam energy and space-charge fields. Measurements are reported from experiments in the BNL linac MEBT at 750keV.

  20. TEA HF laser with a high specific radiation energy

    NASA Astrophysics Data System (ADS)

    Puchikin, A. V.; Andreev, M. V.; Losev, V. F.; Panchenko, Yu. N.

    2017-01-01

    Results of experimental studies of the chemical HF laser with a non-chain reaction are presented. The possibility of the total laser efficiency of 5 % is shown when a traditional C-to-C pumping circuit with the charging voltage of 20-24 kV is used. It is experimentally shown that the specific radiation output energy of 21 J/l is reached at the specific pump energy of 350 J/l in SF6/H2 = 14/1 mixture at the total pressure of 0.27 bar.

  1. United States army tactical high-energy laser program

    NASA Astrophysics Data System (ADS)

    Wachs, John J.; Wilson, Gerald T.

    2013-02-01

    The tactical high energy laser (THEL) program, conducted from 1996 to 2005, successfully demonstrated the capability of a high-energy laser to counter rockets, artillery, and mortars. The program was a US/Israeli cooperative research and development effort that was designated by the Secretary of Defense as an advanced concept technology demonstration with Presidential interest. The THEL system was designed and built under an SMDC/ARSTART prime contract awarded to TRW (now, Northrop Grumman Corporation), jointly managed by the Israel Ministry of Defence Directorate of Defence Research & Development. We summarize the effort and highlight some of the "firsts" of the THEL program.

  2. Dichroic beamsplitter for high energy laser diagnostics

    DOEpatents

    LaFortune, Kai N; Hurd, Randall; Fochs, Scott N; Rotter, Mark D; Hackel, Lloyd

    2011-08-30

    Wavefront control techniques are provided for the alignment and performance optimization of optical devices. A Shack-Hartmann wavefront sensor can be used to measure the wavefront distortion and a control system generates feedback error signal to optics inside the device to correct the wavefront. The system can be calibrated with a low-average-power probe laser. An optical element is provided to couple the optical device to a diagnostic/control package in a way that optimizes both the output power of the optical device and the coupling of the probe light into the diagnostics.

  3. High-Energy Laser-Target Interactions

    DTIC Science & Technology

    1975-10-06

    Second Workshop held at RPI, Hartford Graduate Center, t ,edited by H.J. Schwarz and H Hora , Plenum Press. 23. Keldysh, L. V. (1965) Soviet Physics JETP...insofar as the ac magnetic field contributes to the nonlinear force discussed by Hora 1 7 (22) The wave period T = 2r/u of the laser radiation is much...the laws of classical physics can be used to describe the plasma. (25) The nonlinear force term fNL " 1 [-1eIoEy12 + 1 aIHzI2] (6) discussed by Hora 1

  4. Short Pulse Laser Absorption and Energy Partition at Relativistic Laser Intensities

    SciTech Connect

    Shepherd, R; Chen, H; Ping, Y; Dyer, G; Wilks, S; Chung, H; Kemp, A; Hanson, S; Widmann, K; Fournier, K; Faenov, A; Pikuz, T; Niles, A; Beiersdorfer, P

    2007-02-27

    We have performed experiments at the COMET and Calisto short pulse laser facilities to make the first comprehensive measurements of the laser absorption and energy partition in solid targets heated with an ultrashort laser pulse focused to relativistic laser intensities (>10 10{sup 17} W/cm{sup 2}). The measurements show an exceedingly high absorption for P polarized laser-target interactions above 10{sup 19} W/cm{sup 2}. Additionally, the hot electron population is observed to markedly increase at the same intensity range. An investigation of the relaxation process was initiated u using time sing time-resolved K{sub {alpha}} spectroscopy. Measurements of the time time-resolved K{sub {alpha}} radiation suggest a 10-20 ps relativistic electron relaxation time. However modeling difficulties of these data are apparent and a more detailed investigation on this subject matter is warranted.

  5. A tunable diode laser absorption system for long path atmospheric transmission and high energy laser applications

    NASA Astrophysics Data System (ADS)

    Rice, Christopher A.; Perram, Glen

    2011-03-01

    An open-path Tunable Diode Laser Absorption Spectroscopy (TDLAS) system composed of narrow band (~300 kHz) diodes fiber coupled to a 12" Ritchey-Chrétien transmit telescope has been developed to study atmospheric transmission of key High Energy Laser wavelengths. The ruggedized system has been field deployed and tested for propagation distances of greater than 1 km. Initial experiments were performed in the vicinity of molecular oxygen X3Σ-g to b1Σ+gelectronic transition lines near 760 nm. The potassium version of the Diode Pumped Alkali Laser (DPAL) operates in between two of the sharp oxygen rotational features in the PP and the PQ branches. By scanning across many laser free spectral ranges and monitoring the laser frequency with a very precise wavemeter, the full structure of the oxygen molecular feature is observed. The device can also be used to observe rotational temperatures, oxygen concentrations, and total atmospheric pressure.

  6. An evaluation of the hypothesis that laser light is more conspicuous than incandescent light

    NASA Astrophysics Data System (ADS)

    Winslow, T. S.; Mandler, M. B.

    1986-05-01

    It has been thought that laser aids to navigation might appear more conspicuous than aids employing conventional light sources. Two experiments rigorously tested the hypothesis that laser light is more conspicuous than incandescent light. Incandescent and Helium Neon laser sources were optically filtered and adjusted to present the same illuminance and color to distant observers. Thirty-seven observers viewed 60 random presentations (2 source types, 2 illuminance levels) from a distance of 1500 yards. Group correct source discrimination percentages were 52.6 and 55.2 for the low and high illuminance levels, respectively. The experiment was repeated indoors at higher illuminances with resultant group correct source discrimination percentages of 57, 67.5, and 66 for the low, medium, and high illuminances, respectively. It was concluded that at practical design illuminance levels, no significant conspicuity advantage would be gained by replacing existing navigational aids with laser aids-to-navigation. Calculations show that a significant conspicuity advantage is likely to be obtained if the mariner uses a narrow bandpass filter (3 to 10 nm) centered at the laser wavelength. The illuminance from the laser will be relatively unaffected, while the illuminances from all background lights will be dramatically diminished. An additional section compares the electrical efficiency of a standard Coast Guard FA-240 range light with a laser aid configured for the same application. For equal input power, the FA-240 is shown to produce 10 times the luminous intensity of the laser aid.

  7. Effect of dentine and collagen on the lethal photosensitization of Streptococcus mutans.

    PubMed

    Burns, T; Wilson, M; Pearson, G J

    1995-01-01

    Suspensions of the cariogenic bacterium, Streptococcus mutans were treated with either toluidine blue O or aluminium disulphonated phthalocyanine and then exposed to light from a helium-neon or gallium-aluminium-arsenide laser, respectively, after passing through demineralized dentine slices. Bacteria were also embedded in a collagen matrix prior to sensitization and exposure to the laser light. When dentine slices were interposed between the laser light and the bacterial suspension, substantial kills (10(7) CFU) were achieved at energy doses of 876, 1,752, and 3,504 mJ with the helium-neon laser and of 1,188, 2,376, and 4,752 mJ with the gallium-aluminium-arsenide laser. There was no apparent relationship between the extent of killing and the degree of demineralization of the dentine. Prolonging the exposure of the sensitized bacteria to the laser light increased the kill achieved. Substantial numbers (10(8) to 10(10) CFU) of S. mutans were also killed when embedded in a collagen matrix and exposed to 438 and 1,314 mJ of helium-neon laser light and 594 and 1,782 mJ of light from the gallium-aluminium-arsenide laser. These results imply that lethal photosensitization may be effective at killing S. mutans in a carious lesion, even when the organism is embedded in demineralized dentine.

  8. Laser-material interactions: A study of laser energy coupling with solids

    SciTech Connect

    Shannon, Mark Alan

    1993-11-01

    This study of laser-light interactions with solid materials ranges from low-temperature heating to explosive, plasma-forming reactions. Contained are four works concerning laser-energy coupling: laser (i) heating and (ii) melting monitored using a mirage effect technique, (iii) the mechanical stress-power generated during high-powered laser ablation, and (iv) plasma-shielding. First, a photothermal deflection (PTD) technique is presented for monitoring heat transfer during modulated laser heating of opaque solids that have not undergone phase-change. Of main interest is the physical significance of the shape, magnitude, and phase for the temporal profile of the deflection signal. Considered are the effects that thermophysical properties, boundary conditions, and geometry of the target and optical probe-beam have on the deflection response. PTD is shown to monitor spatial and temporal changes in heat flux leaving the surface due to changes in laser energy coupling. The PTD technique is then extended to detect phase-change at the surface of a solid target. Experimental data shows the onset of melt for indium and tin targets. The conditions for which melt can be detected by PTD is analyzed in terms of geometry, incident power and pulse length, and thermophysical properties of the target and surroundings. Next, monitoring high-powered laser ablation of materials with stress-power is introduced. The motivation for considering stress-power is given, followed by a theoretical discussion of stress-power and how it is determined experimentally. Experiments are presented for the ablation of aluminum targets as a function of energy and intensity. The stress-power response is analyzed for its physical significance. Lastly, the influence of plasma-shielding during high-powered pulsed laser-material interactions is considered. Crater size, emission, and stress-power are measured to determine the role that the gas medium and laser pulse length have on plasma shielding.

  9. High Energy Density Sciences with High Power Lasers at SACLA

    NASA Astrophysics Data System (ADS)

    Kodama, Ryosuke

    2013-10-01

    One of the interesting topics on high energy density sciences with high power lasers is creation of extremely high pressures in material. The pressures of more than 0.1 TPa are the energy density corresponding to the chemical bonding energy, resulting in expectation of dramatic changes in the chemical reactions. At pressures of more than TPa, most of material would be melted on the shock Hugoniot curve. However, if the temperature is less than 1eV or lower than a melting point at pressures of more than TPa, novel solid states of matter must be created through a pressured phase transition. One of the interesting materials must be carbon. At pressures of more than TPa, the diamond structure changes to BC and cubic at more than 3TPa. To create such novel states of matter, several kinds of isentropic-like compression techniques are being developed with high power lasers. To explore the ``Tera-Pascal Science,'' now we have a new tool which is an x-ray free electron laser as well as high power lasers. The XFEL will clear the details of the HED states and also efficiently create hot dense matter. We have started a new project on high energy density sciences using an XFEL (SACLA) in Japan, which is a HERMES (High Energy density Revolution of Matter in Extreme States) project.

  10. Detecting Energy Modulation in a Dielectric Laser Accelerator

    SciTech Connect

    Lukaczyk, Louis

    2015-08-21

    The Dielectric Laser Acceleration group at SLAC uses micro-fabricated dielectric grating structures and conventional infrared lasers to accelerator electrons. These structures have been estimated to produce an accelerating gradient up to 2 orders of magnitude greater than that produced by conventional RF accelerators. The success of the experiment depends on both the laser damage threshold of the structure and the timing overlap of femtosecond duration laser pulses with the electron bunch. In recent dielectric laser acceleration experiments, the laser pulse was shorter both temporally and spatially than the electron bunch. As a result, the laser is theorized to have interacted with only a small portion of the electron bunch. The detection of this phenomenon, referred to as partial population modulation, required a new approach to the data analysis of the electron energy spectra. A fitting function was designed to separate the accelerated electron population from the un-accelerated electron population. The approach was unsuccessful in detecting acceleration in the partial population modulation data. However, the fitting functions provide an excellent figure of merit for previous data known to contain signatures of acceleration.

  11. High Energy Density Physics:. the Laser Field of Tomorrow

    NASA Astrophysics Data System (ADS)

    Freeman, Richard R.

    2013-03-01

    Ever since its invention, the laser has become an increasingly important tool for physics research. Indeed, the laser has made it possible to not only study many extant physical phenomena, but also to actually produce matter in conditions that don't exist in nature, or more precisely, don't exist on the earth. In this lecture, I discuss how the development of lasers that produce ultra-short (˜fsec) and ultra-intense (≥1020 W/cm2) laser pulses actually produce plasmas that are at a density and temperature that exist only in stars. In doing so I discuss some of the basics of these extreme pulses interacting with electrons, yielding surprisingly intriguing physical phenomena. Finally, I argue that this field is an essential element in any comprehensive physical research endeavor, explicitly citing its fundamental relationship with the development of clean, unlimited fusion energy power.

  12. Comparison Between NIST and AF Laser Energy Standards Using High Power Lasers.

    PubMed

    Li, Xiaoyu; Scott Retired, Thomas; Cromer, Chris; Cooper, David; Comisford, Steven

    2007-01-01

    We report the results of a high-energy laser calorimeter comparison conducted by the National Institute of Standards and Technology (NIST), Boulder, Colorado and the U.S. Air Force Primary Standards laboratory (AFPSL), Heath, Ohio. A laser power meter, used as a transfer standard, was calibrated at each laboratory, sequentially, and the measurement results were compared. These measurements were performed at a nominal power of 800 W and a wavelength of 10.6 μm using CO2 lasers. Excellent measurement agreement (1.02 %) was demonstrated, which was well within each of the expanded uncertainties from the two laboratories involved in this comparison.

  13. High-energy laser interaction with solids: a laser safety perspective

    NASA Astrophysics Data System (ADS)

    Daigle, Jean-François; Pudo, Dominik; Théberge, Francis; Châteauneuf, Marc

    2016-10-01

    Laser safety regulating the deployment of kW-class high energy laser (HEL) technologies in outdoor applications can rapidly cause significant planning and operations issues due to the ranges involved. Safety templates based on the American National Standard Institute (ANSI) rules can easily result in ranges of tens of kilometers for kW-class lasers. Due to the complexity of HEL-matter interactions, the assumptions underlying the aforementioned approach are however deemed inappropriate. In this paper, we identify a more suitable approach backed by experimental results.

  14. INTERACTION OF LASER RADIATION WITH MATTER. LASER PLASMA: Implantation of high-energy ions produced by femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Volkov, Roman V.; Golishnikov, D. M.; Gordienko, Vyacheslav M.; Savel'ev, Andrei B.; Chernysh, V. S.

    2005-01-01

    Germanium ions of an expanding plasma were implanted in a silicon collector. The plasma was produced by a femtosecond laser pulse with an intensity of ~1015 W cm-2 at the surface of the solid-state target. A technique was proposed for determining the energy characteristics of the ion component of the laser plasma from the density profile of the ions implanted in the substrate.

  15. Applying laser pulse stretching technique on photoacoustic imaging for efficiently delivering laser energy

    NASA Astrophysics Data System (ADS)

    Wang, Tianheng; Kumavor, Patrick D.; Zhu, Quing

    2012-02-01

    High-energy and short-duration outputs from lasers are desirable to improve the photoacoustic image quality when imaging deeply-seated lesions. In many clinical applications, optical fibers are used to couple the high-energy laser pulse to tissue. These high peak intensity pulses can damage an optical fiber input face if the damage threshold is exceeded. It is necessary to reduce the peak intensity to minimize the fiber damage and to delivery sufficient light for imaging. In this paper, a laser-pulse-stretching technique is introduced to reduce the peak intensity of laser pulses. To demonstrate the technique, an initial 17ns pulse was stretched to 37ns by a ring-cavity laser-pulse-stretching system, and the laser peak power reduced to 42%. The stretched pulse increased the fiber damage threshold by 1.5-fold. Three ultrasound transducers centered at 1.3MHz, 3.5MHz, 6MHz frequencies were simulated and the results showed that the photoacoustic signal of 0.5mm-diameter target obtained with 37ns pulse was about 98%, 91% and 80% respectively using the same energy as with the 17ns pulse. Simulations were validated using a broadband hydrophone. Quantitative comparisons of photoacoustic images obtained with three corresponding ultrasound transducers showed that the image quality was not affected by stretching the pulse.

  16. Atomistic simulations of tungsten surface evolution under low-energy neon implantation

    NASA Astrophysics Data System (ADS)

    Backman, Marie; Hammond, Karl D.; Sefta, Faiza; Wirth, Brian D.

    2016-04-01

    Tungsten is a candidate material for the divertor of fusion reactors, where it will be subject to a high flux of particles coming from the fusion plasma as well as a significant heat load. Under helium plasma exposure in fusion-reactor-like conditions, a nanostructured morphology is known to form on the tungsten surface in certain temperature and incident energy ranges, although the formation mechanism is not fully established. A recent experimental study (Yajima et al 2013 Plasma Sci. Technol. 15 282-6) using neon or argon exposure did not produce similar nanostructure. This article presents molecular dynamics simulations of neon implantation in tungsten aimed at investigating the surface evolution and elucidating the role of noble gas mass in fuzz formation. In contrast to helium, neon impacts can sputter both tungsten and previously implanted neon atoms. The shorter range of neon ions, along with sputtering, limit the formation of large bubbles and likely prevents nanostructure formation.

  17. High-Energy Passive Mode-Locking of Fiber Lasers

    PubMed Central

    Ding, Edwin; Renninger, William H.; Wise, Frank W.; Grelu, Philippe; Shlizerman, Eli; Kutz, J. Nathan

    2012-01-01

    Mode-locking refers to the generation of ultrashort optical pulses in laser systems. A comprehensive study of achieving high-energy pulses in a ring cavity fiber laser that is passively mode-locked by a series of waveplates and a polarizer is presented in this paper. Specifically, it is shown that the multipulsing instability can be circumvented in favor of bifurcating to higher-energy single pulses by appropriately adjusting the group velocity dispersion in the fiber and the waveplate/polarizer settings in the saturable absorber. The findings may be used as practical guidelines for designing high-power lasers since the theoretical model relates directly to the experimental settings. PMID:22866059

  18. Capillary Waves And Energy Coupling In Laser Materials Processing

    NASA Astrophysics Data System (ADS)

    Gasser, A.; Herziger, G.; Holtgen, B.; Kreutz, E. W.; Treusch, H. G.

    1987-09-01

    Static and dynamic measurements of the incident laser power, of the diffuse and specular reflected power have been performed in order to determine the absorption behavior of various metals and semiconductors during the interaction with powerful CO2-and Nd:YAG-laser-radiation. The absorptivity of the vapor and laser-induced plasma was probed by high-speed photography and measurements of conductivity transients as a function of intensity, composition, and pressure of the ambient atmosphere. For Ienergy coupling is given by the temperature-dependent refractive index and absorption coefficient of matter. For I>IB the intensity-dependent energy coupling is governed by the generation of photon-induced plasma in the surface region in combination with the dynamics of the molten and vaporized material within the interaction zone giving in addition indication for capillary waves.

  19. Atmospheric Propagation of High Energy Lasers and Applications

    NASA Astrophysics Data System (ADS)

    Cook, Joung R.

    2005-04-01

    It has been over forty years since the invention of the laser, which has inspired the imagination of scientists and science fiction writers alike. Many ideas have been realized, still many remain as dreams, and new ones are still being conceived. The High Energy Laser (HEL) has been associated with weapon applications during the past three decades. Much of the same technology can be directly applied to power beaming, laser propulsion, and other potential remote energy and power transfer applications. Economically, these application areas are becoming increasingly more viable. This paper reviews the evolutionary history of the HEL device technologies. It points out the basic system components and layouts with associated key technologies that drive the effectiveness and efficiency of the system level performance. It describes the fundamental properties and wavelength dependencies of atmospheric propagation that in turn have become the prescription for wavelength properties that are desired from the device.

  20. High pulse energy 2 µm femtosecond fiber laser.

    PubMed

    Wan, Peng; Yang, Lih-Mei; Liu, Jian

    2013-01-28

    In the paper, a 2 µm high energy fs fiber laser and amplification system is presented based on Tm doped fibers. The seed laser was designed to generate pulse train at 2024 nm at a repetition rate of 2.5 MHz. An AOM was used as a pulse picker to further lower the repetition rate down to 100 kHz. Two-stage fiber pre-amplifiers and a high energy large mode area (LMA) fiber amplifier were used to boost pulse energy up to 54 µJ before pulse compressor with chirped pulse amplification technique. After compressor, pulse energy of 36.7µJ and pulse duration of 910 fs and were obtained.

  1. Vibrational Energy Transfer and Kinetics of High Energy Molecular Lasers.

    DTIC Science & Technology

    1979-08-17

    babi1ities were measured for the—MCi, HP—HCN, DF—HCN, and 1~ ‘-HcN systems from 220—450°K. Two—p~otonp~otodissociation of HgC1, Hg~r, and HgI was observed to...HgBr , and MgI are of considerable current interest.(19 24) Laser output has been recently observed from HgBr(B21) and HgI (B2E) molecules produced by

  2. Calorimetric Measurements of Laser Energy and Power- 1975 Supplement

    DTIC Science & Technology

    1975-07-30

    Bolometer Volume Absorption Partial Reflectance Absorptance Measurement Test Comparison Pages: 00021 Cataloged Date: Dec 07,1992 Document Type: HC...Hollow-Sphere Calorimeters 4 Bolometer Calorimeters 5 Volume- Absorption Calorimeters 5 Partial- Absorption Calorimeters 7 Reflectance and... Absorptance Measurements 7 Test and Comparison Procedures 7 Miscellany 7 References 14 -in- CALORIMETRIC MEASUREMENTS OF LASER ENERGY AND

  3. Integrated Modeling of Polymer Composites Under High Energy Laser Irradiation

    DTIC Science & Technology

    2015-10-30

    the SThM measurements deviates from standard procedures for neat resin and prepreg composites . Individual carbon fibers are suspended or draped across...AFRL-RX-WP-TR-2016-0071 INTEGRATED MODELING OF POLYMER COMPOSITES UNDER HIGH ENERGY LASER IRRADIATION Brent Volk, Gregory Ehlert...DAVIS, Chief Composite Materials and Processing Section Composite Materials and Processing Section Composite Branch

  4. [Equipment for low reactive level laser therapy including that for light therapy].

    PubMed

    Saeki, Shigeru

    2006-09-01

    Equipments used for light therapy include machinery used for irradiation by low reactive level laser, xenon light and linear polarized infra-red ray. Low reactive level laser is divided into two types of laser according to the medium by which laser is obtained ; semiconductor laser and helium-neon laser. Low reactive level laser has only one wave length and produces analgesia by action of light itself. On the other hands, Xenon light and linear polarized infra-red ray produce analgesia by warming effect induced by light in addition to the action of light itself. There are four methods of irradiation by these light sources; irradiation of acupuncture points, of trigger points, along nerves causing pain and of stellate ganglion area. Indication for light therapy includes various kinds of diseases such as herpes zoster, post herpetic neuralgia, cervical pain, lumbago due to muscle contracture, complex regional pain syndrome, arthralgia etc. However, we have to know that light therapy does not exert analgesic effects equally to all patients. But light therapy does not accompany pain and rarely shows any side effects. Therefore it is thought to be an alternative for patients who reject injection or patients who are not indicated for nerve block because of patients' conditions such as bleeding tendency.

  5. Frequency chirping for resonance-enhanced electron energy during laser acceleration

    NASA Astrophysics Data System (ADS)

    Gupta, D. N.; Suk, H.

