Large third-order optical nonlinearity realized in symmetric nonpolar carotenoids
NASA Astrophysics Data System (ADS)
Fujiwara, Masazumi; Yamauchi, Kensei; Sugisaki, Mitsuru; Yanagi, Kazuhiro; Gall, Andrew; Robert, Bruno; Cogdell, Richard J.; Hashimoto, Hideki
2008-10-01
We show that a very large enhancement of third-order optical nonlinearity (γ) of π -conjugated molecules can be realized without a major redshift of the absorption spectrum that disturbs optical transparency in the visible region. By changing the number (n) of C=C bonds of β carotene (n=11) from 7 to 15, a remarkable 3.4-fold increase in the γ value was observed when n=15 relative to that of β carotene. This enhancement of γ mainly originates from three-photon resonance of a lowest optically allowed excited state. The controversial higher-lying essential state is not important for generating the large value of γ .
NASA Technical Reports Server (NTRS)
Paley, M. S.; Frazier, D. O.; Abdeldayem, H.; McManus, S. P.
1994-01-01
One promising class of organic compounds for applications in the field of nonlinear optics (NLO) are polydiacetylenes, which are of interest because they are highly conjugated polymers capable of exhibiting very large optical nonlinearities with fast response times. During the course of crystal growth studies in anticipation of a space experiment, we discovered a novel, simple method for the formation of polydiacetylene thin films by photodeposition from monomer solutions onto quartz or glass substrates. Characterization of these PDAMNA films is not trivial; they are not soluble in common organic solvents, which makes the standard solution-based methods of polymer analysis useless.
NASA Astrophysics Data System (ADS)
Kasatani, Kazuo
2003-01-01
Third-order optical nonlinearities of several cyanine dyes were measured under resonant conditions by the femtosecond degenerate four-wave mixing (DFWM) technique. Temporal profiles of the DFWM signal were measured with a time resolution of 0.3 ps, and were found to consist of at least two components, the coherent instantaneous nonlinear response and the delayed response with a decay time constant of several hundred picoseconds. The latter can be attributed to molecular rotational relaxation of these dyes. The values of electronic component of the optical nonlinear susceptibility, χ e xxxx (3), for these dyes were ≈2×10 -12 esu at the very low concentration of 1×10 -5 mol dm -3. The electronic component of molecular hyperpolarizability, γe, was calculated to be ≈1×10 -28 esu for each dye.
Third-order optical nonlinearity of chlorophenols
NASA Astrophysics Data System (ADS)
Maloney, C.; Blau, W.
1988-02-01
Degenerate four-wave mixing of infrared (1.064 μm) pulses with 130 ps duration was studied in o-, p- and m- chlorophenols. Nonlinear susceptibilities χ (3) of (5.5-6.0) × 10 -20 m 2/V 2 were measured. By temporally delaying the incidence of the second pump pulse contributions from an optical Kerr effect and an electrostrictive effect are observed.
Third order nonlinear optical property of Bi₂Se₃.
Lu, Shunbin; Zhao, Chujun; Zou, Yanhong; Chen, Shuqing; Chen, Yu; Li, Ying; Zhang, Han; Wen, Shuangchun; Tang, Dingyuan
2013-01-28
The third order nonlinear optical property of Bi₂Se₃, a kind of topological insulator (TI), has been investigated under femto-second laser excitation. The open and closed aperture Z-scan measurements were used to unambiguously distinguish the real and imaginary part of the third order optical nonlinearity of the TI. When excited at 800 nm, the TI exhibits saturable absorption with a saturation intensity of 10.12 GW/cm² and a modulation depth of 61.2%, and a giant nonlinear refractive index of 10⁻¹⁴ m²/W, almost six orders of magnitude larger than that of bulk dielectrics. This finding suggests that the TI:Bi₂Se₃ is indeed a promising nonlinear optical material and thus can find potential applications from passive laser mode locker to optical Kerr effect based photonic devices. PMID:23389188
Third-order nonlinear optical response of energy transfer systems
NASA Astrophysics Data System (ADS)
Yang, Mino; Fleming, Graham R.
1999-07-01
The third-order nonlinear optical response of energy transfer systems is theoretically investigated. A system composed of two chromophores having the same electronic transition energies is considered. The dynamics of energy transfer between the two chromophores is assumed to occur via a hopping (incoherent) mechanism. We introduce new types of pathways incorporating the hopping processes occurring while the system is in population states and reconstruct a third-order response function which is computationally viable. The nuclear propagators in the electronic population states are written as convolution integrals between those of the nonreactive two-state system weighted by some factors for the energy transfer. The response function is given by multitime correlation functions and these are analyzed by the cumulant expansion method. Based on this approach, the three-pulse photon echo peak shift for several models of energy transfer systems is discussed. It is shown that the rephasing capability of the induced signal is reduced by the memory loss due to resonant energy transfer. A previous model which incorporates resonant energy transfers in an intuitive way is reviewed and modified to supplement the loss of dynamic correlation of nuclear motion within the framework of the theory. The response function obtained by our new approach gives a more accurate description than the existing theory and a comparative discussion is given. The effect of inhomogeneity in rate constants on the third-order signal is discussed and the temperature dependence of the echo signal is examined.
Third order nonlinear optical properties of bismuth zinc borate glasses
Shanmugavelu, B.; Ravi Kanth Kumar, V. V.; Kuladeep, R.; Narayana Rao, D.
2013-12-28
Third order nonlinear optical characterization of bismuth zinc borate glasses are reported here using different laser pulse durations. Bismuth zinc borate glasses with compositions xBi{sub 2}O{sub 3}-30ZnO-(70-x) B{sub 2}O{sub 3} (where x = 30, 35, 40, and 45 mol. %) have been prepared by melt quenching method. These glasses were characterized by Raman, UV-Vis absorption, and Z scan measurements. Raman and UV-Vis spectroscopic results indicate that non-bridging oxygens increase with increase of bismuth content in the glass. Nonlinear absorption and refraction behavior in the nanosecond (ns), picosecond (ps), and femtosecond (fs) time domains were studied in detail. Strong reverse saturable absorption due to dominant two-photon absorption (TPA) was observed with both ps and fs excitations. In the case of ns pulse excitations, TPA and free-carrier absorption processes contribute for the nonlinear absorption. Two-photon absorption coefficient (β) and the absorption cross section due to free carriers (σ{sub e}) are estimated by theoretical fit of the open aperture Z-scan measurements and found to be dependent on the amount of bismuth oxide in the glass composition. In both ns and fs regimes the sign and magnitude of the third order nonlinearity are evaluated, and the optical limiting characteristics are also reported.
Third order nonlinear optical properties of bismuth zinc borate glasses
NASA Astrophysics Data System (ADS)
Shanmugavelu, B.; Ravi Kanth Kumar, V. V.; Kuladeep, R.; Narayana Rao, D.
2013-12-01
Third order nonlinear optical characterization of bismuth zinc borate glasses are reported here using different laser pulse durations. Bismuth zinc borate glasses with compositions xBi2O3-30ZnO-(70-x) B2O3 (where x = 30, 35, 40, and 45 mol. %) have been prepared by melt quenching method. These glasses were characterized by Raman, UV-Vis absorption, and Z scan measurements. Raman and UV-Vis spectroscopic results indicate that non-bridging oxygens increase with increase of bismuth content in the glass. Nonlinear absorption and refraction behavior in the nanosecond (ns), picosecond (ps), and femtosecond (fs) time domains were studied in detail. Strong reverse saturable absorption due to dominant two-photon absorption (TPA) was observed with both ps and fs excitations. In the case of ns pulse excitations, TPA and free-carrier absorption processes contribute for the nonlinear absorption. Two-photon absorption coefficient (β) and the absorption cross section due to free carriers (σe) are estimated by theoretical fit of the open aperture Z-scan measurements and found to be dependent on the amount of bismuth oxide in the glass composition. In both ns and fs regimes the sign and magnitude of the third order nonlinearity are evaluated, and the optical limiting characteristics are also reported.
Surface plasmon enhanced third-order optical nonlinearity of Ag nanocomposite film
Singh, Vijender; Aghamkar, Praveen
2014-03-17
We obtain a large third-order optical nonlinearity (χ{sup (3)} ≈ 10{sup −10}esu) of silver nanoparticles dispersed in polyvinyl alcohol/tetraethyl orthosilicate matrix using single beam z-scan technique at 532 nm by Q-switched Nd:YAG laser. We have shown that mechanisms responsible for third-order optical nonlinearity of Ag nanocomposite film are reverse saturable absorption (RSA) and self-defocusing in the purlieu of surface plasmon resonance (SPR). Optical band-gap and width of SPR band of Ag nanocomposite film decrease with increasing silver concentration, which leads to enhancement of local electric field and hence third-order optical nonlinearity. Optical limiting, due to RSA has also been demonstrated at 532 nm.
NASA Technical Reports Server (NTRS)
Penn, Benjamin G.; Riley, Clyde
1993-01-01
It has been proposed that NLO thin film properties may be improved by low-gravity processing. Strong candidates for NLO thin film applications are the polythiophenes. Polymeric thiophenes are attractive materials due to their ease of preparation, stability, and high X(exp 3). A simple and convenient method for preparation of polythiophenes is electrochemical oxidation. We will apply some of our experience and lessons learned in low-gravity metal, metal/cermet electrode position to improve the quality of polythiophene(s) thin films. In low gravity electrode position of Ni at a high rate on an Au substrate often results in the production of an x-ray non diffracting surface. Cobalt metal deposition does not give this result nor does Ni when deposited similarly on a glassy carbon substrate. Co/Ni alloy composition produced during electrode position is strongly dependent upon the amount of convection. Code position of neutral inert cermets with metals is influenced significantly by the presence of gravity and the size of the cermets. Tracks left in the 1-g surfaces by unsuccessful particle occlusion indicate suspension of the large particles is not the only reason for poor volume percentages of the larger particles in the deposits. All size particles are more homogeneously distributed in the deposits in low-gravity electrocodeposition than in 1-g. Low gravity gives larger volume percentages for the larger particles in the deposits, while 1-g gives larger volume percentages for the smaller particles. Intermediate size particles give mixed results. The experimental cells were constructed with flat electrode end plates such that 1-g bench reference electrode positions could be carried out at various orientations with respect to gravity. A series of bench studies using similar designed cells are suggested so that convection modification can be applied to electrochemical thin film preparation. Convection effects can then be coupled with other parameter variations in current
Resonant-type third-order optical nonlinearity and optical bandgap in multicomponent oxide glasses
El-Diasty, Fouad; Abdel-Baki, Manal; Bakry, Assem M.
2009-05-01
Optical nonlinearity or the nonlinear hyperpolarizability of amorphous materials (e.g., glasses) is related directly to the complex third-order susceptibility. The imaginary part of third-order susceptibility affects negatively the maximum data rate in telecommunication systems. In addition, many transition metals containing glasses have bandgaps with semiconductor-like behavior. So, due to the necessity of operation near the absorption band edge, the study of optical nonlinearity and band structure in glasses is very essential. In this work, we investigated the relationship between the imaginary third-order nonlinear susceptibility and the bandgap of some different series of prepared oxide glasses. A universal empirical formula is given to correlate the imaginary part of the third-order nonlinear susceptibility of the glasses and their optical bandgaps. The obtained nonlinearity is discussed in view of available theories and mechanisms.
Li, S.; Zhong, X. L. E-mail: jbwang@xtu.edu.cn; Wang, J. B. E-mail: jbwang@xtu.edu.cn; Huang, J.; Song, H. J.; Tan, C. B.; Li, B.; Zhou, Y. C.; Cheng, G. H.; Liu, X.
2014-11-10
Both the linear and nonlinear optical properties of Bi{sub 3.15}Nd{sub 0.85}Ti{sub 3}O{sub 12} (BNT{sub 0.85}) ferroelectric thin films deposited on quartz substrates were investigated. The fundamental optical constants were determined as a function of light wavelength by optical transmittance measurements. By performing single-beam Z-scan experiments with femtosecond laser pulses at a wavelength of 800 nm, the two-photon absorption (TPA) coefficient β and third-order nonlinear refraction index γ were measured to be 1.15 × 10{sup 2 }cm/GW and −8.15 × 10{sup −3} cm{sup 2}/GW, respectively. The large TPA is attributed to an indirect transition process via the intermediate energy levels and the large refractive nonlinearity is the result of the electronic polarization and ferroelectric polarization arisen from the femtosecond midinfrared radiation. The results indicate that the BNT{sub 0.85} thin film is a promising candidate for applications in nonlinear photonic devices.
Optical phase conjugation in third-order nonlinear photonic crystals
Xie Ping; Zhang Zhaoqing
2004-05-01
We predict that the efficiency of the optical phase conjugation generation can be enhanced by more than four orders of magnitude in a {chi}{sup (3)} nonlinear superlattice, as compared with that in a homogeneous nonlinear medium of the same sample thickness and {chi}{sup (3)} nonlinearity. Such an effective enhancement utilizes the localized properties of the fields inside the sample at the band-edge state, gap-soliton state, or defect state. Due to the presence of feedback mechanism at each interface of a superlattice, we also predict that the phase conjugation can still be effectively generated when only one pump wave is used.
Z-scan: A simple technique for determination of third-order optical nonlinearity
Singh, Vijender; Aghamkar, Praveen
2015-08-28
Z-scan is a simple experimental technique to measure intensity dependent nonlinear susceptibilities of third-order nonlinear optical materials. This technique is used to measure the sign and magnitude of both real and imaginary part of the third order nonlinear susceptibility (χ{sup (3)}) of nonlinear optical materials. In this paper, we investigate third-order nonlinear optical properties of Ag-polymer composite film by using single beam z-scan technique with Q-switched, frequency doubled Nd: YAG laser (λ=532 nm) at 5 ns pulse. The values of nonlinear absorption coefficient (β), nonlinear refractive index (n{sub 2}) and third-order nonlinear optical susceptibility (χ{sup (3)}) of permethylazine were found to be 9.64 × 10{sup −7} cm/W, 8.55 × 10{sup −12} cm{sup 2}/W and 5.48 × 10{sup −10} esu, respectively.
Third-Order Nonlinear Optical Properties and Optical Switching of Palladium (I) Complex
NASA Astrophysics Data System (ADS)
Manjunatha, K. B.; Dileep, R.; Vikas, M. Shelar; Umesh, G.; Satyanarayan, M. N.; Bhat, B. Ramachandra
2011-10-01
We report the third-order nonlinear optical, optical power limiting and optical switching study of palladium-N-(2-pyridyl)-N'- (5-amino salicylidene) hydrazine triphenylphosphine, using Z-scan technique and pump-probe technique. The measured nonlinear refractive index is n2 = -6.022×10-9 esu. The complex exhibits the reverse saturable absorption (RSA), the nonlinear absorption coefficient of β = 10.748×10-9 m/W. The good optical power limiting and optical switching behavior were observed in this complex. These suggest that this complex is a potential molecule for photonic applications.
Third order nonlinear optical response exhibited by mono- and few-layers of WS2
NASA Astrophysics Data System (ADS)
Torres-Torres, Carlos; Perea-López, Néstor; Elías, Ana Laura; Gutiérrez, Humberto R.; Cullen, David A.; Berkdemir, Ayse; López-Urías, Florentino; Terrones, Humberto; Terrones, Mauricio
2016-06-01
In this work, strong third order nonlinear optical properties exhibited by WS2 layers are presented. Optical Kerr effect was identified as the dominant physical mechanism responsible for these third order optical nonlinearities. An extraordinary nonlinear refractive index together with an important contribution of a saturated absorptive response was observed to depend on the atomic layer stacking. Comparative experiments performed in mono- and few-layer samples of WS2 revealed that this material is potentially capable of modulating nonlinear optical processes by selective near resonant induced birefringence. We envision applications for developing all-optical bidimensional nonlinear optical devices.
Third-order nonlinear optical property of a polyphenylene oligomer: poly(2,5-dialkozyphenylene)
NASA Astrophysics Data System (ADS)
Wu, Jianyao; Yan, Jun; Sun, Diechi; Li, Fuming; Zhou, Luwei; Sun, Meng
1997-02-01
The third-order nonlinear optical (NLO) property of a soluble, π-backbone conjugated polymer poly(2,5-dialkozyphenylene) (for abbreviation called dialkozy-PP) is studied at the picosecond time region. The near resonance third-order hyperpolarizability γxxxx at 532 nm is 8.2×10 -30 esu, and the corresponding macroscopic third-order susceptibility χ(3)(- ω, ω, ω, - ω) and nonlinear refractive index n2 are estimated to be 6.3×10 -10 esu and 1.4×10 -8 esu, respectively. The half-width of the laser pulse is 35 ps.
NASA Astrophysics Data System (ADS)
Gomez-Sosa, Gustavo; Beristain, Miriam F.; Ortega, Alejandra; Martínez-Viramontes, Jaquelin; Ogawa, Takeshi; Fernández-Hernández, Roberto C.; Tamayo-Rivera, Lis; Reyes-Esqueda, Jorge-Alejandro; Isoshima, Takashi; Hara, Masahiko
2012-03-01
Novel polymers containing xanthene groups with high dye concentrations were prepared, and their third order nonlinear optical properties were studied by electroabsorption spectroscopy technique. The polymers were amorphous with refractive indices above 1.6 in the non-resonant region. The UV-Visible absorption spectra indicate the fluoresceins molecules in the polymers are H-aggregated. They showed third order nonlinear susceptibility, χ(3) (-ω:ω, 0, 0), of 2.5-3.5 × 10-12 esu.
NASA Astrophysics Data System (ADS)
Castro, Hemerson P. S.; Wender, Heberton; Alencar, Márcio A. R. C.; Teixeira, Sergio R.; Dupont, Jairton; Hickmann, Jandir M.
2013-11-01
The nonlinear optical responses of gold nanoparticles dispersed in castor oil produced by sputtering deposition were investigated, using the thermally managed Z-scan technique. Particles with spherical shape and 2.6 nm of average diameter were obtained and characterized by transmission electron microscopy and small angle X-ray scattering. This colloid was highly stable, without the presence of chemical impurities, neither stabilizers. It was observed that this system presents a large refractive third-order nonlinear response and a negligible nonlinear absorption. Moreover, the evaluation of the all-optical switching figures of merit demonstrated that the colloidal nanoparticles prepared by sputtering deposition have a good potential for the development of ultrafast photonic devices.
Castro, Hemerson P. S.; Alencar, Márcio A. R. C.; Hickmann, Jandir M.; Wender, Heberton; Teixeira, Sergio R.; Dupont, Jairton
2013-11-14
The nonlinear optical responses of gold nanoparticles dispersed in castor oil produced by sputtering deposition were investigated, using the thermally managed Z-scan technique. Particles with spherical shape and 2.6 nm of average diameter were obtained and characterized by transmission electron microscopy and small angle X-ray scattering. This colloid was highly stable, without the presence of chemical impurities, neither stabilizers. It was observed that this system presents a large refractive third-order nonlinear response and a negligible nonlinear absorption. Moreover, the evaluation of the all-optical switching figures of merit demonstrated that the colloidal nanoparticles prepared by sputtering deposition have a good potential for the development of ultrafast photonic devices.
Third-order nonlinear optical property of a heterocyclic ladder polymer
NASA Astrophysics Data System (ADS)
Yan, Jun; Wu, Jianyao; Zhu, Heyuan; Zhang, Xiaotian; Sun, Diechi; Li, Fuming; Sun, Meng
1995-02-01
The third-order nonlinear optical (NLO) property of a processable, low-absorption and high thermal stable material, non-either PPQ, is studied. The near-resonance third-order hyperpolarizability γxxxx is measured to be 8.2×10 -30 esu at 532 nm, its response time is faster than 35 ps (the measurement is limited by the pulse width of the laser used). The corresponding third-order NLO susceptibility χ(3)(- ω, ω, ω, - ω) is estimated to be 3.6×10 -10 esu and the figure of merit {χ (3)}/{α}=9×10 -12 esu is larger than that of most currently known nonlinear optical polymers.
Second-order cascading in third-order nonlinear optical processes
NASA Astrophysics Data System (ADS)
Meredith, Gerald R.
1982-12-01
Because cascaded second-order processes make substantial qualitative and quanitative differences to the results of third-order nonlinear optical experiments, a formalism for their treatment is presented. The symmetry dictates concerning the occurrence and relationships of magnitudes of cascading are tabulated for the higher symmetry crystal classes. Angular momentum considerations are applied to the situations allowing circularly polarized light waves.
Third order optical nonlinearity and optical limiting studies of propane hydrazides
NASA Astrophysics Data System (ADS)
Naseema, K.; Manjunatha, K. B.; Sujith, K. V.; Umesh, G.; Kalluraya, Balakrishna; Rao, Vijayalakshmi
2012-09-01
Four hydrazones, 2-(4-isobutylphenyl)-N'-[phenylmethylene] propanehydrazide (P1), 2-(4-isobutylphenyl)-N'-[(4- tolyl)methylene] propane hydrazide (P2), 2-(4-isobutylphenyl)-N'-[1-(4- chlorophenyl)ethylidene] propanehydrazide (P3) and 2-(4-isobutylphenyl)-N'-[1-(4-Nitrrophenyl)ethylidene] propane hydrazide (P4) were synthesized and their third order nonlinear optical properties have been investigated using a single beam Z-scan technique with nanosecond laser pulses at 532 nm. The measurement on the compound-P1 is not reported as there is no detectable nonlinear response. Open aperture data of the other three compounds indicate two photon absorption at this wavelength. The nonlinear refractive index n2, nonlinear absorption coefficient β, magnitude of effective third order susceptibility χ(3), the second order hyperpolarizability γh and the coupling factor ρ have been estimated. The values obtained are comparable with the values obtained for 4-methoxy chalcone derivatives and dibenzylideneacetone derivatives. The experimentally determined values of β, n2, Re χ(3) and Im χ(3), γh and ρ of the compound-P4 are 1.42 cm/GW, -0.619 × 10-11 esu, -0.663 × 10-13 esu, 0.22 × 10-13 esu, 0.34 × 10-32 esu and 0.33 respectively. Further the compound-P4 exhibited the best optical power limiting behavior at 532 nm among the compounds studied. Our studies suggest that compounds P2, P3 and P4 are potential candidates for the optical device applications such as optical limiters and optical switches.
D'silva, E.D.; Podagatlapalli, G. Krishna; Venugopal Rao, S.; Dharmaprakash, S.M.
2012-11-15
Graphical abstract: Photograph and schematic representation of Z-scan experimental setup used to investigate third order nonlinear properties of the chalcone materials. Highlights: ► Br and NO{sub 2} substituted chalcone derivatives were exposed to picosecond laser pulses. ► Third-order nonlinear optical (NLO) properties were investigated. ► Compounds show promising third-order and optical limiting properties. ► These materials found suitable for electrical and optical applications. -- Abstract: In this paper we present results from the experimental study of third-order nonlinear optical (NLO) properties of three molecules of Br and NO{sub 2} substituted chalcone derivatives namely (2E)-1-(4-bromophenyl)-3-[4(methylsulfanyl)phenyl]prop-2-en-1-one (4Br4MSP), (2E)-1-(3-bromophenyl)-3-[4-(methylsulfanyl) phenyl]prop-2-en-1-one (3Br4MSP) and (2E)-3[4(methylsulfanyl) phenyl]-1-(4-nitrophenyl)prop-2-en-1-one (4N4MSP). The NLO properties have been investigated by Z-scan technique using 2 ps laser pulses at 800 nm. The nonlinear refractive indices, nonlinear absorption coefficient, and the magnitude of third-order susceptibility have been determined. The values obtained are of the order of 10{sup −7} cm{sup 2}/GW, 10{sup −3} cm/GW and 10{sup −14} esu respectively. The molecular second hyperpolarizability for the chalcone derivatives is of the order of 10{sup −32} esu. The coupling factor, excited state cross section, ground state cross section etc. were determined. The optical limiting (OL) property was studied. The results suggest that the nonlinear properties investigated for present chalcones are comparable with some of the reported chalcone derivatives and can be desirable for NLO applications.
NASA Astrophysics Data System (ADS)
Mirershadi, S.; Ahmadi-Kandjani, S.; Zawadzka, A.; Rouhbakhsh, H.; Sahraoui, B.
2016-03-01
The nonlinear optical response of CH3NH3PbBr3 perovskites is investigated using Z-scan technique, employing 10 ns laser pulses, at 532 nm. The systems were found to exhibit strong nonlinear optical response, dominated by nonlinear refraction. The effect of organic and inorganic composition ratio on the nonlinear susceptibility is studied experimentally. In all cases, the nonlinear absorption and refraction have been determined. The corresponding third-order susceptibilities and second-order hyperpolarizability are determined to be as large as 10-6 (esu) and 10-28 (esu) under ns laser excitation respectively. Showing large third-order optical nonlinearity in CH3NH3PbBr3 thin films, suggesting their potential for photonics applications.
Evaluation of third order nonlinear optical parameters of CdS/PVA nanocomposite
Sharma, Mamta; Tripathi, S. K. E-mail: surya-tr@yahoo.com
2015-06-24
CdS nanoparticles dispersed in PVA are prepared by Chemical method at room temperature. The nonlinear optical parameters such as nonlinear absorption (β), nonlinear refractive index (n{sub 2}) and nonlinear susceptibility (χ{sup 3}) are calculated for this sample by using Z-scan technique. CdS/PVA samples show the two photon absorption mechanism. The third order nonlinear susceptibility is calculated from n{sub 2} and β and is found to be of the order of 10{sup −7} – 10{sup −8} m{sup 2}/V{sup 2}. The larger value of third order nonlinear susceptibility is due to dielectric and quantum confinement effect.
NASA Technical Reports Server (NTRS)
Sanghadasa, Mohan; Shin, In-Seek; Barr, Thomas A.; Clark, Ronald D.; Guo, Huai-Song; Martinez, Angela; Penn, Benjamin G.
1998-01-01
In recent years, there has been a growing interest in the development of passive optical power limiters for the protection of the human eye and solid-state sensors from damage caused by energetic light pulses and also for other switching applications. One of the key issues involved is the search for appropriate materials that show effective reverse saturable absorption. Phthalocyanines seem to be good candidates for such applications because of their higher third order nonlinearity and the unique electronic absorption characteristics. A series of 1,4,8,11,15, 18,22,25-octa-alkoxy metallophthalocyanines containing various central metal atoms such as zinc, copper, palladium, cobalt and nickel were characterized for their third order nonlinearity and for their nonlinear absorptive properties to evaluate their suitability to function as reverse saturable absorbers.
Anisotropic third-order optical nonlinearity of a single ZnO micro/nanowire.
Wang, Kai; Zhou, Jun; Yuan, Longyan; Tao, Yuting; Chen, Jian; Lu, Peixiang; Wang, Zhong Lin
2012-02-01
We report a systematic study about the anisotropic third-order optical nonlinearity of a single ZnO micro/nanowire by using the Z-scan method with a femtosecond laser. The two-photon absorption coefficient and nonlinear refraction index, which are measured as a function of polarization angle and sample orientation angle, exhibit oscillation curves with a period of π/2, indicating a highly polarized optical nonlinearity of the ZnO micro/nanowire. Further studies show that the polarized optical nonlinearity of the ZnO micro/nanowire is highly size-dependent. The results indicate that ZnO nanowire has great potential in applications of nanolasers, all-optical switching and polarization-sensitive photodetectors. PMID:22214490
Second and third order nonlinear optical properties of conjugated molecules and polymers
NASA Technical Reports Server (NTRS)
Perry, Joseph W.; Stiegman, Albert E.; Marder, Seth R.; Coulter, Daniel R.; Beratan, David N.; Brinza, David E.
1988-01-01
Second- and third-order nonlinear optical properties of some newly synthesized organic molecules and polymers are reported. Powder second-harmonic-generation efficiencies of up to 200 times urea have been realized for asymmetric donor-acceptor acetylenes. Third harmonic generation chi(3)s have been determined for a series of small conjugated molecules in solution. THG chi(3)s have also been determined for a series of soluble conjugated copolymers prepared using ring-opening metathesis polymerization. The results are discussed in terms of relevant molecular and/or macroscopic structural features of these conjugated organic materials.
The third-order nonlinear optical properties of unsymmetrical trimethine cyanine dyes
NASA Astrophysics Data System (ADS)
He, Xuemei; Yang, Junyi; Fang, Yu; Zhou, Feng; Song, Yinglin
2015-10-01
In this paper, we investigate the nonlinear optical properties of unsymmetrical trimethine cyanine dyes(ethyl-4-(3-(3-ethylbenzo[d]xazole-2(3H)-ylidene)prop-1-en-1-yl)quinolin-1-iumiodidebenzo[d]xa zole group) by conducting Z-scan technique at 532 nm and time-resolved pump probe with phase object (POPP). Pronounced reverse saturable absorption (RSA) and positive refraction are observed. Moreover, the relevant third-order NLO photo-physical parameters of unsymmetrical trimethine cyanine dyes determined unambiguously.
Ultrafast control of third-order optical nonlinearities in fishnet metamaterials.
Shorokhov, Alexander S; Okhlopkov, Kirill I; Reinhold, Jörg; Helgert, Christian; Shcherbakov, Maxim R; Pertsch, Thomas; Fedyanin, Andrey A
2016-01-01
Nonlinear photonic nanostructures that allow efficient all-optical switching are considered to be a prospective platform for novel building blocks in photonics. We performed time-resolved measurements of the photoinduced transient third-order nonlinear optical response of a fishnet metamaterial. The mutual influence of two non-collinear pulses exciting the magnetic resonance of the metamaterial was probed by detecting the third-harmonic radiation as a function of the time delay between pulses. Subpicosecond-scale dynamics of the metamaterial's χ((3)) was observed; the all-optical χ((3)) modulation depth was found to be approximately 70% at a pump fluence of only 20 μJ/cm(2). PMID:27335268
Ultrafast control of third-order optical nonlinearities in fishnet metamaterials
NASA Astrophysics Data System (ADS)
Shorokhov, Alexander S.; Okhlopkov, Kirill I.; Reinhold, Jörg; Helgert, Christian; Shcherbakov, Maxim R.; Pertsch, Thomas; Fedyanin, Andrey A.
2016-06-01
Nonlinear photonic nanostructures that allow efficient all-optical switching are considered to be a prospective platform for novel building blocks in photonics. We performed time-resolved measurements of the photoinduced transient third-order nonlinear optical response of a fishnet metamaterial. The mutual influence of two non-collinear pulses exciting the magnetic resonance of the metamaterial was probed by detecting the third-harmonic radiation as a function of the time delay between pulses. Subpicosecond-scale dynamics of the metamaterial’s χ(3) was observed; the all-optical χ(3) modulation depth was found to be approximately 70% at a pump fluence of only 20 μJ/cm2.
Ultrafast control of third-order optical nonlinearities in fishnet metamaterials
Shorokhov, Alexander S.; Okhlopkov, Kirill I.; Reinhold, Jörg; Helgert, Christian; Shcherbakov, Maxim R.; Pertsch, Thomas; Fedyanin, Andrey A.
2016-01-01
Nonlinear photonic nanostructures that allow efficient all-optical switching are considered to be a prospective platform for novel building blocks in photonics. We performed time-resolved measurements of the photoinduced transient third-order nonlinear optical response of a fishnet metamaterial. The mutual influence of two non-collinear pulses exciting the magnetic resonance of the metamaterial was probed by detecting the third-harmonic radiation as a function of the time delay between pulses. Subpicosecond-scale dynamics of the metamaterial’s χ(3) was observed; the all-optical χ(3) modulation depth was found to be approximately 70% at a pump fluence of only 20 μJ/cm2. PMID:27335268
Dhanalakshmi, B.; Ponnusamy, S.; Muthamizhchelvan, C.; Subhashini, V.
2015-10-15
Highlights: • EDA4NPH crystal possesses negative nonlinear refractive index. • The crystal exhibits high third-order NLO susceptibility. • Wide transparency of the crystal makes it suitable for NLO applications. • Dielectric studies substantiate the suitability for electro-optic applications. • The crystal possesses suitable mechanical strength for device fabrication. - Abstract: Bulk crystals of the charge-transfer complex, ethylenediamine-4-nitrophenolate monohydrate, were grown by slow solvent evaporation method from aqueous solution at room temperature. The X-ray diffraction measurements showed that the crystal belongs to centrosymmetric space group C2/c of monoclinic system. The functional groups in the complex were identified using FTIR, FTRaman and FTNMR analyses. The Z-scan measurements revealed the negative nonlinear refractive index of the crystal. The nonlinear absorption coefficient and third order nonlinear optical susceptibility calculated from the measurements were −3.5823 × 10{sup −3} cm/W and 2.3762 × 10{sup −6} esu respectively. The crystal was shown to be highly transparent above 366 nm by UV–vis spectroscopy and a yellow fluorescence was observed from PL spectrum. The TG–DTA and DSC analyses showed that the crystal is thermally stable up to 117.4 °C. The crystals were characterized by dielectric, etching and microhardness studies.
Third-order nonlinear optical properties of phthalocyanines in solution and in polystyrene films
NASA Astrophysics Data System (ADS)
Reeves, Roger J.; Powell, Richard C.; Chang, Young H.; Ford, Warren T.; Zhu, Weiming
1996-01-01
Degenerate four-wave mixing (DFWM) measurements of third-order nonlinear optical (NLO) coefficients of metal-free, Cu, Pt, Pb and Bi octa(2-ethylhexyloxy) phthalocyanines (MPc's) were done with 20 ps duration laser pulses under resonant conditions at 532 nm in polystyrene films and under nonresonant conditions at 1064 nm in chloroform solutions. The NLO coefficients ξxxxx(3) show saturation with increasing incident intensity and no strong dependence on the central metal atom of the MPc below the saturation intensity. Optical delays of the probe-pulse up to 3 ns show an acoustic phonon response in both the polystyrene films and the chloroform solutions. An intensity-dependent absorption coefficient was measured by a pump/probe experiment and used in a simple model to qualitatively account for the saturation of ξ(3) measured by DFWM.
Third-order nonlinear spectra and optical limiting of lead oxifluoroborate glasses
NASA Astrophysics Data System (ADS)
Almeida, J. M. P.; de Boni, L.; Hernandes, A. C.; Mendonça, C. R.
2011-08-01
We have determined two-photon absorption and nonlinear refraction spectra of the 50BO1.5 - (50-x)PbF2 - xPbO glasses (with x = 25, 35, 50 cationic %) at the range of the 470 and 1550 nm. The replacement of fluor atoms by oxygen leads to an increase in the third-order susceptibility, due to the formation of non-bridging oxygens (NBO). The nonlinear index of refraction is one order of magnitude higher than the one for fused silica, and it increases almost twice for the sample with x = 50. This sample has also shown promising features for all-optical switching as well as for optical limiting.
NASA Astrophysics Data System (ADS)
Karakas, A.; Karakaya, M.; Taser, M.; Ceylan, Y.; Gozutok, A.; Arof, A. K.; El Kouari, Y.; Sahraoui, B.
2016-03-01
The electric dipole moments (μ), static dipole polarizabilities (α) and first hyperpolarizabilities (β) of styrylquinolinium dyes, D8 and D21, have been computed by density functional theory (DFT). The one-photon absorption (OPA) characterizations have been investigated using UV-vis spectroscopy and further interpreted using computational chemistry. The time-dependent Hartree-Fock (TDHF) method has been used to describe the dynamic dipole polarizabilities, dynamic second-order and also static and dynamic third-order nonlinear optical (NLO) properties. D8-D21 have rather high β and second hyperpolarizabilities (γ). The highest occupied molecular orbitals (HOMO), the lowest unoccupied molecular orbitals (LUMO) and the HOMO-LUMO band gaps for D8-D21 have been evaluated by DFT.
NASA Astrophysics Data System (ADS)
Kwong, Nai-Hang; Takayama, Ryu; Binder, Rolf H.
2001-07-01
We present a microscopic theory of the coherent third order optical response of semiconductor quantum well micro cavities, specialized to the four-wave-mixing configuration in the spectral vicinity of the lowest exciton frequency. The theory is that of a quantum mechanical many-electron system dipole-coupled to a classical radiation field. The many-electron dynamics is treated within the dynamics- controlled-truncation formalism restricted to the 1s-exciton subspace. Within this limitation, al Coulomb correlation effects are included, resulting in an effective theory of exciton-polariton scattering. The theory is evaluated for various polarization configurations each of which depends differently on the underlying many-body effects, such as phase-space filing, Hartree-Fock exchange, and two-exciton correlations.
Second- and third-order nonlinear optical properties of unsubstituted and mono-substituted chalcones
NASA Astrophysics Data System (ADS)
Abegão, Luis M. G.; Fonseca, Ruben D.; Santos, Francisco A.; Souza, Gabriela B.; Barreiros, André Luis B. S.; Barreiros, Marizeth L.; Alencar, M. A. R. C.; Mendonça, Cleber R.; Silva, Daniel L.; De Boni, Leonardo; Rodrigues, J. J.
2016-03-01
This work describes the second and third orders of nonlinear optics properties of unsubstituted chalcone (C15H12O) and mono-substituted chalcone (C16H14O2) in solution, using hyper-Rayleigh scattering and Z-Scan techniques to determine the first molecular hyperpolarizability (β) and the two-photon absorption (2PA) cross section respectively. β Values of 25.4 × 10-30 esu and 31.6 × 10-30 esu, for unsubstituted and mono-substituted chalcone, respectively, dissolved in methanol have been obtained. The highest values of 2PA cross-sections obtained were 9 GM and 14 GM for unsubstituted and mono-substituted chalcone, respectively. The experimental 2PA cross sections obtained for each chalcone are in good agreement with theoretical results.
NASA Astrophysics Data System (ADS)
Jayakrishnan, K.; Joseph, Antony; Bhattathiripad, Jayakrishnan; Ramesan, M. T.; Chandrasekharan, K.; Siji Narendran, N. K.
2016-04-01
We report our results on the identification of large order enhancement in nonlinear optical coefficients of polymerized indole and its comparative study with reference to its monomer counterpart. Indole monomer shows virtually little third order effects whereas its polymerized version exhibits phenomenal increase in its third order nonlinear optical parameters such as nonlinear refractive index and nonlinear absorption. Open aperture Z-scan trace of polyindole done with Q-switched Nd:YAG laser source (532 nm, 7 ns), shows β value as high as 89 cm/GW at a beam energy of 0.83 GW/cm2. Closed aperture Z-scan done at identical energies reveals nonlinear refractive index of the order of -3.55 × 10-17 m2/W. Band gap measurement of polyindole was done with UV-Vis absorption spectra and compared with that of Indole. FTIR spectra of the monomer and polymerized versions were recorded and relevant bond formations were confirmed from the characteristic peaks. Photo luminescent spectra were investigated to know the emission features of both molecules. Beam energy (I0) versus nonlinear absorption coefficient (β) plot indicates reverse saturable type of absorption behaviour in polyindole molecules. Degenerate Four Wave Mixing (DFWM) plot of polyindole reveals quite a cubic dependence between probe and phase conjugate signal and the resulting χ(3) is comparable with Z-scan results. Optical limiting efficiency of polyindole is comparable with certain derivatives of porphyrins, phthalocyanines and graphene oxides.
NASA Astrophysics Data System (ADS)
Thangaraj, M.; Vinitha, G.; Sabari Girisun, T. C.; Anandan, P.; Ravi, G.
2015-10-01
Optical nonlinearity of metal complexes of p-nitrophenolate (M=Li, Na and K) in ethanol is studied by using a continuous wave (cw) diode pumped Nd:YAG laser (532 nm, 50 mW). The predominant mechanism of observed nonlinearity is thermal in origin. The nonlinear refractive index and the nonlinear absorption coefficient of the samples were found to be in the order of 10-8 cm2/W and 10-3 cm/W respectively. Magnitude of third-order optical parameters varies according to the choice of alkali metal chosen for metal complex formation of p-nitrophenolate. The third-order nonlinear susceptibility was found to be in the order of 10-6 esu. The observed saturable absorption and the self-defocusing effect were used to demonstrate the optical limiting action at 532 nm by using the same cw laser beam.
Third-order optical nonlinearity studies of bilayer Au/Ag metallic films
NASA Astrophysics Data System (ADS)
Mezher, M. H.; Chong, W. Y.; Zakaria, R.
2016-05-01
This paper presents nonlinear optical studies of bilayer metallic films of gold (Au) and silver (Ag) on glass substrate prepared using electron beam evaporation. The preparation of Au and Ag nanoparticles (NPs) on the substrate involved the use of electron beam deposition, then thermal annealing at 600 °C and 270 °C, respectively, to produce a randomly distributed layer of Au and a layer of Ag NPs. Observation of field-effect scanning electron microscope images indicated the size of the NPs. Details of the optical properties related to peak absorption of surface plasmon resonance of the nanoparticle were revealed by use of UV-Vis spectroscopy. The Z-scan technique was used to measure the nonlinear absorption and nonlinear refraction of the fabricated NP layers. The third-order nonlinear refractive index coefficients for Au and Ag are (-9.34 and -1.61) × 10-11 cm2 W-1 given lower n 2, in comparison with bilayer (Au and Ag) NPs at -1.24 × 10-10 cm2 W-1. The results show bilayer NPs have higher refractive index coefficients thus enhance the nonlinearity effects.
Li Yong; Lu Jing; Cui Xiaobing; Xu Jiqing . E-mail: xjq@mail.jlu.edu.cn; Li Kechang; Sun Huaying; Li Guanghua; Pan Lingyun; Yang Qingxin
2005-01-15
Both the homometal cluster [P(ph{sub 4})]{sub 2}[Mo{sub 2}O{sub 2}({mu}-S){sub 2}(S{sub 2}){sub 2}] (1) and [Mo{sub 2}O{sub 2}({mu}-S){sub 2}(Et{sub 2}dtc){sub 2}] (2) (Et{sub 2}dtc=diethyl-dithiocarbamate) were successfully synthesized by low-temperature solid-state reactions. X-ray single-crystal diffraction studies suggest that compound (1) is a dinuclear anion cluster, and compound (2) is a dinuclear neutral cluster. The two compounds were characterized by elemental analyses, IR spectra and UV-Vis spectra. The third-order non-linear optical (NLO) properties of the clusters were also investigated and all exhibited nice non-linear absorption and self-defocusing performance with moduli of the hyperpolarizabilities 5.145x10{sup -30}esu for (1) and 5.428x10{sup -30}esu for (2)
Thangaraj, M; Ravi, G; Sabari Girisun, T C; Vinitha, G; Loganathan, A
2015-03-01
Single crystals of ethylenediaminium di(4-nitrophenolate) [EDA4NP] were grown by slow evaporation solution growth technique using ethanol as solvent at constant temperature. It crystallizes in monoclinic centrosymmetric space group C2/c with cell dimension a=11.326Ǻ, b=7.264Ǻ, c=20.036Ǻ; β=93.55°. Fourier Transform Infra Red (FT-IR) spectrum was recorded to identify various functional groups present in EDA4NP. Nuclear Magnetic Resonance (NMR) spectral studies were performed to confirm the functional groups. Thermogravimetric analysis and differential thermal analysis showed that the compound melts at 142.9°C. The material possesses a wide optical transparency window in the visible and near IR region (500-1200nm). The nonlinear refractive index, nonlinear absorption coefficient and third-order nonlinear susceptibility of EDA4NP were estimated to be n2=5.46×10(-8)cm(2)W(-1), β=0.65×10(-3)cmW(-1) and χ((3))=2.96×10(-6)esu respectively. The limiting behavior observed with the sample is attributed mainly to nonlinear refraction. PMID:25498811
Picosecond Laser Studies of Third-Order Nonlinear Optical Properties in Organic Polymers
NASA Astrophysics Data System (ADS)
Cao, Xiaofan
This dissertation makes the following theoretical and experimental contributions to the understanding of organic nonlinear optical materials in general, and of the nonlinear optical properties of polyquinoxaline (PQL) ladder polymers and metal-phthalocyanines doped in polycarbonate thin films in particular. (1) We developed a new model of the third-order nonlinear polarization density which has both "fast" (compared to 10psec, such as from electronic or lattice excitations) nonlinearity and "slow" (acoustic and thermal) components. This model enables a more accurate analysis than was possible previously of the different nonlinear optical processes seen in the picosecond laser studies of nonlinear optical properties of organic materials than was possible previously. (2) We interpreted our own picosecond four wave mixing measurements in ten polymers (in the PQL family) in terms of the new model parameters. (3) We have performed picosecond four-wave mixing measurement at 1064, (580-640), and 532 nm in Cr-phthalocyanine doped polycarbonate thin films. Our study supports the excitonic picture proposed by Ho et al.^{104 } (4) We observed for the first time a two -photon absorption state in Cr-Phthalocyanine near 0.5 eV. The two photon absorption coefficients which we determined by three independent methods agree well. (5) We showed that measuring the decay of ultrasonic waves induced by picosecond pulses is a superior way to measure acoustic velocity, acoustic damping, acousto-optic coupling constants, and thermal conductivity of materials. With this we studied the anomalous frequency dependence of sound damping in glasses and polymers. We propose a model for the diffusion of lattice "voids" in amorphous materials that accounts for some aspects of the anomalous ultrasonic sound damping. (6) We measured third harmonic generation in several PQL polymers and in a Cr-phthalocyanine doped polymer. Differences in four-wave mixing measurement were compared for five metal
Li, P H; Qu, Y L; Xu, X J; Zhu, Y W; Yu, T; Chin, K C; Mi, J; Gao, X Y; Lim, C T; Shen, Z X; Wee, A T S; Ji, W; Sow, C H
2006-04-01
We report a new morphology of "cactus" top-decorated aligned carbon nanotubes grown by the PECVD method using pure C2H2 gas. Unlike most previous reports, no additional carrier gas is used for pretreatment. Carbon nanotubes can still grow and maintain the tubular structure underneath the "cactus" tops. It is proposed that the H atoms produced by the dissociation of C2H2 activate the catalyst nanoparticles. Scanning electron microscopy (SEM) shows that the top "cactus" morphology is composed of a large quantity of small nanosheets. Transmission electron microscopy (TEM) reveals the amorphous carbon nature of these "cactus" structures. The formation of these "cactus" structures is possibly due to covalent absorption and reconstruction of carbon atoms on the broken graphite layers of nanotubes produced by the strong ion bombardment under plasma. The third-order optical nonlinearities and nonlinear dynamics are also investigated. The third-order nonlinear susceptibility magnitude /chi(3)/ is found to be 2.2 x 10(-11) esu, and the relaxation process takes place in about 1.8 ps. PMID:16736755
NASA Astrophysics Data System (ADS)
Pramodini, S.; Poornesh, P.