    2006-04-01

    The model given by Singh-Tripathi [Phys. Plasmas 11, 743 (2004)] for laser electron acceleration in a magnetic wiggler is revisited by including the effect of laser frequency chirping. Laser frequency chirp helps to maintain the resonance condition longer, which increases the electron energy gain. A significant enhancement in electron energy gain during laser acceleration is observed.

  6. Compact pulsed high-energy Er:glass laser

    NASA Astrophysics Data System (ADS)

    Wan, Peng; Liu, Jian

    2012-03-01

    Bulk Erbium-doped lasers are widely used for long-distance telemetry and ranging. In some applications such as coherent Doppler radars, laser outputs with a relatively long pulse width, good beam profile and pulse shape are required. High energy Q-switched Er:glass lasers were demonstrated by use of electro-optic (E/O) Q-switching or frustrated total internal reflection (FTIR) Q-switching. However, the output pulse durations in these lasers were fixed to relatively small values and extremely hard to tune. We report here on developing a novel and compact Q-switched Er:Yb co-doped phosphate glass laser at an eye-safe wavelength of 1.5 μm. A rotating mirror was used as a Q-switch. Co-linear pump scheme was used to maintain a good output beam profile. Near-perfect Gaussian temporal shape was obtained in our experiment. By changing motor rotation speed, pulse duration was tunable and up to 240 ns was achieved. In our preliminary experiment, output pulse energies of 44 mJ and 4.5 mJ were obtained in free-running and Q-switched operation modes respectively.

  7. Thermoelectronic laser energy conversion for power transmission in space

    NASA Technical Reports Server (NTRS)

    Britt, E. J.; Yuen, C.

    1977-01-01

    Long distance transmission of power in space by means of laser beams is an attractive concept because of the very narrow beam divergence. Such a system requires efficient means to both generate the laser beam and to convert the light energy in the beam into useful electric output at the receiver. A plasma-type device known as a Thermo-Electronic Laser Energy Converter (TELEC) has been studied as a method of converting a 10.6 micron CO2 laser beam into electric power. In the TELEC process, electromagnetic radiation is absorbed directly in the plasma electrons producing a high electron temperature. The energetic electrons diffuse out of the plasma striking two electrodes with different areas. Since more electrons are collected by the larger electrode there is a net transport of current, and an EMF is generated in the external circuit. The smaller electrode functions as an electron emitter to provide continuity of the current. Waste heat is rejected from the large electrode. A design for a TELEC system with an input 1 MW laser beam was developed as part of the study. The calculated performance of the system showed an overall efficiency of about 42%.

  8. Thermoelectronic laser energy conversion for power transmission in space

    NASA Technical Reports Server (NTRS)

    Britt, E. J.; Yuen, C.

    1977-01-01

    Long distance transmission of power in space by means of laser beams is an attractive concept because of the very narrow beam divergence. Such a system requires efficient means to both generate the laser beam and to convert the light energy in the beam into useful electric output at the receiver. A plasma-type device known as a Thermo-Electronic Laser Energy Converter (TELEC) has been studied as a method of converting a 10.6 micron CO2 laser beam into electric power. In the TELEC process, electromagnetic radiation is absorbed directly in the plasma electrons producing a high electron temperature. The energetic electrons diffuse out of the plasma striking two electrodes with different areas. Since more electrons are collected by the larger electrode there is a net transport of current, and an EMF is generated in the external circuit. The smaller electrode functions as an electron emitter to provide continuity of the current. Waste heat is rejected from the large electrode. A design for a TELEC system with an input 1 MW laser beam was developed as part of the study. The calculated performance of the system showed an overall efficiency of about 42%.

  9. High-temperature diode laser pumps for directed energy fiber lasers (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Kanskar, Manoj; Bao, Ling; Chen, Zhigang; DeVito, Mark; Dong, Weimin; Grimshaw, Mike P.; Guan, Xinguo; Hemenway, David M.; Martinsen, Robert; Zhang, Jim; Zhang, Shiguo

    2017-05-01

    Kilowatt-class fiber lasers and amplifiers are becoming increasingly important building blocks for power-scaling laser systems in various different architectures for directed energy applications. Currently, state-of-the-art Yb-doped fiber lasers operating near 1060 nm operate with optical-to-optical power-conversion efficiency of about 66%. State-of-the-art fiber-coupled pump diodes near 975 nm operate with about 50% electrical-to-fiber-coupled optical power conversion efficiency at 25C heatsink temperature. Therefore, the total system electrical-to-optical power conversion efficiency is about 33%. As a result, a 50-kW fiber laser will generate 75 kW of heat at the pump module and 25 kW at the fiber laser module with a total waste heat of 100 kW. It is evident that three times as much waste heat is generated at the pump module. While improving the efficiency of the diodes primarily reduces the input power requirement, increasing the operating temperature primarily reduces the size and weight for thermal management systems. We will discuss improvement in diode laser design, thermal resistance of the package as well as improvement in fiber-coupled optical-to-optical efficiency to achieve high efficiency at higher operating temperature. All of these factors have a far-reaching implication in terms of significantly improving the overall SWAP requirements thus enabling DEW-class fiber lasers on airborne and other platforms.

  10. Study on methods for measuring laser energy of large-aperture beam

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Gao, Haoran; Jia, Jing; Hu, Shaoyun; Fan, Hongying

    2014-12-01

    A experimental method measuring laser energy and energy distributing of large-aperture beam is presented. The experimental equipment is established. The energy and energy distribution of beam, the beam size is Φ100mm and Φ360mm, are measured. The result show measuring error for laser energy is less than 8%. The energy distribution is basically consistent.

  11. High-energy laser weapons since the early 1960s

    NASA Astrophysics Data System (ADS)

    Cook, Joung

    2013-02-01

    Both the U.S. and Russia/USSR have made great strides toward developing high-energy laser weapons for their future national defense systems since the early 1960s. Many billions of dollars and rubles were invested in the effort. Many hundreds of gifted scientists and engineers devoted their careers to working on the problems. They achieved major technological advances and made impressive and successful demonstrations. After more than half a century, however, neither side has yet adapted the first laser weapon for a military use. Why? This paper discusses the history of key technological advancements and successes, as well as some of the difficulties encountered. It also discusses fundamental technological advantages and limitations of high-energy laser weapons, and also the unique social, cultural, and political environments that have contributed to the history. The high-energy laser technical community is in the process of finding ways to adapt to the new warfare environment by taking advantage of the lessons learned in the past while incorporating the new technologies and ideas evolved in recent years.

  12. Plasmonic energy nanofocusing for high-efficiency laser fusion ignition

    NASA Astrophysics Data System (ADS)

    Tanabe, Katsuaki

    2016-08-01

    We propose an efficient laser fusion ignition system consisting of metal nanoparticles or nanoshells embedded in conventional deuterated polystyrene fuel targets. The incident optical energy of the heating laser is highly concentrated around the metallic particulates randomly dispersed inside imploded targets due to the electromagnetic-field-enhancement effect by surface plasmon resonance, and thus effectively triggers nuclear-fusion chain reactions. Our preliminary calculations exhibit field enhancement factors of around 50 and 1100 for spherical Ag nanoparticles and Ag/SiO2 nanoshells, respectively, in the 1-µm band.

  13. Laser, light, and energy devices for cellulite and lipodystrophy.

    PubMed

    Peterson, Jennifer D; Goldman, Mitchel P

    2011-07-01

    Cellulite affects all races, and it is estimated that 85% of women older than 20 years have some degree of cellulite. Many currently accepted cellulite therapies target deficiencies in lymphatic drainage and microvascular circulation. Devices using radiofrequency, laser, and light-based energies, alone or in combination and coupled frequently with tissue manipulation, are available for improving cellulite. Laser assisted liposuction may improve cellulite appearance. Although improvement using these devices is temporary, it may last several months. Patients who want smoother skin with less visible cellulite can undergo a series of treatments and then return for additional treatments as necessary. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Reflective attenuator for high-energy laser measurements

    SciTech Connect

    Lehman, John H.; Livigni, David; Li Xiaoyu; Cromer, Christopher L.; Dowell, Marla L

    2008-06-20

    A high-energy laser attenuator in the range of 250 mJ (20 ns pulse width, 10 Hz repetition rate, 1064 nm wavelength) is described. The optical elements that constitute the attenuator are mirrors with relatively low reflectance, oriented at a 45 deg. angle of incidence. By combining three pairs of mirrors, the incoming radiation is collinear and has the same polarization orientation as the exit. We present damage testing and polarization-dependent reflectance measurements for 1064 nm laser light at 45 deg. angle of incidence for molybdenum, silicon carbide, and copper mirrors. A six element, 74 times (18 dB) attenuator is presented as an example.

  15. Reflective attenuator for high-energy laser measurements.

    PubMed

    Lehman, John H; Livigni, David; Li, Xiaoyu; Cromer, Christopher L; Dowell, Marla L

    2008-06-20

    A high-energy laser attenuator in the range of 250 mJ (20 ns pulse width, 10 Hz repetition rate, 1064 nm wavelength) is described. The optical elements that constitute the attenuator are mirrors with relatively low reflectance, oriented at a 45 degrees angle of incidence. By combining three pairs of mirrors, the incoming radiation is collinear and has the same polarization orientation as the exit. We present damage testing and polarization-dependent reflectance measurements for 1064 nm laser light at 45 degrees angle of incidence for molybdenum, silicon carbide, and copper mirrors. A six element, 74 times (18 dB) attenuator is presented as an example.

  16. Developing high energy dissipative soliton fiber lasers at 2 micron

    PubMed Central

    Huang, Chongyuan; Wang, Cong; Shang, Wei; Yang, Nan; Tang, Yulong; Xu, Jianqiu

    2015-01-01

    While the recent discovered new mode-locking mechanism - dissipative soliton - has successfully improved the pulse energy of 1 μm and 1.5 μm fiber lasers to tens of nanojoules, it is still hard to scale the pulse energy at 2 μm due to the anomalous dispersion of the gain fiber. After analyzing the intracavity pulse dynamics, we propose that the gain fiber should be condensed to short lengths in order to generate high energy pulse at 2 μm. Numerical simulation predicts the existence of stable 2 μm dissipative soliton solutions with pulse energy over 10 nJ, comparable to that achieved in the 1 μm and 1.5 μm regimes. Experimental operation confirms the validity of the proposal. These results will advance our understanding of mode-locked fiber lasers at different wavelengths and lay an important step in achieving high energy ultrafast laser pulses from anomalous dispersion gain media. PMID:26348563

  17. Developing high energy dissipative soliton fiber lasers at 2 micron.

    PubMed

    Huang, Chongyuan; Wang, Cong; Shang, Wei; Yang, Nan; Tang, Yulong; Xu, Jianqiu

    2015-09-08

    While the recent discovered new mode-locking mechanism--dissipative soliton--has successfully improved the pulse energy of 1 μm and 1.5 μm fiber lasers to tens of nanojoules, it is still hard to scale the pulse energy at 2 μm due to the anomalous dispersion of the gain fiber. After analyzing the intracavity pulse dynamics, we propose that the gain fiber should be condensed to short lengths in order to generate high energy pulse at 2 μm. Numerical simulation predicts the existence of stable 2 μm dissipative soliton solutions with pulse energy over 10 nJ, comparable to that achieved in the 1 μm and 1.5 μm regimes. Experimental operation confirms the validity of the proposal. These results will advance our understanding of mode-locked fiber lasers at different wavelengths and lay an important step in achieving high energy ultrafast laser pulses from anomalous dispersion gain media.

  18. Solar-pumped electronic-to-vibrational energy transfer lasers

    NASA Technical Reports Server (NTRS)

    Harries, W. L.; Wilson, J. W.

    1981-01-01

    The possibility of using solar-pumped lasers as solar energy converters is examined. The absorbing media considered are halogens or halogen compounds, which are dissociated to yield excited atoms, which then hand over energy to a molecular lasing medium. Estimates of the temperature effects for a Br2-CO2-He system with He as the cooling gas are given. High temperatures can cause the lower energy levels of the CO2 laser transition to be filled. The inverted populations are calculated and lasing should be possible. However, the efficiency is less than 0.001. Examination of other halogen-molecular lasant combinations (where the rate coefficients are known) indicate efficiencies in all cases of less than 0.005.

  19. High Energy Ion Acceleration by Extreme Laser Radiation Pressure

    DTIC Science & Technology

    2017-03-14

    AFRL-AFOSR-UK-TR-2017-0015 High energy ion acceleration by extreme laser radiation pressure Paul McKenna UNIVERSITY OF STRATHCLYDE VIZ ROYAL COLLEGE...MM-YYYY)   14-03-2017 2. REPORT TYPE  Final 3. DATES COVERED (From - To)  01 May 2013 to 31 Dec 2016 4. TITLE AND SUBTITLE High energy ion acceleration...Prescribed by ANSI Std. Z39.18 Page 1 of 1FORM SF 298 3/15/2017https://livelink.ebs.afrl.af.mil/livelink/llisapi.dll 1 HIGH ENERGY ION ACCELERATION BY

  20. Energy Conversion Process in Laser Supported Detonation Waves Induced by a Line-Focusing Laser

    NASA Astrophysics Data System (ADS)

    Ushio, Masato; Kawamura, Koichi; Komurasaki, Kimiya; Katsurayama, Hiroshi; Koizumi, Hiroyuki; Arakawa, Yoshihiro

    2006-05-01

    Propagation of two-dimensional and quasi-one-dimensional Laser Supported Detonation (LSD) waves driven by a line-focusing laser beam was investigated using the shadowgraph method. As a result, fractional laser absorption during the LSD regime for 2D and quasi-1D cases was 68% and 81%, respectively, which was lower than that of three-dimensional LSD wave driven by a point-focusing beam (typically 90%.) However, the blast wave energy efficiency was found proportional to the fractional absorption. Besides, the LSD threshold intensity was apparently lowered in the quasi-1D case due to the momentum confinement effect. Comparison with the quasi-1D simulation considering the real gas effects suggests that non-equilibrium effects and radiation loss should be playing an important role in the energy conversion process in the LSD regime.

  1. Records for conversion of laser energy to nuclear energy in exploding nanostructures

    NASA Astrophysics Data System (ADS)

    Jortner, Joshua; Last, Isidore

    2017-09-01

    Table-top nuclear fusion reactions in the chemical physics laboratory can be driven by high-energy dynamics of Coulomb exploding, multicharged, deuterium containing nanostructures generated by ultraintense, femtosecond, near-infrared laser pulses. Theoretical-computational studies of table-top laser-driven nuclear fusion of high-energy (up to 15 MeV) deuterons with 7Li, 6Li and D nuclei demonstrate the attainment of high fusion yields within a source-target reaction design, which constitutes the highest table-top fusion efficiencies obtained up to date. The conversion efficiency of laser energy to nuclear energy (0.1-1.0%) for table-top fusion is comparable to that for DT fusion currently accomplished for 'big science' inertial fusion setups.

  2. Electro-optical equivalent calibration technology for high-energy laser energy meters

    NASA Astrophysics Data System (ADS)

    Wei, Ji Feng; Chang, Yan; Sun, Li Qun; Zhang, Kai; Hu, Xiao Yang; Zhang, Wei

    2016-04-01

    Electro-optical equivalent calibration with high calibration power and high equivalence is particularly well-suited to the calibration of high-energy laser energy meters. A large amount of energy is reserved during this process, however, which continues to radiate after power-off. This study measured the radiation efficiency of a halogen tungsten lamp during power-on and after power-off in order to calculate the total energy irradiated by a lamp until the high-energy laser energy meter reaches thermal equilibrium. A calibration system was designed based on the measurement results, and the calibration equivalence of the system was analyzed in detail. Results show that measurement precision is significantly affected by the absorption factor of the absorption chamber and by heat loss in the energy meter. Calibration precision is successfully improved by enhancing the equivalent power and reducing power-on time. The electro-optical equivalent calibration system, measurement uncertainty of which was evaluated as 2.4% (k = 2), was used to calibrate a graphite-cone-absorption-cavity absolute energy meter, yielding a calibration coefficient of 1.009 and measurement uncertainty of 3.5% (k = 2). A water-absorption-type high-energy laser energy meter with measurement uncertainty of 4.8% (k = 2) was considered the reference standard, and compared to the energy meter calibrated in this study, yielded a correction factor of 0.995 (standard deviation of 1.4%).

  3. Electro-optical equivalent calibration technology for high-energy laser energy meters

    SciTech Connect

    Wei, Ji Feng; Chang, Yan; Zhang, Kai; Hu, Xiao Yang; Zhang, Wei; Sun, Li Qun

    2016-04-15

    Electro-optical equivalent calibration with high calibration power and high equivalence is particularly well-suited to the calibration of high-energy laser energy meters. A large amount of energy is reserved during this process, however, which continues to radiate after power-off. This study measured the radiation efficiency of a halogen tungsten lamp during power-on and after power-off in order to calculate the total energy irradiated by a lamp until the high-energy laser energy meter reaches thermal equilibrium. A calibration system was designed based on the measurement results, and the calibration equivalence of the system was analyzed in detail. Results show that measurement precision is significantly affected by the absorption factor of the absorption chamber and by heat loss in the energy meter. Calibration precision is successfully improved by enhancing the equivalent power and reducing power-on time. The electro-optical equivalent calibration system, measurement uncertainty of which was evaluated as 2.4% (k = 2), was used to calibrate a graphite-cone-absorption-cavity absolute energy meter, yielding a calibration coefficient of 1.009 and measurement uncertainty of 3.5% (k = 2). A water-absorption-type high-energy laser energy meter with measurement uncertainty of 4.8% (k = 2) was considered the reference standard, and compared to the energy meter calibrated in this study, yielded a correction factor of 0.995 (standard deviation of 1.4%).

  4. Widely tunable laser frequency offset lock with 30 GHz range and 5 THz offset.

    PubMed

    Biesheuvel, J; Noom, D W E; Salumbides, E J; Sheridan, K T; Ubachs, W; Koelemeij, J C J

    2013-06-17

    We demonstrate a simple and versatile method to greatly extend the tuning range of optical frequency shifting devices, such as acousto-optic modulators (AOMs). We use this method to stabilize the frequency of a tunable narrow-band continuous-wave (CW) laser to a transmission maximum of an external Fabry-Perot interferometer (FPI) with a tunable frequency offset. This is achieved through a servo loop which contains an in-loop AOM for simple radiofrequency (RF) tuning of the optical frequency over the full 30 GHz mode-hop-free tuning range of the CW laser. By stabilizing the length of the FPI to a stabilized helium-neon (HeNe) laser (at 5 THz offset from the tunable laser) we simultaneously transfer the ~ 1 MHz absolute frequency stability of the HeNe laser to the entire 30 GHz range of the tunable laser. Thus, our method allows simple, wide-range, fast and reproducible optical frequency tuning and absolute optical frequency measurements through RF electronics, which is here demonstrated by repeatedly recording a 27-GHz-wide molecular iodine spectrum at scan rates up to 500 MHz/s. General technical aspects that determine the performance of the method are discussed in detail.

  5. Interaction of Repetitively Pulsed High Energy Laser Radiation With Matter

    NASA Astrophysics Data System (ADS)

    Hugenschmidt, Manfred

    1986-10-01

    The paper is concerned with laser target interaction processes involving new methods of improving the overall energy balance. As expected theoretically, this can be achieved with high repetition rate pulsed lasers even for initially highly reflecting materials, such as metals. Experiments were performed by using a pulsed CO2 laser at mean powers up to 2 kW and repetition rates up to 100 Hz. The rates of temperature rise of aluminium for example were thereby increased by lore than a factor of 3 as compared to cw-radiation of comparable power density. Similar improvements were found for the overall absorptivities that were increased by this method by more than an order of magnitude.

  6. High Energy Directly Pumped Ho:YLF Laser

    NASA Technical Reports Server (NTRS)

    Petros, Mulugeta; Yu, Ji-Rong; Singh, Upendra N.; Barnes, Norman P.

    2000-01-01

    The most commonly used crystal architecture to produce 2 micrometer laser is co-doping Ho and Tm into a single host crystal. In this method, the stored energy transfer from the Tm (3)F4 to the Ho (5)I7 manifold is not fast enough to warrant high efficiency for short pulse applications. By separating the Ho and the Tm ions and doping the Tm in YALO3 and the Ho in YLF, we were able to directly pump the Ho (5)I7 manifold with 1.94 micrometers. The Ho:YLF laser has produced 33 mJ at 2.062 micrometers with a quantum efficiency of 0.88. The performance of each laser will be presented.

  7. High energy protons generation by two sequential laser pulses

    SciTech Connect

    Wang, Xiaofeng; Shen, Baifei E-mail: zhxm@siom.ac.cn; Zhang, Xiaomei E-mail: zhxm@siom.ac.cn; Wang, Wenpeng; Xu, Jiancai; Yi, Longqing; Shi, Yin

    2015-04-15

    The sequential proton acceleration by two laser pulses of relativistic intensity is proposed to produce high energy protons. In the scheme, a relativistic super-Gaussian (SG) laser pulse followed by a Laguerre-Gaussian (LG) pulse irradiates dense plasma attached by underdense plasma. A proton beam is produced from the target and accelerated in the radiation pressure regime by the short SG pulse and then trapped and re-accelerated in a special bubble driven by the LG pulse in the underdense plasma. The advantages of radiation pressure acceleration and LG transverse structure are combined to achieve the effective trapping and acceleration of protons. In a two-dimensional particle-in-cell simulation, protons of 6.7 GeV are obtained from a 2 × 10{sup 22 }W/cm{sup 2} SG laser pulse and a LG pulse at a lower peak intensity.

  8. U.S. Army High Energy Laser (HEL) technology program

    NASA Astrophysics Data System (ADS)

    Lavan, Michael J.; Wachs, John J.

    2011-11-01

    The US Army is investing in Solid State Laser (SSL) technology to assess counter rocket, artillery, and mortar (C-RAM) and counter unmanned aerial vehicle (C-UAV) capabilities of solid state based HEL systems, as well as other potential applications for HELs of interest to the Army. The Army HEL program thrust areas are systematically moving the technology forward toward weaponization, including solid state laser technologies, advances in beam control technology, and conducting major demonstrations. The High Energy Laser Mobile Demonstrator (HELMD) will be a major step toward demonstrating HEL weapon capability to the soldier. The US Army will continue to pursue technologies that enable more compact systems compatible with, for example, a Stryker tactical vehicle as a crucial part of our strategy to provide a capability to the warfighter that can maneuver with the force.

  9. Categorizing High Energy Laser Effects for the Joint Munitions Effectiveness Manual

    DTIC Science & Technology

    2005-06-01

    CATEGORIZING HIGH ENERGY LASER EFFECTS FOR THE JOINT MUNITIONS EFFECTIVENESS MANUAL THESIS...AFIT/GOR/ENS/05-11 CATEGORIZING HIGH ENERGY LASER EFFECTS FOR THE JOINT MUNITIONS EFFECTIVENESS MANUAL THESIS Presented to the Faculty...Captain, USAF June 2005 APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED AFIT/GOR/ENS/05-11 CATEGORIZING HIGH ENERGY LASER EFFECTS FOR

  10. Low level laser therapy on experimental myopathy

    PubMed Central

    Dávila, Soledad; Vignola, María Belén; Cremonezzi, David; Simes, Juan C.; Soriano, Fernando; Campana, Vilma R.