2014-11-01
We report thermally induced third-order nonlinearity and optical limiting behaviour of Indigo Carmine dye. z-Scan technique was used to determine the sign and magnitude of absorptive and refractive nonlinearities. Continuous wave (CW) He-Ne laser operating at 633 nm was used as source of excitation. In open aperture z-scan experiments, samples exhibited reverse saturable absorption (RSA) process. For closed aperture z-scan experiments, samples revealed self-defocusing property. The presence of donor and acceptor groups in the structure increases the conjugation length and in turn increases the optical nonlinearity. Induced self-diffraction rings pattern was recorded for the samples and it is attributed to refractive index change and thermal lensing. Also, optical limiting and clamping studies were carried out for various input power. Optical clamping of about ~1 mW was observed. This endorses that the dye under investigation is a positive candidate for opto-electronic and photonic applications.
Third-order nonlinear optical properties of methylammonium lead halide perovskite films
Johnson, Justin C.; Li, Zhen; Ndione, Paul F.; Zhu, Kai
2016-01-01
We report third-order nonlinear coefficient values and decay time kinetics vs. halide composition (CH3NH3PbBr3 and CH3NH3PbBr2I), temperature, and excitation wavelength. The maximum values of the third-order nonlinear susceptibility X(3) (-1.6 x 10-6 esu) are similar to or larger than many common third-order materials. The source of the nonlinearity is shown to be primarily excitonic in the tribromide film by virtue of its strong enhancement near the exciton resonance. Nonresonant excitation reduces the nonlinearity significantly, as does increasing the temperature. Substitution of one I for one Br also reduces the nonlinearity by at least one order of magnitude, presumably due to the lack of strong exciton resonance in the substituted form. The thin films are stable, highly homogenous (lacking significant light scattering), and simple and inexpensive to fabricate, making them potentially useful in a variety of optoelectronic applications in which wavelength selectivity is important.
Pokladek, Ziemowit; Ripoche, Nicolas; Betou, Marie; Trolez, Yann; Mongin, Olivier; Olesiak-Banska, Joanna; Matczyszyn, Katarzyna; Samoc, Marek; Humphrey, Mark G; Blanchard-Desce, Mireille; Paul, Frédéric
2016-07-11
The synthesis and characterization of four new tetracyanobutadiene (TCBD) derivatives (1-3 and 2') incorporating 2- or 2,7-fluorenyl and diphenylamino moieties are reported. The electroactivity of 1-3 and 2' was studied by cyclic voltammetry (CV), while the linear optical and (third-order) nonlinear optical (NLO) properties were investigated by electronic spectroscopy and Z-scan studies, respectively. All experimental investigations were rationalized by DFT computations, providing an insight into the electronic structure of these derivatives and on their application potential. We show that these derivatives are nonluminescent in solution at ambient temperatures, but become fluorescent in solvent glasses. This finding constitutes an unprecedented observation for TCBD derivatives. Also, we show by Z-scan studies that these derivatives behave as two-photon absorbers in the near-IR range (800-1050 nm). These third-order NLO properties are discussed and compared with those of their alkynyl precursors (4-6), which have been investigated by two-photon excited fluorescence (TPEF). PMID:27297358
NASA Astrophysics Data System (ADS)
Thankappan, Aparna; Thomas, Sheenu; Nampoori, V. P. N.
2013-10-01
We report on the solvent effect on the third order optical nonlinearity of betanin natural dye extracted from red beet root and their third order nonlinear optical (NLO) properties have been studied using a Q-switched Nd:YAG laser at 532 nm. The third order nonlinearity of these samples are dominated by nonlinear absorption, which leads to strong optical limiting and their strength is influenced by the solvent used, suggesting that betanin natural dyes are promising candidate for the development of photonic nonlinear optic devices.
Linear and third order nonlinear optical properties of LiRbB4O7 single crystal
NASA Astrophysics Data System (ADS)
Sukumar, M.; Babu, R. Ramesh; Ramamurthi, K.
2016-01-01
Lithium rubidium borate (LiRbB4O7) single crystal has been grown by the Czochralski method. Crystalline perfection and optical homogeneity of the grown LiRbB4O7 crystal are analyzed by high resolution X-ray diffraction and birefringence interferometric technique, respectively. Third order nonlinear optical parameters of LiRbB4O7 crystal are determined by Z-scan experimental technique. The nonlinear refractive index (n2) and third-order nonlinear optical susceptibility (χ3) are estimated to be -4.935 × 10-11 cm2/W and 2.719 × 10-7 esu, respectively. The measured (n2) value reveals the self-focusing nature of LiRbB4O7 crystal.
NASA Astrophysics Data System (ADS)
Carrillo-Delgado, C.; García-Gil, C. I.; Trejo-Valdez, M.; Torres-Torres, C.; García-Merino, J. A.; Martínez-Gutiérrez, H.; Khomenko, A. V.; Torres-Martínez, R.
2016-01-01
Measurements of the third-order nonlinear optical properties exhibited by a ZnO thin solid film deposited on a SnO2 substrate are presented. The samples were prepared by a spray pyrolysis processing route. Scanning electron microscopy analysis and UV-Vis spectroscopy studies were carried out. The picosecond response at 1064 nm was explored by the z-scan technique. A large optical Kerr effect with two-photon absorption was obtained. The inhibition of the nonlinear optical absorption together with a noticeable enhancement in the optical Kerr effect in the sample was achieved by the incorporation of Au nanoparticles into the ZnO film. Additionally, a two-wave mixing configuration at 532 nm was performed and an optical Kerr effect was identified as the main cause of the nanosecond third-order optical nonlinearity. The relaxation time of the photothermal response of the sample was estimated to be about 1 s when the sample was excited by nanosecond single-shots. The rotation of the sample during the nanosecond two-wave mixing experiments was analyzed. It was stated that a non-monotonic relation between rotating frequency and pulse repetition rate governs the thermal contribution to the nonlinear refractive index exhibited by a rotating film. Potential applications for switching photothermal interactions in rotating samples can be contemplated. A rotary logic system dependent on Kerr transmittance in a two-wave mixing experiment was proposed.
Spectral dependence of third-order nonlinear optical properties in InN
Ahn, H. Lee, M.-T.; Chang, Y.-M.
2014-05-19
We report on the nonlinear optical properties of InN measured in a wide near-infrared spectral range with the femtosecond Z-scan technique. The above-bandgap nonlinear absorption in InN is found to originate from the saturation of absorption by the band-state-filling and its cross-section increases drastically near the bandgap energy. With below-bandgap excitation, the nonlinear absorption undergoes a transition from saturation absorption (SA) to reverse-SA (RSA), attributed to the competition between SA of band-tail states and two-photon-related RSA. The measured large nonlinear refractive index of the order of 10{sup −10} cm{sup 2}/W indicates InN as a potential material for all-optical switching and related applications.
Spectral dependence of third-order nonlinear optical properties in InN
NASA Astrophysics Data System (ADS)
Ahn, H.; Lee, M.-T.; Chang, Y.-M.
2014-05-01
We report on the nonlinear optical properties of InN measured in a wide near-infrared spectral range with the femtosecond Z-scan technique. The above-bandgap nonlinear absorption in InN is found to originate from the saturation of absorption by the band-state-filling and its cross-section increases drastically near the bandgap energy. With below-bandgap excitation, the nonlinear absorption undergoes a transition from saturation absorption (SA) to reverse-SA (RSA), attributed to the competition between SA of band-tail states and two-photon-related RSA. The measured large nonlinear refractive index of the order of 10-10 cm2/W indicates InN as a potential material for all-optical switching and related applications.
NASA Astrophysics Data System (ADS)
Sharifimehr, Mohammad Reza; Ayoubi, Kazem; Mohajerani, Ezeddin
2015-11-01
Measuring nonlinear optical response of a specific material in a mixture, not only leads to investigate the behavior of a particular component in various circumstances, but also can be a way to select suitable combination and optimum concentration of additives and therefore obtaining the maximum nonlinear optical signals. In this work, by using dual-arm Z-scan technique, the nonlinear refractive index of Disperse Red1 (DR1) organic dye molecules inside the core of prepared polymeric nanocapsules was measured among various materials which prepared nanocapsules were made of them. Then the measured value was compared with nonlinear refractive index of DR1 solved in dichloromethane.
Investigation of third-order optical nonlinearity in KBe2BO3F2 crystal by Z-scan
NASA Astrophysics Data System (ADS)
Li, F.-Q.; Zong, N.; Zhang, F.-F.; Yang, J.; Yang, F.; Peng, Q.-J.; Cui, D.-F.; Zhang, J.-Y.; Wang, X.-Y.; Chen, C.-T.; Xu, Z.-Y.
2012-08-01
The third-order optical nonlinearity of deep-ultraviolet (DUV) nonlinear optical (NLO) crystal KBe2BO3F2 (KBBF) was investigated using single-beam Z-scan technique for the first time. The Z-scans were performed on a c-cut KBBF crystal and a KBBF prism-coupling device (PCD) with picosecond pulses at 355 nm. No two-photon absorption was observed in the experiment. The measured nonlinear refraction index n 2 showed positive signs, indicating self-focusing Kerr effects. The n 2 values were estimated to be (1.75±0.35)×10-15 cm2/W with the c-cut sample and (1.85±0.37)×10-15 cm2/W with the PCD, corresponding to the third-order nonlinear optical susceptibilities χ_{eff}^{(3)} of (0.99±0.20)×10-13 esu and (0.94±0.19)×10-13 esu, respectively. The results are expected to promote the investigation of frequency conversion processes with ultra-short laser in KBBF crystal.
Xiang, Weidong; Gao, Haihong; Ma, Li; Ma, Xin; Huang, Yunyun; Pei, Lang; Liang, Xiaojuan
2015-05-20
The integrated and transparent sodium borosilicate glasses that contain copper exhibiting different colors, that is, red, green, and blue were synthesized by combining the sol-gel process and heat treatment in H2 gas. To reveal substantially the cause of different colors in the glass, X-ray diffraction (XRD), transmission electron microscopy (TEM) and high resolution TEM (HRTEM) were systematically applied to investigate and determine the microstructure of the doped matter. The results showed three different crystals had formed in the red, green and blue glass, and the sizes of these crystals were range from 9 to 34, 1 to 6, and 1 to 5 nm, respectively. The valence state of copper was further analyzed by X-ray photoelectron spectroscopy (XPS) and electron energy loss spectroscopy (EELS). The third-order nonlinear optical properties of the glasses were investigated by using Z-scan technique at the wavelength of 800 nm. Interestingly, the third-order nonlinear absorption of the red, green, and blue glass can be successfully controlled from reverse saturable absorption, no absorption to saturable absorption and the optical nonlinear susceptibility χ((3)) of the red, green and blue glass were estimated to be 6.4 × 10(-14), 1.6 × 10(-14), and 2.6 × 10(-14) esu in the single-pulse energy of 0.36 μJ, respectively. PMID:25928895
Effect of acid/base on the third-order optical nonlinearity of polypyrrole
NASA Astrophysics Data System (ADS)
Wang, Aijian; Zhao, Wei; Yu, Wang
2015-11-01
Polypyrrole (PPy) and its acid/base composites (PPy·H2SO4, PPy·HCl and PPy·NH3·H2O) were successfully synthesized and were characterized respectively by using fourier transform infrared, ultraviolet/visible absorption, X-ray diffraction, transmission electron microscopy and Raman spectroscopic techniques. The nonlinear optical properties of PPy and its acid/base composites were investigated using nanosecond Z-scan measurements at 532 nm. At the identical linear transmittance, the saturable absorption of pure PPy was changed to reverse saturable absorption by doping with acid (HCl and H2SO4) and base (NH3·H2O). The possible mechanisms for the different nonlinear properties were also discussed.
Third Order Optical Nonlinearity of Colloidal Metal Nanoclusters Formed by MeV Ion Implantation
NASA Technical Reports Server (NTRS)
Sarkisov, S. S.; Williams, E.; Curley, M.; Ila, D.; Venkateswarlu, P.; Poker, D. B.; Hensley, D. K.
1997-01-01
We report the results of characterization of nonlinear refractive index of the composite material produced by MeV Ag ion implantation of LiNbO(sub 3) crystal (z-cut). The material after implantation exhibited a linear optical absorption spectrum with the surface plasmon peak near 430 nm attributed to the colloidal silver nanoclusters. Heat treatment of the material at 500 deg C caused a shift of the absorption peak to 550 nm. The nonlinear refractive index of the sample after heat treatment was measured in the region of the absorption peak with the Z-scan technique using a tunable picosecond laser source (4.5 ps pulse width).The experimental data were compared against the reference sample made of MeV Cu implanted silica with the absorption peak in the same region. The nonlinear index of the Ag implanted LiNbO(sub 3) sample produced at five times less fluence is on average two times greater than that of the reference.
Mi, Yongsheng; Liang, Pengxia; Yang, Zhou; Wang, Dong; Cao, Hui; He, Wanli; Yang, Huai; Yu, Lian
2016-02-01
Recently, third-order nonlinear properties of porphyrins and porphyrin polymers and coordination compounds have been extensively studied in relation to their use in photomedicine and molecular photonics. A new functionalized porphyrin dye containing electron-rich alkynes was synthesized and further modified by formal [2+2] click reactions with click reagents tetracyanoethylene (TCNE) and 7, 7, 8, 8-tetracyanoquinodimethane (TCNQ). The photophysical properties of these porphyrin dyes, as well as the click reaction, were studied by UV/Vis spectroscopy. In particular, third-order nonlinear optical properties of the dyes, which showed typical d-π-A structures, were characterized by Z-scan techniques. In addition, the self-assembly properties were investigated through the phase-exchange method, and highly organized morphologies were observed by scanning electron microscopy (SEM). The effects of the click post-functionalization on the properties of the porphyrins were studied, and these functionalized porphyrin dyes represent an interesting set of candidates for optoelectronic device components. PMID:27308215
NASA Astrophysics Data System (ADS)
Castro, Adailton N.; Almeida, Leonardo R.; Anjos, Murilo M.; Oliveira, Guilherme R.; Napolitano, Hamilton B.; Valverde, Clodoaldo; Baseia, Basílio
2016-06-01
Coumarin derivatives exist widely in nature and show a wide range of biological activities such as anti-inflammatory, anti-oxidative and anti-cancer. The structure of C11H7BrO3 has been redetermined using 3330 measured reflections with 1666 unique [Rint = 0.0088] with final indices R1 = 0.0128 [I > 2σ(I)] and wR2 = 0.0347 (all data). The bromocoumarin molecule is almost planar and has three planar dimers stabilized by interaction of type Csbnd H⋯Br and Csbnd H⋯O, which form parallel layers connected via several π-π interactions [centroid-centroid distances = 3.958(1) Å]. To provide a view of the non-linear optical behavior of third order of the crystal bromocoumarin in both cases static and dynamic, we calculate the linear polarizability (α) and the second hyperpolarizability (γ) using a new supermolecule approach combined with an iterative electrostatic scheme where the neighboring molecules are represented by point charges. The results of calculations of the HOMO and LUMO energies show the occurrence of charge transfer inside the molecule. The computational results of the second (static and dynamics) hyperpolarizabilities show the molecule exhibiting second hyperpolarizability with values different of zero, which implies a third order microscopic behavior.
Chen, L.X.; Laible, P.D.; Spano, F.C.; Manas, E.S.
1997-09-01
Enhancement of the nonresonant second order molecular hyperpolarizabilities {gamma} were observed in stacked macrocyclic molecular systems, previously in a {micro}-oxo silicon phthalocyanine (SiPcO) monomer, dimer and trimer series, and now in bacteriochlorophyll a (BChla) arrays of light harvesting (LH) proteins. Compared to monomeric BChla in a tetrahydrofuran (THF) solution, the <{gamma}> for each macrocycle was enhanced in naturally occurring stacked macrocyclic molecular systems in the bacterial photosynthetic LH proteins where BChla`s are arranged in tilted face-to-face arrays. In addition, the {gamma} enhancement is more significant in B875 of LH1 than in B850 in LH2. Theoretical modeling of the nonresonant {gamma} enhancement using simplified molecular orbitals for model SiPcO indicated that the energy level of the two photon state is crucial to the {gamma} enhancement when a two photon process is involved, whereas the charge transfer between the monomers is largely responsible when one photon near resonant process is involved. The calculated results can be extended to {gamma} enhancement in B875 and B850 arrays, suggesting that BChla in B875 are more strongly coupled than in B850. In addition, a 50--160 fold increase in <{gamma}> for the S{sub 1} excited state of relative to S{sub 0} of bacteriochlorophyll in vivo was observed which provides an alternative method for probing excited state dynamics and a potential application for molecular switching.
Cobb, J.W.
1995-02-01
There is an increasing need for more accurate numerical methods for large-scale nonlinear magneto-fluid turbulence calculations. These methods should not only increase the current state of the art in terms of accuracy, but should also continue to optimize other desired properties such as simplicity, minimized computation, minimized memory requirements, and robust stability. This includes the ability to stably solve stiff problems with long time-steps. This work discusses a general methodology for deriving higher-order numerical methods. It also discusses how the selection of various choices can affect the desired properties. The explicit discussion focuses on third-order Runge-Kutta methods, including general solutions and five examples. The study investigates the linear numerical analysis of these methods, including their accuracy, general stability, and stiff stability. Additional appendices discuss linear multistep methods, discuss directions for further work, and exhibit numerical analysis results for some other commonly used lower-order methods.
Kildishev, Alexander V; Sivan, Yonatan; Litchinitser, Natalia M; Shalaev, Vladimir M
2009-11-01
An enhanced method is developed for analysis of third-order nonlinearities in optical nanostructures with a scalar magnetic field frequency-domain formulation; it is shown to produce fast and accurate results for 2D problems without a superfluous vector electric field formalism. While a standard TM representation using cubic nonlinear susceptibility results in an intractable implicit equation, our technique alleviates this problem. In addition to a universal approach, simpler, more efficient solutions are proposed for media having solely either a real (lossless Kerr-type medium) or an imaginary (nonlinear absorbing medium) nonlinearity. Combining these solutions with a finite-element method, we show simulation examples validated with alternative approaches. PMID:19881595
NASA Astrophysics Data System (ADS)
Hamanaka, Yasushi; Ogawa, Tetsuya; Tsuzuki, Masakazu; Kuzuya, Toshihiro; Sumiyama, Kenji
2013-07-01
Third-order nonlinear optical susceptibilities (χ(3)) have been investigated for chalcopyrite CuInS2 and AgInS2 nanocrystals within a strong confinement regime. The imaginary part of χ(3) (Imχ(3)) of 2.0- and 4.9-nm-sized CuInS2 nanocrystals and 2.6- and 4.3-nm-sized AgInS2 nanocrystals are negative and exhibit resonant enhancement around the absorption between the highest quantized levels of valence band and the lowest conduction band due to the state-filling effect. Figure of merit of |Imχ(3)| ranges 10-20-10-19 m3/V2, which is comparable to those of CdSSe nanocrystals.
NASA Astrophysics Data System (ADS)
Dhavamurthy, M.; Raja, R.; Syed Suresh Babu, K.; Mohan, R.
2016-08-01
Guanidinium cinnamate (GUCN), a single crystal, was grown by slow evaporation technique. Single-crystal X-ray diffraction study revealed that GUCN crystal belongs to monoclinic crystal system with the space group P21/c. Thermal studies revealed that the GUCN is thermally stable up to 238 °C. The optical transmittance studies were carried out for the crystal, and the lower cutoff wavelength of the grown crystal was observed at 322 nm. The luminescent study showed that the GUCN crystal has high degree of luminescence. Third-order nonlinear refractive index n2, nonlinear absorption coefficient β and susceptibility χ(3) parameters were estimated by Z-scan technique. The four independent tensor coefficients ɛ11, ɛ22, ɛ33 and ɛ13 of dielectric permittivities for monoclinic GUCN were calculated. The mechanical properties of the grown crystals were studied using Vickers micro-hardness tester at different planes.
Third-order spontaneous parametric down-conversion in thin optical fibers as a photon-triplet source
Corona, Maria; Garay-Palmett, Karina; U'Ren, Alfred B.
2011-09-15
We study the third-order spontaneous parametric down-conversion (TOSPDC) process, as a means to generate entangled photon triplets. Specifically, we consider thin optical fibers as the nonlinear medium to be used as the basis for TOSPDC in configurations where phase matching is attained through the use of more than one fiber transverse modes. Our analysis in this paper, which follows from our earlier paper [Opt. Lett. 36, 190-192 (2011)], aims to supply experimentalists with the details required in order to design a TOSPDC photon-triplet source. Specifically, our analysis focuses on the photon triplet state, on the rate of emission, and on the TOSPDC phase-matching characteristics for the cases of frequency-degenerate and frequency nondegenerate TOSPDC.