    2011-01-01

    Purpose: The aim of the present work was to study the effect of Helium-Neon (HeNe) and Gallium Arsenide (GaAs) laser upon nitric oxide (NO) plasma levels, an inflammatory biomarker associated with oxidative stress, in rats with experimental myopathy. These were evaluated through histological assessment. Materials and Methods: The groups studied were: (A) control (intact rats that received LLLT sham exposures), (B) rats with myopathy and sacrificed at 24 h later, (C) rats with myopathy and sacrificed 8 days later, (D) rats with myopathy and treated with HeNe laser, (E) rats with myopathy and treated with GaAs laser, (F) intact rats treated with HeNe laser and (G) intact rats treated with GaAs laser. Myopathy was induced by injecting 50μl of 1% carrageenan λ (type IV) in the left gastrocnemius muscle. Low Level Laser Therapy (LLLT) was applied with 9.5 J.cm−2 daily for 10 consecutive days with each laser. The determination of the NO was made by spectrophotometry. The muscles were stained with Hematoxylin-Eosin and examined by optic microscopy. Quantitative variables were statistically analyzed by the Fisher test, and categorical by applying Pearson's Chi Squared test at p <0.05 for all cases. Results: In groups B and C, NO was significantly increased compared to groups A, D, E, F and G (p<0.05). In group C, the percentage of area with inflammatory infiltration was significantly increased compared to the other groups (p<0.001). Conclusions: LLLT decreased plasma levels of NO in rats with experimental myopathies and significant muscle recovery. PMID:24155539

  11. A spectrophotometric microassay for sulfated glycosaminoglycans using a laser densitometer.

    PubMed

    Klompmakers, A A; Hendriks, T

    1986-02-15

    The absorption spectrum of the dye 1,9-dimethylmethylene blue shifts if complexed with sulfated glycosaminoglycans. The present method uses the decrease in A633 rather than the increase in A535, described in a recent method, to measure the sulfated glycosaminoglycan content of biological samples. A conventional spectrophotometer was used to estimate the levels of sulfated glycosaminoglycan in papain extracts from intestinal wall tissue, by measuring both the A535 and the A633 and comparing them with a chondroitin sulfate standard: a highly significant correlation (r = 0.974, n = 17) was obtained. Also, interference by substances like RNA, DNA, and hyaluronic acid was similar for both methods. These results allowed us to employ a laser densitometer with a helium/neon laser emitting at 633 nm to improve the sensitivity and the capacity of the assay. The combination of a small reaction volume and a high-intensity light source allows the detection of less than 0.1 microgram chondroitin sulfate, a 40-fold improvement in sensitivity as compared with the original method. A very significant correlation (r = 0.885, n = 17) existed between results obtained with the macroassay, using a spectrophotometer, and those found by employing the microassay, using the laser densitometer. The use of microtiter plates and the screening potential of the densitometer yields an assay which is fast, very sensitive, and suitable for processing large numbers of samples.

  12. A laser unequal path interferometer for the optical shop.

    PubMed

    Houston, J B; Buccini, C J; O'Neill, P K

    1967-07-01

    The application of laser technology has been extended to optical shop testing by incorporating a cw, helium-neon gas laser in a package that houses a modified Twyman-Green interferometer. This modification provides for optical testing over large path differences with an auxiliary set of lenses used in the long path and a small reference flat used in the short path of the interferometer. With this technique, f/0.7 spherical mirrors have been tested (at the center of curvature) to an accuracy of 1/10 wavelength at the surface, and various other optical systems have been tested in both double pass and single pass. Two of the advantages of this testing method are (1) the capability of testing spherical concave surfaces without physically contacting the surface and (2) the ability to use small reference surfaces for large optical components or systems. The device known as a laser unequal path interferometer can be used with a set of null lenses to qualify aspheric surfaces. The unit is portable and capable of testing in any orientation under various environmental conditions. Several applications of this device are presented to illustrate its versatility.

  13. Enterotomy fusion with laser energy: preliminary results in rabbit ileum.

    PubMed

    Vlasak, J; Kopchok, G; Dayhovsky, L; Grundfest, W; White, R A

    1989-01-01

    The utility of enterotomy closure with the argon and CO2 lasers was examined in New Zealand white rabbit ileum. Thermal properties of 10 argon (0.5 W power for 30 s, energy fluence 230 J/cm2) and 10 CO2 (1.0 W power for 30 s, energy fluence 2700 J/cm2) laser-fused enterotomies were determined during acute fusion experiments using an AGA 782 digital thermographic camera. Healing of the fusions created by the two lasers was subsequently assessed in an additional group of 28 rabbits by comparing three 1.0-cm longitudinal ileal enterotomies, with each rabbit having both types of laser-welded closures and a sutured control. Thermal measurements made from the 10 closures with each laser revealed that the CO2 fusions generated significantly higher temperatures (max. 198 degrees C, mean 106 +/- 37 degrees C, n = 100) than argon (max. 85.2 degrees C, mean 60.5 + 8.1 degrees C, n = 100) p less than 0.001. In the healing studies, four rabbits died from weld failures (one argon and one CO2 disruption, two rabbits with both welds disrupted). Two additional rabbits died at 1 day and one at 10 days for undetermined reasons. The remainder of the animals were sacrificed at 1 (n = 11), 2 (n = 2) and 4 (n = 9) weeks postoperatively. Sutured closures exhibited more granulation tissue and adhesions surrounding the wounds than did welded closures and seven microabscesses were noted adjacent to sutured repairs. One of the CO2 repairs had an abscess at 4 weeks and none of the argon laser fusions had evidence of disruption or abscess.(ABSTRACT TRUNCATED AT 250 WORDS)

  14. Laser-Plasma Interactions in High-Energy-Density Plasmas

    SciTech Connect

    Baldis, H

    2006-10-17

    High temperature hohlraums (HTH) are designed to reach high radiation temperatures by coupling a maximum amount of laser energy into a small target in a short time. These 400-800 {micro}m diameter gold cylinders rapidly fill with hot plasma during irradiation with multiple beams in 1ns laser pulses. The high-Z plasmas are dense, (electron density, n{sub e}/n{sub c} {approx} 0.1-0.4), hot (electron temperature, T{sub e} {approx} 10keV) and are bathed in a high-temperature radiation field (radiation temperature, T{sub rad} {approx} 300eV). Here n{sub c}, the critical density, equals 9 x 10{sup 21}/cm{sup 3}. The laser beams heating this plasma are intense ({approx} 10{sup 15} - 10{sup 17} W/cm{sup 2}). The coupling of the laser to the plasma is a rich regime for Laser-Plasma Interaction (LPI) physics. The LPI mechanisms in this study include beam deflection and forward scattering. In order to understand the LPI mechanisms, the plasma parameters must be known. An L-band spectrometer is used to measure the and electron temperature. A ride-along experiment is to develop the x-radiation emitted by the thin back wall of the half-hohlraum into a thermal radiation source.

  15. Biophysics behavior of acupuncture points irradiated with low energy lasers.

    PubMed

    Moldovan, C

    2007-01-01

    This work describes the Low Energy Laser (LEL) coherent light interaction with the skin cover on acupuncture loci for the purpose of detecting and measuring the spatial and temporal alteration of the thermal, electric and optical properties of the LI4 (HEGU) acupoint, irradiated with a 685 nm, 30 mW, III.B Laser. Novel electrostatic imaging technique, an original Acupuncture 3-D Thermal and Electric Mapping Technique and an original Method for Laser-Skin Reflectance, were used in the study. The results indicate that the visible laser light, with low frequency and low power, specifically modify the 3-D pattern of the temperature, electric potential and electric impedance outline of an acupuncture point, meanwhile with a significant decrease of the laser reflectance index, all measured on a 27 apparently healthy subject lot (48 years mean age, 54% male), when comparing with a non-active, non-acupunctural skin area, placed on the volar side of the same hand. The biophysical method presented, combines in a complex way and reproducible the electro stasis exploration (bioelectric homeostasis), with cutaneous thermodynamic exploration and photo-optical exploration of the derma and provides information that can be appreciated in dynamics and compared depending on the exploration target.

  16. Incoherent Combining of High-Power Fiber Lasers for Directed-Energy Applications

    DTIC Science & Technology

    2008-01-16

    fiber lasers , IPG Photonics currently holds the record, producing over 3 kW per fiber of single-mode laser ...energy laser systems. The first field demonstration of incoherent beam combining using kilowatt -class, single-mode fiber lasers over a kilometer...combining using kilowatt -class, single-mode fiber lasers . The experiment combined four fiber lasers using a beam director consisting of

  17. Energy balance in laser ablation of metal targets

    SciTech Connect

    Sobral, H.; Villagran-Muniz, M.; Bredice, F.

    2005-10-15

    Laser-generated plasma was induced on metallic targets glued to a piezoelectric microphone and placed between the plates of a planar charged capacitor. The plasma generates a temporal redistribution of electric charge on the plates that can easily be measured by a resistor connected to the ground plate; this signal is proportional to the total number of ions removed by breakdown. Both the absorbed and scattered energies were simultaneously monitored by the photoacoustic signal and an energy meter. From these signals it was possible to determine the energy involved in each of the processes. Just above the ablation threshold most of the delivered energy is absorbed and the acoustic signal prevails compared to other contributions. Above this region, the electric signal, which is proportional to the energy involved in the ablation process, becomes dominant.

  18. [Study of laser energy in multi-element detection of pulverized coal flow with laser-induced breakdown spectroscopy].

    PubMed

    Zheng, Jian-Ping; Lu, Ji-Dong; Zhang, Bo; Chen, Shi-He; Yao, Shun-Chun; Pan, Feng-Ping; Dong, Xuan; Zhang, Xi

    2014-01-01

    The logical range of laser power density and optimum laser power density were explored for multi-element analysis of pulverized coal flow with laser-induced breakdown spectroscopy in the present paper. The range of laser energy was chosen from 20 to 160 mJ in the experiment. Pulverized coal less than 200 microm in diameter of particles fell freely through feeder outlet and the rate of flow was controlled by screw feeder. Emissions were collected with pulse laser at 1 064 nm focusing on pulverized coal flow and plasma was generated. The intensity and cause of fluctuation of emission spectra at various laser energy levels were studied. A suitable range of laser power density is from 14.4 to 34.4 GW x cm(-2), and the optimum laser power density is 19.5 GW x cm(-2) for the determination of pulverized coal flow with LIBS.

  19. Chamber Design for the Laser Inertial Fusion Energy (LIFE) Engine

    SciTech Connect

    Latkowski, J F; Abbott, R P; Aceves, S; Anklam, T; Badders, D; Cook, A W; DeMuth, J; Divol, L; El-Dasher, B; Farmer, J C; Flowers, D; Fratoni, M; ONeil, R G; Heltemes, T; Kane, J; Kramer, K J; Kramer, R; Lafuente, A; Loosmore, G A; Morris, K R; Moses, G A; Olson, B; Pantano, C; Reyes, S; Rhodes, M; Roe, K; Sawicki, R; Scott, H; Spaeth, M; Tabak, M; Wilks, S

    2010-11-30

    The Laser Inertial Fusion Energy (LIFE) concept is being designed to operate as either a pure fusion or hybrid fusion-fission system. The present work focuses on the pure fusion option. A key component of a LIFE engine is the fusion chamber subsystem. It must absorb the fusion energy, produce fusion fuel to replace that burned in previous targets, and enable both target and laser beam transport to the ignition point. The chamber system also must mitigate target emissions, including ions, x-rays and neutrons and reset itself to enable operation at 10-15 Hz. Finally, the chamber must offer a high level of availability, which implies both a reasonable lifetime and the ability to rapidly replace damaged components. An integrated design that meets all of these requirements is described herein.

  20. Laser hard tissue interactions: energy transmission through human dental tissue using a holmium:YAG laser

    NASA Astrophysics Data System (ADS)

    Chen, Wei R.; Holt, Raleigh A.; Nordquist, Robert E.

    1995-05-01

    Laser energy transmission through hard tissue was investigated using a pulsed Holmium:YAG laser (2.12 micrometers wavelength). The surface of extracted human dental tissue, 200 micrometers to 700 micrometers in thickness, was irradiated by a laser beam of various fluences between 3 J/cm2 to 28 J/cm2. The transmitted energy through different dentinal components of the tooth was measured. For the mature teeth, the region of the dentinoenamel junction showed the least transmission and the coronal the most; the difference between the two regions could be as large as 20%. The unerupted or young teeth revealed the opposite transmission characteristics. Repeated laser treatment revealed an enhanced transmissibility and the transmitted energy reached a plateau after certain irradiation exposure. Also studied were the effects of various media on the dental transmissibility. For example, surface application of a smear layer of unfilled resin did not change the transmissibility but appeared to slow down the temperature build-up. Visible surface damage -- a yellow or a white spot on the treatment site -- appeared when the fluence reached beyond 20 J/cm2. SEM samples revealed three different surface structural changes: melting with tubule closures, surface removal with tubule exposures, and surface cracking with crater formation, depending on the level of irradiation.

  1. Improved Beam Jitter Control Methods for High Energy Laser Systems

    DTIC Science & Technology

    2009-12-01

    REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour...7540-01-280-5500 Standard Form 298 (Rev. 2-89) Prescribed by ANSI Std. 239-18 ii THIS PAGE INTENTIONALLY LEFT BLANK iii Approved for public...Gyro FSM Fast Steering Mirror FX-LMS Filtered-X Least Mean Squares FX-RLS Filtered-X Recursive Least Square HEL High Energy Laser JCT

  2. High energy laser optics manufacturing: a preliminary study

    SciTech Connect

    Baird, E.D.

    1980-07-01

    This report presents concepts and methods, major conclusions, and major recommendations concerning the fabrication of high energy laser optics (HELO) that are to be machined by the Large Optics Diamond Turning Machine (LODTM) at the Lawrence Livermore National Laboratory (LLNL). Detailed discussions of concepts and methods proposed for metrological operations, polishing of reflective surfaces, mounting of optical components, construction of mirror substrates, and applications of coatings are included.

  3. The research of 3D visualization techniques for the test of laser energy distribution

    NASA Astrophysics Data System (ADS)

    Liu, Lixin; Wang, Bo

    2013-07-01

    In the process of laser transmission in the atmosphere, the complexity and instability of the atmospheric composition that seriously interfere with, even change, the performance of the laser beam. The image of laser energy distribution can be captured and analyzed through infrared CCD and digital image processing technology. The basic features of laser energy density distribution, such as the location and power of the peak point and other basic parameters could be acquired; laser energy density distribution can display in real time continuous multi-frame; the 3D visualization of pseudo-color for laser energy density distribution could be displayed, that reflect the relative size and position of the energy distribution in the different regions of the laser spot, using the VC++, windows APIs and OpenGL programming. The laser energy density distribution can be observed from all angles.

  4. Research on energy transmission calculation problem on laser detecting submarine

    NASA Astrophysics Data System (ADS)

    Fu, Qiang; Li, Yingchao; Zhang, Lizhong; Wang, Chao; An, Yan

    2014-12-01

    The laser detection and identification is based on the method of using laser as the source of signal to scan the surface of ocean. If the laser detection equipment finds out the target, it will immediately reflect the returning signal, and then through receiving and disposing the returning signal by the receiving system, to realize the function of detection and identification. Two mediums channels should be though in the process of laser detection transmission, which are the atmosphere and the seawater. The energy loss in the process of water transport, mainly considering the surface reflection and scattering attenuation and internal attenuation factors such as seawater. The energy consumption though atmospheric transmission, mainly considering the absorption of atmospheric and the attenuation causing by scattering, the energy consumption though seawater transmission, mainly considering the element such as surface reflection, the attenuation of scattering and internal attenuation of seawater. On the basis of the analysis and research, through the mode of establishment of atmospheric scattering, the model of sea surface reflection and the model of internal attenuation of seawater, determine the power dissipation of emitting lasers system, calculates the signal strength that reaches the receiver. Under certain conditions, the total attenuation of -98.92 dB by calculation, and put forward the related experiment scheme by the use of Atmospheric analog channel, seawater analog channel. In the experiment of the theory, we use the simulation pool of the atmosphere and the sea to replace the real environment where the laser detection system works in this kind of situation. To start with, we need to put the target in the simulating seawater pool of 10 meters large and then control the depth of the target in the sea level. We, putting the laser detection system in position where it is 2 kilometers far from one side, secondly use the equipment to aim at the target in some

  5. Latest Developments to the FLASH Laser Energy Deposition Package

    NASA Astrophysics Data System (ADS)

    Flocke, Norbert; Daley, Chris; Fatenejad, Milad; Tzeferacos, Petros; Lamb, Don Q.

    2013-10-01

    We describe recent improvements to the FLASH laser energy deposition package. FLASH is an open source, compressible, spatially-adaptive, radiation hydro/MHD code based on an Eulerian AMR grid. Laser energy deposition is modeled using geometric optics ray-tracing algorithms and the inverse-Bremsstrahlung process. A large variety of options exist for users, which allows for a flexible setup of the laser. Several domain geometries are possible (1D, 2D cartesian and cylindrical, 3D in 2D ray-tracing, 3D cartesian) and several beam cross-sections are available (ray placements on square, radial or statistical grids). The original treatment is based on the Kaiser algorithm, which represents the electron number density as a cell-by-cell, piece-wise linear continuous function. We have added a second option that uses cubic interpolation of the electron number density, resulting in a smoother distribution of the energy deposition. We have also improved the computational performance of the package through threading and asynchronous communication when rays cross a block boundary. We present the results of performance and verification tests of the improved package. This work was supported by DOE NNSA ASC.

  6. Extreme dynamic compression with a low energy laser pulse

    NASA Astrophysics Data System (ADS)

    Armstrong, Michael R.; Crowhurst, Jonathan C.; Zaug, Joseph M.; Radousky, Harry B.

    2017-01-01

    Here we review the scaling of pulse energy with duration for sub-ns laser-driven dynamic compression experiments, which suggests that extreme pressures (multiple Mbar) might be achieved in rapidly equilibrating materials with substantially lower energy than used in traditional experiments. For instance, conventional scaling of pressure with laser intensity indicates that pressures well into the multiple Mbar range should be accessible by compressing with a hundreds of picosecond duration drive pulse with some tens of mJ of energy - orders of magnitude less than required for conventional experiments. Via a related scaling argument, we also show that the throughput of time-resolved pulsed x-ray dynamic compression experiments (such as those performed at x-ray free electron lasers) varies as the inverse square of the time scale of the experiment. The strong variation of throughput with the scale of the experiment should be a significant consideration in the design of such experiments - to obtain high throughput, the time scale of compression should be no longer than required (via material equilibration) to achieve the desired final material state.

  7. High-energy, efficient, 30-Hz ultraviolet laser sources for airborne ozone-lidar systems.

    PubMed

    Elsayed, Khaled A; Chen, Songsheng; Petway, Larry B; Meadows, Byron L; Marsh, Waverly D; Edwards, William C; Barnes, James C; DeYoung, Russell J

    2002-05-20

    Two compact, high-pulse-energy, injection-seeded, 30-Hz frequency-doubled Nd:YAG-laser-pumped Ti: sapphire lasers were developed and operated at infrared wavelengths of 867 and 900 nm. Beams with laser pulse energy >30 mJ at ultraviolet wavelengths of 289 and 300 nm were generated through a tripling of the frequencies of these Ti:sapphire lasers. This work is directed at the replacement of dye lasers for use in an airborne ozone differential absorption lidar system. The ultraviolet pulse energy at 289 and 300 nm had 27% and 31% absolute optical energy conversion efficiencies from input pulse energies at 867 and 900 nm, respectively.

  8. Noncatalytic dissociation of MgO by laser pulses towards sustainable energy cycle

    NASA Astrophysics Data System (ADS)

    Yabe, T.; Mohamed, M. S.; Uchida, S.; Baasandash, C.; Sato, Y.; Tsuji, M.; Mori, Y.

    2007-06-01

    We succeeded in dissociating MgO using laser pulses without a reducing agent. The energy efficiency from laser to magnesium reaction energy exceeded 42.5%. Although 1kW CO2 cw laser and Nd-YAG pulse laser are used in this experiment, the laser can be pumped by natural resources such as solar light or wind power. Thus natural resources are stored in the form of magnesium, which can be used through the reaction with water whenever we need the energy, and thus a renewable energy system will be established. This paper reports the preliminary experiments of MgO reduction toward a sustainable energy cycle.

  9. Changes in the germination process and growth of pea in effect of laser seed irradiation

    NASA Astrophysics Data System (ADS)

    Podleśna, Anna; Gładyszewska, Bożena; Podleśny, Janusz; Zgrajka, Wojciech

    2015-10-01

    The aim of this study was to determine the effect of pre-sowing helium-neon (He-Ne) laser irradiation of pea seeds on changes in seed biochemical processes, germination rate, seedling emergence, growth rate, and yield. The first experimental factor was exposure to laser radiation: D0 - no irradiation, D3 - three exposures, D5 - five exposures, and the harvest dates were the second factor. Pre-sowing treatment of pea seeds with He-Ne laser light increased the concentrations of amylolytic enzymes and the content of indole-3-acetic acid (IAA) in pea seeds and seedlings. The exposure of seeds to He-Ne laser light improved the germination rate and uniformity and modified growth stages, which caused acceleration of flowering and ripening of pea plants. Laser light stimulation improved the morphological characteristics of plants by increasing plant height and leaf surface area. Irradiation improved the yield of vegetative and reproductive organs of pea, although the effects varied at the different growth stages. The increase in the seed yield resulted from a higher number of pods and seeds per plant, whereas no significant changes were observed in the number of seeds per pod. Both radiation doses exerted similarly stimulating effects on pea growth, development, and yield.

  10. Phototherapeutic Effect of Low-Level Laser on Thyroid Gland of Gamma-Irradiated Rats.

    PubMed

    Morcos, Nadia; Omran, Manar; Ghanem, Hala; Elahdal, Mahmoud; Kamel, Nashwa; Attia, Elbatoul

    2015-01-01

    One inescapable feature of life on the earth is exposure to ionizing radiation. The thyroid gland is one of the most sensitive organs to gamma-radiation and endocrine disrupters. Low-level laser therapy (LLLT) has been used to stimulate tissue repair, and reduce inflammation. The aim of this study was to gauge the value of using Helium-Neon laser to repair the damaged tissues of thyroid gland after gamma-irradiation. Albino rats were used in this study (144 rats), divided into control, gamma, laser, and gamma plus laser-irradiated groups, each group was divided into six subgroups according to time of treatment (total six sessions). Rats were irradiated once with gamma radiation (6 Gy), and an external dose of laser (Wavelength 632.8 nm, 12 mW, CW, Illuminated area 5.73 cm(2), 2.1 mW cm(-2) 120 s, 1.4 J, 0.252 J cm(-2)) twice weekly localized on thyroid region of the neck, for a total of six sessions. Animals were sacrificed after each session. Analysis included thyroid function, oxidative stress markers, liver function and blood picture. Results revealed improvement in thyroid function, liver function and antioxidant levels, and the blood cells count after LLLT.