NASA Astrophysics Data System (ADS)
Altürk, Sümeyye; Avci, Davut; Tamer, Ömer; Atalay, Yusuf
2016-03-01
It is well known that the practical applications of second-order and third-order nonlinear optical (NLO) materials have been reported in modern technology, such as optical data processing, transmission and storage, etc. In this respect, the linear and nonlinear optical parameters (the molecular static polarizability (α), and the first-order static hyperpolarizability (β0), the second-order static hyperpolarizability (γ)), UV-vis spectra and HOMO and LUMO energies of 2-(1'-(4'''-Methoxyphenyl)-5'-(thien-2″-yl)pyrrol-2'-yl)-1,3-benzothiazole were investigated by using the HSEh1PBE/6-311G(d,p) level of density functional theory. The UV-vis spectra were simulated using TD/HSEh1PBE/6- 311G(d,p) level, and the major contributions to the electronic transitions were obtained. The molecular hardness (η) and electronegativity (χ) parameters were also obtained by using molecular frontier orbital energies. The NLO parameters of the title compound were calculated, and obtained data were compared with that of para-Nitroaniline (pNA) which is a typical NLO material and the corresponding experimental data. Obtained data of the chromosphere display significant molecular second-and third-nonlinearity.
NASA Astrophysics Data System (ADS)
Mao, L.; Andreoli, A.; Comiti, F.; Lenzi, M. A.; Iturraspe, R.; Burns, S.; Novillo, M. G.
2007-05-01
Dead wood pieces, especially when organized in jams, play an important geomorphic role in streams because of the effects on flow hydraulics, pool formation and sediments storage. The increase of stream morphological diversity and complexity also exerts also an important ecological role. This work reports on geomorphic role of large wood pieces and jams in a third order mountain stream located in the Southern Tierra del Fuego (Argentina), and draining an old-growth nothofagus forested basin not influenced by the beavers damming activity. Even if the in-stream number of wood pieces (length > 1m; diameter > 0.1 m) is comparable to what observed in other climatic areas, the slow growth of the nothofagus forest causes a lower wood abundance in terms of volumetric load. Since the relatively small dimensions of the surveyed large wood pieces, almost the 70% of them demonstrated to have been fluvial transported and the also wood jams reflect the apparent dynamic of wood in the channel. Wood jams exert a significant influence on the channel morphology, representing almost the half of the drop caused by steps and being responsible for the creation of 30% of the pools. The LW-forced pool volume is strongly and positively correlated to the height of the LW jam, and a significant inverse relationship between pool spacing and wood density within is evident if only the LW-forced pools are considered. The geomorphic influence of LW jams is also exerted by a considerable sediment storing capacity.
NASA Astrophysics Data System (ADS)
Ganguly, Jayanta; Saha, Surajit; Pal, Suvajit; Ghosh, Manas
2016-03-01
We perform a meticulous analysis of profiles of third-order nonlinear optical susceptibility (TONOS) of impurity doped quantum dots (QDs) in the presence and absence of noise. We have invoked Gaussian white noise in the present study and noise has been introduced to the system additively and multiplicatively. The QD is doped with a Gaussian impurity. A magnetic field applied perpendicularly serves as a confinement source and the doped system has been exposed to a static external electric field. The TONOS profiles have been monitored against a continuous variation of incident photon energy when several important parameters such as electric field strength, magnetic field strength, confinement energy, dopant location, Al concentration, dopant potential, relaxation time, anisotropy, and noise strength assume different values. Moreover, the influence of mode of introduction of noise (additive/multiplicative) on the TONOS profiles has also been addressed. The said profiles are found to be consisting of interesting observations such as shift of TONOS peak position and maximization/minimization of TONOS peak intensity. The presence of noise alters the features of TONOS profiles and sometimes enhances the TONOS peak intensity from that of noise-free state. Furthermore, the mode of application of noise also often tailors the TONOS profiles in diverse fashions. The observations accentuate the possibility of tuning the TONOS of doped QD systems in the presence of noise.
Kishi, Ryohei; Ochi, Shoki; Izumi, Shioh; Makino, Akihiro; Nagami, Takanori; Fujiyoshi, Jun-ya; Matsushita, Naoyuki; Saito, Michika; Nakano, Masayoshi
2016-01-22
To create a design guideline for efficient third-order nonlinear optical (NLO) molecules, the chain-length (n) dependences of the diradical character y and the longitudinal second hyperpolarizability γ of quinoidal oligothiophenes (QTs), from monomers to octamers, involving thiophene-S,S-dioxide rings are investigated by using the density functional theory method. It turns out that the diradical character of the modified QTs is reduced as compared to those of the pristine QTs. By introducing an appropriate number of oxidized rings into the QT framework, intermediate y values can be achieved even in the systems with large values of n, in which the pristine QTs are predicted to have pure diradical character. Such intermediate diradical oligomers are shown to exhibit enhanced γ values as compared to the pristine QTs with the same value for n. From the calculation results, the introduction of the optimal number of thiophene-S,S-dioxide rings is predicted to be an efficient chemical modification for optimizing the third-order NLO properties of open-shell QTs through tuning the diradical characters. PMID:26670676
NASA Astrophysics Data System (ADS)
Altürk, Sümeyye; Avcı, Davut; Tamer, Ömer; Atalay, Yusuf; Şahin, Onur
2016-11-01
A cobalt(II) complex of 6-methylpicolinic acid, [Co(6-Mepic)2(H2O)2]·2H2O, was prepared and fully determined by single crystal X-ray crystal structure analysis as well as FT-IR, FT-Raman. UV-vis spectra were recorded within different solvents, to illustrate electronic transitions and molecular charge transfer within complex 1. The coordination sphere of complex 1 is a distorted octahedron according to single crystal X-ray results. Moreover, DFT (density functional theory) calculations with HSEH1PBE/6-311 G(d,p) level were carried out to back up the experimental results, and form base for future work in advanced level. Hyperconjugative interactions, intramolecular charge transfer (ICT), molecular stability and bond strength were researched by the using natural bond orbital (NBO) analysis. X-ray and NBO analysis results demonsrate that O-H···O hydrogen bonds between the water molecules and carboxylate oxygen atoms form a 2D supramolecular network, and also adjacent 2D networks connected by C-H···π and π···π interactions to form a 3D supramolecular network. Additionally, the second- and third-order nonlinear optical parameters of complex 1 were computed at DFT/HSEH1PBE/6-311 G(d,p) level. The refractive index (n) was calculated by using the Lorentz-Lorenz equation in order to investigate polarization behavior of complex 1 in different solvent polarities. The first-order static hyperpolarizability (β) value is found to be lower than pNA value because of the inversion symmetry around Co (II). But the second-order static hyperpolarizability (γ) value is 2.45 times greater than pNA value (15×10-30 esu). According to these results, Co(II) complex can be considered as a candidate to NLO material. Lastly molecular electrostatic potential (MEP), frontier molecular orbital energies and related molecular parameters for complex 1 were evaluated.
NASA Astrophysics Data System (ADS)
Orczyk, M. E.; Samoc, M.; Swiatkiewicz, J.; Manickam, N.; Tomoaia-Cotisel, M.; Prasad, P. N.
1992-06-01
It is shown that ultrafast optically stimulated birefringence and dichroism may be conveniently investigated by combining polarization sensitive optically heterodyned detection with phase tune-up between the optical Kerr gate signal and the local oscillator. The real and the imaginary parts of complex third-order optical nonlinearity can be effectively separated and their values and signs determined. 60 fs pulses at 620 nm were used in experiments carried on tetrahydrofuran solutions of canthaxanthin, a carotenoid important for photobiology. The values of both parts of the complex second hyperpolarizability gamma as well as the sign of its real part determined by this method compare well with that obtained from the concentration dependence method employing the homodyne-detection optical Kerr gate technique.
NASA Astrophysics Data System (ADS)
Williams, G. R. J.
1996-07-01
Excited-State Absorption (ESA), Two-Photon Absorption (TPA) and the third-order polarizability γ(ω;ω,ω, - ω) have been investigated for a model dichloride derivative of a symmetrically substituted benzylidene analine (SBAC), using a multielectron configuration-interaction procedure. The calculations indicate that SBAC exhibits ESA across the visible region of the spectrum, but that it is not as extensive as for molecules such as the phthalocyanines. The magnitude of the third-order polarizability is dominated by resonance enhancement from a very strong A g → B u one-photon absorption. The calculated off-resonance value for γ(ω;ω,ω, - ω) suggests that SBAC is a potential candidate for ultrafast switching applications.
NASA Astrophysics Data System (ADS)
Siji Narendran, N. K.; Soman, Rahul; Arunkumar, Chellaiah; Chandrasekharan, K.
2015-02-01
We report here the experimental investigation on third-order nonlinear optical parameters of 5,10,15,20-tetrakis(2,3,5,6-tetrafluoro-N,N-dimethyl-4-anilinyl)porphyrin and its various metal complexes, using Z-scan technique at 532 nm. The third-order nonlinear optical susceptibilities (χ(3)) were of the order 10-12 esu and are compared through degenerate four wave mixing (DFWM). The operating mechanism is reverse saturable absorption (RSA) as the effective excited-state absorption cross-section was found higher than ground state absorption cross-section as well as the magnitude of nonlinear absorption coefficient was found decreasing with on-axis input intensity. The compounds found to exhibit good optical limiting at 532 nm, 7 ns excitation steering applications in laser safety.
Third Order Distortion And Spectacle Lens Design
NASA Astrophysics Data System (ADS)
Atchison, David A.
1986-05-01
Third order (primary) aberration theory has had little application to the design of aspheric spectacle lenses. Such an application would be useful because: 1. Third order theory is useful in designing simple optical systems, as relatively simple equations can be used to obtain approximate magnitudes of aberrations and to show how these aberrations change with variations in design parameters without recourse to a large mass of data. 2. Aspherising one or both surfaces of spectacle lenses allows the correction of off-axis power errors in high positive power lenses where this would be otherwise impossible, and enables other factors, such as distortion correction, to be considered simultaneously with off-axis power error correction over the total range of lens powers. Third order formulae are developed for calculation of distortion in thin spectacle lenses, when one or both surfaces are conicoid aspherics. Results are presented which show the validity of using third order theory. Solutions which allow correction of rotatory or peripheral distortion, when one lens surface is a conicoid aspheric, are illustrated. A study of these solutions shows that one of the off-axis power errors (eg. oblique astigmatism) and one of the distortions can be simultaneously eliminated, but the lens forms required are too curved to be cosmetically feasible.
NASA Astrophysics Data System (ADS)
Patil, P. S.; Maidur, Shivaraj R.; Rao, S. Venugopal; Dharmaprakash, S. M.
2016-07-01
Transparent good quality single crystals of organic nonlinear optical material, 3, 4-Dimethoxy -4‧-methoxychalcone (DMMC) were grown by slow evaporation solution growth technique in acetone at ambient temperature. The lattice parameters were estimated from powder X-ray diffraction. The crystalline perfection has been evaluated by high resolution X-ray diffractometry (HRXRD). The UV-vis-NIR absorption spectrum reveals that the crystal is transparent between 440 nm and 900 nm for optical applications. The fluorescence spectrum shows a peak at about 482 nm and indicates that the crystal has a blue fluorescence emission. The third order nonlinear optical properties of solution of DMMC in N, N-Dimethylformamide (DMF) solvent has been investigated using Z-scan technique with femtosecond (fs) Ti:sapphire laser pulses at 800 nm wavelength. The calculated values of nonlinear refractive index, nonlinear absorption coefficient, and the magnitude of third-order susceptibility are of the order of - 7.7×10-14cm2/W, 1.7×10-9 cm/W and 6.7×10-12 e.s.u. respectively. The two photon absorption (2PA) cross section and molecular second-order hyperpolarizability values obtained is of the order of 10-49 cm4 s/photon/molecule and 2.8×10-31 e.s.u. respectively. The crystal shows optical-limiting (OL) effects for femtosecond laser pulses at 800 nm. The results suggest that the nonlinear properties investigated for DMMC are comparable with some of the reported chalcone derivatives and can be desirable for nonlinear optical applications.
Ju, Seongmin; Watekar, Pramod R; Jeong, Seongmook; Kim, Youngwoong; Han, Won-Taek
2012-01-01
Cu/Zn-codoped germano-silicate optical glass fiber was manufactured by using the modified chemical vapor deposition (MCVD) process and solution doping process. To investigate the reduction effect of Zn addition on Cu metal formation in the core of the Cu/Zn-codoped germano-silicate optical glass fiber, the optical absorption property and the non-resonant third-order optical nonlinearity were measured. Absorption peaks at 435 nm and 469 nm in the Cu/Zn-codoped germano-silicate optical glass fiber were contributed to Cu metal particles and ZnO semiconductor particles, respectively. The effective non-resonant optical nonlinearity, gamma, of the Cu/Zn-codoped germano-silicate optical glass fiber was measured to be 1.5097 W(-1) x km(-1) by using the continuous-wave self-phase modulation method. The gamma of the Cu/Zn-codoped germano-silicate optical glass fiber was about four times larger than that of the reference germano-silicate optical glass fiber without any dopants. The increase of the effective non-resonant optical nonlinearity, gamma, of the Cu/Zn-codoped germano-silicate optical glass fiber, can be attributed to the enhanced nonlinear polarization due to incorporated ZnO semiconductor particles and Cu metal ions in the glass network. The Cu/Zn-codoped germano-silicate optical glass fiber showed high nonlinearity and low transmission loss at the optical communication wavelength, which makes it suitable for high-speed-high-capacity optical communication systems. PMID:22524031
NASA Astrophysics Data System (ADS)
Zhou, Tao-Yu; Song, Ying-Lin; Hong, Jian-Ming; Xin, Xin-Quan
2005-04-01
The room-temperature solid-state reactions occurring in the preparation of nanotubes of zinc sulfide are further investigated by x-ray powder diffractometry (XRD) and infra-red (IR) spectrometry measurements, and the nanotube ZnS product obtained is measured by Z-scan technology to investigate the third-order nonlinear optical (NLO) properties. The XRD result suggests that the reactions leading to the formation of the nanotubules have occurred through reaction-controlled to growth-controlled procedures, and the IR result indicates that the procedures involve a coordination effect of the additive DABCO as ligand on the reactant. The result of NLO measurements shows that the nanotube ZnS products obtained have the behaviours of the third-order nonlinear optical properties of both NLO absorption and NLO refraction with self-focusing effects.
NASA Astrophysics Data System (ADS)
Fu, Gang; Yoda, Takefumi; Kasatani, Kazuo; Okamoto, Hiroaki; Takenaka, Shunsuke
2005-06-01
Third-order optical nonlinearities of several polymer films doped with naphthalocyanine derivatives have been measured under resonant conditions by femtosecond degenerate four-wave mixing (DFWM). The metal substitution and the peripheral groups influence both the magnitude and the response of the third-order optical nonlinearities. Temporal profiles of the DFWM signal were measured with a time resolution of 0.3 ps and were found to consist of at least two components, the coherent instantaneous nonlinear response and the slow response. The latter for the films decayed much faster than that for the solutions due to effects of aggregation or intermolecular interactions. The electronic component of the effective third-order nonlinear optical suscepitibilities, χe(3), of the polymer films was evaluated and a film of poly(methyl methacrylate) doped with 20 wt% octabutoxy-substituted zinc 2,3-naphthalocyanine showed the largest χe(3) value of 8.9× 10-9 esu. The results were compared with those in the literature.
NASA Astrophysics Data System (ADS)
Silambarasan, A.; Krishna Kumar, M.; Thirunavukkarasu, A.; Md Zahid, I.; Mohan Kumar, R.; Umarani, P. R.
2015-05-01
Organic Uronium 3-carboxy-4-hydroxybenzenesulfonate (UCHBS) nonlinear optical single crystal was grown by solution growth technique. The solubility and nucleation studies were performed for UCHBS at different temperatures 30, 35, 40, 45, 50 and 55 °C. The crystal structure of UCHBS was elucidated from single crystal X-ray diffraction study. High resolution X-ray diffraction technique was employed to study the perfection and internal defects of UCHBS crystal. Infrared and Raman spectra were recorded to analyze the vibrational behavior of chemical bonds and its functional groups. The physico-chemical changes, stability and decomposition stages of the UCHBS compound were established by TG-DTA studies. The dielectric phenomenon of UCHBS crystal was studied at different temperatures with respect to frequency. Linear optical properties of transmittance, cut-off wavelength, band gap of UCHBS were found from UV-visible spectral studies. Third-order nonlinear optical susceptibility, nonlinear refractive index, nonlinear optical absorption coefficient values were measured by Z-scan technique. The mechanical properties of UCHBS crystal was studied by using Vicker's microhardness test. The growth features of UCHBS crystal were analyzed from etching studies.
Tian, Si-Cong Tong, Cun-Zhu Zhang, Jin-Long; Shan, Xiao-Nan; Fu, Xi-Hong; Zeng, Yu-Gang; Qin, Li; Ning, Yong-Qiang; Wan, Ren-Gang
2015-06-15
The optical bistability of a triangular quantum dot molecules embedded inside a unidirectional ring cavity is studied. The type, the threshold and the hysteresis loop of the optical bistability curves can be modified by the tunneling parameters, as well as the probe laser field. The linear and nonlinear susceptibilities of the medium are also studied to interpret the corresponding results. The physical interpretation is that the tunneling can induce the quantum interference, which modifies the linear and the nonlinear response of the medium. As a consequence, the characteristics of the optical bistability are changed. The scheme proposed here can be utilized for optimizing and controlling the optical switching process.
NASA Astrophysics Data System (ADS)
Sivanandan, T.; Kalainathan, S.
2015-04-01
The third order nonlinear optical properties of Monothiourea-cadmium Sulphate Dihydrate crystal were measured using a He-Ne laser (λ=632.8 nm) by a Z-scan technique. The magnitude of nonlinear refractive index (n2) and nonlinear absorption coefficient was found to be 4.4769×10-11 m2/W and 1.233×10-2 m/W respectively. The third order non-linear optical susceptibility χ(3) was found to be in the order of 3.6533×10-2 esu. The negative sign of non-linear refractive index shows the self-defocusing nature of the gel grown crystal. The second-order molecular hyperpolarizability γ of the grown crystal is 1.2822×10-33 esu. Laser damage threshold was measured by using an Nd: YAG laser (1064 nm). Photoconductivity studies of the gel grown crystal revealed that the crystal possesses positive photoconducting nature. The results obtained from Z-scan, laser damage threshold and photoconducting studies reveal that the crystal can be a possible candidate material for photonics device, optical switches, and optical power limiting application.
NASA Astrophysics Data System (ADS)
Saha, Surajit; Pal, Suvajit; Ganguly, Jayanta; Ghosh, Manas
2016-03-01
We inspect the influence of position-dependent effective mass (PDEM) on the third-order nonlinear optical susceptibility (TONOS) of impurity doped quantum dots (QDs) in the presence and absence of noise. The TONOS profiles have been followed as a function of incident photon energy for different values of PDEM. Using PDEM the said profile considerably deviates from that of fixed effective mass (FEM). However, a switch from one mode of application of noise to another primarily alters the TONOS peak intensity. The observations highlight the possibility of tuning the TONOS profiles of doped QD systems exploiting noise and PDEM.
NASA Astrophysics Data System (ADS)
Dehghani, Z.; Saievar Iranizad, E.; Nadafan, M.
2015-01-01
Third order nonlinearity of Fe3O4 nanoparticles (NPs) doped in nematic liquid crystals (NLCs) was evaluated due to laser induced self-phase modulation. The influence of electric field on the nonlinear optical responses of the NLCs doped with Fe3O4 NPs was considered in different voltages. The measurements were performed for two commonly initial alignments (homogeneous and homeotropic) with different small compositional percentages of magnetic NPs. The experimental results show that the homogenous- aligned cell was considerably affected on the applied electric field while the nonlinearity of homeotropic-aligned NLCs with the Fe3O4 NPs did not approximately change in the presence of electric field.
NASA Astrophysics Data System (ADS)
Jayakrishnan, K.; Joseph, Antony; Mathew, K. Paulson; Siji, T. B.; Chandrasekharan, K.; Narendran, N. K. Siji; Jaseela, M. A.; Muraleedharan, K.
2016-08-01
The third order nonlinear optical features of certain novel thiocoumarin derivatives have been studied. Single beam Z-scan study on these compounds reveals that the compounds exhibit self defocusing effect upon irradiation with 532 nm, 7 ns pulses of Nd:YAG laser. Nonlinear absorption coefficient, nonlinear refractive index and second-order molecular hyperpolarizability values were estimated. The optical power limiting properties of the compounds are found to be attributable to both two-photon and excited state absorption. Some of the samples show nonlinear absorption coefficient (βeff) as high as 24.5 cm/GW. UV-Visible and photoluminescence outputs of these compounds reveal remarkable absorptive and emissive properties. This article also reports extraordinary growth of third order optical nonlinearity in pure coumarin upon certain donor substitutions in lieu of hydrogen. Degenerate Four Wave Mixing (DFWM) signals of the compounds were analyzed to verify the Z-scan results. Electrostatic Surface Potential (ESP) mapping and structure optimization techniques have been employed to interpret the structure-property relationship of each molecule.