  11. Slow-motion acquisition of laser beam profiles after propagation through gun blast

    NASA Astrophysics Data System (ADS)

    Kay, Armin V.

    1991-07-01

    Degradation of laser beam quality by special effects is considered to be of increasing importance for investigations concerning combat field communications. An 8-bit transient memory device has been developed which allows storing of a series of up to 15 laser beam intensity profiles using a CCD linear array of 1754 diodes with a spatial resolution of 10 micrometers . The shortest time interval between consecutive profiles amounts to 2 ms. Data reduction of the measured profiles can be achieved by best fit of a Gaussian normal distribution with four parameters representing bias level, peak amplitude, width (FWHM), and peak position. This procedure was applied to helium-neon-laser radiation after transmission through the gas blast expanding from a powder gun. Two different experimental arrangements have been realized so far. The first one comprises a large vessel which limits the expansion of the combustion products from a 20 mm-bore gun, and the laser beam traverses the barrel axis in front of the muzzle. The second set-up allows free gas blast expansion from a 40 mm-bore gun, the laser beam being adjusted parallel to the barrel axis. For both cases, the time behavior of beam extinction, broadening and wandering is reported. Absorption and scattering of radiation by shock waves, turbulent structures and aerosols in the exhaust cause considerable temporary alterations: peak intensity attenuation down to 0.1 beam width reaching up to twice its initial value, and beam deflection up to 2 mrad.

  12. Laser Doppler perfusion imaging of skin blood flow using red and near-infrared sources.

    PubMed

    Abbot, N C; Ferrell, W R; Lockhart, J C; Lowe, J G

    1996-12-01

    At present, scanning laser Doppler imaging uses a 633-nm helium-neon laser (RED) as the only light source, but this restricts its ability to measure blood flow (i) at darkly pigmented skin and (ii) from deeper or subdermal structures. Because near-infrared (NIR) light is known to penetrate deeper into tissue and to be less absorbed than RED, two imagers were adapted to include a NIR laser diode source (one of 830 nm for UK studies; one of 780 nm for leprosy field trials) in parallel with the existing RED source. In human hands representing a range of skin pigmentations, RED scans were unobtainable at the darkest areas of skin, but intact NIR scans could be collected in all cases. In experiments at the rat knee and the dorsal human hand, NIR and RED values were similar on normal skin. Over underlying vessels, however, NIR values greatly exceeded RED values, an effect abolished by occlusion. Similarly, in patients with leprosy and in healthy controls in Spain, fingerpulp NIR values exceeded RED values to the greatest degree when thermoregulatory flow was highest, i.e., when the deeper-lying arteriovenous anastomoses were open. Over areas of experimental inflammation, NIR gave higher values and also exhibited a greater degree of spatial heterogeneity than RED. We conclude that some current limitations of laser Doppler imaging technology can be overcome by the use of NIR laser diode sources.

  13. Reaction of cells to local, regional, and general low-intensive laser irradiation

    NASA Astrophysics Data System (ADS)

    Baibekov, Iskander M.; Kasymov, A. S.; Musaev, Erkin S.; Vorojeikin, V. M.; Artikov, S. N.

    1993-07-01

    Local influence of low intensive laser irradiation (LILI) of Helium-Neon (HNL), Copper vapor (CVL), Nitrogen (UVL) and Arsenic Gallium (AGL) lasers cause stimulation of processes of physiological and reparative regeneration in intact skin, and mucous membrane of stomach and duodenum, dermatome wounds and gastroduodenal ulcers. Structural bases of these effects are the acceleration of cell proliferation and differentiation and also the activation of intracellular structures and intensification of cell secretion. Regional influence of the pointed types of LILI on hepar in cirrhosis and hepatitis causes decreasing of the inflammatory and cirrhotic changes. After endo- and exo-vascular laser irradiations of blood the decreasing of the number of pathological forms of erythrocytes and the increasing of their catalase activity, are indicated. General (total) laser irradiation of the organism--laser shower, increases the bone marrow cells proliferation, especially myeloid series. It is accompanied with acceleration of their differentiation and migration in circulation. It was revealed, that HNL to a considerable extent influences the epithelial cells and CVL the connective tissue cells. UVL increases the amount of microorganisms on cell surfaces (membrane bound microorganisms). Regional irradiation of the LILI causes both direct and indirect influence of cells. Structural changes of bone marrow cells and gut mucous membrane cells indicate intersystemic interaction.

  14. Applications of tunable high energy/pressure pulsed lasers to atmospheric transmission and remote sensing

    NASA Technical Reports Server (NTRS)

    Hess, R. V.; Seals, R. K.

    1974-01-01

    Atmospheric transmission of high energy C12 O2(16) lasers were improved by pulsed high pressure operation which, due to pressure broadening of laser lines, permits tuning the laser 'off' atmospheric C12 O2(16) absorption lines. Pronounced improvement is shown for horizontal transmission at altitudes above several kilometers, and for vertical transmission through the entire atmosphere. The atmospheric transmission of tuned C12 O2(16) lasers compares favorably with C12 O2(18) isotope lasers and CO lasers. The advantages of tunable, high energy, high pressure pulsed lasers over tunable diode lasers and waveguide lasers, in combining high energies with a large tuning range, are evaluated for certain applications to remote sensing of atmospheric constituents and pollutants. Pulsed operation considerably increases the signal to noise ratio without seriously affecting the high spectral resolution of signal detection obtained with laser heterodyning.

  15. Coatings for high energy applications. The Nova laser

    NASA Astrophysics Data System (ADS)

    Wirtenson, G. R.

    The combined requirements of energy density, multiple wavelength, and aperture make the coatings for the Nova Inertial Confinement Fusion (ICF) laser unique. This ten beam neodymium glass laser system, built at the Lawrence Livermore National Laboratory (LLNL), has over a thousand major optical components; some larger than one meter in diameter and weighing 380 Kg. The laser operates at 1054 nm and can be frequency doubled to 527 nm or tripled to 351 nm by means of full aperture potassium dihydrogen phosphate (KDP) crystal arrays. The 1.0 nsec fluence varies along the laser chain, sometimes reaching values as high as 16 J/cm(2) at the input lens to one of the spatial filters. The design specifications of this massive optical system were changed several times as the state-of-the-art advanced. Each change required redesign of the optical coatings even as vendors were preparing for production runs. Frequency conversion to include shorter wavelengths mandated the first major coating redesign and was followed almost immediately by a second redesign to reduce solarization effects in borosilicate crown glass. The conventional thermal evaporation process although successful for the deposition of mirror coatings, was not able to produce antireflection coatings able to survive the locally high chain fluences. As a consequence it became necessary to develop another technique. Solution produced coatings were developed having transmissions exceeding 99% per part and damage threshold values equal to the bare substrate. The unique requirement of the Nova laser necessitated special deposition and metrology equipment. These programmatic developments will be reviewed in the context of the cooperative working relationship developed between LLNL and its vendors. It was this excellent relationship which has enabled LLNL to obtain these highly specialized coatings for the Nova laser.

  16. Coatings for high energy applications. The Nova laser

    SciTech Connect

    Wirtenson, G.R.

    1986-01-01

    The combined requirements of energy density, multiple wavelength, and aperture make the coatings for the Nova Inertial Confinement Fusion (ICF) laser unique. This ten beam neodymium glass laser system, built at the Lawrence Livermore National Laboratory (LLNL), has over a thousand major optical components; some larger than one meter in diameter and weighing 380 Kg. The laser operates at 1054 nm and can be frequency doubled to 527 nm or tripled to 351 nm by means of full aperture potassium dihydrogen phosphate (KDP) crystal arrays. The 1.0 nsec fluence varies along the laser chain, sometimes reaching values as high as 16 J/cm/sup 2/ at the input lens to one of the spatial filters. The design specifications of this massive optical system were changed several times as the state-of-the-art advanced. Each change required redesign of the optical coatings even as vendors were preparing for production runs. Frequency conversion to include shorter wavelengths mandated the first major coating redesign and was followed almost immediately by a second redesign to reduce solarization effects in borosilicate crown glass. The conventional thermal evaporation process although successful for the deposition of mirror coatings, was not able to produce antireflection coatings able to survive the locally high chain fluences. As a consequence it became necessary to develop another technique. Solution produced coatings were developed having transmissions exceeding 99% per part and damage threshold values equal to the bare substrate. The unique requirement of the Nova laser necessitated special deposition and metrology equipment. These programmatic developments will be reviewed in the context of the cooperative working relationship developed between LLNL and its vendors. It was this excellent relationship which has enabled LLNL to obtain these highly specialized coatings for the Nova laser.

  17. Application of laser pulse stretching scheme for efficiently delivering laser energy in photoacoustic imaging.

    PubMed

    Wang, Tianheng; Kumavor, Patrick D; Zhu, Quing

    2012-06-01

    High-energy and short-duration laser pulses are desirable to improve the photoacoustic image quality when imaging deeply seated lesions. In many clinical applications, the high-energy pulses are coupled to tissue using optical fibers. These pulses can damage fibers if the damage threshold is exceeded. While keeping the total energy under the Food and Drug Administration limit for avoiding tissue damage, it is necessary to reduce the peak intensity and increase the pulse duration for minimizing fiber damage and delivering sufficient light for imaging. We use laser-pulse-stretching to address this problem. An initial 17-ns pulse was stretched to 27 and 37 ns by a ring-cavity laser-pulse-stretching system. The peak power of the 37-ns stretched pulse reduced to 42% of the original, while the fiber damage threshold was increased by 1.5-fold. Three ultrasound transducers centered at 1.3-, 3.5-, and 6-MHz frequencies were simulated, and the results showed that the photoacoustic signal of a 0.5-mm-diameter target obtained with 37-ns pulse was about 98, 91, and 80%, respectively, using the same energy as the 17-ns pulse. Simulations were validated using a broadband hydrophone. Quantitative comparisons of photoacoustic images obtained with three corresponding transducers showed that the image quality was not affected by stretching the pulse.

  18. Application of laser pulse stretching scheme for efficiently delivering laser energy in photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Wang, Tianheng; Kumavor, Patrick D.; Zhu, Quing

    2012-06-01

    High-energy and short-duration laser pulses are desirable to improve the photoacoustic image quality when imaging deeply seated lesions. In many clinical applications, the high-energy pulses are coupled to tissue using optical fibers. These pulses can damage fibers if the damage threshold is exceeded. While keeping the total energy under the Food and Drug Administration limit for avoiding tissue damage, it is necessary to reduce the peak intensity and increase the pulse duration for minimizing fiber damage and delivering sufficient light for imaging. We use laser-pulse-stretching to address this problem. An initial 17-ns pulse was stretched to 27 and 37 ns by a ring-cavity laser-pulse-stretching system. The peak power of the 37-ns stretched pulse reduced to 42% of the original, while the fiber damage threshold was increased by 1.5-fold. Three ultrasound transducers centered at 1.3-, 3.5-, and 6-MHz frequencies were simulated, and the results showed that the photoacoustic signal of a 0.5-mm-diameter target obtained with 37-ns pulse was about 98, 91, and 80%, respectively, using the same energy as the 17-ns pulse. Simulations were validated using a broadband hydrophone. Quantitative comparisons of photoacoustic images obtained with three corresponding transducers showed that the image quality was not affected by stretching the pulse.

  19. Study of application and key technology of the high-energy laser weapon in optoelectronic countermeasure

    NASA Astrophysics Data System (ADS)

    Qu, Zhou; Xing, Hao; Wang, Dawei; Wang, Qiugui

    2015-10-01

    High-energy Laser weapon is a new-style which is developing rapidly nowadays. It is a one kind of direction energy weapon which can destroy the targets or make them invalid. High-energy Laser weapon has many merits such as concentrated energy, fast transmission, long operating range, satisfied precision, fast shift fire, anti-electromagnetic interference, reusability, cost-effectiveness. High-energy Laser weapon has huge potential for modern warfare since its laser beam launch attack to the target by the speed of light. High-energy Laser weapon can be deployed by multiple methods such as skyborne, carrier borne, vehicle-mounted, foundation, space platform. Besides the connection with command and control system, High-energy Laser weapon is consist of high-energy laser and beam steering. Beam steering is comprised of Large diameter launch system and Precision targeting systems. Meanwhile, beam steering includes the distance measurement of target location, detection system of television and infrared sensor, adaptive optical system of Laser atmospheric distortion correction. The development of laser technology is very fast in recent years. A variety of laser sources have been regarded as the key component in many optoelectronic devices. For directed energy weapon, the progress of laser technology has greatly improved the tactical effectiveness, such as increasing the range and strike precision. At the same time, the modern solid-state laser has become the ideal optical source for optical countermeasure, because it has high photoelectric conversion efficiency and small volume or weight. However, the total performance is limited by the mutual cooperation between different subsystems. The optical countermeasure is a complex technique after many years development. The key factor to evaluate the laser weapon can be formulated as laser energy density to target. This article elaborated the laser device technology of optoelectronic countermeasure and Photoelectric tracking

  20. Loss of vasoreactivity by laser thermal energy or argon laser irradiation.

    PubMed

    Tomaru, T; Uchida, Y; Nakamura, F; Miwa, A Y; Kawai, S; Okada, R; Sugimoto, T

    1993-05-01

    by laser energy, additional balloon dilatation can reduce residual stenosis, and 3) laser thermal or argon laser angioplasty may prevent severe coronary spasm.

  1. Laser safety evaluation for high-energy laser interaction with solids

    NASA Astrophysics Data System (ADS)

    Daigle, Jean-François; Pudo, Dominik; Théberge, Francis; Châteauneuf, Marc

    2017-02-01

    Laser safety regulating the deployment of kW-class high-energy laser (HEL) technologies in outdoor applications can rapidly cause significant planning and operations issues due to the ranges involved. Safety templates based on a simplistic approach of assuming a continuous wave laser beam incident on a highly reflective totally flat solid surface of infinite size can easily result in ranges of tens of kilometers for kW-class lasers. Due to the complexity of HEL-matter interactions, the assumptions underlying the aforementioned approach are, however, deemed inappropriate. We identify a more suitable approach, which assumes a time-variant reflection pattern as well as a change in the variance of beam divergence as it reflects from the target's surface. Based on experimental results, we instead propose to assess the nominal ocular hazard distance by applying the American National Standard Institute rules for time-variant multipulse laser exposure and using measured divergence angles from the target's surface. The resulting safety templates, thus, exhibit a higher fidelity with respect to the behavior of the reflection patterns while reducing the hazard zones.

  2. Systemic effects of low-power laser irradiation on the peripheral and central nervous system, cutaneous wounds, and burns

    SciTech Connect

    Rochkind, S.; Rousso, M.; Nissan, M.; Villarreal, M.; Barr-Nea, L.; Rees, D.G.

    1989-01-01

    In this paper, we direct attention to the systemic effect of low-power helium-neon (HeNe) laser irradiation on the recovery of the injured peripheral and central nervous system, as well as healing of cutaneous wounds and burns. Laser irradiation on only the right side in bilaterally inflicted cutaneous wounds enhanced recovery in both sides compared to the nonirradiated control group (P less than .01). Similar results were obtained in bilateral burns: irradiating one of the burned sites also caused accelerated healing in the nonirradiated site (P less than .01). However, in the nonirradiated control group, all rats suffered advanced necrosis of the feet and bilateral gangrene. Low-power HeNe laser irradiation applied to a crushed injured sciatic nerve in the right leg in a bilaterally inflicted crush injury, significantly increased the compound action potential in the left nonirradiated leg as well. The statistical analysis shows a highly significant difference between the laser-treated group and the control nonirradiated group (P less than .001). Finally, the systemic effect was found in the spinal cord segments corresponding to the crushed sciatic nerves. The bilateral retrograde degeneration of the motor neurons of the spinal cord expected after the bilateral crush injury of the peripheral nerves was greatly reduced in the laser treated group. The systemic effects reported here are relevant in terms of the clinical application of low-power laser irradiation as well as for basic research into the possible mechanisms involved.

  3. Energy Spread Reduction of Electron Beams Produced via Laser Wake

    SciTech Connect

    Pollock, Bradley Bolt

    2012-01-01

    Laser wakefield acceleration of electrons holds great promise for producing ultra-compact stages of GeV scale, high quality electron beams for applications such as x-ray free electron lasers and high energy colliders. Ultra-high intensity laser pulses can be self-guided by relativistic plasma waves over tens of vacuum diffraction lengths, to give >1 GeV energy in cm-scale low density plasma using ionization-induced injection to inject charge into the wake at low densities. This thesis describes a series of experiments which investigates the physics of LWFA in the self-guided blowout regime. Beginning with high density gas jet experiments the scaling of the LWFA-produced electron beam energy with plasma electron density is found to be in excellent agreement with both phenomenological theory and with 3-D PIC simulations. It is also determined that self-trapping of background electrons into the wake exhibits a threshold as a function of the electron density, and at the densities required to produce electron beams with energies exceeding 1 GeV a different mechanism is required to trap charge into low density wakes. By introducing small concentrations of high-Z gas to the nominal He background the ionization-induced injection mechanism is enabled. Electron trapping is observed at densities as low as 1.3 x 1018 cm-3 in a gas cell target, and 1.45 GeV electrons are demonstrated for the first time from LWFA. This is currently the highest electron energy ever produced from LWFA. The ionization-induced trapping mechanism is also shown to generate quasi-continuous electron beam energies, which is undesirable for accelerator applications. By limiting the region over which ionization-induced trapping occurs, the energy spread of the electron beams can be controlled. The development of a novel two-stage gas cell target provides the capability to tailor the gas composition in the longitudinal direction, and confine the trapping process to occur only in a

  4. Lear jet boundary layer/shear layer laser propagation experiments

    NASA Technical Reports Server (NTRS)

    Gilbert, K.

    1980-01-01

    Optical degradations of aircraft turbulent boundary layers with shear layers generated by aerodynamic fences are analyzed. A collimated 2.5 cm diameter helium-neon laser (0.63 microns) traversed the approximate 5 cm thick natural aircraft boundary layer in double pass via a reflective airfoil. In addition, several flights examined shear layer-induced optical degradation. Flight altitudes ranged from 1.5 to 12 km, while Mach numbers were varied from 0.3 to 0.8. Average line spread function (LSF) and Modulation Transfer Function (MTF) data were obtained by averaging a large number of tilt-removed curves. Fourier transforming the resulting average MTF yields an LSF, thus affording a direct comparison of the two optical measurements. Agreement was good for the aerodynamic fence arrangement, but only fair in the case of a turbulent boundary layer. Values of phase variance inferred from the LSF instrument for a single pass through the random flow and corrected for a large aperture ranged from 0.08 to 0.11 waves (lambda = .63 microns) for the boundary layer. Corresponding values for the fence vary from 0.08 to 0.16 waves. Extrapolation of these values to 10.6 microns suggests negligible degradation for a CO2 laser transmitted through a 5 cm thick, subsonic turbulent boundary layer.

  5. Application of laser therapy in the treatment of brain ischemia

    NASA Astrophysics Data System (ADS)

    Zalesskaya, G. A.; Nechipurenko, N. I.; Musienko, J. I.; Kuchinsky, A. V.

    2007-06-01

    Intravenous laser irradiation of blood (ILIB) by helium-neon laser (HNL) with λ=632.8 nm, 2.5-4.5 mW at the light guide outlet was employed to investigate ILIB influence on blood oxygen transport (BOT), hydro-ion balance for normal rabbits and after modeling of local ischemia of brain (LIB). Marked improvement of disturbances typical for ischemia was revealed for both hydro-ion balance characteristics and BOT parameters such as oxygen tension (p vO II), oxygen hemoglobin saturation (s vO II), p vO II of blood under its 50% saturation by O II (p50) and tendency was found to their normalization. To identify the molecular photoacceptors and the mechanisms of primary photoreactions the spectral data were used both in visible and infrared regions. On the basis of spectral analysis hemoglobin was discussed as a possible photoacceptor when blood is irradiated with HNL radiation. Variations in the redox properties of respiratory chain components were considered as primary mechanisms of light action on photoacceptor molecules that initiated a cascade of secondary reactions controlling cellular homeostasis parameters.

  6. Energy boost in laser wakefield accelerators using sharp density transitions

    SciTech Connect

    Döpp, A.; Guillaume, E.; Thaury, C.; Lifschitz, A.; Ta Phuoc, K.; Malka, V.

    2016-05-15

    The energy gain in laser wakefield accelerators is limited by dephasing between the driving laser pulse and the highly relativistic electrons in its wake. Since this phase depends on both the driver and the cavity length, the effects of dephasing can be mitigated with appropriate tailoring of the plasma density along propagation. Preceding studies have discussed the prospects of continuous phase-locking in the linear wakefield regime. However, most experiments are performed in the highly non-linear regime and rely on self-guiding of the laser pulse. Due to the complexity of the driver evolution in this regime, it is much more difficult to achieve phase locking. As an alternative, we study the scenario of rapid rephasing in sharp density transitions, as was recently demonstrated experimentally. Starting from a phenomenological model, we deduce expressions for the electron energy gain in such density profiles. The results are in accordance with particle-in-cell simulations, and we present gain estimations for single and multiple stages of rephasing.

  7. High peak power diode stacks for high energy lasers

    NASA Astrophysics Data System (ADS)

    Negoita, Viorel C.; Vethake, Thilo; Jiang, John; Roff, Robert; Shih, Ming; Duck, Richard; Bauer, Marc; Mite, Roberto; Boucke, Konstantin; Treusch, Georg

    2015-02-01

    High energy solid state lasers are being developed for fusion experiments and other research applications where high energy per pulse is required but the repetition rate is rather low, around 10Hz. We report our results on high peak power diode laser stacks used as optical pumps for these lasers. The stacks are based on 10 mm bars with 4 mm cavity length and 55% fill factor, with peak power exceeding 500 W per bar. These bars are stacked and mounted on a cooler which provides backside cooling and electrical insulation. Currently we mount 25 bars per cooler for a nominal peak power of 12.5 kW, but in principle the mounting scheme can be scaled to a different number of devices depending on the application. Pretesting of these bars before soldering on the cooler enables us to select devices with similar wavelength and thus we maintain tight control of the spectral width (FWHM less than 6 nm). Fine adjustments of the centroid wavelength can be done by means of temperature of the cooling fluid or bias current. The available wavelength range spans from 880 nm to 1000 nm, and the wavelength of the entire assembly of stacks can be controlled to within 0.5 nm of the target value, which makes these stacks suitable for pumping a variety of gain media. The devices are fast axis collimated, with over 95% power being collimated in 6 mrad (full angle). The slow axis divergence is 9° (full angle) for 95% power content.