Teran, Natasha B; He, Guang S; Baev, Alexander; Shi, Yanrong; Swihart, Mark T; Prasad, Paras N; Marks, Tobin J; Reynolds, John R
2016-06-01
Exploiting synergistic cooperation between multiple sources of optical nonlinearity, we report the design, synthesis, and nonlinear optical properties of a series of electron-rich thiophene-containing donor-acceptor chromophores with condensed π-systems and sterically regulated inter-aryl twist angles. These structures couple two key mechanisms underlying optical nonlinearity, namely, (i) intramolecular charge transfer, greatly enhanced by increased electron density and reduced aromaticity at chromophore thiophene rings and (ii) a twisted chromophore geometry, producing a manifold of close-lying excited states and dipole moment changes between ground and excited states that are nearly twice that of untwisted systems. Spectroscopic, electrochemical, and nonlinear Z-scan measurements, combined with quantum chemical calculations, illuminate relationships between molecular structure and mechanisms of enhancement of the nonlinear refractive index. Experiment and calculations together reveal ground-state structures that are strongly responsive to the solvent polarity, leading to substantial negative solvatochromism (Δλ ≈ 10(2) nm) and prevailing zwitterionic/aromatic structures in the solid state and in polar solvents. Ground-to-excited-state energy gaps below 2.0 eV are obtained in condensed π-systems, with lower energy gaps for twisted versus untwisted systems. The real part of the second hyperpolarizability in the twisted structures is much greater than the imaginary part, with the highest twist angle chromophore giving |Re(γ)/Im(γ)| ≈ 100, making such chromophores very promising for all-optical-switching applications. PMID:27232098
Han, Xiuyou; Chen, Xiang; Yao, Jianping
2016-06-27
A microwave photonic link (MPL) with simultaneous suppression of the even-order and third-order distortions using a polarization modulator (PolM), an optical bandpass filter (OBPF), and a balanced photodetector (BPD) is proposed and experimentally demonstrated. The even-order distortions are suppressed by utilizing orthogonal polarization modulation based on the PolM and balanced differential detection based on the BPD. The third-order distortions (IMD3) are suppressed by optimizing the spectral response of the OBPF with an optimal power ratio between the optical carrier and the sidebands of the phase-modulated signals from the PolM. Since the suppression of the IMD3 is achieved when the MPL is optimized for even-order distortion suppression, the proposed MPL can operate with simultaneous suppression of the even-order and third-order distortions. The proposed MPL is analyzed theoretically and is verified by an experiment. For a two-tone RF signal of f_{1} = 10 GHz and f_{2} = 19.95 GHz, the spurious-free dynamic range (SFDR2) is enhanced by 23.4 dB for the second harmonic (2f_{1}), and 29.1 and 27.6 dB for the second intermodulation (f_{2}-f_{1} and f_{1} + f_{2}), as compared with a conventional MPL. For a two-tone RF signal of f_{1} = 9.95 GHz and f_{2} = 10 GHz, the SFDR3 is increased by 13.1 dB as compared with a conventional MPL. PMID:27410633
Miller, Steven; Luke, Kevin; Okawachi, Yoshitomo; Cardenas, Jaime; Gaeta, Alexander L; Lipson, Michal
2014-11-01
Microresonator-based frequency comb generation at or near visible wavelengths would enable applications in precise optical clocks, frequency metrology, and biomedical imaging. Comb generation in the visible has been limited by strong material dispersion and loss at short wavelengths, and only very narrowband comb generation has reached below 800 nm. We use the second-order optical nonlinearity in an integrated high-Q silicon nitride ring resonator cavity to convert a near-infrared frequency comb into the visible range. We simultaneously demonstrate parametric frequency comb generation in the near-infrared, second-harmonic generation, and sum-frequency generation. We measure 17 comb lines converted to visible wavelengths extending to 765 nm. PMID:25401803
NASA Astrophysics Data System (ADS)
Kong, Ming; Liu, Yanqiu; Wang, Hui; Luo, Junshan; Li, Dandan; Zhang, Shengyi; Li, Shengli; Wu, Jieying; Tian, Yupeng
2015-01-01
Four novel Zn(II) terpyridine complexes (ZnLCl2, ZnLBr2, ZnLI2, ZnL(SCN)2) based on carbazole derivative group were designed, synthesized and fully characterized. Their photophysical properties including absorption and one-photon excited fluorescence, two-photon absorption (TPA) and optical power limiting (OPL) were further investigated systematically and interpreted on the basis of theoretical calculations (TD-DFT). The influences of different solvents on the absorption and One-Photon Excited Fluorescence (OPEF) spectral behavior, quantum yields and the lifetime of the chromophores have been investigated in detail. The third-order nonlinear optical (NLO) properties were investigated by open/closed aperture Z-scan measurements using femtosecond pulse laser in the range from 680 to 1080 nm. These results revealed that ZnLCl2 and ZnLBr2 exhibited strong two-photon absorption and ZnLCl2 showed superior optical power limiting property.
Zhang, Xiaoyan; Zhang, Saifeng; Chang, Chunxia; Feng, Yanyan; Li, Yuanxin; Dong, Ningning; Wang, Kangpeng; Zhang, Long; Blau, Werner J; Wang, Jun
2015-02-21
Wafer-scale MoS2 neat films with controllable thicknesses were successfully fabricated by vacuum filtering liquid-exfoliated MoS2 dispersions. The obtained MoS2 filtered thin films were systematically characterized by UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, atomic force microscopy (AFM) and scanning electron microscopy (SEM). It was found that the fabricated scalable MoS2 films have a smooth surface and high optical homogeneity verified by AFM and a collimated 532 nm beam, respectively. We investigated the ultrafast nonlinear optical (NLO) properties of the filtered films by an open aperture Z-scan method using 515 and 1030 nm femtosecond laser pulses. Saturable absorption was observed at both 515 and 1030 nm with the figure of merit (FOM) values as ∼3.3 × 10(-12) esu cm and ∼3.4 × 10(-14) esu cm, respectively. The observation of ultrafast NLO performance of the MoS2 filtered films indicates that vacuum filtration is a feasible method for the fabrication of optical thin films, which can be expanded to fabricate other two-dimensional films from the corresponding dispersions. This easy film fabrication technology will greatly enlarge the application of graphene analogues including graphene in photonic devices, especially of MoS2 as a saturable absorber. PMID:25597818
NASA Astrophysics Data System (ADS)
Kasatani, Kazuo; Okamoto, Hiroaki; Takenaka, Shunsuke
2003-11-01
Third-order optical nonlinearities of sol-gel silica coating films containing metal porphyrin derivatives were measured under resonant conditions by the femtosecond degenerate four-wave mixing (DFWM) technique. Temporal profiles of the DFWM signal were measured with a time resolution of 0.3 ps, and were found to consist of two components, the coherent instantaneous nonlinear response and the delayed response with a decay time constant of several to several hundred ps. The latter can be attributed to population grating of an excited state, and contribution of slow component was very little for a zinc porphyrin derivative. The values of electronic component of the optical nonlinear susceptibility, χ(3) xxxx, for these films were ca. 2 x 10-10 esu.
NASA Astrophysics Data System (ADS)
Sivasubramani, V.; Pandian, Muthu Senthil; Ramasamy, P.
2016-05-01
2-amino-5-nitropyridinium nitrate (2A5NPN) is a semi-organic nonlinear optical crystal and optically good quality 2A5NPN single crystals were successfully grown by slow evaporation solution growth technique (SEST) at ambient temperature. The crystallographic structure of the grown crystal was determined by single crystal X-Ray diffraction analysis and it belongs to Monoclinic crystal system with centro symmetric crystalline nature. The crystallinity of the grown crystal was confirmed by powder X-ray diffraction analysis. The other physical properties of grown crystals are also characterized using TG-DTA, UV-Visible NIR, chemical etching, photoconductivity and Z-scan measurements. The Z-scan method reveals that the 2A5NPN crystal possesses multi photon absorption behaviour and the significantly higher third order susceptibility and it is a promising potential NLO material.
NASA Astrophysics Data System (ADS)
Htwe, Zin Maung; Zhang, Yun-Dong; Yao, Cheng-Bao; Li, Hui; Li, Han-Yang; Yuan, Ping
2016-02-01
We report the investigation of third order nonlinear optical properties of undoped zinc oxide and indium doped zinc oxide thin films using nanosecond (6 ns, 18 μJ at 532 nm) Z-scan technique. Undoped (ZnO) and indium doped zinc oxide (InZnO) thin films were synthesized on quart silica substrate by using radio frequency (RF) magnetron sputtering technique. The structural and characterization of deposited thin films were analyzed by X-ray diffraction (XRD). In XRD results show different behaviors as amorphous oxide semiconductor and polycrystalline oxide semiconductor for ZnO and InZnO thin films respectively. Elemental compositions of thin films were analyzed by energy dispersive spectrometer (EDS). Surface morphology of ZnO and InZnO films were measured by using scanning electron microscopy (SEM), which show uniform and regular surface with small grain size distribution. Linear optical transmission and reflection thin films were analyzed by UV-VIS spectrometer. The UV-VIS results reveal that the optical transmittances of deposited thin films were increased after doping indium. The third order nonlinear optical properties of ZnO and InZnO thin films were carried out using nanosecond (6 ns) laser Z-scan technique at 532 nm wavelength. In open aperture case, both ZnO and InZnO thin films are show reverse saturable absorption (RSA) behaviors. For close-aperture Z-scan, the transmittance curve of ZnO thin film occurs as valley-peak (positive nonlinear refraction) characteristic, which indicates self-focusing behavior.
NASA Astrophysics Data System (ADS)
Li, Haipeng; Xu, Hu; Shen, Xiaopeng; Han, Kui; Bi, Zetong; Xu, Runfeng
2016-06-01
We investigated the electronic properties and second hyperpolarizabilities of hydrogenated silicon nanoclusters (H-SiNCs) by using the density functional theory method. The effects of cluster size, external electric field and incident frequency on the second hyperpolarizability were also examined, respectively. We found that small H-SiNCs exhibit large second hyperpolarizability. With the increase of the number of silicon atoms in H-SiNCs, the frontier molecular orbital energy gap decreases, attributed to the enhancement of the second hyperpolarizability. Interestingly, we also found the electric-field-induced gigantic enhancement of the second hyperpolarizability for H-SiNCs due to the change of electron density distributions. In addition, our results demonstrate a significant dependence on the frequency of incident light.
Li, Haipeng; Xu, Hu; Shen, Xiaopeng; Han, Kui; Bi, Zetong; Xu, Runfeng
2016-01-01
We investigated the electronic properties and second hyperpolarizabilities of hydrogenated silicon nanoclusters (H-SiNCs) by using the density functional theory method. The effects of cluster size, external electric field and incident frequency on the second hyperpolarizability were also examined, respectively. We found that small H-SiNCs exhibit large second hyperpolarizability. With the increase of the number of silicon atoms in H-SiNCs, the frontier molecular orbital energy gap decreases, attributed to the enhancement of the second hyperpolarizability. Interestingly, we also found the electric-field-induced gigantic enhancement of the second hyperpolarizability for H-SiNCs due to the change of electron density distributions. In addition, our results demonstrate a significant dependence on the frequency of incident light. PMID:27305957
Li, Haipeng; Xu, Hu; Shen, Xiaopeng; Han, Kui; Bi, Zetong; Xu, Runfeng
2016-01-01
We investigated the electronic properties and second hyperpolarizabilities of hydrogenated silicon nanoclusters (H-SiNCs) by using the density functional theory method. The effects of cluster size, external electric field and incident frequency on the second hyperpolarizability were also examined, respectively. We found that small H-SiNCs exhibit large second hyperpolarizability. With the increase of the number of silicon atoms in H-SiNCs, the frontier molecular orbital energy gap decreases, attributed to the enhancement of the second hyperpolarizability. Interestingly, we also found the electric-field-induced gigantic enhancement of the second hyperpolarizability for H-SiNCs due to the change of electron density distributions. In addition, our results demonstrate a significant dependence on the frequency of incident light. PMID:27305957
Pei, Lang; Xiang, Weidong; Zhao, Xiuli; Liang, Xiaojuan; Yang, Xinyu; Liu, Haitao; Chen, Zhaoping; Xie, Cuiping; Ma, Xin; Zhang, Chenglong; Ma, Li; Zhao, Jialong
2014-11-15
Highlights: • We prepared Ag-doped sodium borosilicate monolithic glass. • The influence of temperature on the SPR absorption peak intensity was studied. • Nonlinear optical properties of the glass were investigated. • A mechanism for the formation of Ag quantum dots glass was proposed. - Abstract: We report the preparation of uniform spherical shape silver nanocrystals doped sodium borosilicate monolithic transparent glass by sol–gel method. The characterization of the resulting Ag nanocrystals was accomplished by using X-ray powder diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and energy dispersive X-ray spectrum. Surface plasma resonance absorption peaks of the silver nanocrystals glass at about 406 nm have been obtained from ultraviolet–visible absorption spectrometer and their intensity is changed with different heat treatment temperatures. We have investigated the nonlinear optical properties of silver quantum dots doped glass using Z-scan technique. Third-order nonlinear optical susceptibility χ{sup (3)} of the glass was estimated to be 1.01 × 10{sup −11} esu. In particular, a mechanism for the formation of Ag quantum dots glass is proposed. This work will significantly promote the obtained material applications in optical devices.
Chen, Yuxiang; Cao, Wei; Wang, Chiming; Qi, Dongdong; Wang, Kang; Jiang, Jianzhuang
2016-03-21
2(3),9(10),16(17),23(24)-Tetrakis(dibutylamino)phthalocyanine compounds M{Pc[N(C4H9)2]4} (1-5; M = 2H, Mg, Ni, Cu, Zn) were prepared and characterized by a range of spectroscopic methods in addition to elemental analysis. Electrochemical and electronic absorption spectroscopic studies revealed the more effective conjugation of the nitrogen lone pair of electrons in the dibutylamino side chains with the central phthalocyanine π system in M{Pc[N(C4H9)2]4} than in M{Pc[N(C4H9)2]8}, which, in turn, results in superior third-order nonlinear-optical (NLO) properties of H2{Pc[N(C4H9)2]4} (1) over H2{Pc[N(C4H9)2]8}, as revealed by the obviously larger effective imaginary third-order molecular hyperpolarizability (Im{χ((3))}) of 6.5 × 10(-11) esu for the former species than for the latter one with a value of 3.4 × 10(-11) esu. This is well rationalized on the basis of both structural and theoretical calculation results. The present result seems to represent the first effort toward directly connecting the peripheral functional substituents, electronic structures, and NLO functionality together for phthalocyanine molecular materials, which will be helpful for the development of functional phthalocyanine materials via molecular design and synthesis even through only tuning of the peripheral functional groups. PMID:26931202
NASA Astrophysics Data System (ADS)
Thirupugalmani, K.; Karthick, S.; Shanmugam, G.; Kannan, V.; Sridhar, B.; Nehru, K.; Brahadeeswaran, S.
2015-11-01
The title compound, 2-amino-4-picolinium-nitrophenolate-nitrophenol (2A4PNN), has been synthesized and optical quality single crystals of 2A4PNN were grown by solution growth technique. The crystal structure was solved by single crystal X-ray diffraction method. The 2A4PNN molecule was found to possess intermolecular herringbone structure and to crystallize in orthorhombic crystal system with a noncentrosymmetric space group of Pna21 (Point group mm2). The functional groups of 2A4PNN were confirmed through FT-IR and Raman vibrational spectroscopic studies and NMR spectrum was recorded to study its molecular structure. The UV-Vis and photoluminescence spectra were recorded to explore its optical transmittance and emission properties respectively. The SHG efficiency and phasematchability were investigated through Kurtz and Perry powder technique using sieved/graded powders derived from polycrystals of 2A4PNN. The laser damage threshold studies of 2A4PNN single crystal were performed on (1 0 0) plane using a pulsed Nd:YAG laser (1064 nm). The third-order optical properties of 2A4PNN single crystal were measured by Z-scan technique. In addition, the quantum chemical studies were performed on the isolated 2A4PNN molecule using density functional theory (DFT) calculations at the B3LYP/6-311++G (d, p) basis set.
NASA Astrophysics Data System (ADS)
Tamgadge, Y. S.; Pahurkar, V. G.; Talwatkar, S. S.; Sunatkari, A. L.; Muley, G. G.
2015-08-01
We report synthesis, linear and third-order nonlinear optical properties of Cd-doped CuO-PVA nanocomposite thin films. Cd-doped CuO nanoparticles (NPs) were obtained by chemical synthesis method, and spin coating technique was used to obtain thin films in polyvinyl alcohol matrix. X-ray diffraction (XRD) shows formation of crystalline CuO having monoclinic phase with average particle size of 10 nm. Ultraviolet-visible (UV-Vis) spectroscopy attests formation of NPs by witnessing strong blue shift in the excitonic absorption. Absorption wavelength of CuO NPs shifts from 365 to 342 nm for Cd doping of 1-5 wt%. Both XRD and UV-Vis data confirm decrease in particle size with increase in Cd-doping concentration. Thin films have been characterized by Z-scan technique under continuous-wave He-Ne laser, and enhanced values of nonlinear refractive index n 2 and nonlinear absorption coefficient β have been obtained. Enhancements in the nonlinear optical properties have been attributed to the thermal effect due to strong linear absorption coefficient combined with increased thermo-optic coefficient. Contributing mechanisms such as photoacoustic effect, surface states effect and dielectric effect due to dopant and thin film structure have been discussed.
Thukral, Kanika; Vijayan, N; Haranath, D; Jayaramakrishnan, V; Philip, J; Sreekanth, P; Bhagavannaryana, G
2015-12-01
Single crystal of l-Asparagine Monohydrate, an organic material has been successfully grown by slow evaporation solution growth technique at ambient condition. The lattice parameters and its strain of the grown crystal have been evaluated from powder X-ray diffraction and found that it belongs to orthorhombic crystal system. The polarizability has been measured by using the Clausius-Mossotti relation. The crystalline perfection of grown single crystal has been examined by high resolution X-ray diffraction and its imperfection in the diffraction plane was clearly visible by recording topographical image of the plane. From the high resolution XRD, it confirms that the crystal contained high crystalline perfection. The optical behavior was analyzed by photoluminescence and birefringence methods. In the photoluminescence, a broad peak has been observed at 475 nm which suggest that it emits blue light. The decay tendency of the material has also been observed by calculating decay constant. The optical homogeneity has been determined by the dispersion pattern of the material. The two photon absorption coefficient was further calculated by Z-scan, which gives the information about the third order non linear optical behavior of the material. The value of two-photon absorption coefficient is 4.25 × 10(-12)m/W. The thermal parameters like thermal effusivity, thermal diffusivity, specific heat and thermal conductivity was obtained by using photopyroelectric technique. The ferroelectric behavior of the grown specimen was analyzed from PE (polarization VS electric field) loop. The loop suggests that the material was a nearly equivalent to ideal capacitor. PMID:26148830
NASA Astrophysics Data System (ADS)
Janardhana, K.; Ravindrachary, V.; Rajesh Kumar, P. C.; Yogisha; Ismayil
2013-04-01
A chalcone, 1-(4-chloro phenyl)-3-(4-dimethylamino phenyl) prop-2-en-1-one, abbreviated as CDAC was synthesized by the Claisen-Schmidt condensation method and single crystals were grown by the slow evaporation technique at ambient temperature. The structural confirmation was done using 1H-NMR, FT-IR, powder XRD and single crystal XRD studies. The crystal crystallizes in the monoclinic space group P21/c with a=33.082(3) Å, b=14.4722(13) Å, c=6.0799(5) Å, α=90°, β=92.030(4)°, γ=90° and Z=8. The high temperature DSC shows a phase transition at temperature 141.53 °C that corresponds to the melting point of the crystal. This is confirmed in DTA study which shows an endothermic dip corresponding to this melting point. The optical studies were made with UV-visible and Z-scan techniques. The nonlinear absorption and nonlinear refraction coefficients of the sample were obtained by performing the Z-scan experimental measurements. The real and imaginary parts of third-order bulk susceptibility χ(3) were evaluated. The coefficient of nonlinear refraction (γ) of the compound is found to be negative as revealed by the signature of closed aperture data.
NASA Astrophysics Data System (ADS)
Li, Yong; Zhang, Zhaoxia; Cui, Xiaobing; Li, Teng; Li, Kechang
2010-05-01
Two-dimensional (2-D) metal-organic polymer [Zn 3(μ 2-4,4'-bipy) 2(μ 2-be) 2(be) 2(μ 2-N 3) 2] n1 (4,4'-bipy = 4,4'-bipyridine, be = benzoate, N 3- = azide anion) has been synthesized by low-hot reaction and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and UV-visible spectra. The 2-D structure is built from the linkage of secondary building units of trinuclear [Zn 3(μ 2-4,4'-bipy) 2(μ 2-be) 2(be) 2(μ 2-N 3) 2] clusters by a mixed connector of 4,4'-bipyridine, benzoate and azide. The third-order non-linear optical (NLO) properties of the 1 were also investigated with modulus of the hyperpolarizability ( γ) 8.51 × 10 -30 esu for 1 in a 3.17 × 10 -4 mol dm -3 DMF solution.
ERIC Educational Resources Information Center
Rijmen, Frank; Jeon, Minjeong; von Davier, Matthias; Rabe-Hesketh, Sophia
2014-01-01
Second-order item response theory models have been used for assessments consisting of several domains, such as content areas. We extend the second-order model to a third-order model for assessments that include subdomains nested in domains. Using a graphical model framework, it is shown how the model does not suffer from the curse of…
NASA Astrophysics Data System (ADS)
Pardo, A.; Camacho, J. J.; Poyato, J. M. L.; Fernandez-Alonso, J. I.
1986-03-01
Potential energy curves for the X 1Σ +state of 6LiH, 7LiH and 6LiD, 7LiD molecules have been calculated by the third-order RKR inversion procedure by including the Kaise correction. The results are in agreement with previously obtained curves by other authors using differents methods. As a check, the exact vibrational eigenfunctions, appropriate to these potentials, are obtained by direct numerical solutions of the radical Schrödinger equation.
Zhao, Huajian; Simpson, Peter V; Barlow, Adam; Moxey, Graeme J; Morshedi, Mahbod; Roy, Nivya; Philip, Reji; Zhang, Chi; Cifuentes, Marie P; Humphrey, Mark G
2015-08-10
The synthesis of fac-[Ir{N,C1′-(2,2′-NC5H4C6H3-5′-C≡C-1-C6H2-3,5-Et2-4-C≡CC6H4-4-C≡CH)}3] (10), which bears pendant ethynyl groups, and its reaction with [RuCl(dppe)2]PF6 to afford the heterobimetallic complex fac-[Ir{N,C1′-(2,2′-NC5H4C6H3-5′-C≡C-1-C6H2-3,5-Et2-4-C≡CC6H4-4-C≡C-trans-[RuCl(dppe)2])}3] (11) is described. Complex 10 is available from the two-step formation of iodo-functionalized fac-tris[2-(4-iodophenyl)pyridine]iridium(III) (6), followed by ligand-centered palladium-catalyzed coupling and desilylation reactions. Structural studies of tetrakis[2-(4-iodophenyl)pyridine-N,C1′](μ-dichloro)diiridium 5, 6, fac-[Ir{N,C1′-(2,2′-NC5H4C6H3-5′-C≡C-1-C6H2-3,5-Et2-4-C≡CH)}3] (8), and 10 confirm ligand-centered derivatization of the tris(2-phenylpyridine)iridium unit. Electrochemical studies reveal two (5) or one (6–10) Ir-centered oxidations for which the potential is sensitive to functionalization at the phenylpyridine groups but relatively insensitive to more remote derivatization. Compound 11 undergoes sequential Ru-centered and Ir-centered oxidation, with the potential of the latter significantly more positive than that of Ir(N,C′-NC5H4-2-C6H4-2)3. Ligand-centered π–π* transitions characteristic of the Ir(N,C′-NC5H4-2-C6H4-2)3 unit red-shift and gain in intensity following the iodo and alkynyl incorporation. Spectroelectrochemical studies of 6, 7, 9, and 11 reveal the appearance in each case of new low-energy LMCT bands following formal IrIII/IV oxidation preceded, in the case of 11, by the appearance of a low-energy LMCT band associated with the formal RuII/III oxidation process. Emission maxima of 6–10 reveal a red-shift upon alkynyl group introduction and arylalkynyl π-system lengthening; this process is quenched upon incorporation of the ligated ruthenium moiety on proceeding to 11. Third-order nonlinear optical studies of 11 were undertaken at the benchmark wavelengths of 800 nm (fs pulses) and 532
Liu, Runqiang; Zhao, Ning; Liu, Ping; An, Caixia; Lian, Zhaoxun
2016-05-01
π-Conjugated organic materials exhibit high and tunable nonlinear optical (NLO) properties, and fast response times. 4'-Phenyl-2,2':6',2''-terpyridine (PTP) is an important N-heterocyclic ligand involving π-conjugated systems, however, studies concerning the third-order NLO properties of terpyridine transition metal complexes are limited. The title binuclear terpyridine Co(II) complex, bis(μ-4,4'-oxydibenzoato)-κ(3)O,O':O'';κ(3)O'':O,O'-bis[(4'-phenyl-2,2':6',2''-terpyridine-κ(3)N,N',N'')cobalt(II)], [Co2(C14H8O5)2(C21H15N3)2], (1), has been synthesized under hydrothermal conditions. In the crystal structure, each Co(II) cation is surrounded by three N atoms of a PTP ligand and three O atoms, two from a bidentate and one from a symmetry-related monodentate 4,4'-oxydibenzoate (ODA(2-)) ligand, completing a distorted octahedral coordination geometry. Neighbouring [Co(PTP)](2+) units are bridged by ODA(2-) ligands to form a ring-like structure. The third-order nonlinear optical (NLO) properties of (1) and PTP were determined in thin films using the Z-scan technique. The title compound shows a strong third-order NLO saturable absorption (SA), while PTP exhibits a third-order NLO reverse saturable absorption (RSA). The absorptive coefficient β of (1) is -37.3 × 10(-7) m W(-1), which is larger than that (8.96 × 10(-7) m W(-1)) of PTP. The third-order NLO susceptibility χ((3)) values are calculated as 6.01 × 10(-8) e.s.u. for (1) and 1.44 × 10(-8) e.s.u. for PTP. PMID:27146576
NASA Astrophysics Data System (ADS)
Giraldo-Tobón, Eugenio; Ospina, Walter; Miranda-Pedraza, Guillermo L.; Mora-Ramos, Miguel E.