  8. Electron energy spectrum in circularly polarized laser irradiated overdense plasma

    SciTech Connect

    Liu, C. S.; Tripathi, V. K.; Shao, Xi; Kumar, Pawan

    2014-10-15

    A circularly polarized laser normally impinged on an overdense plasma thin foil target is shown to accelerate the electrons in the skin layer towards the rear, converting the quiver energy into streaming energy exactly if one ignores the space charge field. The energy distribution of electrons is close to Maxwellian with an upper cutoff ε{sub max}=mc{sup 2}[(1+a{sub 0}{sup 2}){sup 1/2}−1], where a{sub 0}{sup 2}=(1+(2ω{sup 2}/ω{sub p}{sup 2})|a{sub in}|{sup 2}){sup 2}−1, |a{sub in}| is the normalized amplitude of the incident laser of frequency ω, and ω{sub p} is the plasma frequency. The energetic electrons create an electrostatic sheath at the rear and cause target normal sheath acceleration of protons. The energy gain by the accelerated ions is of the order of ε{sub max}.

  9. High-energy ionization by relativistically intense laser pulses

    NASA Astrophysics Data System (ADS)

    Kamiński, J. Z.; Cajiao Vélez, F.; Krajewska, K.

    2017-07-01

    High-energy ionization by relativistically intense, 30~\\text{fs} laser pulses is investigated within the relativistic strong-field approximation. It is shown that the momentum distribution of photoelectrons is focused around a spiral, the analytical form of which is derived from the saddle-point analysis of probability amplitudes. The geometry of this spiral allows one to clearly interpret the exact numerical results of the ionization probability distributions and to identify the photoelectron momentum domains in which the interference- and the interference-free patterns are observed. It is also demonstrated that attosecond single-electron wave packets can be created in this process. Thus, it opens new research opportunities for the four-dimensional electron diffraction experiments, which can be conducted in large-scale laser facilities such as ELI or XCELS.

  10. Low-energy laser radioprotective effects on animal models

    NASA Astrophysics Data System (ADS)

    Gomberg, Vladimir G.; Boiko, Vladimir A.; Pavlova, Rimma N.; Pupkova, Ludmila S.; Dadali, Vladimir A.; Bell, Hobart; Reznikov, Leonid L.

    1997-05-01

    The ability of low-energy laser radiation (LLR) to counteract the detrimental effects of gamma radiation was studied with a murine model. Three control and two experimental groups of mice were used. Control group I consisted of animals unexposed to either gamma or laser irradiation. Group II consisted of mice exposed solely to gamma radiation. Control group III consisted of mice exposed solely to LLR. Experimental group I included mice exposed to gamma radiation initially, followed by LLR for three days. In experimental group II, LLR was applied each of three days prior to gamma irradiation. Gamma radiation was produced by 137 Cs with a total dose of 8.75 Gr (0.02 Gr/min). The source of laser radiation was He-Ne (632.8 nm), and a power density of 0.5 Wt/cm2. Irradiation was performed once every three days for 15 sec. In an additional set of experiments, the effect of LLR in various doses on survival of gamma-irradiated mice was examined. The effects of laser exposure prior to and after gamma radiation, percent survival, changes in lipid peroxidation in serum and liver, the concentration of S-H groups in serum, and catalase activity in erythrocytes were obtained. LLR reduced average lethality. Successful results were achieved in all sets of experiments and were dependent mostly on the dose of LLR. The biochemical tests exhibited the ability of LLR to modify the damaging effects of gamma radiation when laser is applied prior to or after gamma radiation. However, the protective effect of LLR was greater in the group with exposure before gamma radiation.

  11. High energy diode-pumped solid-state laser development at the Central Laser Facility

    NASA Astrophysics Data System (ADS)

    Mason, Paul D.; Banerjee, Saumyabrata; Ertel, Klaus; Phillips, P. Jonathan; Butcher, Thomas; Smith, Jodie; De Vido, Mariastefania; Chekhlov, Oleg; Hernandez-Gomez, Cristina; Edwards, Chris; Collier, John

    2016-04-01

    In this paper we review the development of high energy, nanosecond pulsed diode-pumped solid state lasers within the Central Laser Facility (CLF) based on cryogenic gas cooled multi-slab ceramic Yb:YAG amplifier technology. To date two 10J-scale systems, the DiPOLE prototype amplifier and an improved DIPOLE10 system, have been developed, and most recently a larger scale system, DiPOLE100, designed to produce 100 J pulses at up to 10 Hz. These systems have demonstrated amplification of 10 ns duration pulses at 1030 nm to energies in excess of 10 J at 10 Hz pulse repetition rate, and over 100 J at 1 Hz, with optical-to-optical conversion efficiencies of up to 27%. We present an overview of the cryo-amplifier concept and compare the design features of these three systems, including details of the amplifier designs, gain media, diode pump lasers and the cryogenic gas cooling systems. The most recent performance results from the three systems are presented along with future plans for high energy DPSSL development within the CLF.

  12. Pulse energy dependence of subcellular dissection by femtosecond laser pulses

    NASA Technical Reports Server (NTRS)

    Heisterkamp, A.; Maxwell, I. Z.; Mazur, E.; Underwood, J. M.; Nickerson, J. A.; Kumar, S.; Ingber, D. E.

    2005-01-01

    Precise dissection of cells with ultrashort laser pulses requires a clear understanding of how the onset and extent of ablation (i.e., the removal of material) depends on pulse energy. We carried out a systematic study of the energy dependence of the plasma-mediated ablation of fluorescently-labeled subcellular structures in the cytoskeleton and nuclei of fixed endothelial cells using femtosecond, near-infrared laser pulses focused through a high-numerical aperture objective lens (1.4 NA). We find that the energy threshold for photobleaching lies between 0.9 and 1.7 nJ. By comparing the changes in fluorescence with the actual material loss determined by electron microscopy, we find that the threshold for true material ablation is about 20% higher than the photobleaching threshold. This information makes it possible to use the fluorescence to determine the onset of true material ablation without resorting to electron microscopy. We confirm the precision of this technique by severing a single microtubule without disrupting the neighboring microtubules, less than 1 micrometer away. c2005 Optical Society of America.

  13. Energy transport in short-pulse-laser-heated targets measured using extreme ultraviolet laser backlighting.

    PubMed

    Wilson, L A; Tallents, G J; Pasley, J; Whittaker, D S; Rose, S J; Guilbaud, O; Cassou, K; Kazamias, S; Daboussi, S; Pittman, M; Delmas, O; Demailly, J; Neveu, O; Ros, D

    2012-08-01

    The accurate characterization of thermal electron transport and the determination of heating by suprathermal electrons in laser driven solid targets are both issues of great importance to the current experiments being performed at the National Ignition Facility, which aims to achieve thermonuclear fusion ignition using lasers. Ionization, induced by electronic heat conduction, can cause the opacity of a material to drop significantly once bound-free photoionization is no longer energetically possible. We show that this drop in opacity enables measurements of the transmission of extreme ultraviolet (EUV) laser pulses at 13.9 nm to act as a signature of the heating of thin (50 nm) iron layers with a 50-nm thick parylene-N (CH) overlay irradiated by 35-fs pulses at irradiance 3×10(16) Wcm(-2). Comparing EUV transmission measurements at different times after irradiation to fluid code simulations shows that the target is instantaneously heated by hot electrons (with approximately 10% of the laser energy), followed by thermal conduction with a flux limiter of ≈0.05.

  14. Method for reducing energy losses in laser crystals

    DOEpatents

    Atherton, L. Jeffrey; DeYoreo, James J.; Roberts, David H.

    1992-01-01

    A process for reducing energy losses in crystals is disclosed which comprises: a. heating a crystal to a temperature sufficiently high as to cause dissolution of microscopic inclusions into the crystal, thereby converting said inclusions into point-defects, and b. maintaining said crystal at a given temperature for a period of time sufficient to cause said point-defects to diffuse out of said crystal. Also disclosed are crystals treated by the process, and lasers utilizing the crystals as a source of light.

  15. Method for reducing energy losses in laser crystals

    DOEpatents

    Atherton, L.J.; DeYoreo, J.J.; Roberts, D.H.

    1992-03-24

    A process for reducing energy losses in crystals is disclosed which comprises: a. heating a crystal to a temperature sufficiently high as to cause dissolution of microscopic inclusions into the crystal, thereby converting said inclusions into point-defects, and b. maintaining said crystal at a given temperature for a period of time sufficient to cause said point-defects to diffuse out of said crystal. Also disclosed are crystals treated by the process, and lasers utilizing the crystals as a source of light. 12 figs.

  16. Our clinical experience in low-energy laser medical treatments

    NASA Astrophysics Data System (ADS)

    Antipa, Ciprian; Bruckner, Ion I.; Crangulescu, Nicolae; Moldovan, Corneliu I.; Podoleanu, Adrian G.; Stanciulescu, Viorica; Ionescu, Elena

    1996-05-01

    In clinical research the efficiency of low-energy laser (LEL) therapy remains controversial. We present here some of the most important results of our clinical experience in this field. We summarize our opinions about the LEL effects in rheumatic diseases, in chronic pelvic inflammatory disorders, in the treatment of some dermatological disorders, and in the recovery of the distal forearm nerve from traumatic lesion after surgical suture. We conclude that these results may be important evidence for the real clinical efficiency of the LEL.

  17. Improvement of energy-conversion efficiency from laser to proton beam in a laser-foil interaction.

    PubMed

    Nodera, Y; Kawata, S; Onuma, N; Limpouch, J; Klimo, O; Kikuchi, T

    2008-10-01

    Improvement of energy-conversion efficiency from laser to proton beam is demonstrated by particle simulations in a laser-foil interaction. When an intense short-pulse laser illuminates the thin-foil target, the foil electrons are accelerated around the target by the ponderomotive force. The hot electrons generate a strong electric field, which accelerates the foil protons, and the proton beam is generated. In this paper a multihole thin-foil target is proposed in order to increase the energy-conversion efficiency from laser to protons. The multiholes transpiercing the foil target help to enhance the laser-proton energy-conversion efficiency significantly. Particle-in-cell 2.5-dimensional ( x, y, vx, vy, vz) simulations present that the total laser-proton energy-conversion efficiency becomes 9.3% for the multihole target, though the energy-conversion efficiency is 1.5% for a plain thin-foil target. The maximum proton energy is 10.0 MeV for the multihole target and is 3.14 MeV for the plain target. The transpiercing multihole target serves as a new method to increase the energy-conversion efficiency from laser to ions.

  18. Laser energy deposition and its dynamic uniformity for direct-drive capsules

    NASA Astrophysics Data System (ADS)

    Xu, Yan; Wu, SiZhong; Zheng, WuDi

    2015-04-01

    The total laser energy deposition of multi-laser-beam irradiation is not only associated with the dynamic behavior of capsule but also the time-dependent angular distribution of the energy deposition of each beam around its axis. The dynamic behavior of laser energy deposition does not linearly respond to the dynamic behavior of laser irradiation. The laser energy deposition uniformity determines the symmetry of implosion. The dynamic behavior of laser energy deposition non-uniformity in OMEGA for laser with square beam shape intensity profile is investigated. In the case of smaller laser spot, the initial non-uniformity caused by laser beam overlap is very high. The shell asymmetry caused by the high initial laser irradiation non-uniformity is estimated by the extent of distortion of shock front which is not as severe as expected before the shock driven by main pulse arrives. This suggests that the large initial non-uniformity due to smaller laser spot is one of the elements that seed disturbance before the main pulse. The rms of laser energy deposition during the main pulse remains above 2%. Since the intensity of main driving pulse usually is several times higher than that of picket pulses, the non-uniformity in main pulse period may jeopardize the symmetrical implosion. When dynamic behavior of capsule is considered, the influence of beam pointing error, the target positioning error, and beam-to-beam power unbalance is quite different for the case of static capsule.

  19. Laser energy deposition and its dynamic uniformity for direct-drive capsules

    SciTech Connect

    Xu, Yan; Wu, SiZhong; Zheng, WuDi

    2015-04-15

    The total laser energy deposition of multi-laser-beam irradiation is not only associated with the dynamic behavior of capsule but also the time-dependent angular distribution of the energy deposition of each beam around its axis. The dynamic behavior of laser energy deposition does not linearly respond to the dynamic behavior of laser irradiation. The laser energy deposition uniformity determines the symmetry of implosion. The dynamic behavior of laser energy deposition non-uniformity in OMEGA for laser with square beam shape intensity profile is investigated. In the case of smaller laser spot, the initial non-uniformity caused by laser beam overlap is very high. The shell asymmetry caused by the high initial laser irradiation non-uniformity is estimated by the extent of distortion of shock front which is not as severe as expected before the shock driven by main pulse arrives. This suggests that the large initial non-uniformity due to smaller laser spot is one of the elements that seed disturbance before the main pulse. The rms of laser energy deposition during the main pulse remains above 2%. Since the intensity of main driving pulse usually is several times higher than that of picket pulses, the non-uniformity in main pulse period may jeopardize the symmetrical implosion. When dynamic behavior of capsule is considered, the influence of beam pointing error, the target positioning error, and beam-to-beam power unbalance is quite different for the case of static capsule.

  20. Optical and laser spectroscopic diagnostics for energy applications

    NASA Astrophysics Data System (ADS)

    Tripathi, Markandey Mani

    The continuing need for greater energy security and energy independence has motivated researchers to develop new energy technologies for better energy resource management and efficient energy usage. The focus of this dissertation is the development of optical (spectroscopic) sensing methodologies for various fuels, and energy applications. A fiber-optic NIR sensing methodology was developed for predicting water content in bio-oil. The feasibility of using the designed near infrared (NIR) system for estimating water content in bio-oil was tested by applying multivariate analysis to NIR spectral data. The calibration results demonstrated that the spectral information can successfully predict the bio-oil water content (from 16% to 36%). The effect of ultraviolet (UV) light on the chemical stability of bio-oil was studied by employing laser-induced fluorescence (LIF) spectroscopy. To simulate the UV light exposure, a laser in the UV region (325 nm) was employed for bio-oil excitation. The LIF, as a signature of chemical change, was recorded from bio-oil. From this study, it was concluded that phenols present in the bio-oil show chemical instability, when exposed to UV light. A laser-induced breakdown spectroscopy (LIBS)-based optical sensor was designed, developed, and tested for detection of four important trace impurities in rocket fuel (hydrogen). The sensor can simultaneously measure the concentrations of nitrogen, argon, oxygen, and helium in hydrogen from storage tanks and supply lines. The sensor had estimated lower detection limits of 80 ppm for nitrogen, 97 ppm for argon, 10 ppm for oxygen, and 25 ppm for helium. A chemiluminescence-based spectroscopic diagnostics were performed to measure equivalence ratios in methane-air premixed flames. A partial least-squares regression (PLS-R)-based multivariate sensing methodology was investigated. It was found that the equivalence ratios predicted with the PLS-R-based multivariate calibration model matched with the

  1. Pulsed laser versus electrical energy for peripheral nerve stimulation

    PubMed Central

    Wells, Jonathon; Konrad, Peter; Kao, Chris; Jansen, E. Duco; Mahadevan-Jansen, Anita

    2010-01-01

    Transient optical neural stimulation has previously been shown to elicit highly controlled, artifact-free potentials within the nervous system in a non-contact fashion without resulting in damage to tissue. This paper presents the physiologic validity of elicited nerve and muscle potentials from pulsed laser induced stimulation of the peripheral nerve in a comparative study with the standard method of electrically evoked potentials. Herein, the fundamental physical properties underlying the two techniques are contrasted. Key laser parameters for efficient optical stimulation of the peripheral nerve are detailed. Strength response curves are shown to be linear for each stimulation modality, although fewer axons can be recruited with optically evoked potentials. Results compare the relative transient energy requirements for stimulation using each technique and demonstrate that optical methods can selectively excite functional nerve stimulation. Adjacent stimulation and recording of compound nerve potentials in their entirety from optical and electrical stimulation are presented, with optical responses shown to be free of any stimulation artifact. Thus, use of a pulsed laser exhibits some advantages when compared to standard electrical means for excitation of muscle potentials in the peripheral nerve in the research domain and possibly for clinical diagnostics in the future. PMID:17537515

  2. A pathway to laser fusion energy in Japan

    NASA Astrophysics Data System (ADS)

    Azechi, Hiroshi

    2016-10-01

    High-density compression of DT to one thousand times its liquid density is the critical path of inertial fusion and was demonstrated in Japan and US in late 1980's. The Osaka group has achieved high-density compression that meets one of the critical requirements for thermonuclear ignition and bum. Although the compression densities were well reproduced by computer simulations, the neutron yields were much lower than the simulation predictions by three orders of magnitudes, suggesting catastrophic collapse of a hot spark, from which thermonuclear reactions are triggered. In order to overcome this difficulty the international ICF community has adopted two approaches: one is to generate a larger hot spark than the mixed layer with MJ-Class lasers, such as NIF and LMJ. The other approach is to externally heat the compressed fuel. The second approach is the fast ignition. After the proof-of-concept experiment in 2002, we started the Fast Ignition Realization Experiment (FlREX) project to complete the world most powerful high-energy peta-watt laser "LFEX" as a heating laser.

  3. A pathway to laser fusion energy in Japan

    NASA Astrophysics Data System (ADS)

    Azechi, Hiroshi

    2016-05-01

    High-density compression of DT to one thousand times its liquid density is the critical path of inertial fusion and was demonstrated in Japan and US in late 1980's. The Osaka group has achieved high-density compression that meets one of the critical requirements for thermonuclear ignition and burn. Although the compression densities were well reproduced by computer simulations, the neutron yields were much lower than the simulation predictions by three orders of magnitudes, suggesting catastrophic collapse of a hot spark, from which thermonuclear reactions are triggered. In order to overcome this difficulty the international ICF community has adopted two approaches: one is to generate a larger hot spark than the mixed layer with MJ-Class lasers, such as NIF and LMJ. The other approach is to externally heat the compressed fuel. The second approach is the fast ignition. After the proof-of-concept experiment in 2002, we started the Fast Ignition Realization Experiment (FIREX) project to complete the world most powerful high-energy peta-watt laser “LFEX” as a heating laser.

  4. Electron energy enhancement by frequency chirped axicon Gaussian laser pulse in vacuum

    NASA Astrophysics Data System (ADS)

    Rajput, Jyoti; Kant, Niti; Singh, Arvinder

    2017-07-01

    Electron acceleration by a frequency - chirped lowest axicon Gaussian laser pulse in vacuum is studied. Terawatt RP laser can be focussed down by an axicon optical element, which produces a very strong longitudinal electric field. A linear frequency chirp increases the time duration of interaction of laser pulse with electron and hence, influences electron motion significantly. It is noticed that an electron with initial energy of few MeV, accelerates upto GeV energy under optimized laser parameters. Significant higher energy gain is observed with intense chirped laser pulse in vacuum.

  5. Research and Development of High Energy 2 - Micron Lasers Based on TM: Doped Ceramic Laser Gain Media and TM: Doped Optical Fibers

    DTIC Science & Technology

    2016-07-20

    AFRL-AFOSR-VA-TR-2016-0257 RESEARCH AND DEVELOPMENT OF HIGH ENERGY 2 - MICRON LASERS BASED ON TM: DOPED CERAMIC LASER GAIN MEDIA AND TM: DOPED...2010 to 01/03/2016 4. TITLE AND SUBTITLE RESEARCH AND DEVELOPMENT OF HIGH ENERGY 2 - MICRON LASERS BASED ON TM: DOPED CERAMIC LASER GAIN MEDIA AND...TERMS Development of high energy 2-micron lasers 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 14 19a. NAME OF

  6. Channels of energy redistribution in short-pulse laser interactions with metal targets

    NASA Astrophysics Data System (ADS)

    Zhigilei, Leonid V.; Ivanov, Dmitriy S.

    2005-07-01

    The kinetics and channels of laser energy redistribution in a target irradiated by a short, 1 ps, laser pulse is investigated in computer simulations performed with a model that combines molecular dynamics (MD) simulations with a continuum description of the laser excitation and relaxation of the conduction band electrons, based on the two-temperature model (TTM). The energy transferred from the excited electrons to the lattice splits into several parts, namely the energy of the thermal motion of the atoms, the energy of collective atomic motions associated with the relaxation of laser-induced stresses, the energy carried away from the surface region of the target by a stress wave, the energy of quasi-static anisotropic stresses, and, at laser fluences above the melting threshold, the energy transferred to the latent heat of melting and then released upon recrystallization. The presence of the non-thermal channels of energy redistribution (stress wave and quasi-static stresses), not accounted for in the conventional TTM model, can have important implications for interpretation of experimental results on the kinetics of thermal and mechanical relaxation of a target irradiated by a short laser pulse as well as on the characteristics of laser-induced phase transformations. The fraction of the non-thermal energy in the total laser energy partitioning increases with increasing laser fluence.

  7. Laser modulation of human immune system: inhibition of lymphocyte proliferation by a gallium-arsenide laser at low energy

    SciTech Connect

    Ohta, A.; Abergel, R.P.; Uitto, J.

    1987-01-01

    Cultured human lymphocytes were subjected to irradiation with a gallium-arsenide laser at energy fluence varying from 2.17 to 651 mJ/cm2, and the cell proliferation was assessed by (/sup 3/H)thymidine incorporation. Both mitogenic proliferation in response to phytohemagglutinin and spontaneous cell proliferation were markedly inhibited by the laser irradiation at energy fluence as low as 10.85 mJ/cm2. Similarly, the functional response of cells to antigen stimulation in a one-way mixed-lymphocyte reaction was also diminished as a result of laser irradiation. The results indicate that laser irradiation at low energy can interfere with immune system in vitro, and similar modulation could potentially occur in human subjects exposed to laser irradiation in vivo.

  8. Low-energy electron rescattering in laser-induced ionization

    NASA Astrophysics Data System (ADS)

    Becker, W.; Goreslavski, S. P.; Milošević, D. B.; Paulus, G. G.

    2014-10-01

    The low-energy structure (LES) in the energy spectrum of above-threshold ionization of rare-gas atoms is reinvestigated from three different points of view. First, the role of forward rescattering in the completely classical simple-man model (SMM) is considered. Then, the corresponding classical electronic trajectories are retrieved in the quantum-mechanical ionization amplitude derived in the strong-field approximation augmented to allow for rescattering. Third, classical trajectories in the presence of both the laser field and the Coulomb field are scrutinized in order to see how they are related to the LES. It is concluded that the LES is already rooted in the SMM. The Coulomb field enhances the structure so that it can successfully compete with other contributions and become visible in the total spectrum.

  9. Spatial filter pinhole for high-energy pulsed lasers

    SciTech Connect

    Celliers, P.M.; Estabrook, K.G.; Wallace, R.J.; Murray, J.E.; Da Silva, L.B.; MacGowan, B.J.; Van Wonterghem, B.M.; Manes, K.R.

    1998-04-01

    Spatial filters are essential components for maintaining high beam quality in high-energy pulsed laser systems. The long-duration (21 ns) high-energy pulses envisioned for future inertial-confinement fusion drive systems, such as the U. S. National Ignition Facility (NIF), are likely to lead to increased plasma generation and closure effects within the pinholes in the spatial filters. The design goal for the pinhole spatial filter for the NIF design is to remove small-angle scatter in the beam to as little as a {plus_minus}100-{mu}rad divergence. It is uncertain whether this design requirement can be met with a conventional pinhole design. We propose a new pinhole architecture that addresses these issues by incorporating features intended to reduce the rate of plasma generation. Initial experiments with this design have verified its performance improvement relative to a conventional pinhole design. {copyright} 1998 Optical Society of America

  10. A focal-spot diagnostic for on-shot characterization of high-energy petawatt lasers.

    PubMed

    Bromage, J; Bahk, S-W; Irwin, D; Kwiatkowski, J; Pruyne, A; Millecchia, M; Moore, M; Zuegel, J D

    2008-10-13

    An on-shot focal-spot diagnostic for characterizing high-energy, petawatt-class laser systems is presented. Accurate measurements at full energy are demonstrated using high-resolution wavefront sensing in combination with techniques to calibrate on-shot measurements with low-power sample beams. Results are shown for full-energy activation shots of the OMEGA EP Laser System.

  11. Effects of Relative Platform and Target Motion on Propagation of High Energy Lasers

    DTIC Science & Technology

    2016-06-01

    ATMOSPHERIC PROPAGATION OF HIGH ENERGY LASERS ...............7  A.  ATMOSPHERIC EXTINCTION ...Calculated aerosol absorption and extinction coefficients for 23-km visibility conditions and a continental aerosol model. Source: [8]. ...........10...power levels. 7 III. ATMOSPHERIC PROPAGATION OF HIGH ENERGY LASERS A. ATMOSPHERIC EXTINCTION Light loses some of its energy along the path it

  12. Variation of laser energy transfer efficiency with well pool depth

    SciTech Connect

    Fuerschbach, P.W.; MacCallum, D.O.

    1995-12-01

    A series of CO{sub 2} laser welds were made at a constant beam irradiance of 6 MW/cm{sup 2} on 304 stainless steel with travel speeds selected to produce welds with varying levels of weld penetration. Using a Seebeck envelope calorimeter, the net heat input to the part was measured for each weld. It was found that the energy transfer efficiencies varied from 0.29 to 0.86, and decreased at high travel speeds where the weld penetration depth was as shallow as 0.13 mm. The decrease in beam absorption with decreasing weld pool depth is consistent with an absorption mechanism that requires multiple internal reflections within the weld pool. Equations have been developed which conn -ct the keyhole cavity dimensions with the energy transfer efficiency, and correlations with the experimental data have determined the keyhole cavity radius to be 0.1 mm for a focused laser beam with a spot radius of 0.059 mm.

  13. Experimental Design of a UCAV-Based High-Energy Laser Weapon

    DTIC Science & Technology

    2016-12-01

    DESIGN OF A UCAV-BASED HIGH- ENERGY LASER WEAPON by Antonios Lionis December 2016 Thesis Advisor: Keith R. Cohn Co-Advisor: Eugene Paulo...COVERED Master’s thesis 4. TITLE AND SUBTITLE EXPERIMENTAL DESIGN OF A UCAV-BASED HIGH- ENERGY LASER WEAPON 5. FUNDING NUMBERS 6. AUTHOR(S...12b. DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) The deployment of a High Energy Laser (HEL) weapon in an airborne platform is a

  14. Carbon dioxide laser laparoscopy by means of a 3.0-mm diameter rigid wave guide.

    PubMed

    Baggish, M S; Sze, E; Badawy, S; Choe, J

    1988-09-01

    Rigid carbon dioxide wave guides measuring 300 to 500 mm in length and 3.0 mm in diameter were evaluated in rabbits and humans. The wave guide provided an effective laser delivery system for operative laparoscopy. The tested guide was introduced into the abdominal cavity alternatively via the operating channel of a 9-mm operating laparoscope, through the central channel of a smoke evacuation/irrigation cannula, or via a 3.25-mm second puncture trocar. In contrast to previously tested flexible guides, the rigid device transmitted a visible helium-neon aiming beam, power up to 50 watts, and a beam diameter of less than 1 mm. The hollow guide was kept free of smoke by-products by continuous purging with carbon dioxide gas flowing at 800 to 1000 cc per minute. All wave guides could be sterilized by ethylene oxide gas or Cidex (Surgikos, Arlington, TX) soaking. Fourteen women with a variety of reproductive disorders underwent laser laparoscopy. The rigid wave guide was fired at distances ranging from less than 1 mm to 30 mm from the target and performed with maximal impact at distances of 3 to 5 mm. Perhaps the greatest advantage of this system is its ability to focus-defocus while directly coupling to the handpiece of standard lasers and requiring no special alignment procedures.

  15. A laser scanner for imaging fluorophore labeled molecules in electrophoretic gels

    SciTech Connect

    Fisk, D.J.; Sutherland, J.C.

    1995-08-01

    A laser scanner for imaging electrophoretic gels was constructed and tested. The scanner incorporates a green helium-neon (HeNe) laser (543.5nm wavelength) and can achieve a spatial resolution of 19{micro}m. The instrument can function in two modes : snap-shot and finish-line. In snapshot mode, all samples are electrophoresed for the same time and the gel is scanned after completion of electrophoresis, while in finish-line mode, fluorophore labeled samples are electrophoresed for a constant distance and the image is formed as the samples pass under the detector. The resolving power of the finish-line mode of imaging is found to be greater than that of the snapshot mode of imaging. This laser scanner is also compared with a Charge Coupled Device (CCD) camera and in terms of resolving power is found to be superior. Sensitivity of the instrument is presented in terms of the minimum amount of DNA that can be detected verses its molecular length.

  16. Laser radiation in the treatment of prosthetic graft stenosis. A preliminary study of prosthesis damage by laser energy

    SciTech Connect

    Seeger, J.M.; Abela, G.S.; Klingman, N.

    1987-09-01

    Transluminal laser recanalization is potentially an important new treatment of anastomotic intimal hyperplasia. However, currently used grafts or sutures may be damaged by laser radiation at power and energy levels required for plaque removal. To investigate this problem, two commonly used grafts (Dacron and polytetrafluoroethylene (PTFE)) and two types of vascular suture (polypropylene and PTFE) were exposed to argon laser radiation in vitro. Dacron and PTFE grafts recovered from amputations were also studied to determine whether graft healing affected graft resistance to laser damage. Power and energy levels required to perforate atherosclerotic superficial femoral arteries were determined for comparison. PTFE grafts were significantly (1.5 to 7 times) more resistant to perforation by laser energy than atherosclerotic arteries under all conditions. In contrast, Dacron grafts perforated at power and energy levels one half to one third of that required for vaporization of atherosclerotic plaque. PTFE sutures remained intact at power and energy levels above the levels that perforated atherosclerotic arteries, whereas polypropylene sutures were destroyed by very low levels of power and energy (0.5 joules at 0.5 watts). Because of the variable levels of power and energy that damage different types of prosthetic grafts and sutures, laser angioplasty should only be investigated clinically as a therapy for anastomotic intimal hyperplasia when PTFE grafts and sutures are present.

  17. The effect of laser energy on V2O5 thin film growth prepared by laser assisted molecular beam deposition

    NASA Astrophysics Data System (ADS)

    Abdel Samad, B.; Ashrit, P. V.

    2014-09-01

    Vanadium pentoxide V2O5 thin films were grown on glass substrates by the LAMBD deposition system with different laser energies. The structure, composition and optical properties of the films have been investigated with atomic force microscopy, x-ray photoemission spectroscopy, ellipsometry and the transmittance analysis. Upon the increase of laser energy, the results showed that the changes in the optical constants are consistent with the thickness changes of the film. The refractive index increases and the absorption coefficient increases when the laser energy increases. The AFM analysis showed a change of the roughness and structure of the deposited films at different laser energies. The prepared films deposited by LAMBD showed interesting properties with correct V2O5 phase without need of annealing after deposition.

  18. Effects of low level laser treatment on the survival of axotomized retinal ganglion cells in adult Hamsters

    PubMed Central

    So, Kwok-Fai; Leung, Mason Chin Pang; Cui, Qi

    2014-01-01

    Injury to axons close to the neuronal bodies in the mammalian central nervous system causes a large proportion of parenting neurons to degenerate. It is known that optic nerve transection close to the eye in rodents leads to a loss of about half of retinal ganglion cells in 1 week and about 90% in 2 weeks. Using low level laser treatment in the present study, we demonstrated that treatment with helium-neon (660 nm) laser with 15 mW power could delay retinal ganglion cell death after optic nerve axotomy in adult hamsters. The effect was most apparent in the first week with a short period of treatment time (5 minutes) in which 65–66% of retinal ganglion cells survived the optic nerve axotomy whereas 45–47% of retinal ganglion cells did so in optic nerve axotomy controls. We also found that single dose and early commencement of laser irradiation were important in protecting retinal ganglion cells following optic nerve axotomy. These findings thus convincingly show that appropriate laser treatment may be neuroprotective to retinal ganglion cells. PMID:25558230

  19. Energy-based approach as an example for a process signature for laser microprocessing

    NASA Astrophysics Data System (ADS)

    Zhao, Tong; Mehrafsun, Salar; Vollertsen, Frank

    2016-11-01

    Taking laser ablation and laser chemical machining as examples, this paper explores the challenges to implement the energy-based approach of process signature in laser micro processing. It is expected that laser processes and specific materials independent mechanisms can be found, which are deeper causes of the generation of the surface integrity behind the interactions among the specific energy sources, mediums, surface, subsurface, base material and environment. With the aim of dealing with the challenges, this paper discusses a new point of view, cumulation of modifications, concerning more effects in laser micro processing.

  20. Effects of laser energy and wavelength on the analysis of LiFePO₄ using laser assisted atom probe tomography

    DOE PAGES

    Santhanagopalan, Dhamodaran; Schreiber, Daniel K.; Perea, Daniel E.; ...

    2014-09-21

    The effects of laser wavelength (355 nm and 532 nm) and laser pulse energy on the quantitative analysis of LiFePO₄ by atom probe tomography are considered. A systematic investigation of ultraviolet (UV, 355 nm) and green (532 nm) laser assisted field evaporation has revealed distinctly different behaviors. With the use of a UV laser, the major issue was identified as the preferential loss of oxygen (up to 10 at%) while other elements (Li, Fe and P) were observed to be close to nominal ratios. Lowering the laser energy per pulse to 1 pJ/pulse from 50 pJ/pulse increased the observed oxygenmore » concentration to nearer its correct stoichiometry, which was also well correlated with systematically higher concentrations of ¹⁶O₂⁺ ions. Green laser assisted field evaporation led to the selective loss of Li (33% deficiency) and a relatively minor O deficiency. The loss of Li is likely a result of selective dc evaporation of Li between or after laser pulses. Comparison of the UV and green laser data suggests that the green wavelength energy was absorbed less efficiently than the UV wavelength because of differences in absorption at 355 and 532 nm for LiFePO₄. Plotting of multihit events on Saxey plots also revealed a strong neutral O₂ loss from molecular dissociation, but quantification of this loss was insufficient to account for the observed oxygen deficiency.« less

  1. Method for controlling energy density for reliable pulsed laser deposition of thin films

    SciTech Connect

    Dowden, P. C. E-mail: qxjia@lanl.gov; Bi, Z.; Jia, Q. X. E-mail: qxjia@lanl.gov

    2014-02-15

    We have established a methodology to stabilize the laser energy density on a target surface in pulsed laser deposition of thin films. To control the focused laser spot on a target, we have imaged a defined aperture in the beamline (so called image-focus) instead of focusing the beam on a target based on a simple “lens-focus.” To control the laser energy density on a target, we have introduced a continuously variable attenuator between the output of the laser and the imaged aperture to manipulate the energy to a desired level by running the laser in a “constant voltage” mode to eliminate changes in the lasers’ beam dimensions. This methodology leads to much better controllability/reproducibility for reliable pulsed laser deposition of high performance electronic thin films.

  2. Injection of a Phase Modulated Source into the Z-Beamlet Laser for Increased Energy Extraction.

    SciTech Connect

    Rambo, Patrick K.; Armstrong, Darrell J.; Schwarz, Jens; Smith, Ian C; Shores, Jonathon; Speas, Christopher; Porter, John L.

    2014-11-01

    The Z-Beamlet laser has been operating at Sandia National Laboratories since 2001 to provide a source of laser-generated x-rays for radiography of events on the Z-Accelerator. Changes in desired operational scope have necessitated the increase in pulse duration and energy available from the laser system. This is enabled via the addition of a phase modulated seed laser as an alternative front-end. The practical aspects of deployment are discussed here.

  3. The influence of energy deposition parameters on laser plasma drag reduction

    NASA Astrophysics Data System (ADS)

    Dou, Zhiguo; Liu, Zhun; Yao, Honglin; Li, Xiuqian

    2013-09-01

    Laser plasma drag reduction is a new method to reduce the wave drag of hypersonic flight. The research of the laser plasma drag reduction performance is an important work. The purpose of this paper is investigating laser plasma drag reduction by numerical simulation to enhance the understanding of the drag reduction mechanism, get the drag reduction performance in different conditions, and provide references for laser plasma drag reduction experiment in the future. Based on summarizing correlative references systematically, through building the model of energy deposition and comparison the simulated results to the empirical formula and computation results to verify the program correctness, the influence of laser energy parameters to laser plasma drag reduction were simulated numerically for optimize the performance. The follow conclusions were got by numerical simulation: The computation program can well simulate the interacting of LSDW(laser supported detonation wave) to the bow shock in front of the blunt body. Results indicate that the blunt body drag could be decreased by injecting laser energy into the incoming hypersonic flow. The correctness of program was verified by compare result to the experiment and computation results. Blunt body drag will be greatly decreased with injected laser power increased, The bigger laser power is injected, the more drag decreases. There's an energy saturation value for each laser power level, the injecting laser power effectiveness values are never quite high for all laser power level. There is an optimized energy deposition location in upstream flow, this location is right ahead of the blunt body. When the distance from deposition location to the surface of blunt body is 5 times the blunt radius, blunt body drag decreased the most. This paper investigated the parameters which primary influence the performance of drag reduction. The numerical simulation data and obtained results are meaningful for laser plasma drag reduction

  4. Repetitively pulsed, high energy KrF lasers for inertial fusion energy

    NASA Astrophysics Data System (ADS)

    Myers, M. C.; Sethian, J. D.; Giuliani, J. L.; Lehmberg, R.; Kepple, P.; Wolford, M. F.; Hegeler, F.; Friedman, M.; Jones, T. C.; Swanekamp, S. B.; Weidenheimer, D.; Rose, D.

    2004-12-01

    Krypton fluoride (KrF) lasers produce highly uniform beams at 248 nm, allow the capability of 'zooming' the spot size to follow an imploding pellet, naturally assume a modular architecture and have been developed into a pulsed-power-based industrial technology that readily scales to a fusion power plant sized system. There are two main challenges for the fusion power plant application: to develop a system with an overall efficiency of greater than 6% (based on target gains of 100) and to achieve a durability of greater than 3 × 108 shots (two years at 5 Hz). These two issues are being addressed with the Electra (700 J, 5 Hz) and Nike (3000 J, single shot) KrF lasers at the Naval Research Laboratory. Based on recent advances in pulsed power, electron beam generation and transport, hibachi (foil support structure) design and KrF physics, wall plug efficiencies of greater than 7% should be achievable. Moreover, recent experiments show that it may be possible to realize long lived electron beam diodes using ceramic honeycomb cathodes and anode foils that are convectively cooled by periodically deflecting the laser gas. This paper is a summary of the progress in the development of the critical KrF technologies for laser fusion energy.

  5. Thermal Blooming and Air Breakdown Interaction for Pulsed High Energy Lasers,

    DTIC Science & Technology

    1978-06-01

    illustrates the exoerimental arrangement. A single shot Lumonics 602A CO2 Transversely Excited Atmospheric (TEA) laser beam, 45 3 energy output, with...BREAKDOWN INTERACTION (~~~~ Jf~fl fl~~~~ThFOR PULSED HIGH ENERGY LASERS fl ~~~~~~~~~~~~~~~~~ ~,; JUN~~~ U JUL 12 1918 j ’ *~OBERF $ / I~QHDE,~~~ RUDOLF G... Laser pulse transmission as related to Army high energy laser systems involves many interacting effects which generally degrade the performance of the

  6. Ion acceleration with a narrow energy spectrum by nanosecond laser-irradiation of solid target

    SciTech Connect

    Altana, C.; Lanzalone, G.; Mascali, D.; Cirrone, G. A. P.; Schillaci, F.; Tudisco, S.; Muoio, A.

    2016-02-15

    In laser-driven plasma, ion acceleration of aluminum with the production of a quasi-monoenergetic beam has occurred. A useful device to analyze the ions is the Thomson parabolas spectrometer, a well-known diagnostic that is able to obtain information on charge-to-mass ratio and energy distribution of the charged particles. At the LENS (Laser Energy for Nuclear Science) laboratory of INFN-LNS in Catania, experimental measures were carried out; the features of LENS are: Q-switched Nd:YAG laser with 2 J laser energy, 1064 nm fundamental wavelengths, and 6 ns pulse duration.

  7. Increased laser-accelerated proton energies via direct laser-light-pressure acceleration of electrons in microcone targets

    SciTech Connect

    Gaillard, S. A.; Kluge, T.; Bussmann, M.; Cowan, T. E.; Flippo, K. A.; Offermann, D. T.; Gall, B.; Lockard, T.; Sentoku, Y.; Geissel, M.; Schollmeier, M.

    2011-05-15

    We present experimental results showing a laser-accelerated proton beam maximum energy cutoff of 67.5 MeV, with more than 5 x 10{sup 6} protons per MeV at that energy, using flat-top hollow microcone targets. This result was obtained with a modest laser energy of {approx}80 J, on the high-contrast Trident laser at Los Alamos National Laboratory. From 2D particle-in-cell simulations, we attribute the source of these enhanced proton energies to direct laser-light-pressure acceleration of electrons along the inner cone wall surface, where the laser light wave accelerates electrons just outside the surface critical density, in a potential well created by a shift of the electrostatic field maximum with respect to that of the magnetic field maximum. Simulations show that for an increasing acceleration length, the continuous loading of electrons into the accelerating phase of the laser field yields an increase in high-energy electrons.

  8. Method and apparatus for delivering high power laser energy over long distances

    DOEpatents

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2013-08-20

    Systems, devices and methods for the transmission of 1 kW or more of laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser drilling of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to advance such boreholes deep into the earth and at highly efficient advancement rates.

  9. Method and apparatus for delivering high power laser energy over long distances

    DOEpatents

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2015-04-07

    Systems, devices and methods for the transmission and delivery of high power laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser drilling of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to advance such boreholes deep into the earth and at highly efficient advancement rates.

  10. Recent development and future perspectives of low energy laser shock peening

    NASA Astrophysics Data System (ADS)

    Kalainathan, S.; Prabhakaran, S.

    2016-07-01

    The first part of the review involves the parameters controlling and optimization of low energy laser shock peening process. The second part presents the effect of laser peening without coating on ferrous, aluminum and titanium alloys. Therefore, the recently developed techniques and challenges on it are discussed. Opportunities to tackle the current challenges are overviewed. Finally, in the third part, the future perspectives of low energy laser peening on metal matrix composites and single crystals for several typical applications are deliberated.

  11. Unique aspects of laser energy deposition in the fs pulse regime

    SciTech Connect

    Feit, M.D.; Rubenchik, A.M.; Shore, B.W.

    1996-02-02

    Ultrashort laser pulse tissue ablation has demonstrated advantages of greatly reduced required energy and collateral damage. These advantages stem directly from the fact that laser energy is absorbed nonlinearly in a time too hsort for significant thermal dn hydrodynamic response. The high peak power and short pulse duration both have implications for practical fiber delivery systems.

  12. Method for generating high-energy and high repetition rate laser pulses from CW amplifiers

    SciTech Connect

    Zhang, Shukui

    2013-06-18

    A method for obtaining high-energy, high repetition rate laser pulses simultaneously using continuous wave (CW) amplifiers is described. The method provides for generating micro-joule level energy in pico-second laser pulses at Mega-hertz repetition rates.

  13. Investigation of possibilities for solar powered high energy lasers in space

    NASA Technical Reports Server (NTRS)

    Rather, J. D. G.; Gerry, E. T.; Zeiders, G. W.

    1977-01-01

    The feasibility of solar powered high energy lasers in space has been studied. Preliminary analysis indicates that both direct and indirect pumping methods lead to high energy lasers having interesting efficiencies and capabilities. Many topics for further research have been identified.

  14. Laser Metrology for an Optical-Path-Length Modulator

    NASA Technical Reports Server (NTRS)

    Gursel, Yekta

    2005-01-01

    Laser gauges have been developed to satisfy requirements specific to monitoring the amplitude of the motion of an optical-path-length modulator that is part of an astronomical interferometer. The modulator includes a corner-cube retroreflector driven by an electromagnetic actuator. During operation of the astronomical interferometer, the electromagnet is excited to produce linear reciprocating motion of the corner-cube retroreflector at an amplitude of 2 to 4 mm at a frequency of 250, 750, or 1,250 Hz. Attached to the corner-cube retroreflector is a small pick-off mirror. To suppress vibrations, a counterweight having a mass equal to that of the corner-cube retroreflector and pick-off mirror is mounted on another electromagnetic actuator that is excited in opposite phase. Each gauge is required to measure the amplitude of the motion of the pick-off mirror, assuming that the motions of the pick-off mirror and the corner-cube retroreflector are identical, so as to measure the amplitude of motion of the corner- cube retroreflector to within an error of the order of picometers at each excitation frequency. Each gauge is a polarization-insensitive heterodyne interferometer that includes matched collimators, beam separators, and photodiodes (see figure). The light needed for operation of the gauge comprises two pairs of laser beams, the beams in each pair being separated by a beat frequency of 80 kHz. The laser beams are generated by an apparatus, denoted the heterodyne plate, that includes stabilized helium-neon lasers, acousto-optical modulators, and associated optical and electronic subsystems. The laser beams are coupled from the heterodyne plate to the collimators via optical fibers.

  15. Evaluation of retinal exposures from repetitively pulsed and scanning lasers.

    PubMed

    Ham, W T; Mueller, H A; Wolbarsht, M L; Sliney, D H

    1988-03-01

    Threshold damage in the macaque retina is shown to be equivalent for the argon-krypton (Ar-Kr) 647 nm and the helium-neon (He-Ne) 632.8-nm lines for exposures to continuous wave (CW) radiation from 1 to 1,000 s. This equivalence allows interpolation from experiments with 647-nm, exposures at power levels that are unavailable with the He-Ne laser. To simulate He-Ne laser scanner exposures, 40-microseconds pulses of 647-nm light transmitted through a revolving disk with holes in the periphery were used to expose the retinas of monkeys under deep anesthesia at pulse repetition frequencies (PRFs) of 100, 200, 400, and 1,600 Hz for exposure durations of 1, 10, 100, and 1,000 s. The thresholds between laser exposure at 488 nm (Ar-Kr) and between laser exposure at 647 nm (Kr) are compared to assess thermal versus photochemical effects on the retina. The threshold for 488-nm pulses was consistently lower than that for 647-nm pulses at all PRFs and exposure times. The difference in thresholds increased with exposure time and PRF. The sharp decreases in 488-nm thresholds at 100-s exposure times for each PRF can be interpreted as a basically photochemical effect. The radiant exposure required for damage at 647 nm was several orders of magnitude above the radiant exposure from typical He-Ne scanner applications. From the similarity of the macaque retina to the human retina, it is concluded that no realistic ocular hazard exists from exposure to scanning laser systems of 1 mW or less, operating at higher than 100 Hz.