2015-07-01
The coefficients of the second-order nonlinear optical rectification and the generation of second and third harmonics, related to electron energy transitions in a two-dimensional elliptical quantum dot are calculated. The conduction band states are obtained using the finite element method to numerically solve the effective mass Schrödinger differential equation in the parabolic approximation, including the influence of an externally applied static electric field. It comes about that the geometry of the ellipse has a strong influence on the optical response, being the large eccentricity case the more favorable one. Furthermore, it is shown that the application of an electric field is of most importance for achieving well-resolved higher harmonics signals.
Grenier, P. ); Houde, D. ); Jandl, S. ); Boatner, L.A. )
1993-01-01
Determinations of the third-order optical susceptibility have been used to investigate the dynamical properties of the [ital A][sub 1](TO) soft-polariton mode in KTa[sub 0.93]Nb[sub 0.07]O[sub 3] as a function of temperature. Saturation of the soft-polariton frequency as [ital T][r arrow][ital T][sub [ital c
NASA Astrophysics Data System (ADS)
de la Garza-Rubí, R. M. A.; Güizado-Rodríguez, M.; Mayorga-Cruz, D.; Basurto-Pensado, M. A.; Guerrero-Álvarez, J. A.; Ramos-Ortiz, G.; Rodríguez, M.; Maldonado, J. L.
2015-08-01
A copolymer of 3-hexylthiophene and thiophene functionalized with disperse red 1, poly(3-HT-co-TDR1), was synthesized. Chemical structure, molecular weight distribution, optical and thermal properties of this copolymer were characterized by NMR, FT-IR, UV-vis, GPC and DSC-TGA. An optical nonlinear analysis by Z-scan method was also performed for both continuous wave (CW) and pulsed laser pumping. In the CW regime the nonlinearities were evaluated in solid films, and a negative nonlinear refractive index in the range 2.7-4.1 × 10-4 cm2/W was obtained. These values are notoriously high and allowed to observe self-defocusing effects at very low laser intensities: below 1 mW. Further, nonlinear self-phase modulation patterns, during laser irradiation, were also observed. In the pulsed excitation the nonlinear response was evaluated in solution resulting in large two-photon absorption cross section of 5725 GM for the whole copolymer chain and with a value of 232 GM per repeated monomeric unit.
NASA Astrophysics Data System (ADS)
Elavarasu, N.; Karuppusamy, S.; Muralidharan, S.; Anantharaja, M.; Gopalakrishnan, R.
2015-08-01
The results of electro-optical modulator and third order nonlinearity of an organic single crystal of Imidazolium L-tartrate (IMLT) <0 1 0> grown by unidirectional growth method of Sankaranarayanan-Ramasamy (SR) are discussed for the first time in literature. The grown IMLT seed crystals were characterized by single crystal XRD and the lattice parameters were confirmed. The UV-Visible transmittance analysis shows that SR method grown IMLT single crystal possesses good transmittance in the entire visible region with a low cut-off wavelength at 240 nm. The mechanical study on the (0 1 0) plane of the IMLT single crystal analyzed by Vickers microhardness tester reveals the moderate hardness of the material. Photoconductivity studies on pure IMLT single crystal enumerated the positive photoconducting nature. Refractive index of the IMLT single crystal was determined by Brewster angle method. Second Harmonic Generation (SHG) efficiency of IMLT is 4.3 times greater than the standard Potassium Dihydrogen Phosphate (KDP) crystal. Nonlinear refractive index (n2), nonlinear absorption coefficient (β) and third-order nonlinear optical susceptibility χ(3) were evaluated using Z-scan method. The half wave voltage and electro-optical coefficient of IMLT crystal were determined using polarimetric technique. The electro-optical coefficient (r12) of IMLT is found to be greater than that of KDP crystal which represents the suitability of IMLT crystal to design the electro-optical modulator with low half wave voltage for nonlinear optical applications.
Bharath, D; Kalainathan, S
2014-01-01
A new polyene like organic molecule (E)-2-{3-[2-(4-chlorophenyl) vinyl]-5,5-dimethylcyclo-hex-2-en-1-ylidene}malononitrile (Cl1) was synthesized by knoevenagel condensation method. The Cl1 Single crystals were successfully grown by the slow evaporation method at a constant temperature 35°C. Single crystal XRD confirms the Cl1 molecule belongs to monoclinic crystal system and space group P21/C with a=10.114, b=11.127, c=14.929 and V=1668.9 and Z=4. The grown Cl1 crystals were subjected to FTIR and 13C NMR studies to confirm the synthesized compound. The linear optical property of Cl1 crystal has been studied using UV-Vis-NIR spectroscopy in the wavelength range 190 nm-1100 nm. The thermal properties of Cl1 crystal were studied by using TG and DTA analysis. The refractive index of Cl1 crystal has measured using Abbe's refractometer and found to be 1.648. The third order nonlinear optical property of Cl1 crystal has been investigated using Z-scan technique with HeNe laser. Photoluminescence (PL) spectrum of Cl1 crystal was carried out using xenon lamp, which shows high intense emission peak at wavelength 614 nm. Laser optical damage threshold (LDT) of Cl1 crystal has studied using Nd-YAG laser (10 Hz, 420 mJ, 1064 nm). PMID:24177866
Iliopoulos, K.; Kasprowicz, D.; Majchrowski, A.; Michalski, E.; Gindre, D.; Sahraoui, B.
2013-12-02
Bi{sub 2}ZnOB{sub 2}O{sub 6} nonlinear optical single crystals were grown by means of the Kyropoulos method from stoichiometric melt. The second and third harmonic generation (SHG/THG) of Bi{sub 2}ZnOB{sub 2}O{sub 6} crystals were investigated by the SHG/THG Maker fringes technique. Moreover, SHG microscopy studies were carried out providing two-dimensional SHG images as a function of the incident laser polarization. The high nonlinear optical efficiency combined with the possibility to grow high quality crystals make Bi{sub 2}ZnOB{sub 2}O{sub 6} an excellent candidate for photonic applications.
NASA Astrophysics Data System (ADS)
Chidan Kumar, C. S.; Raghavendra, S.; Chia, Tze Shyang; Chandraju, Siddegowda; Dharmaprakash, S. M.; Fun, Hoong-Kun; Quah, Ching Kheng
2015-11-01
A new third order centrosymmetric organic crystal: 1-(3,4-dimethoxyphenyl)-3-(2-fluorophenyl) prop-2-en-1-one (2FRDP) belonging to chalcone family has been synthesized and characterized by FTIR, CHNS and UV-Visible spectroscopy. Single crystal X-ray diffraction reveals that compound crystallizes in C2/c monoclinic space group. The X-ray powder diffraction of the crystal was carried out and hkl values are indexed for the diffraction pattern using mercury software. UV-Visible spectrum showed that 2FRDP is transparent in the entire visible region. The thermal stability of the grown 2FRDP crystal was analyzed by thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The dielectric study revealed that, 2FRDP possesses low dielectric constant and dielectric loss at high frequency. The third order nonlinear optical absorption and the optical limiting experiment were carried out using open aperture Z-scan data using an Nd:YAG laser operating at the wavelength 532 nm.
Achromatic phase matching at third orders of dispersion
Richman, Bruce
2003-10-21
Achromatic phase-matching (APM) is used for efficiently multiplying the frequency of broad bandwidth light by using a nonlinear optical medium comprising a second-harmonic generation (SHG) crystal and stationary optical elements whose configuration, properties, and arrangement have been optimized to match the angular dispersion characteristics of the SHG crystal to at least the third order. These elements include prisms and diffraction gratings for directing an input light beam onto the SHG crystal such that each ray wavelength is aligned to match the phase-matching angle for the crystal at each wavelength of light to at least the third order and such that every ray wavelength overlap within the crystal.
Photographic evidence for the third-order rainbow.
Grossmann, Michael; Schmidt, Elmar; Haussmann, Alexander
2011-10-01
The first likely photographic observation of the tertiary rainbow caused by sunlight in the open air is reported and analyzed. Whereas primary and secondary rainbows are rather common and easily seen phenomena in atmospheric optics, the tertiary rainbow appears in the sunward side of the sky and is thus largely masked by forward scattered light. Up to now, only a few visual reports and no reliable photographs of the tertiary rainbow are known. Evidence of a third-order rainbow has been obtained by using image processing techniques on a digital photograph that contains no obvious indication of such a rainbow. To rule out any misinterpretation of artifacts, we carefully calibrated the image in order to compare the observed bow's angular position and dispersion with those predicted by theory. PMID:22016237
NASA Astrophysics Data System (ADS)
Zhang, Jun; Dolg, Michael
2014-01-01
The third-order incremental dual-basis set zero-buffer approach was combined with CCSD(T)-F12x (x = a, b) theory to develop a new approach, i.e., the inc3-db-B0-CCSD(T)-F12 method, which can be applied as a black-box procedure to efficiently obtain the near complete basis set (CBS) limit of the CCSD(T) energies also for large systems. We tested this method for several cases of different chemical nature: four complexes taken from the standard benchmark sets S66 and X40, the energy difference between isomers of water hexamer and the rotation barrier of biphenyl. The results show that our method has an error relative to the best estimation of CBS energy of only 0.2 kcal/mol or less. By parallelization, our method can accomplish the CCSD(T)-F12 calculations of about 60 correlated electrons and 800 basis functions in only several days, which by standard implementation are impossible for ordinary hardware. We conclude that the inc3-db-B0-CCSD(T)-F12a/AVTZ method, which is of CCSD(T)/AV5Z quality, is close to the limit of accuracy that one can achieve for large systems currently.
Zhang, Jun Dolg, Michael
2014-01-28
The third-order incremental dual-basis set zero-buffer approach was combined with CCSD(T)-F12x (x = a, b) theory to develop a new approach, i.e., the inc3-db-B0-CCSD(T)-F12 method, which can be applied as a black-box procedure to efficiently obtain the near complete basis set (CBS) limit of the CCSD(T) energies also for large systems. We tested this method for several cases of different chemical nature: four complexes taken from the standard benchmark sets S66 and X40, the energy difference between isomers of water hexamer and the rotation barrier of biphenyl. The results show that our method has an error relative to the best estimation of CBS energy of only 0.2 kcal/mol or less. By parallelization, our method can accomplish the CCSD(T)-F12 calculations of about 60 correlated electrons and 800 basis functions in only several days, which by standard implementation are impossible for ordinary hardware. We conclude that the inc3-db-B0-CCSD(T)-F12a/AVTZ method, which is of CCSD(T)/AV5Z quality, is close to the limit of accuracy that one can achieve for large systems currently.
Transmission Measurement of the Third-Order Susceptibility of Gold
NASA Technical Reports Server (NTRS)
Smith, David D.; Yoon, Youngkwon; Boyd, Robert W.; Crooks, Richard M.; George, Michael
1999-01-01
Gold nanoparticle composites are known to display large optical nonlinearities. In order to assess the validity of generalized effective medium theories (EMT's) for describing the linear and nonlinear optical properties of metal nanoparticle composites, knowledge of the linear and nonlinear susceptibilities of the constituent materials is a prerequisite. In this study the inherent nonlinearity of the metal is measured directly (rather than deduced from a suitable EMT) using a very thin gold film. Specifically, we have used the z-scan technique at a wavelength near the transmission window of bulk gold to measure the third-order susceptibility of a continuous thin gold film deposited on a quartz substrate surface-modified with a self-assembled monolayer to promote adhesion and uniformity without affecting the optical properties. We compare our results with predictions which ascribe the nonlinear response to a Fermi-smearing mechanism. Further, we note that the sign of the nonlinear susceptibility is reversed from that of gold nanoparticle composites.
Filter for third order phase locked loops
NASA Technical Reports Server (NTRS)
Crow, R. B.; Tausworthe, R. C. (Inventor)
1973-01-01
Filters for third-order phase-locked loops are used in receivers to acquire and track carrier signals, particularly signals subject to high doppler-rate changes in frequency. A loop filter with an open-loop transfer function and set of loop constants, setting the damping factor equal to unity are provided.
NASA Astrophysics Data System (ADS)
Zhang, Zhao-Xia; Pan, Wei-Cheng; Hong, Peng-Zhi; Li, Ke-Chang; Li, Yong
2015-02-01
A novel two-dimensional (2-D) Cd(II) coordination network [Cd(AcO)2(L)2(H2O)] 1 (AcO = acetate, L = 4-(1,2,4-triazol-1-yl) benzoic acid ethyl ester) has been synthesized by low-temperature solid-state reaction and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and UV-visible spectra. The molecules of the complex are interconnected into layers by O-H⋯O and C-H⋯O hydrogen bonds in which participate AcO-, L and H2O ligands. The intermolecular hydrogen-bonds interactions are the most significant factors controlling the novel supramolecular sheet fashion packing of the title compound in the crystal state. The third-order non-linear optical (NLO) properties of the title compound 1 were also investigated and they exhibit the reverse saturable absorption and self-defocusing performance with modulus of the hyperpolarizability (γ) 2.30 × 10-30 esu for 1 in a 2.15 × 10-4 mol dm-3 DMF solution.
Novel third-order Lovelock wormhole solutions
NASA Astrophysics Data System (ADS)
Mehdizadeh, Mohammad Reza; Lobo, Francisco S. N.
2016-06-01
In this work, we consider wormhole geometries in third-order Lovelock gravity and investigate the possibility that these solutions satisfy the energy conditions. In this framework, by applying a specific equation of state, we obtain exact wormhole solutions, and by imposing suitable values for the parameters of the theory, we find that these geometries satisfy the weak energy condition in the vicinity of the throat, due to the presence of higher-order curvature terms. Finally, we trace out a numerical analysis, by assuming a specific redshift function, and find asymptotically flat solutions that satisfy the weak energy condition throughout the spacetime.
Third Order Elastic Coefficients of Rocks
NASA Astrophysics Data System (ADS)
Bandyopadhyay, K.
2006-12-01
We present a methodology to determine third order elastic (TOE) coefficients of rock from velocity measurements at different hydrostatic stress level. TOE coefficients help us to obtain a quantitative measure of the variation of velocity with stress. It is one of the most general ways to parameterize the stress sensitivity of rocks. We usually determine the isotropic TOE coefficients from measurements of all the independent stiffness elements under non-hydrostatic stress. However, for initially isotropic or weakly anisotropic rocks, most of the laboratory experiments are carried out under hydrostatic stress. In that case, the measurements of P- and S-wave velocities at different hydrostatic pressure alone are not enough to invert for the isotropic TOE parameters. In this underdetermined situation, more information about the rock microstructure causing the non-linearity is required to predict seismic velocities at any arbitrary stress state. Our workflow is based on the model of Mavko et al. (1995) to compute stress-induced anisotropy. This model assumes that the cause of elastic nonlinearity is the presence of compliant crack-like pore. The pressure dependence of generalized compliances is mainly governed by normal tractions resolved across cracks. This assumption allows one to map the pressure dependence from hydrostatic stress to any state of stress. Applying the model of Mavko et al. (1995), we obtain the full stiffness tensor at different non-hydrostatic stress levels from the usual Vp and Vs measurements. Changes in elastic stiffness elements from a reference state of stress are then used to invert for the TOE coefficients, C111, C112 and C123 using the third order stress- strain relations. This method allows us to compute the TOE elements using hydrostatic measurements of an initially isotropic rock. We show an application of the workflow with laboratory measurements of P- and S-wave velocities under varying hydrostatic stress. This enables us to express
Correcting variable third-order astigmatism introduced by conformal aspheric surfaces
NASA Astrophysics Data System (ADS)
Whalen, Michael R.
1998-09-01
Conformal dome surfaces may enhance the overall performance of missile systems employing optical sensors by providing a more aerodynamically shaped airframe, however realistic implementation of these highly aspheric surfaces is currently limited by the severe image aberrations they introduce to the transmitted wavefront. This paper proposes an optical correction technique designed to combat the large magnitude and varying nature of third order astigmatism introduced by conformal missile domes. The newly developed technique utilizes axial translation of crossed cylindrical elements to provide variable astigmatism correction as a function of sensor gimbal angle. Theoretical motivation for the optical correction technique is provided, and its performance is assessed in a sample conformal dome and optical sensor systems.
Suppression of third-order intermodulation in a klystron by third-order injection.
Bhattacharjee, S; Marchewka, C; Welter, J; Kowalczyk, R; Wilsen, C B; Lau, Y Y; Booske, J H; Singh, A; Scharer, J E; Gilgenbach, R M; Neumann, M J; Keyser, M W
2003-03-01
The first observations and measurements are reported on suppression of the third-order intermodulation (IM3) product arising from nonlinear mixing of two drive frequencies in a klystron, by externally injecting a wave at the IM3 product frequency. Optimum amplitude and phase of the injected wave for maximum suppression are examined. Results indicate that suppression of the IM3 product by as much as 30 dB can be achieved. Experimental results compare favorably with predictions of a 1D simulation code that takes into account all kinematical and dynamical effects including charge overtaking and space charge forces. PMID:12689260
Thermodynamic instability of black holes of third order Lovelock gravity
Dehghani, M. H.; Pourhasan, R.
2009-03-15
In this paper, we compute the mass and the temperature of the uncharged black holes of third order Lovelock gravity as well as the entropy using the first law of thermodynamics. We perform a stability analysis by studying the curves of the temperature versus the mass parameter, and find that an intermediate thermodynamically unstable phase exists for black holes with a hyperbolic horizon. This unstable phase for the uncharged topological black holes of third order Lovelock gravity does not exist in lower order Lovelock gravity. We also perform a stability analysis for a spherical, seven-dimensional black hole of Lovelock gravity and find that, while these kinds of black holes for small values of Lovelock coefficients have an intermediate unstable phase, they are stable for large values of Lovelock coefficients. We also find that an intermediate unstable phase exists for these black holes in higher dimensions. This analysis shows that the thermodynamic stability of black holes with curved horizons is not a robust feature of all the generalized theories of gravity.
Ghost imaging with thermal light by third-order correlation
Bai Yanfeng; Han Shensheng
2007-10-15
Ghost imaging with classical incoherent light by third-order correlation is investigated. We discuss the similarities and the differences between ghost imaging by third-order correlation and by second-order correlation, and analyze the effect from each correlation part of the third-order correlation function on the imaging process. It is shown that the third-order correlated imaging includes richer correlated imaging effects than the second-order correlated one, while the imaging information originates mainly from the correlation of the intensity fluctuations between the test detector and each reference detector, as does ghost imaging by second-order correlation.
Third-order chromatic dispersion stabilizes Kerr frequency combs.
Parra-Rivas, Pedro; Gomila, Damià; Leo, François; Coen, Stéphane; Gelens, Lendert
2014-05-15
Using numerical simulations of an extended Lugiato-Lefever equation we analyze the stability and nonlinear dynamics of Kerr frequency combs generated in microresonators and fiber resonators, taking into account third-order dispersion effects. We show that cavity solitons underlying Kerr frequency combs, normally sensitive to oscillatory and chaotic instabilities, are stabilized in a wide range of parameter space by third-order dispersion. Moreover, we demonstrate how the snaking structure organizing compound states of multiple cavity solitons is qualitatively changed by third-order dispersion, promoting an increased stability of Kerr combs underlined by a single cavity soliton. PMID:24978250
Third order TRANSPORT with MAD (Methodical Accelerator Design) input
Carey, D.C.
1988-09-20
This paper describes computer-aided design codes for particle accelerators. Among the topics discussed are: input beam description; parameters and algebraic expressions; the physical elements; beam lines; operations; and third-order transfer matrix. (LSP)
A third order Runge-Kutta algorithm on a manifold
NASA Technical Reports Server (NTRS)
Crouch, P. E.; Grossman, R. G.; Yan, Y.
1992-01-01
A third order Runge-Kutta type algorithm is described with the property that it preserves certain geometric structures. In particular, if the algorithm is initialized on a Lie group, then the resulting iterates remain on the Lie group.
Effect of third-order dispersion on dark solitons
NASA Astrophysics Data System (ADS)
Afanasjev, Vsevolod V.; Kivshar, Yuri S.; Menyuk, Curtis R.
1996-12-01
Third-order dispersion has a detrimental effect on dark solitons, leading to resonant generation of growing soliton tails and soliton decay. This effect is shown to be much stronger than that for bright solitons.