  16. Efficient energy absorption of intense ps-laser pulse into nanowire target

    SciTech Connect

    Habara, H.; Honda, S.; Katayama, M.; Tanaka, K. A.; Sakagami, H.; Nagai, K.

    2016-06-15

    The interaction between ultra-intense laser light and vertically aligned carbon nanotubes is investigated to demonstrate efficient laser-energy absorption in the ps laser-pulse regime. Results indicate a clear enhancement of the energy conversion from laser to energetic electrons and a simultaneously small plasma expansion on the surface of the target. A two-dimensional plasma particle calculation exhibits a high absorption through laser propagation deep into the nanotube array, even for a dense array whose structure is much smaller than the laser wavelength. The propagation leads to the radial expansion of plasma perpendicular to the nanotubes rather than to the front side. These features may contribute to fast ignition in inertial confinement fusion and laser particle acceleration, both of which require high current and small surface plasma simultaneously.

  17. Guideline Implementation: Energy-Generating Devices, Part 2-Lasers.

    PubMed

    Burlingame, Byron L

    2017-04-01

    Lasers have been used in the OR for many years and are essential tools in many different types of procedures. However, laser beams that come into contact with unintended targets directly or via reflection can cause injury to patients or personnel or pose other hazards, such as fires. The new AORN "Guideline for safe use of energy-generating devices" provides guidance on the use of all energy-generating devices in the OR. This article focuses on key points of the guideline that address the safe use of lasers. These include the components of the laser safety program, the responsibilities of the personnel in roles specific to use of a laser, laser safety measures, and documentation of laser use. Perioperative RNs should review the complete guideline for additional information and for guidance when writing and updating policies and procedures. Copyright © 2017 AORN, Inc. Published by Elsevier Inc. All rights reserved.

  18. Efficient energy absorption of intense ps-laser pulse into nanowire target

    NASA Astrophysics Data System (ADS)

    Habara, H.; Honda, S.; Katayama, M.; Sakagami, H.; Nagai, K.; Tanaka, K. A.

    2016-06-01

    The interaction between ultra-intense laser light and vertically aligned carbon nanotubes is investigated to demonstrate efficient laser-energy absorption in the ps laser-pulse regime. Results indicate a clear enhancement of the energy conversion from laser to energetic electrons and a simultaneously small plasma expansion on the surface of the target. A two-dimensional plasma particle calculation exhibits a high absorption through laser propagation deep into the nanotube array, even for a dense array whose structure is much smaller than the laser wavelength. The propagation leads to the radial expansion of plasma perpendicular to the nanotubes rather than to the front side. These features may contribute to fast ignition in inertial confinement fusion and laser particle acceleration, both of which require high current and small surface plasma simultaneously.

  19. Fusion technologies for Laser Inertial Fusion Energy (LIFE)

    NASA Astrophysics Data System (ADS)

    Kramer, K. J.; Latkowski, J. F.; Abbott, R. P.; Anklam, T. P.; Dunne, A. M.; El-Dasher, B. S.; Flowers, D. L.; Fluss, M. J.; Lafuente, A.; Loosmore, G. A.; Morris, K. R.; Moses, E.; Reyes, S.

    2013-11-01

    The Laser Inertial Fusion-based Energy (LIFE) engine design builds upon on going progress at the National Ignition Facility (NIF) and offers a near-term pathway to commercial fusion. Fusion technologies that are critical to success are reflected in the design of the first wall, blanket and tritium separation subsystems. The present work describes the LIFE engine-related components and technologies. LIFE utilizes a thermally robust indirect-drive target and a chamber fill gas. Coolant selection and a large chamber solid-angle coverage provide ample tritium breeding margin and high blanket gain. Target material selection eliminates the need for aggressive chamber clearing, while enabling recycling. Demonstrated tritium separation and storage technologies limit the site tritium inventory to attractive levels. These key technologies, along with the maintenance and advanced materials qualification program have been integrated into the LIFE delivery plan. This describes the development of components and subsystems, through prototyping and integration into a First Of A Kind power plant. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  20. Pulse energy measurement at the hard x-ray laser in Japan

    SciTech Connect

    Kato, M.; Tanaka, T.; Saito, N.; Kurosawa, T.; Richter, M.; Sorokin, A. A.; Tiedtke, K.; Kudo, T.; Yabashi, M.; Tono, K.; Ishikawa, T.

    2012-07-09

    The pulse energies of a free electron laser have accurately been measured in the hard x-ray spectral range. In the photon energy regime from 4.4 keV to 16.8 keV, pulse energies up to 100 {mu}J were obtained at the hard x-ray laser facility SACLA (SPring-8 Angstrom Compact free-electron LAser). Two independent methods, using a cryogenic radiometer and a gas monitor detector, were applied and agreement within 3.3% was achieved. Based on our validated pulse energy measurement, a SACLA online monitor detector could be calibrated for all future experiments.

  1. [Impact of laser energy on measurement of fly ash carbon content].

    PubMed

    Yao, Shun-Chun; Lu, Ji-Dong; Xie, Cheng-Li; Li, Jie; Pan, Sheng-Hua; He, Ze-Xiong

    2009-08-01

    A laser induced breakdown spectroscopy-based apparatus for the analysis of element, employing a 532 nm laser and a multi-channel optical spectrometer with a non-intensified CCD array, has been built and tested. It was applied to analyze the carbon content of coal fly ash. Seven groups of pulse laser in the range of 35 to 98 mJ were used to ablate the fly ash samples. The electron densities and plasma temperatures with different laser energy were determined, and the influence of laser energy on the intensity of analysis carbon lines was also analyzed. The results show that carbon line intensity increases slowly with the increase in laser energy in the range of 35 to 46 mJ, and increases fast in the range of 46 to 78 mJ, then trends to saturation and has a little drop. At the same time, air breakdown has increased significantly, and has an obvious effect on sample plasma. Furthermore, the electron density and plasma temperature increase with the laser energy until 78 mJ and then begin to decrease. It indicates that a proper laser energy can enhance the plasma emission signal, and avoid the negative impact of air breakdown that prevent the pulse laser from reaching the surface of sample and ablating it. In this experiment situation, the measurement accuracy of the carbon line can be improved.

  2. Laser-induced Multi-energy Processing in Diamond Growth

    DTIC Science & Technology

    2012-05-01

    film deposition via chemical channels . Through laser-assisted chemical vapor deposition (LCVD), a variety of materials, such as metals (from metal ...37 Figure 3.2 Images of flames (a) without laser, (b) with CO2 laser irradiation at 10.591 µm, 800 W, and (c) with CO2 laser irradiation at...Optical emission spectra of the flame before (dashed curve) and after (solid curve) CO2 laser irradiation at a wavelength of 10.532 μm and a power of 800

  3. Myocardial tissue ablation by single high-energy laser pulses for ELR and TMR

    NASA Astrophysics Data System (ADS)

    Theisen, Dirk; Brinkmann, Ralf; Stubbe, Hans-Martin; Birngruber, Reginald

    1999-02-01

    The objective of this study is to compare the ablation sites induced by two different laser and application systems for myocardial laser revascularization. One system used was an 800 W CO2 laser, which is clinically established for transmyocardial laser revascularization (TMR). The second system was a self-designed Holmium laser emitting single high energy pulses for the minimal invasive approach of endocardial laser revascularization (ELR), whereby the laser light is transmitted via optical fiber into the left ventricle to ablate the myocardial channels from the inside. The laser energy was applied to Polyacrylamide (PAA) as transparent tissue phantom and in water as blood phantom. The ablation dynamics were investigated by high speed flash photography recording a picture series of a single event. Reperfused ex- vivo porcine hearts were treated to quantify differences in the thermal-mechanical damage ranges by polarization light microscopy. Ablation dynamics in water revealed oscillatory changes of the axial length of the steam bubbles between 3 mm and 12 mm during the CO2 laser pulse. For the Holmium laser pulse a maximal axial and lateral length of 5 mm was observed. The lateral dimensions of the bubbles were maximal 1 mm with the CO2- and 3.5 mm with the Holmium laser system. In PAA bubbles also collapse during the laser pulse which affects the size of the ablated channels. Using 12 J Holmium laser pulses for ablation of PAA, channel depths around 7 mm were found. Single Holmium laser pulses demonstrate ablations comparable in size and thermal- mechanical collateral damage to those achieved with the standard CO2 laser. The results are very encouraging for single pulse ELR and demonstrate the potential of a catheter based minimal invasive procedure for laser heart reperfusion.

  4. Diode pumped distributed Bragg reflector lasers based on a dye-to-polymer energy transfer blend.

    PubMed

    Vasdekis, A E; Tsiminis, G; Ribierre, J-C; O' Faolain, Liam; Krauss, T F; Turnbull, G A; Samuel, I D W

    2006-10-02

    We report the demonstration of a compact, all-solid-state polymer laser system comprising of a Gallium Nitride (GaN) semiconductor diode laser as the pump source. The polymer laser was configured as a surface emitting, distributed Bragg reflector laser (DBR), based on a novel energy transfer blend of Coumarin 102 and the conjugated polymer poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene). In this configuration, diode pumping was possible both due to the improved quality of the resonators and the improved harvesting of the diode laser light.

  5. Spacecraft Power Beaming and Solar Cell Annealing Using High-Energy Lasers

    DTIC Science & Technology

    2002-12-01

    powered lasers are used in industry for cutting, welding , and etching, and are also being considered for many military missions. The concept of the...Fluoride (HF) 2.8 Deuterium Fluoride (DF) 3.8 Carbon Dioxide ( CO2 ) 10.6 Table 2.1 Common High-Energy Lasers 6 Although iodine, HF/DF, and CO2 lasers...that are used for lidar research, active tracking, and other purposes. There is a 9 J CO2 laser, a 0.35 J tunable alexandrite laser, a 6 W tunable

  6. Mid-infrared lasers for energy frontier plasma accelerators

    NASA Astrophysics Data System (ADS)

    Pogorelsky, I. V.; Polyanskiy, M. N.; Kimura, W. D.

    2016-09-01

    Plasma wake field accelerators driven with solid-state near-IR lasers have been considered as an alternative to conventional rf accelerators for next-generation TeV-class lepton colliders. Here, we extend this study to the mid-IR spectral domain covered by CO2 lasers. We conclude that the increase in the laser driver wavelength favors the regime of laser wake field acceleration with a low plasma density and high electric charge. This regime is the most beneficial for gamma colliders to be converted from lepton colliders via inverse Compton scattering. Selecting a laser wavelength to drive a Compton gamma source is essential for the design of such a machine. The revealed benefits from spectral diversification of laser drivers for future colliders and off-spring applications validate ongoing efforts in advancing the ultrafast CO2 laser technology.

  7. Mid-infrared lasers for energy frontier plasma accelerators

    DOE PAGES

    Pogorelsky, I. V.; Polyanskiy, M. N.; Kimura, W. D.

    2016-09-12

    Plasma wake field accelerators driven with solid-state near-IR lasers have been considered as an alternative to conventional rf accelerators for next-generation TeV-class lepton colliders. Here, we extend this study to the mid-IR spectral domain covered by CO2 lasers. We conclude that the increase in the laser driver wavelength favors the regime of laser wake field acceleration with a low plasma density and high electric charge. This regime is the most beneficial for gamma colliders to be converted from lepton colliders via inverse Compton scattering. Selecting a laser wavelength to drive a Compton gamma source is essential for the design ofmore » such a machine. In conclusion, the revealed benefits from spectral diversification of laser drivers for future colliders and off-spring applications validate ongoing efforts in advancing the ultrafast CO2 laser technology.« less

  8. Theoretical Understanding of Enhanced Proton Energies from Laser-Cone Interactions

    SciTech Connect

    Kluge, T.; Gaillard, S. A.; Bussmann, M.; Burris-Mog, T.; Kraft, S. D.; Metzkes, J.; Rassuchine, J.; Schramm, U.; Zeil, K.; Cowan, T. E.; Flippo, K. A.; Offermann, D. T.; Gall, B.; Geissel, M.; Schollmeier, M.; Lockard, T.; Sentoku, Y.

    2010-11-04

    For the past ten years, the highest proton energies accelerated with high-intensity lasers was 58 MeV, observed in 2000 at the LLNL NOVA Petawatt laser, using flat foil targets. Recently, 67.5 MeV protons were observed in experiments at the Los Alamos National Laboratory (LANL) Trident laser, using one-fifth of the PW laser pulse energy, incident into novel conical targets. We present a focused study of new theoretical understanding of this measured enhancement from collisional Particle-in-Cell simulations, which shows that the hot electron temperature, number and maximum energy, responsible for the Target Normal Sheath Acceleration (TNSA) at the cone-top, are significantly increased when the laser grazes the cone wall. This is mainly due to the extraction of electrons from the cone wall by the laser electric field, and their boost in the forward direction by the vxB term of the Lorentz force. This result is in contrast to previous predictions of optical collection and wall-guiding of electrons in angled cones. This new wall-grazing mechanism offers the prospect to linearly increase the hot electron temperature, and thereby the TNSA proton energy, by extending the length over which the laser interacts in a grazing fashion in suitably optimized targets. This may allow achieving much higher proton energies for interesting future applications, with smaller, lower energy laser systems that allow for a high repetition rate.

  9. Several methods and apparatus of low-energy laser therapy in veterinary practice

    NASA Astrophysics Data System (ADS)

    Svirin, Vaytcheslav N.; Rogatkin, Dmitrii A.; Barybin, Vitalii F.

    1998-12-01

    During same years various medical effect of low-energy laser therapy in veterinary were tested. We established that the laser low-energy therapy can be very effective for treatment such animal's diseases as mastitis and demodekose when certain combinations of laser beam parameters are used. This combinations were taken as the principle of a number of laser veterinary apparatus, which we started to produce at `POLUS'. It is our series of apparatus `VEGA-MB' and `VETLAS-3', which is real used today for dogs and cows treatment in Russia.

  10. Temperature dependent spectroscopic characterization of Tm:YAG crystals as potential laser medium for pulsed high energy laser amplifiers

    NASA Astrophysics Data System (ADS)

    Körner, Jörg; Reiter, Jürgen; Lühder, Tilman; Hein, Joachim; Jambunathan, V.; Lucianetti, Antonio; Mocek, Tomáš; Kaluza, Malte C.

    2017-05-01

    Similar to ytterbium doped laser materials laser operation with thulium doped media is possible within a quasi-three level scheme, which especially for pulse pumped lasers is a drawback for efficient laser operation, as a significant amount of energy is required to bleach out the laser medium. Since this energy cannot be extracted, it is lost for the amplification process. Hence, operation of such lasers at cryogenic temperatures seems to be an appropriate solution. For further modeling and derivation of design rules for future laser systems based on such a scheme reliable spectral data is needed. We will present absorption and emission measurements on Tm:YAG as a function of temperature in the range from 80 K to 300 K covering both the absorption bands around 800 nm and the emission bands up to 2.1 μm. The spectral measurements were carried out on two samples of Tm:YAG with doping levels of 2 at.% and 8 at.%. Precautions for reabsorption effects were taken to allow for accurate results over the whole measurement range. From these measurements we have derived absorption and emission cross sections and radiative lifetimes. By comparing the latter values to values obtained by highly accurate measurements of the lifetime using the pinhole method we could also estimate the quantum efficiency.

  11. Addressing Control of Hazardous Energy (COHE) Requirements in a Laser Safety Program

    SciTech Connect

    Woods, Michael; /SLAC

    2012-02-15

    OSHA regulation 29CFR1910.147 specifies control of hazardous energy requirements for 'the servicing and maintenance of machines and equipment in which the unexpected energization or start up of the machines or equipment, or release of stored energy could cause injury to employees.' Class 3B and Class 4 laser beams must be considered hazardous energy sources because of the potential for serious eye injury; careful consideration is therefore needed to safely de-energize these lasers. This paper discusses and evaluates control of hazardous energy principles in this OSHA regulation, in ANSI Z136.1 ''Safe Use of Lasers,'' and in ANSI Z244.1 ''Control of Hazardous Energy, Lockout/Tagout and Alternative Methods.'' Recommendations are made for updating and improving CoHE (control of hazardous energy) requirements in these standards for their applicability to safe laser operations.

  12. Damage detection using modal strain energy and laser vibrometer measurements

    NASA Astrophysics Data System (ADS)

    Otieno, Andrew W.; Liu, Pengxiang; Rao, Vittal S.; Koval, Leslie R.

    2000-06-01

    Structural health monitoring for complex systems can contribute significantly to reduced life cycle costs. Many damage detection algorithms have been proposed in the literature for investigating the structural integrity of systems. Changes in modal strain energy have been used to detect the location and extent of damage in structures. In the previous studies, the stiffness matrix is analytically derived and assumed constant even after damage. This paper reports a study on the sensitivity of the modal strain energy method to the stiffness matrix and its accuracy in detecting the location and extent of damage. The modal strain energies for each element of the undamaged structure are computed for each mode using the original analytical matrix and measured modal data. Modal data from the damaged case is used to update the stiffness matrix by a simplified matrix update scheme. This updated matrix is used to correct the elemental matrices for the damaged system. Two case studies are presented in this work. The first is an experimental and analytical model of a cantilever beam and the second, a truss model of the European Space Agency. In the first case three identical aluminum cantilever beams are used. Damage is simulated on two of them by milling 1-inch long slots at two different locations on the beams. Modal data are obtained from experiment using Scanning Laser Vibrometer (SLV) and STAR software to extract the mode shape vectors from the experimental results. These are also compared with finite element simulations of the beams. The second case is an analytical example in which damage is simulated by reducing the area of one of the truss elements hypothetically by 50%. Results from these studies show a slight improved accuracy in determining the location of damage using an updated elemental stiffness matrix. For experimental results however, modal strain energy change method does not give an accurate location of the damages. There is need for further analysis of the

  13. The determination of energy transfer rates in the Ho:Tm:Cr:YAG laser material

    NASA Technical Reports Server (NTRS)

    Koker, Edmond B.

    1988-01-01

    Energy transfer processes occurring between atomic, ionic, or molecular systems are very widespread in nature. The applications of such processes range form radiation physics and chemistry to biology. In the field of laser physics, energy transfer processes have been used to extend the lasing range, increase the output efficiency, and influence the spectral and temporal characteristics of the output pulses of energy transfer dye lasers or solid-state laser materials. Thus in the development of solid state lasers, it is important to investigate the basic energy transfer (ET) mechanisms and processes in order to gain detailed knowledge so that successful technical utilization can be achieved. The aim of the present research is to measure the ET rate from a given manifold associated with the chromium sensitizer atom to a given manifold in the holmium activator atom via the thulium transfer atom, in the Ho:Cr:YAG laser material.

  14. MgO Deoxidization by Focused Laser Pulse for a New Energy Cycle

    NASA Astrophysics Data System (ADS)

    Yabe, Takashi; Ikuta, Kazunari; Baasandash, Choijil; Katano, Ryoichi; Uchida, Shigeaki; Tsuji, Minoru; Mori, Yuichi; Maehara, Jun; Mahmoud, Mohamed Salah; Toya, Tomohiro

    2006-05-01

    In order to resolve the environmental problem, we proposed a new energy cycle that uses the reaction of magnesium with water. In order to realize the sustainable society, we need to deoxidize MgO to obtain Mg again. Such deoxidization will be achieved with a high-power laser. Actually the preliminary experiments implie that 70% of pure magnesium among ablated materials can be separated. Candidates for such lasers will be solar-energy-pumped laser or diode-pumped solid-state laser powered by wind power generator. Thus Mg acts as a reservoir of energy for such unsteady energy sources like solar and wind power. This paper reports the preliminary experiments toward this goal by using Nd-YAG laser.

  15. Numerical laser energy deposition on supersonic cavity flow and sensor placement strategies to control the flow.

    PubMed

    Yilmaz, Ibrahim; Aradag, Selin

    2013-01-01

    In this study, the impact of laser energy deposition on pressure oscillations and relative sound pressure levels (SPL) in an open supersonic cavity flow is investigated. Laser energy with a magnitude of 100 mJ is deposited on the flow just above the cavity leading edge and up to 7 dB of reduction is obtained in the SPL values along the cavity back wall. Additionally, proper orthogonal decomposition (POD) method is applied to the x-velocity data obtained as a result of computational fluid dynamics simulations of the flow with laser energy deposition. Laser is numerically modeled using a spherically symmetric temperature distribution. By using the POD results, the effects of laser energy on the flow mechanism are presented. A one-dimensional POD methodology is applied to the surface pressure data to obtain critical locations for the placement of sensors for real time flow control applications.

  16. Increasing energy coupling into plasma waves by tailoring the laser radial focal spot distribution in a laser wakefield accelerator

    SciTech Connect

    Genoud, G.; Burza, M.; Persson, A.; Svensson, K.; Wahlström, C.-G.; Bloom, M. S.; Najmudin, Z.; Mangles, S. P. D.; Vieira, J.; Silva, L. O.

    2013-06-15

    By controlling the focal spot quality with a deformable mirror, we are able to show that increasing the fraction of pulse energy contained within the central part of the focal spot, while keeping the total energy and central spot size constant, significantly increases the amount of energy transferred to the wakefield: Our measurements show that the laser loses significantly more laser energy and undergoes greater redshifting and that more charge is produced in the accelerated beam. Three dimensional particle in cell simulations performed with accurate representations of the measured focal spot intensity distribution confirm that energy in the wings of the focal spot is effectively wasted. Even though self-focusing occurs, energy in the wings of the focal spot distribution is not coupled into the wakefield, emphasising the vital importance of high quality focal spot profiles in experiments.

  17. Calcium fluoride windows for high-energy chemical lasers

    NASA Astrophysics Data System (ADS)

    Klein, Claude A.

    2006-10-01

    The development of high-energy lasers requires optical windows capable of handling megajoule beam energies without compromising the system's performance. Calcium fluoride (CaF2) has been identified as a prime candidate for windows operating at chemical laser wavelengths due to very low bulk absorption and exceptionally small thermal lensing coefficients; it is, however, vulnerable to structural failure owing to poor mechanical strength characteristics and a large thermal stress factor. It is, therefore, essential to properly assess the ultimate potential of this material, which we attempt to do here in the following manner: (a) We assemble reliable numbers for all pertinent properties of (111)-oriented CaF2 single crystals and polycrystalline isotropic aggregates (PIAs), such as fusion-cast CaF2, which requires addressing issues relating to the elastic properties, the stress-optic coefficients, and the flexural strength. (b) We provide correct analytical expressions for evaluating the impact of pressure- and beam-induced effects on wave-front phase distortions and mechanical failure modes, taking advantage of a previous investigation [J. Appl. Phys. 98, 043103 (2005)]. (c) We perform detailed calculations on "model" windows made of either (111)CaF2 or (PIA )CaF2 that transmit optimally truncated Gaussian beams at wavelengths of 1.15 and 3.39μm, for run times such that lateral heat conduction and surface cooling can be ignored. Our main conlusions are as follows: (a) With CaF2 windows thermal lensing, as measured in terms of the Strehl ratio and on assuming coating absorptances of no more than 3×10-5, is of no consequence in the sense that catastrophic failure may occur at fluence levels way below the threshold for optical distortion. (b) Evidence of a poor Weibull shape factor (m ≃3.5) degrades the design safety margins, which requires operating at peak intensities of no more than 100kW/cm2 to achieve optimum on-target fluences. (c) Regarding the issue of (111

  18. Therapeutic effect of the NMDA antagonist MK-801 on low-level laser induced retinal injury

    NASA Astrophysics Data System (ADS)

    Yan, W.-H.; Wu, J.; Chen, P.; Dou, J.-T.; Pan, C.-Y.; Mu, Y.-M.; Lu, J.-M.

    2009-03-01

    The aim of this article was to explore the mechanism of injury in rat retina after constant low-level helium-neon (He-Ne) laser exposure and therapeutic effects of MK-801, an N-methyl-D-aspartate (NMDA) receptor antagonist, on laser-induced retinal injury. He-Ne laser lesions were created in the central retina of adult Wistar Kyoto rats and were followed immediately by intraperitoneal injection of MK-801 (2 mg/kg) or saline, macroscopical and microscopical lesion were observed by funduscope and light microscope. Ultrastructural changes of the degenerating cells were examined by electron microscopy. Photoreceptor apoptosis was evaluated by TdT-mediated dUTP nick end-labeling (TUNEL). mRNA levels were measured by in situ hybridization and NMDA receptor expression was determined by immunohistochemistry. Laser induced damage was histologically quantified by image-analysis morphometry. Electroretinograms (ERGs) were recorded at different time point after the cessation of exposure to constant irradiation. There was no visible bleeding, exudation or necrosis under funduscope. TUNEL and electron microscopy showed photoreceptor apoptosis after irradiation. MK-801-treated animals had significantly fewer TUNEL-positive cells in the photoreceptors than saline-treated animals after exposure to laser. In situ hybridization (ISH) showed that the NMDAR mRNA level of MK-801-treated rats decreased in the inner plexiform layer 6 h after the cessation of exposure to constant irradiation when compared with that of saline-treated rats. So did Immunohistochemistry (IHC). Electroretinogram showed that b-wave amplitudes of MK-801-treated group were higher than that of saline-treated group after laser exposure. These findings suggest that Low level laser may cause the retinal pathological changes under given conditions. High expression of NMDAR is one of the possible mechanisms causing experimental retinal laser injury of rats. MK-801 exhibits the therapeutic effect due to promote the

  19. High-energy density experiments on planetary materials using high-power lasers and X-ray free electron laser

    NASA Astrophysics Data System (ADS)

    Ozaki, Norimasa

    2015-06-01

    Laser-driven dynamic compression allows us to investigate the behavior of planetary and exoplanetary materials at extreme conditions. Our high-energy density (HED) experiments for applications to planetary sciences began over five years ago. We measured the equation-of-state of cryogenic liquid hydrogen under laser-shock compression up to 55 GPa. Since then, various materials constituting the icy giant planets and the Earth-like planets have been studied using laser-driven dynamic compression techniques. Pressure-volume-temperature EOS data and optical property data of water and molecular mixtures were obtained at the planetary/exoplanetary interior conditions. Silicates and oxides data show interesting behaviors in the warm-dense matter regime due to their phase transformations. Most recently the structural changes of iron were observed for understanding the kinetics under the bcc-hcp transformation phenomena on a new HED science platform coupling power-lasers and the X-ray free electron laser (SACLA). This work was performed under the joint research project at the Institute of Laser Engineering, Osaka University. It was partially supported by a Grant-in-Aid for Scientific Research (Grant Nos. 20654042, 22224012, 23540556, and 24103507) and also by grants from the Core-to-Core Program of JSPS on International Alliance for Material Science in Extreme States with High Power Laser and XFEL, and the X-ray Free Electron Laser Priority Strategy Program of MEXT.

  20. LEAP Phase II, Net Energy Gain From Laser Fields in Vacuum

    SciTech Connect

    Barnes, C.D.; Colby, E.R.; Plettner, T.; /SLAC /Stanford U., Appl. Mech. Dept.

    2005-09-27

    The current Laser Electron Acceleration Program (LEAP) seeks to modulate the energy of an electron bunch by interaction of the electrons with a copropagating pair of crossed laser beams at 800 nm. We present an optical injector design for a LEAP cell so that it can be used to give net energy gain to an electron bunch. Unique features of the design are discussed which will allow this net energy gain and which will also provide a robust signature for the LEAP interaction.

  1. Large energy mode locking of an erbium-doped fiber laser with atomic layer graphene.

    PubMed

    Zhang, H; Tang, D Y; Zhao, L M; Bao, Q L; Loh, K P

    2009-09-28

    We report on large energy pulse generation in an erbium-doped fiber laser passively mode-locked with atomic layer graphene. Stable mode locked pulses with single pulse energy up to 7.3 nJ and pulse width of 415 fs have been directly generated from the laser. Our results show that atomic layer graphene could be a promising saturable absorber for large energy mode locking.

  2. Vaporization front in the interaction of a high-energy laser with aerosols - A solitary wave

    NASA Astrophysics Data System (ADS)

    Lee, C. T.; Miller, T. G.

    1982-06-01

    If a high-energy laser beam were to propagate through highly absorbent aerosols, the aerosols might be subject to extinction by evaporation. This could occur, for instance, if a high-energy CO2 laser beam were to propagate through a medium containing a mist of water droplets. The incident energy would evaporate the droplets, thus increasing the transmission with time. In this paper, solitary waves are obtained as the asymptotic solution to the coupled nonlinear equations describing such an interaction.

  3. Accelerating protons to therapeutic energies with ultraintense, ultraclean, and ultrashort laser pulses

    PubMed Central

    Bulanov, Stepan S.; Brantov, Andrei; Bychenkov, Valery Yu.; Chvykov, Vladimir; Kalinchenko, Galina; Matsuoka, Takeshi; Rousseau, Pascal; Reed, Stephen; Yanovsky, Victor; Krushelnick, Karl; Litzenberg, Dale William; Maksimchuk, Anatoly

    2008-01-01

    Proton acceleration by high-intensity laser pulses from ultrathin foils for hadron therapy is discussed. With the improvement of the laser intensity contrast ratio to 10−11 achieved on the Hercules laser at the University of Michigan, it became possible to attain laser-solid interactions at intensities up to 1022 W∕cm2 that allows an efficient regime of laser-driven ion acceleration from submicron foils. Particle-in-cell (PIC) computer simulations of proton acceleration in the directed Coulomb explosion regime from ultrathin double-layer (heavy ions∕light ions) foils of different thicknesses were performed under the anticipated experimental conditions for the Hercules laser with pulse energies from 3 to 15 J, pulse duration of 30 fs at full width half maximum (FWHM), focused to a spot size of 0.8 μm (FWHM). In this regime heavy ions expand predominantly in the direction of laser pulse propagation enhancing the longitudinal charge separation electric field that accelerates light ions. The dependence of the maximum proton energy on the foil thickness has been found and the laser pulse characteristics have been matched with the thickness of the target to ensure the most efficient acceleration. Moreover, the proton spectrum demonstrates a peaked structure at high energies, which is required for radiation therapy. Two-dimensional PIC simulations show that a 150–500 TW laser pulse is able to accelerate protons up to 100–220 MeV energies. PMID:18561651

  4. Instantaneous x-ray radiation energy from laser produced polystyrene plasmas for shock ignition conditions

    SciTech Connect

    Shang, Wanli; Wei, Huiyue; Li, Zhichao; Yi, Rongqing; Zhu, Tuo; Song, Tianmin; Huang, Chengwu; Yang, Jiamin

    2013-10-15

    Laser target energy coupling mechanism is crucial in the shock ignition (SI) scheme, and x-ray radiation energy is a non-negligible portion of the laser produced plasma energy. To evaluate the x-ray radiation energy amount at conditions relevant to SI scheme, instantaneous x-ray radiation energy is investigated experimentally with continuum phase plates smoothed lasers irradiating layer polystyrene targets. Comparative laser pulses without and with shock spike are employed. With the measured x-ray angular distribution, full space x-ray radiation energy and conversion efficiency are observed. Instantaneous scaling law of x-ray conversion efficiency is obtained as a function of laser intensity and time. It should be pointed out that the scaling law is available for any laser pulse shape and intensity, with which irradiates polystyrene planar target with intensity from 2 × 10{sup 14} to 1.8 × 10{sup 15} W/cm{sup 2}. Numerical analysis of the laser energy transformation is performed, and the simulation results agree with the experimental data.

  5. Effects of low-power laser radiation on mice immunity.

    PubMed

    Novoselova, E G; Glushkova, O V; Cherenkov, D A; Chudnovsky, V M; Fesenko, E E

    2006-02-01

    Because of large interest in biological effects of laser radiation used in laser therapy, the effect of extremely low-level red laser light intensity on the immune cell activity has been studied in the animal model with well-characterized macrophage and T cell populations as responder cells producing cytokines, protective proteins, active oxygen, and nitric compounds. To study of the possible side effects of laser immunotherapy we monitored the productions of cytokines, nitric oxide (NO), and heat shock protein 70 (Hsp70) in mice subjected to a periodic laser exposure for 1 month. Helium-neon laser radiation with the power of 0.2 mW/cm2 and wavelength of 632.8 nm was applied on two different mouse skin surfaces, i.e. a thymus projection area or a hind limb. Healthy NMRI male mice were irradiated repeatedly with laser light for 1 min with 48-h intervals for 30 days. The animals were divided into three groups of 25 mice. The first and the second groups were exposed to laser light, on the thymus and hind limb area, respectively. The third, sham-irradiated group served as a control. Early and prolonged effects of laser radiation on the levels of NO (by Griess assay), Hsp70 (by Western blot assay), tumor necrosis factors (TNF-alpha and TNF-beta) (by cytotoxic assay using L929 cells as targets), and interleukin-2 (IL-2) (by ELISA assay) were determined. The dynamics of immune responses to low-power laser light intensity was shown to be dependent on two factors, i.e. the cumulative dose and the localization of the irradiated surface. Besides, various populations of cells demonstrated different sensitivity to laser radiation, with T cells being more responsive among examined populations of the cells. Low intensity laser light induced an immune cell activity when the exposure duration did not exceed 10 days, while a more prolonged period of treatment generated more severe changes in the immune system, up to immunosuppression. The treatment of the thymus zone resulted in

  6. A Laser Technology Test Facility for Laser Inertial Fusion Energy (LIFE)

    SciTech Connect

    Bayramian, A J; Campbell, R W; Ebbers, C A; Freitas, B L; Latkowski, J; Molander, W A; Sutton, S B; Telford, S; Caird, J A

    2009-10-06

    A LIFE laser driver needs to be designed and operated which meets the rigorous requirements of the NIF laser system while operating at high average power, and operate for a lifetime of >30 years. Ignition on NIF will serve to demonstrate laser driver functionality, operation of the Mercury laser system at LLNL demonstrates the ability of a diode-pumped solid-state laser to run at high average power, but the operational lifetime >30 yrs remains to be proven. A Laser Technology test Facility (LTF) has been designed to specifically address this issue. The LTF is a 100-Hz diode-pumped solid-state laser system intended for accelerated testing of the diodes, gain media, optics, frequency converters and final optics, providing system statistics for billion shot class tests. These statistics will be utilized for material and technology development as well as economic and reliability models for LIFE laser drivers.

  7. [Influence of laser energy on measurement of unburned carbon in fly Ash particle flow].

    PubMed

    Bai, Kai-Jie; Tian, Hao-Chen; Yao, Shun-Chun; Zhang, Bo; Shen, Yue-Liang; Xu, Qi-Sheng; Lu, Ji-Dong

    2014-05-01

    The fly ash particle flow was produced by a screw feeder and then ablated by a pulse laser to create plasma. The emission spectra of fly ash were detected by laser-induced breakdown spectroscopy. The present paper focused on the influence of laser energy on the measurement of unburned carbon. Seven groups of pulse laser in the range of 40 to 130 mJ were used to ablate the fly ash particle flow. The results show that the carbon line intensity is increased linearly with the increases in laser energy, but the SNR of carbon line increases in the range of 40 to 90 mJ and then trends to saturation, while the elimination rate of false data decreases. In this experiment, laser energy ranging from 90 to 100 mJ can enhance the plasma emission signal and improve the true spectral data of fly ash particle flow. So laser energy has close correlations with the ablation of the particle flow and the carbon line intensity. Reasonable laser energy is good for the effective ablation of the fly ash particle flow to get plasma spectra signals with good SNR.

  8. Evaluating the damage process of dynamic target by high-energy laser in ocean environment

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Ye, Demao

    2013-12-01

    The high-energy laser, as one of directed energy weapon, is famous for its unique advantage of speed-of-light response which was considered as an ideal weapon against anti-ship missile. This paper commits to evaluate the damage process of missile by high-energy laser weapon. We analyze the propagation properties which are susceptible to atmospheric attenuation effects, atmospheric turbulence effects, thermal blooming effects in sky-sea atmosphere firstly. Then because laser weapons attack one target at a time and it takes several seconds at a minimum for the target engaged, a model of calculating the required t ime for damaging the attack target was built . In the end effective evaluation methods of hot-ablated and high-energy laser weapon's damaging effectiveness are made, when the body or the optical elements of the missile is irradiated by the concatenation wave laser weapon. And one of the issues just as laser power, propagation distance is changed; the model can make different evaluation. The above model can provide the theoretical basis for the high-energy laser weapon intercept anti-ship missile and tactic deraign rationality for naval ship-borne laser weapons.

  9. Simulation and modeling of high-energy laser systems

    NASA Astrophysics Data System (ADS)

    Link, Donald J.; St. John, Richard

    2004-09-01

    Since the beginning of High Energy Laser systems, simulations have been used to predict performance, do parameter trades, and assist in troubleshooting. Today, simulations benefit from higher speed computers with more memory, but they are also being asked to do more. New types of HEL devices are being proposed, more hardware details are being incorporated, beam control systems are becoming more complex, innovative new systems are being designed to work under conditions of strong turbulence, and more types of targets are being considered. There are three types of physics level codes: resonator, beam control, and lethality. All three are slow running and require a high level of expertise to use. Scaling law codes are much easier to use and much faster running. These codes are based on analytical predictions and anchored to the wave optics simulations and to experiments. Scaling law codes can quickly predict performance, weight, and volume for various scenarios and conditions. Now that HEL systems are closer to reality, there is more interest in incorporating the scaling law codes into engagement codes, which predict overall system effectiveness in battle situations.

  10. INTERACTION OF LASER RADIATION WITH MATTER. LASER PLASMA: Efficiency of ablative loading of material upon the fast-electron transfer of absorbed laser energy

    NASA Astrophysics Data System (ADS)

    Gus'kov, Sergei Yu; Kasperczuk, A.; Pisarczyk, T.; Borodziuk, S.; Kalal, M.; Limpouch, J.; Ullschmied, J.; Krousky, E.; Masek, K.; Pfeifer, M.; Rohlena, K.; Skala, J.; Pisarczyk, P.

    2006-05-01

    We present the results of experiments on the short-term irradiation of a solid material by a laser beam. The data testify to a rise in efficiency of the energy transfer from the laser pulse to a shock wave due to the fast-electron energy transfer. The experiments were performed with massive aluminium targets on the PALS iodine laser, whose pulse duration (0.4 ns) was much shorter than the time of shock decay and crater formation in the target (50-200 ns). The irradiation experiments were carried out using the fundamental laser harmonic (1.315 μm) with an energy of 360 J. The greater part of the experiments were performed for the radiation intensity exceeding 1015 W cm-2, which corresponded to the efficient generation of fast electrons under the conditions where the relatively long-wavelength iodine-laser radiation was employed. The irradiation intensity was varied by varying the laser beam radius for a specified pulse energy.

  11. Lasers.

    ERIC Educational Resources Information Center

    Schewe, Phillip F.

    1981-01-01

    Examines the nature of laser light. Topics include: (1) production and characteristics of laser light; (2) nine types of lasers; (3) five laser techniques including holography; (4) laser spectroscopy; and (5) laser fusion and other applications. (SK)

  12. Lasers.

    ERIC Educational Resources Information Center

    Schewe, Phillip F.

    1981-01-01

    Examines the nature of laser light. Topics include: (1) production and characteristics of laser light; (2) nine types of lasers; (3) five laser techniques including holography; (4) laser spectroscopy; and (5) laser fusion and other applications. (SK)

  13. Laser controlled coupled cantilevers for precise measurements and energy transfer (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Cao, Gengyu

    2016-09-01

    Coupled cantilevers are trapped by laser in a 3-mirror configuration. We studied the signal transduction between the cantilevers by laser control. A force or displacement sensor with such laser trapping technique could achieve much higher sensitivity, as high as 3-4 orders as compared to a single cantilever. We also studied the energy transfer processes by laser trapping and manipulation. Rabi oscillations are observed. Quantum analog Landau-Zener Tunneling and Landau-Zener-Stuckelburg interferometry are realized in the classical regime. We have proved that the energy or signals could be transferred from one cantilever to the other in the real-space by laser manipulation. Laser manipulated coupled cantilvers have great potentials in precision measurements and in quantum information processing.

  14. High-Power Fiber Lasers for Directed-Energy Applications

    DTIC Science & Technology

    2008-01-01

    demonstrated in a moder- ately turbulent environment. HIgH-PowEr FIbEr LAsErs Although a number of companies manufacture high-power fiber lasers , IPG ...in approximately one year. Multi- kilowatt , single-mode fiber lasers are robust, compact, and have high wall- plug efficiency, random polarization...and large band- width (~0.1%). A 1 kW, single-mode IPG fiber laser module, operating at wavelength l = 1.075 μm, exclud- ing power supply, measures w

  15. Modeling of High-Energy Pulsed Laser Interactions with Coupons

    SciTech Connect

    Boley, C D; Rubenchik, A M

    2003-02-06

    We describe a computational model of laser-materials interactions in the regime accessed by the solid state heat capacity lasers (SSHCLs) built at LLNL. We show that its predictions compare quite favorably with coupon experiments by the 10 kW SSHCL at LLNL. The body of this paper describes the following topics, listed by section number: (2) model in quiescent air, (3) comparison with experiments in quiescent air, (4) effects of air flow, (5) comparison with experiments involving air flow, (6) importance of material properties, (7) advantage of pulsed lasers over CW lasers, and (8) conclusions and recommendations.

  16. Coulomb-driven energy boost of heavy ions for laser-plasma acceleration.

    PubMed

    Braenzel, J; Andreev, A A; Platonov, K; Klingsporn, M; Ehrentraut, L; Sandner, W; Schnürer, M

    2015-03-27

    An unprecedented increase of kinetic energy of laser accelerated heavy ions is demonstrated. Ultrathin gold foils have been irradiated by an ultrashort laser pulse at a peak intensity of 8×10^{19}  W/  cm^{2}. Highly charged gold ions with kinetic energies up to >200  MeV and a bandwidth limited energy distribution have been reached by using 1.3 J laser energy on target. 1D and 2D particle in cell simulations show how a spatial dependence on the ion's ionization leads to an enhancement of the accelerating electrical field. Our theoretical model considers a spatial distribution of the ionization inside the thin target, leading to a field enhancement for the heavy ions by Coulomb explosion. It is capable of explaining the energy boost of highly charged ions, enabling a higher efficiency for the laser-driven heavy ion acceleration.

  17. Beam-energy and laser beam-profile monitor at the BNL LINAC

    SciTech Connect

    Connolly, R.; Briscoe, B.; Degen, C.; DeSanto, L.; Meng, W.; Minty, M.; Nayak, S.; Raparia, D.; Russo, T.

    2010-05-02

    We are developing a non-interceptive beam profile and energy monitor for H{sup -} beams in the high energy beam transport (HEBT) line at the Brookhaven National Lab linac. Electrons that are removed from the beam ions either by laser photodetachment or stripping by background gas are deflected into a Faraday cup. The beam profile is measured by stepping a narrow laser beam across the ion beam and measuring the electron charge vs. transverse laser position. There is a grid in front of the collector that can be biased up to 125kV. The beam energy spectrum is determined by measuring the electron charge vs. grid voltage. Beam electrons have the same velocity as the beam and so have an energy of 1/1836 of the beam protons. A 200MeV H{sup -} beam yields 109keV electrons. Energy measurements can be made with either laser-stripped or gas-stripped electrons.

  18. Laser performance operation model and its application to LIL energy and power balance

    NASA Astrophysics Data System (ADS)

    LeGarrec, B. J.; Nicolas, O.

    2008-05-01

    LMJ is a 240 high power laser beam facility for achieving laser matter interaction experiments, high energy density science, including the demonstration of fusion ignition through Inertial Confinement. The Laser Integration Line (LIL) facility is currently a 4-beam prototype for LMJ. In order to achieve precisely specified energies over a wide range of energies, power, temporal shapes and pulse lengths, a computational model has been developed and optimised on every LIL shot. This optimisation is based on the best fit possible between the predicted performances and the measured ones. It is therefore possible to predict the characteristics of a given shot in the 4- beam LIL configuration.

  19. Diode-Pumped Solid-State Lasers for Internal Fusion Energy

    SciTech Connect

    Payne, S A; Bibeau, C; Beach, R J; Bayramian, A; Chanteloup, J C; Ebbers, C A; Emanuel, M A; Orth, C D; Rothenberg, J. E; Schaffers, K I; Skidmore, J A; Sutton, S B; Zapata, L E; Powell, H T

    1999-11-15

    We have begun building the ''Mercury'' laser system as the first in a series of new generation diode-pumped solid-state lasers for inertial fusion research. Mercury will integrate three key technologies: diodes, crystals, and gas cooling, within a unique laser architecture that is scalable to kilojoule and megajoule energy levels for fusion energy applications. The primary near-term performance goals include 10% electrical efficiencies at 10 Hz and 100J with a 2-10 ns pulse length at 1.047 mm wavelength. When completed, Mercury will allow rep-rated target experiments with multiple chambers for high energy density physics research.

  20. Laser acceleration of electrons to giga-electron-volt energies using highly charged ions.

    PubMed

    Hu, S X; Starace, Anthony F

    2006-06-01

    The recent proposal to use highly charged ions as sources of electrons for laser acceleration [S. X. Hu and A. F. Starace, Phys. Rev. Lett. 88, 245003 (2002)] is investigated here in detail by means of three-dimensional, relativistic Monte Carlo simulations for a variety of system parameters, such as laser pulse duration, ionic charge state, and laser focusing spot size. Realistic laser focusing effects--e.g., the existence of longitudinal laser field components-are taken into account. Results of spatial averaging over the laser focus are also presented. These numerical simulations show that the proposed scheme for laser acceleration of electrons from highly charged ions is feasible with current or near-future experimental conditions and that electrons with GeV energies can be obtained in such experiments.