Tailored hybrid hyperbranched polyglycidol-silica nanocomposites with high third-order nonlinearity
NASA Astrophysics Data System (ADS)
Postnova, Irina; Bezverbny, Alexander; Golik, Sergey; Kulchin, Yury; Li, Haiqing; Wang, Jing; Kim, Il; Ha, Chang-Sik; Shchipunov, Yury
2012-07-01
One of the most convenient techniques for optical material fabrication is the sol-gel processing. It can be performed at low temperature that enables one to entrap even relatively unstable organic substances into silica matrix at the nanometer scale, thus developing homogeneous hybrid organic-inorganic nanocomposite materials of various functionalities. Here, novel hybrid organic-inorganic nanocomposites with good optical transparency and high third-order nonlinearity were prepared biomimetically through the mineralization of dendritic macromolecules (hyperbranched polyglycidols) using a compatible ethylene glycol-containing silica precursor. The synthesis was performed at neutral pH media in aqueous solutions without addition of organic solvents at ambient conditions owing to the catalysis of processing. Polyglycidols provided also the formation of gold nanoparticles localized in their core. They served as reducing and stabilizing agents. It is shown that trace amounts of nanoparticles could regulate nonlinear properties of a nanocomposite. High nonlinearity manifests itself in a supercontinuum generation at remarkably short lengths ca. 1 mm. The phenomenon consists of filamentous intense white lighting due to the spectral broadening of initial ultrashort (femtosecond) laser pulses propagating through the material. The developed hybrid nanocomposites possessing large nonlinearity, high-speed optical response, stability under intense lighting, low-cost, and easy preparation are promising for a diverse range of applications as active components for all-optical signal processing from chemical sensing to biological cell imaging and lighting control in telecommunication.
Third-order nonlinearity and passive Q-switching of Cr⁴⁺:YGG garnet crystal.
Wang, Shuxian; Zhang, Yuxia; Wu, Kui; Zhang, Rui; Yu, Haohai; Zhang, Huaijin; Zhang, Guanghui; Xiong, Qihua
2015-05-15
We demonstrate the third-order nonlinear optical properties of Cr(4+):Y(3)Ga(5)O(12) (Cr(4+):YGG) and Q-switched lasers with Cr(4+):YGG as the saturable absorber for the first time to our knowledge. The third-order nonlinear properties, including the optical Kerr nonlinearity and saturable absorption, were systematically measured and analyzed in detail by using a Z-scan technique. The measured data show that Cr(4+):YGG has a large nonlinear refractive index, ground-state absorption cross section, and excited-state absorption cross section in contrast to Cr(4+):Y(3)Al(5)O(12) (Cr(4+):YAG). With a Nd:YGG crystal as the gain medium and a Cr(4+):YGG crystal as the saturable absorber, the passively Q-switched laser was performed. The shortest pulse width and largest pulse energy were achieved at the absorbed pump power of 8 W with the values of 9.1 ns and 26.1 μJ, respectively, corresponding to the average output power of 0.87 W and peak power of 2.9 kW. The results indicate that Cr(4+):YGG is an available and promising optical switcher for pulsed lasers. PMID:26393755
Mark, J. Abraham Hudson Peter, A. John
2014-04-24
Third order susceptibility of third order harmonic generation is investigated in a Zn{sub 0.1}Mg{sub 0.9}Se/Zn{sub 0.8}Mg{sub 0.2}Se/Zn{sub 0.1}Mg{sub 0.9}Se quantum well in the presence of magnetic field strength. The confinement potential is considered as the addition of energy offsets of the conduction band (or valence band) and the strain-induced potential in our calculations. The material dependent effective mass is followed throughout the computation because it has a high influence on the electron energy levels in low dimensional semiconductor systems.
Constructing higher-order hydrodynamics: The third order
NASA Astrophysics Data System (ADS)
Grozdanov, Sašo; Kaplis, Nikolaos
2016-03-01
Hydrodynamics can be formulated as the gradient expansion of conserved currents in terms of the fundamental fields describing the near-equilibrium fluid flow. In the relativistic case, the Navier-Stokes equations follow from the conservation of the stress-energy tensor to first order in derivatives. In this paper, we go beyond the presently understood second-order hydrodynamics and discuss the systematization of obtaining the hydrodynamic expansion to an arbitrarily high order. As an example of the algorithm that we present, we fully classify the gradient expansion at third order for neutral fluids in four dimensions, thus finding the most general next-to-leading-order corrections to the relativistic Navier-Stokes equations in curved space-time. In doing so, we list 20 new transport coefficient candidates in the conformal case and 68 in the nonconformal case. As we do not consider any constraints that could potentially arise from the local entropy current analysis, this is the maximal possible set of neutral third-order transport coefficients. To investigate the physical implications of these new transport coefficients, we obtain the third-order corrections to the linear dispersion relations that describe the propagation of diffusion and sound waves in relativistic fluids. We also compute the corrections to the scalar (spin-2) two-point correlation function of the third-order stress-energy tensor. Furthermore, as an example of a nonlinear hydrodynamic flow, we calculate the third-order corrections to the energy density of a boost-invariant Bjorken flow. Finally, we apply our field theoretic results to the N =4 supersymmetric Yang-Mills fluid at infinite 't Hooft coupling and an infinite number of colors to find the values of five new linear combinations of the conformal transport coefficients.
Third-order solution of an artificial-satellite theory
NASA Technical Reports Server (NTRS)
Kinoshita, H.
1977-01-01
A third-order solution was developed for the motions of artificial satellites moving in the gravitational field of the earth, whose potential includes the second-, third-, and fourth-order zonal harmonics. Third-order periodic perturbations with fourth-order secular perturbations were derived by the Hori perturbation method. All quantities were expanded into power series of the eccentricity, but the solution was obtained so as to be closed with respect to the inclination. A comparison with the results of numerical integration of the equations of motion indicates that the solution can predict the position of a close-earth, small-eccentricity satellite with an accuracy of better than one cm over a period of one month.
Xu, Tiefeng; Chen, Feifei; Shen, Xiang; Dai, Shixun; Nie, Qiuhua; Wang, Xunsi
2010-10-15
Bi{sub 2}O{sub 3}-B{sub 2}O{sub 3}-SiO{sub 2} ternary glasses embedded with Ag nanoparticles were prepared by introducing AgCl into the bismuthate glasses using conventional melt quenching method and characterized by several experimental techniques. Scanning electron microscopic studies indicated the formation of Ag contained nanoclusters which crack and become regular with increase of AgCl content in these composites. Optical absorption spectra of the nanocomposites showed the presence of absorption band of surface plasmon resonance (SPR) due to Ag nanoparticles at {approx}600 nm. Z-scan measurement with femtosecond laser was used to investigate third-order optical nonlinearities of the nanocomposites. The results show that the nonlinear refraction {gamma} was dramatically increased up to 30 times by the appearance of Ag nanoparticles when excited within its SPR region, while nonlinear absorption due to two-photon absorption exhibited opposite tendency or even saturated behavior. The calculation of figure of merit suggests that the Ag particle embedded Bi{sub 2}O{sub 3}-B{sub 2}O{sub 3}-SiO{sub 2} glass composites are promising candidates for optoelectronic devices.
Third order equations of motion and the Ostrogradsky instability
NASA Astrophysics Data System (ADS)
Motohashi, Hayato; Suyama, Teruaki
2015-04-01
It is known that any nondegenerate Lagrangian containing time derivative terms higher than first order suffers from the Ostrogradsky instability, pathological excitation of positive and negative energy degrees of freedom. We show that, within the framework of analytical mechanics of point particles, any Lagrangian for third order equations of motion, which evades the nondegeneracy condition, still leads to the Ostrogradsky instability. Extension to the case of higher odd order equations of motion is also considered.
Mueller, Alexander; Fuerbach, Alexander
2016-03-20
The standard technique commonly utilized to introduce large amounts of negative group delay dispersion (GDD) into the beam path of ultrashort laser pulses with low insertion losses is the use of a pair of prisms in a double pass configuration. However, one disadvantage of this approach is the unavoidable introduction of additional high-order spectral phase errors, most notably third-order dispersion (TOD) due to the characteristics of the refractive index of available optical materials. In this paper we provide an overview of the dispersive properties of more than 100 common types of optical glasses, used either as a bulk stretcher or in a prism compressor configuration. In addition, we present a novel method that enables independent control of GDD and TOD in a prism-only setup. The performance of different prism combinations is analyzed numerically, and design guidelines are given. PMID:27140563
Third order nonlinearity in pulsed laser deposited LiNbO3 thin films
NASA Astrophysics Data System (ADS)
Tumuluri, Anil; Rapolu, Mounika; Rao, S. Venugopal; Raju, K. C. James
2016-05-01
Lithium niobate (LiNbO3) thin films were prepared using pulsed laser deposition technique. Structural properties of the same were examined from XRD and optical band gap of the thin films were measured from transmittance spectra recorded using UV-Visible spectrophotometer. Nonlinear optical properties of the thin films were recorded using Z-Scan technique. The films were exhibiting third order nonlinearity and their corresponding two photon absorption, nonlinear refractive index, real and imaginary part of nonlinear susceptibility were calculated from open aperture and closed aperture transmission curves. From these studies, it suggests that these films have potential applications in nonlinear optical devices.
Global attractors for a third order in time nonlinear dynamics
NASA Astrophysics Data System (ADS)
Caixeta, Arthur H.; Lasiecka, Irena; Cavalcanti, Valéria N. D.
2016-07-01
Long time behavior of a third order (in time) nonlinear PDE equation is considered. This type of equations arises in the context of nonlinear acoustics [12,20,22,24] where modeling accounts for a finite speed of propagation paradox, the latter results in hyperbolic nature of the dynamics. It will be proved that the underlying PDE generates a well-posed dynamical system which admits a global and finite dimensional attractor. The main difficulty associated with the problem studied is the lack of Lyapunov function along with the lack of compactness of trajectories, which fact prevents applicability of standard tools in the area of dynamical systems.
Multifield cosmological perturbations at third order and the ekpyrotic trispectrum
Lehners, Jean-Luc; Renaux-Petel, Sebastien
2009-09-15
Using the covariant formalism, we derive the equations of motion for adiabatic and entropy perturbations at third order in perturbation theory for cosmological models involving two scalar fields. We use these equations to calculate the trispectrum of ekpyrotic and cyclic models in which the density perturbations are generated via the entropic mechanism. In these models, the conversion of entropy into curvature perturbations occurs just before the big bang, either during the ekpyrotic phase or during the subsequent kinetic energy dominated phase. In both cases, we find that the nonlinearity parameters f{sub NL} and g{sub NL} combine to leave a very distinct observational imprint.
Is there a third order phase transition for supercritical fluids?
Zhu, Jinglong; Zhang, Pingwen; Wang, Han; Site, Luigi Delle
2014-01-01
We prove that according to Molecular Dynamics (MD) simulations of liquid mixtures of Lennard-Jones (L-J) particles, there is no third order phase transition in the supercritical regime beyond Andrew's critical point. This result is in open contrast with recent theoretical studies and experiments which instead suggest not only its existence but also its universality regarding the chemical nature of the fluid. We argue that our results are solid enough to go beyond the limitations of MD and the generic character of L-J models, thus suggesting a rather smooth liquid-vapor thermodynamic behavior of fluids in supercritical regime. PMID:24410228
Third-order nonlinearity of Er3+-doped lead phosphate glass
Santos, C. C.; Guedes Da Silva, Ilde; Siqueira, J. P.; Misoguti, L.; Zilio, S. C.; Boatner, Lynn A
2010-01-01
The third-order optical susceptibility and dispersion of the linear refractive index of Er3+-doped lead phosphate glass were measured in the wavelength range between 400 and 1940 nm by using the spectrally resolved femtosecond Maker fringes technique. The nonlinear refractive index obtained from the third-order susceptibility was found to be five times higher than that of silica, indicating that Er3+-doped lead phosphate glass is a potential candidate to be used as the base component for the fabrication of photonic devices. For comparison purposes, the Z-scan technique was also employed to obtain the values of the nonlinear refractive index of E-doped lead phosphate glass at several wavelengths, and the values obtained using the two techniques agree to within 15%.
Magnetic branes in third order Lovelock-Born-Infeld gravity
Dehghani, M. H.; Bostani, N.; Hendi, S. H.
2008-09-15
Considering both the nonlinear invariant terms constructed by the electromagnetic field and the Riemann tensor in gravity action, we obtain a new class of (n+1)-dimensional magnetic brane solutions in third order Lovelock-Born-Infeld gravity. This class of solutions yields a spacetime with a longitudinal nonlinear magnetic field generated by a static source. These solutions have no curvature singularity and no horizons but have a conic geometry with a deficit angle {delta}. We find that, as the Born-Infeld parameter decreases, which is a measure of the increase of the nonlinearity of the electromagnetic field, the deficit angle increases. We generalize this class of solutions to the case of spinning magnetic solutions and find that, when one or more rotation parameters are nonzero, the brane has a net electric charge which is proportional to the magnitude of the rotation parameters. Finally, we use the counterterm method in third order Lovelock gravity and compute the conserved quantities of these spacetimes. We found that the conserved quantities do not depend on the Born-Infeld parameter, which is evident from the fact that the effects of the nonlinearity of the electromagnetic fields on the boundary at infinity are wiped away. We also find that the properties of our solution, such as deficit angle, are independent of Lovelock coefficients.
Asymptotically flat radiating solutions in third order Lovelock gravity
Dehghani, M. H.; Farhangkhah, N.
2008-09-15
In this paper, we present an exact spherically symmetric solution of third order Lovelock gravity in n dimensions which describes the gravitational collapse of a null dust fluid. This solution is asymptotically (anti-)de Sitter or flat depending on the choice of the cosmological constant. Using the asymptotically flat solution for n{>=}7 with a power-law form of the mass as a function of the null coordinate, we present a model for a gravitational collapse in which a null dust fluid radially injects into an initially flat and empty region. It is found that a naked singularity is inevitably formed whose strength is different for the n=7 and n{>=}8 cases. In the n=7 case, the limiting focusing condition for the strength of curvature singularity is satisfied. But for n{>=}8, the strength of curvature singularity depends on the rate of increase of mass of the spacetime. These considerations show that the third order Lovelock term weakens the strength of the curvature singularity.
Bounding Quantum Contextuality with Lack of Third-Order Interference.
Henson, Joe
2015-06-01
Recently, many simple principles have been proposed that can explain quantum limitations on possible sets of experimental probabilities in nonlocality and contextuality experiments. However, few implications between these principles are known. Here it is shown that the lack of irreducible third-order interference (a generalization of the idea that no probabilistic interference remains unaccounted for once we have taken into account interference between pairs of slits in a n-sit experiment) implies the principle known as the E principle or consistent exclusivity (that, if each pair of a set of experimental outcomes are exclusive alternatives in some measurement, then their probabilities are consistent with the existence of a further measurement in which they are all exclusive). This is a step towards a more unified understanding of quantum nonlocality and contextuality, which promises to allow derivations of important results from minimal, easily grasped assumptions. As one example, this result implies that lack of third-order interference bounds violation of the Clauser-Horne-Shimony-Holt-Bell inequality to 2.883. PMID:26196605
Bounding Quantum Contextuality with Lack of Third-Order Interference
NASA Astrophysics Data System (ADS)
Henson, Joe
2015-06-01
Recently, many simple principles have been proposed that can explain quantum limitations on possible sets of experimental probabilities in nonlocality and contextuality experiments. However, few implications between these principles are known. Here it is shown that the lack of irreducible third-order interference (a generalization of the idea that no probabilistic interference remains unaccounted for once we have taken into account interference between pairs of slits in a n -sit experiment) implies the principle known as the E principle or consistent exclusivity (that, if each pair of a set of experimental outcomes are exclusive alternatives in some measurement, then their probabilities are consistent with the existence of a further measurement in which they are all exclusive). This is a step towards a more unified understanding of quantum nonlocality and contextuality, which promises to allow derivations of important results from minimal, easily grasped assumptions. As one example, this result implies that lack of third-order interference bounds violation of the Clauser-Horne-Shimony-Holt-Bell inequality to 2.883.
Third-order intermodulation distortion in graphene resonant channel transistors
NASA Astrophysics Data System (ADS)
Lekas, Michael; Lee, Sunwoo; Cha, Wujoon; Hone, James; Shepard, Kenneth
2015-02-01
Third-order intermodulation distortion (IM3) is an important metric for electromechanical resonators used in radio frequency signal processing applications since it characterizes the nonlinearity of the device, and the amount of in-band interference it generates when subject to unwanted, out-of-band signals. In this letter, we measure and model IM3 in a strain-engineered graphene mechanical resonator operated as a graphene resonant channel transistor (G-RCT). The device analyzed in this work has a voltage third-order intercept point (VIIP3) of 69.5 dBm V at a gate-to-source DC bias (Vgs) of 2.5 V, which drops to 52.1 dBm V at Vgs = 4.5 V when driven with two out-of-band input tones spaced 5 and 10 MHz from the resonant frequency. The decrease in the VIIP3 with Vgs coincides with an increase in the transmission response (S21) of the device, illustrating a trade-off between transduction efficiency and linearity. In addition, we find that conventional micro-electro-mechanical systems theory for IM3 calculation does not accurately describe our measurement data. To resolve this discrepancy, we develop a model for IM3 in G-RCTs that takes into account all of the output current terms present in the embedded transistor structure, as well as an effective Duffing parameter (αeff).
Effect of the counter cation on the third order nonlinearity in anionic Au dithiolene complexes
NASA Astrophysics Data System (ADS)
Iliopoulos, K.; El-Ghayoury, A.; Derkowska, B.; Ranganathan, A.; Batail, P.; Gindre, D.; Sahraoui, B.
2012-12-01
In this work, we present the third order nonlinear optical investigation of two gold complexes, which differ by the nature of the counter cations. The impact of the different design in the architecture through a set of hydrogen bonds in the case of Au-Mel of the systems on the nonlinearity has been studied by means of the Z-scan setup under 532 nm, 30 ps laser excitation, allowing for the determination of the nonlinear absorption and refraction of the samples. Significant modification of the nonlinear optical response between the two metal complexes has been found suggesting a clear effect of the counter cation.
Large optics inspection, tilting, and washing stand
Ayers, Marion Jay; Ayers, Shannon Lee
2012-10-09
A large optics stand provides a risk free means of safely tilting large optics with ease and a method of safely tilting large optics with ease. The optics are supported in the horizontal position by pads. In the vertical plane the optics are supported by saddles that evenly distribute the optics weight over a large area.
Large optics inspection, tilting, and washing stand
Ayers, Marion Jay; Ayers, Shannon Lee
2010-08-24
A large optics stand provides a risk free means of safely tilting large optics with ease and a method of safely tilting large optics with ease. The optics are supported in the horizontal position by pads. In the vertical plane the optics are supported by saddles that evenly distribute the optics weight over a large area.
New Third-Order Moments for the PBL
NASA Technical Reports Server (NTRS)
Canuto, V. M.; Cheng, Y.; Howard, A.; Hansen, James E. (Technical Monitor)
2000-01-01
Turbulent convection is inherently non-local and a primary condition for a successful treatment of the PBL is a reliable model of non-locality. In the dynamic equations governing the convective flux, turbulent kinetic energy, etc, non-locality enters through the third-order moments, TOMs. Since the simplest form, the so-called down gradient approximation (DGA , severely underestimates the TOMs (by up to an order of magnitude), a more physical model is needed. In 1994, an analytical model was presented which was derived directly from the dynamical equations for the TOMs. It considerably improved the DGA but was a bit cumbersome to use. Here, we present a new analytic expression for the TOMs which is considerably simpler than the 1994 expression and which at the same time yields a much better fit to the LES data.
Third order LPF type compensator for flexible rotor suspension
NASA Astrophysics Data System (ADS)
Matsushita, Osami; Takahashi, Naohiko; Takagi, Michiyuki
1994-05-01
The tuning job of the compensator for levitating flexible rotors supported by active magnetic bearings (AMB) concerns providing a good damping effect to the critical speed modes while avoiding the spillover problem on the instability of higher bending modes. In this paper, an idea for design of the control law of the compensator based on utilizing a third order low pass filter (LPF) is proposed to essentially enable elimination of the spillover instability. According to the proposed design method, good damping effects for the critical speeds are obtained by the usual phase lead/lag function. Stabilization for all of higher bending modes is completed by the additional function of the 3rd order LPF due to its phase lag approaching about -270 degrees in the high frequency domain. This idea is made clear by experiments and simulations.
Third order LPF type compensator for flexible rotor suspension
NASA Technical Reports Server (NTRS)
Matsushita, Osami; Takahashi, Naohiko; Takagi, Michiyuki
1994-01-01
The tuning job of the compensator for levitating flexible rotors supported by active magnetic bearings (AMB) concerns providing a good damping effect to the critical speed modes while avoiding the spillover problem on the instability of higher bending modes. In this paper, an idea for design of the control law of the compensator based on utilizing a third order low pass filter (LPF) is proposed to essentially enable elimination of the spillover instability. According to the proposed design method, good damping effects for the critical speeds are obtained by the usual phase lead/lag function. Stabilization for all of higher bending modes is completed by the additional function of the 3rd order LPF due to its phase lag approaching about -270 degrees in the high frequency domain. This idea is made clear by experiments and simulations.
NASA Astrophysics Data System (ADS)
Masella, Biagio; Zhang, Xiupu
2006-09-01
We present a simplified radio over fiber balanced system that uses only one wavelength, optical modulator and fiber. In this balanced system the upper and lower sidebands produced by subcarrier modulation along with its optical carrier are separated before balanced photodetection. Optical time delays are introduced to one of the sidebands by means of two cascaded tunable nonlinearly chirped fiber Bragg gratings. The first nonlinearly chirped fiber Bragg grating produces relative time delay that has the following relationship τ delay ~ 1/2f, while the second produces a relative time delay of τ delay ~ 1/f. The first nonlinearly chirped fiber Bragg grating will have a large enough bandwidth and group velocity dispersion to introduce a relative time delay for the subcarrier and second order distortion, while the second will have the bandwidth and group velocity dispersion to introduce a different relative time delay for the third order distortion. The net effect of the relative time delays is to provide a phase shift of π for the subcarrier, second order distortion currents and a phase shift of 2π for the third order distortion current. Simulated results show a suppression of 2nd and 3rd harmonic distortion of 25.4 dB and 2.6 dB, respectively. In the case of 2 nd and 3 rd intermodulation distortion suppression of 33 dB and 20 dB, respectively have been reported. Simulation also shows that the power penalty improvement is approximately 2.5 dB for bit error rate of 10-9 for subcarrier at 10 and 35 GHz and relative intensity noise is suppressed by 3 dB.
Large Optical Nonlinearity Induced by Singlet Fission in Pentacene Films
NASA Astrophysics Data System (ADS)
Liu, Yunlong; Zhang, Chunfeng; Xiao, Min
2015-03-01
By creating two triplet excitons from one photo-excited singlet exciton, singlet fission in organic semiconductors has drawn tremendous attention for its potential application in boosting the efficiency of solar conversion. Here, we show that this carrier-multiplication effect can be used to dramatically improve the nonlinear optical response in organic materials. With the technique of dual-wavelength optical Kerr effect (OKE), we have observed large optical nonlinearity with a magnitude of χ (3) up to 10-9 esu in pentacene films, which is further shown to be a result of singlet fission as demonstrated by the detailed temporal dynamics and wavelength dependence experiment. Through the use of optical heterodyne detected OKE experiment, we have determined both the sign and value of Reχ (3) of the pentacene film. Such efficient third order nonlinear optical response has been successfully applied to demonstrate the all-optical switching. The results observed in this work indicate that the singlet fission could be served as an effective strategy to promote the optical nonlinearity in organic molecule systems. This work is supported by the National Basic Research Program of China (2013CB932903 and 2012CB921801, MOST), the National Science Foundation of China (91233103, 61108001, 11227406 and 11321063).
Second-order closure PBL model with new third-order moments: Comparison with LES data
NASA Technical Reports Server (NTRS)
Canuto, V. M.; Minotti, F.; Ronchi, C.; Ypma, R. M.; Zeman, O.
1994-01-01
This paper contains two parts. In the first part, a new set of diagnostic equations is derived for the third-order moments for a buoyancy-driven flow, by exact inversion of the prognostic equations for the third-order moment equations in the stationary case. The third-order moments exhibit a universal structure: they all are a linear combination of the derivatives of all the second-order moments, bar-w(exp 2), bar-w theta, bar-theta(exp 2), and bar-q(exp 2). Each term of the sum contains a turbulent diffusivity D(sub t), which also exhibits a universal structure of the form D(sub t) = a nu(sub t) + b bar-w theta. Since the sign of the convective flux changes depending on stable or unstable stratification, D(sub t) varies according to the type of stratification. Here nu(sub t) approximately equal to wl (l is a mixing length and w is an rms velocity) represents the 'mechanical' part, while the 'buoyancy' part is represented by the convective flux bar-w theta. The quantities a and b are functions of the variable N(sub tau)(exp 2), where N(exp 2) = g alpha derivative of Theta with respect to z and tau is the turbulence time scale. The new expressions for the third-order moments generalize those of Zeman and Lumley, which were subsequently adopted by Sun and Ogura, Chen and Cotton, and Finger and Schmidt in their treatments of the convective boundary layer. In the second part, the new expressions for the third-order moments are used to solve the ensemble average equations describing a purely convective boundary laye r heated from below at a constant rate. The computed second- and third-order moments are then compared with the corresponding Large Eddy Simulation (LES) results, most of which are obtained by running a new LES code, and part of which are taken from published results. The ensemble average results compare favorably with the LES data.
Adaptive Optics for Large Telescopes
Olivier, S
2008-06-27
The use of adaptive optics was originally conceived by astronomers seeking to correct the blurring of images made with large telescopes due to the effects of atmospheric turbulence. The basic idea is to use a device, a wave front corrector, to adjust the phase of light passing through an optical system, based on some measurement of the spatial variation of the phase transverse to the light propagation direction, using a wave front sensor. Although the original concept was intended for application to astronomical imaging, the technique can be more generally applied. For instance, adaptive optics systems have been used for several decades to correct for aberrations in high-power laser systems. At Lawrence Livermore National Laboratory (LLNL), the world's largest laser system, the National Ignition Facility, uses adaptive optics to correct for aberrations in each of the 192 beams, all of which must be precisely focused on a millimeter scale target in order to perform nuclear physics experiments.
Third-order theory of the Risley-prism-based beam steering system.
Li, Yajun
2011-02-10
Nonparaxial ray tracing is performed to investigate the field scanned out by a single beam through two rotatable thick prisms with different parameters, and a general solution is obtained and then expanded into a power series to establish the third-order theory for Risley prisms that paves the way to investigate topics of interest such as optical distortions in the scan pattern and an analytical solution of the inverse problem of a Risley-prism-based laser beam steering system; i.e., the problem is concerned with how to direct a laser beam to any specified direction within the angular range of the system. PMID:21343989
NASA Astrophysics Data System (ADS)
Podesta, J. J.
It is known that Kolmogorov's four-fifths law for statistically homogeneous and isotropic turbulence can be generalized to anisotropic turbulence. This fundamental result for homogeneous anisotropic turbulence says that in the inertial range the divergence of the vector third-order moment |v(r) is constant and is equal to -4, where is the dissipation rate of the turbulence. This law can be extended to incompressible magnetohydrodyamic (MHD) turbulence where statistical isotropy is often not valid due, for example, to the presence of a large-scale magnetic field. Laws for anisotropic incompressible MHD turbulence were first derived by Politano and Pouquet. In this paper, the laws for vector third-order moments in homogeneous non-isotropic incompressible MHD turbulence are derived by a technique due to Frisch that clarifies the relationship between the energy flux in Fourier space and the vector third-order moments in physical space. This derivation is different from the original derivation of Politano and Pouquet which is based on the Kn-Howarth equation, and provides some new physical insights. Separate laws are derived for the cascades of energy, cross-helicity and magnetic-helicity, the three ideal invariants of incompressible MHD for flows in three dimensions. These laws are of fundamental importance in the theory of MHD turbulence where non-isotropic turbulence is much more prevalent than isotropic turbulence.
NASA Astrophysics Data System (ADS)
Gao, Yingjie; Zhang, Jinhai; Yao, Zhenxing
2016-06-01
The symplectic integration method is popular in high-accuracy numerical simulations when discretizing temporal derivatives; however, it still suffers from time-dispersion error when the temporal interval is coarse, especially for long-term simulations and large-scale models. We employ the inverse time dispersion transform (ITDT) to the third-order symplectic integration method to reduce the time-dispersion error. First, we adopt the pseudospectral algorithm for the spatial discretization and the third-order symplectic integration method for the temporal discretization. Then, we apply the ITDT to eliminate time-dispersion error from the synthetic data. As a post-processing method, the ITDT can be easily cascaded in traditional numerical simulations. We implement the ITDT in one typical exiting third-order symplectic scheme and compare its performances with the performances of the conventional second-order scheme and the rapid expansion method. Theoretical analyses and numerical experiments show that the ITDT can significantly reduce the time-dispersion error, especially for long travel times. The implementation of the ITDT requires some additional computations on correcting the time-dispersion error, but it allows us to use the maximum temporal interval under stability conditions; thus, its final computational efficiency would be higher than that of the traditional symplectic integration method for long-term simulations. With the aid of the ITDT, we can obtain much more accurate simulation results but with a lower computational cost.
Non-local bias contribution to third-order galaxy correlations
NASA Astrophysics Data System (ADS)
Bel, J.; Hoffmann, K.; Gaztañaga, E.
2015-10-01
We study halo clustering bias with second- and third-order statistics of halo and matter density fields in the Marenostrum Institut de Ciències de l'Espai (MICE) Grand Challenge simulation. We verify that two-point correlations deliver reliable estimates of the linear bias parameters at large scales, while estimations from the variance can be significantly affected by non-linear and possibly non-local contributions to the bias function. Combining three-point auto- and cross-correlations we find, for the first time in configuration space, evidence for the presence of such non-local contributions. These contributions are consistent with predicted second-order non-local effects on the bias functions originating from the dark matter tidal field. Samples of massive haloes show indications of bias (local or non-local) beyond second order. Ignoring non-local bias causes 20-30 and 5-10 per cent overestimation of the linear bias from three-point auto- and cross-correlations, respectively. We study two third-order bias estimators that are not affected by second-order non-local contributions. One is a combination of three-point auto- and cross-correlations. The other is a combination of third-order one- and two-point cumulants. Both methods deliver accurate estimations of the linear bias. Ignoring non-local bias causes higher values of the second-order bias from three-point correlations. Our results demonstrate that third-order statistics can be employed for breaking the growth-bias degeneracy.
New Third-Order Moments for the CBL
NASA Technical Reports Server (NTRS)
Canuto, V. M.; Cheng, Y.; Howard, A.; Hansen, James E. (Technical Monitor)
2001-01-01
Turbulent convection is an inherently non-local phenomenon and a primary condition for a successful treatment of the CBL (convective boundary layer) is a reliable model of non-locality. In the dynamic equations governing the convective flux, the turbulent kinetic energy, etc., non-locality is represented by the third-order moments, TOMs. Since the simplest form, the so-called down gradient approximation (DGA), severely underestimates the TOMs (up to an order of magnitude), a more physical model is needed. In 1994, an analytical model was presented which was derived directly from the dynamical equations for the TOMs. It considerably improved the DGA but was a bit cumbersome to use and, more importantly, it was based on the quasi-normal (QN) approximation for the fourth-order moments. Here, we present a new analytic expression for the TOMs which is structurally simpler than the 1994 expression and which avoids the QN approximation. The resulting fit to the LES data is superior to that of the 1994 model.
Cerebral hydrodynamics are at a most a third order system.
Shepherd, Simon J; Beggs, Clive B
2011-05-01
The human body employs a sophisticated windkessel mechanism to dampen the arterial pulse entering the brain, thus ensuring the smooth flow of blood through the cerebral capillary bed. The energy from the arterial pulse is transferred to the cerebrospinal fluid (CSF), which pulses backwards and forwards across the foramen magnum. The dynamics associated with this system are complex and poorly understood. In an attempt to better understand the physiology, a number of researchers have constructed electrical analogue circuits to simulate the hydrodynamic behaviour of the brain. These generally consist of several low-pass filters. While such models have great potential, to date, they have met with only limited success. We suspect that this is in part due to a failure to identify the order of the model required to successfully capture the hydrodynamics of the brain. Here, we advance the hypothesis that the cerebral hydrodynamic system is at most a third order system, using evidence collected from the spectral eigen-system of the arterial, venous and CSF flows. Using singular spectrum analysis we computed the singular vectors for the measured arterial, venous and CSF flows from an individual. This revealed that the first singular vector contributes 67% of the observed variance; the first plus the second singular vectors contribute 96% of the variance; and sum of the first three singular vectors contribute more than 99.5% of the observed variance. PMID:21292407
NASA Astrophysics Data System (ADS)
Rambaux, N.; Chambat, F.; Castillo-Rogez, J. C.
2015-12-01
Context. We investigate the hydrostatic shape and gravitational potential coefficients of self-gravitating and rotating bodies large enough to have undergone internal differentiation and chemical stratification. Quantifying these properties under the assumption of hydrostatic equilibrium forms the basis for interpreting shape and gravity data in terms of interior structure and infer deviations from hydrostaticity that can bring information on the thermal and chemical history of the objects. Aims: The main purpose is to show the importance of developing the reference hydrostatic shape for relatively fast rotating bodies up to third order to reach an accuracy of a few tens of meters. This paper especially focuses on Ceres, for which high-resolution shape data are being obtained by the Dawn spacecraft, with a projected accuracy better than 200 m/pixel. Methods: To improve the accuracy on the determination of geodetic parameters, we numerically integrated Clairaut's equations of rotational equilibrium expanded up to third order in a small parameter m, the geodetic parameter. Results: Previous studies of Ceres have been based on shape models developed to first order. However, we show that the first-order theory underestimates (a-c) (where a and c are the equatorial and polar radii) by 1.8 km, which leads to underestimating the extent of mass concentration and is insufficient to interpret the upcoming observations by Dawn space mission. Instead, by using the third-order theory, we obtain an accuracy of 25 meters that is better than the accuracy expected from Dawn. Then, we derive the following geodetical quantities: flattening and other shape parameters, gravitational potential coefficients, and moments of inertia, by using the Ceres models constrained by observations obtained with the Hubble Space Telescope and ground-based adaptive optics telescopes. The difference in equatorial and polar radii for a large parametric space of interior models is investigated, and the
Marhic, M E; Kagi, N; Chiang, T K; Kazovsky, L G
1995-04-15
We show that in principle it is possible to cancel third-order nonlinear effects in optical fiber links. The necessary conditions exist in two-segment links, with dispersion compensation, phase conjugation, and amplification between the two, as well as opposite chromatic dispersion coefficients in the segments. The cancellation is independent of loss, modulation format, and modulation frequency. PMID:19859355
Growth and characterization of potassium acid phthalte for third order NLO applications
NASA Astrophysics Data System (ADS)
Sivakumar, B.; Raj, S. Gokul; Kumar, G. Ramesh; Mohan, R.
2013-02-01
Nonlinear optical crystals of potassium acid phthalate (COOK C6H4 COOH)-KAP were grown from aqueous solution. Transparent crystals of size (21×17×4) mm3 with well defined morphology were grown from slow cooling techniques. The grown crystals were characterized by single crystal X-ray diffraction. The crystal structure of Potassium Acid Phthalate C8H5K+O4 was orthorhombic with the following unit-cell dimensions at 298(2) K; a = 9.5970(3) Å; b = 13.2869(5) Å; c = 6.4643(3) Å; α = 90°; β = 90°; γ = 90°; with a space group PCa21. Spectral analysis were carried out to investigate confirm its presence of various functional groups and to study the optical absorption properties. Third order nonliner studies have also been studied by Z-scan techniques. Nonlinear absorption and nonlinear refractive index were found out and the third order bulk susceptibility of compound was also estimated. The results have been discussed in detail.
Computation of turbulent pipe and duct flow using third order upwind scheme
NASA Technical Reports Server (NTRS)
Kawamura, T.
1986-01-01
The fully developed turbulence in a circular pipe and in a square duct is simulated directly without using turbulence models in the Navier-Stokes equations. The utilized method employs a third-order upwind scheme for the approximation to the nonlinear term and the second-order Adams-Bashforth method for the time derivative in the Navier-Stokes equation. The computational results appear to capture the large-scale turbulent structures at least qualitatively. The significance of the artificial viscosity inherent in the present scheme is discussed.
NASA Astrophysics Data System (ADS)
Zhong, Jianghong; Tian, Jie; Yang, Xin; Qin, Chenghu
2011-03-01
Applying Cerenkov luminescence tomography (CLT) to localizing Cerenkov light sources in situ is still in its nascent stage. One of the obstacles hindering the development of the CLT is the lack of dedicated imaging mode. In this contribution, the paper presented a Cerenkov optical imaging mode, in which the propagation of optical photons inside tissues generated by the Vavilov-Cerenkov effect is modeled based on simplified spherical harmonics approximation. As a significantly more transport-like and computational-efficient approximation theory, the performance of the third-order simplified spherical harmonics approximation (SP3) in the CLT forward is investigated in stages. Finally, the performance of the proposed forward model is validated using numerical phantoms and compared with the simulation data based on the Monte Carlo method.
Interplay between Graph Topology and Correlations of Third Order in Spiking Neuronal Networks.
Jovanović, Stojan; Rotter, Stefan
2016-06-01
The study of processes evolving on networks has recently become a very popular research field, not only because of the rich mathematical theory that underpins it, but also because of its many possible applications, a number of them in the field of biology. Indeed, molecular signaling pathways, gene regulation, predator-prey interactions and the communication between neurons in the brain can be seen as examples of networks with complex dynamics. The properties of such dynamics depend largely on the topology of the underlying network graph. In this work, we want to answer the following question: Knowing network connectivity, what can be said about the level of third-order correlations that will characterize the network dynamics? We consider a linear point process as a model for pulse-coded, or spiking activity in a neuronal network. Using recent results from theory of such processes, we study third-order correlations between spike trains in such a system and explain which features of the network graph (i.e. which topological motifs) are responsible for their emergence. Comparing two different models of network topology-random networks of Erdős-Rényi type and networks with highly interconnected hubs-we find that, in random networks, the average measure of third-order correlations does not depend on the local connectivity properties, but rather on global parameters, such as the connection probability. This, however, ceases to be the case in networks with a geometric out-degree distribution, where topological specificities have a strong impact on average correlations. PMID:27271768
Interplay between Graph Topology and Correlations of Third Order in Spiking Neuronal Networks
Jovanović, Stojan
2016-01-01
The study of processes evolving on networks has recently become a very popular research field, not only because of the rich mathematical theory that underpins it, but also because of its many possible applications, a number of them in the field of biology. Indeed, molecular signaling pathways, gene regulation, predator-prey interactions and the communication between neurons in the brain can be seen as examples of networks with complex dynamics. The properties of such dynamics depend largely on the topology of the underlying network graph. In this work, we want to answer the following question: Knowing network connectivity, what can be said about the level of third-order correlations that will characterize the network dynamics? We consider a linear point process as a model for pulse-coded, or spiking activity in a neuronal network. Using recent results from theory of such processes, we study third-order correlations between spike trains in such a system and explain which features of the network graph (i.e. which topological motifs) are responsible for their emergence. Comparing two different models of network topology—random networks of Erdős-Rényi type and networks with highly interconnected hubs—we find that, in random networks, the average measure of third-order correlations does not depend on the local connectivity properties, but rather on global parameters, such as the connection probability. This, however, ceases to be the case in networks with a geometric out-degree distribution, where topological specificities have a strong impact on average correlations. PMID:27271768
Perception of second- and third-order orientation signals and their interactions
Victor, Jonathan D.; Thengone, Daniel J.; Conte, Mary M.
2013-01-01
Orientation signals, which are crucial to many aspects of visual function, are more complex and varied in the natural world than in the stimuli typically used for laboratory investigation. Gratings and lines have a single orientation, but in natural stimuli, local features have multiple orientations, and multiple orientations can occur even at the same location. Moreover, orientation cues can arise not only from pairwise spatial correlations, but from higher-order ones as well. To investigate these orientation cues and how they interact, we examined segmentation performance for visual textures in which the strengths of different kinds of orientation cues were varied independently, while controlling potential confounds such as differences in luminance statistics. Second-order cues (the kind present in gratings) at different orientations are largely processed independently: There is no cancellation of positive and negative signals at orientations that differ by 45°. Third-order orientation cues are readily detected and interact only minimally with second-order cues. However, they combine across orientations in a different way: Positive and negative signals largely cancel if the orientations differ by 90°. Two additional elements are superimposed on this picture. First, corners play a special role. When second-order orientation cues combine to produce corners, they provide a stronger signal for texture segregation than can be accounted for by their individual effects. Second, while the object versus background distinction does not influence processing of second-order orientation cues, this distinction influences the processing of third-order orientation cues. PMID:23532909
Time-Resolved Third Order Harmonic Generation on Shocked Silicon Crystals
NASA Astrophysics Data System (ADS)
Dalton, D. A.; Grigsby, W.; Quevedo, H.; Bernstein, A. C.; Ditmire, T.
2008-04-01
We are using nonlinear optical diagnostics to probe the shock-induced melt transition in silicon. Pump-probe shock experiments on [100] Si crystals were carried out using the Ti:Sapphire THOR laser (800 nm, 1 J, 600 ps-chirped, 40 fs-compressed). Two dimensional interferometry was used to map rear surface displacement at discrete times to infer a peak shock pressure. Third order harmonic generation (THG) is used to probe the bulk material's long range order, while a reflectivity diagnostic is used in conjuction with the THG diagnostic to determine it's validity. Preliminary evidence shows the anomalous response that at shock pressures <100 kbar (˜elastic limit) the THG signal does not decrease; however, at higher pressures of ˜300-400 kbar the THG signal falls dramatically indicating fast crystalline disordering.
Efficient Third-Order Distributed Feedback Laser with Enhanced Beam Pattern
NASA Technical Reports Server (NTRS)
Hu, Qing (Inventor); Lee, Alan Wei Min (Inventor); Kao, Tsung-Yu (Inventor)
2015-01-01
A third-order distributed feedback laser has an active medium disposed on a substrate as a linear array of segments having a series of periodically spaced interstices therebetween and a first conductive layer disposed on a surface of the active medium on each of the segments and along a strip from each of the segments to a conductive electrical contact pad for application of current along a path including the active medium. Upon application of a current through the active medium, the active medium functions as an optical waveguide, and there is established an alternating electric field, at a THz frequency, both in the active medium and emerging from the interstices. Spacing of adjacent segments is approximately half of a wavelength of the THz frequency in free space or an odd integral multiple thereof, so that the linear array has a coherence length greater than the length of the linear array.
Large core fiber optic cleaver
Halpin, John M.
1996-01-01
The present invention relates to a device and method for cleaving optical fibers which yields cleaved optical fiber ends possessing high damage threshold surfaces. The device can be used to cleave optical fibers with core diameters greater than 400 .mu.m.
A third-order-accurate upwind scheme for Navier-Stokes solutions at high Reynolds numbers
NASA Astrophysics Data System (ADS)
Agarwal, R. K.
1981-01-01
A third-order-accurate upwind scheme is presented for solution of the steady two-dimensional Navier-Stokes equations in stream-function/vorticity form. The scheme is found to be accurate and stable at high Reynolds numbers. A series of test computations is performed on flows with large recirculating regions. In particular, highly accurate solutions are obtained for flow in a driven square cavity up to Reynolds numbers of 10,000. These computations are used to critically evaluate the accuracy of other existing first- and second-order-accurate upwind schemes. In addition, computations are carried out for flow in a channel with symmetric sudden expansion, flow in a channel with a symmetrically placed blunt base, and the flowfield of an impinging jet. Good agreement is obtained with the computations of other investigators as well as with the available experimental data.
First- and third-order analysis of aperture stop location in infrared zoom lens systems
NASA Astrophysics Data System (ADS)
Mann, Allen
1995-10-01
First and third order principles for location of the aperture stop in infrared zoom lens systems are discussed. Factors to be considered include lens diameters, third order aberrations, chromatic correction, and illumination requirements at the image plane. In particular, the importance of aperture stop location in infrared applications is considered. An example illustrating these principles is presented.
Relativistic third-order viscous corrections to the entropy four-current from kinetic theory
NASA Astrophysics Data System (ADS)
Chattopadhyay, Chandrodoy; Jaiswal, Amaresh; Pal, Subrata; Ryblewski, Radoslaw
2015-02-01
By employing a Chapman-Enskog like iterative solution of the Boltzmann equation in relaxation-time approximation, we derive a new expression for the entropy four-current up to third order in gradient expansion. We show that unlike second-order and third-order entropy four-current obtained using Grad's method, there is a nonvanishing entropy flux in the present third-order expression. We further quantify the effect of the higher-order entropy density in the case of boost-invariant one-dimensional longitudinal expansion of a system. We demonstrate that the results obtained using the third-order evolution equation for the shear stress tensor, derived by employing the method of Chapman-Enskog expansion, show better agreement with the exact solution of the Boltzmann equation as well as with the parton cascade bamps, as compared to those obtained using the third-order equations from the method of Grad's 14-moment approximation.
Photoassociation dynamics driven by second- and third-order phase-modulated laser fields
NASA Astrophysics Data System (ADS)
Wang, Meng; Chen, Mao-Du; Hu, Xue-Jin; Li, Jing-Lun; Cong, Shu-Lin
2016-05-01
We investigate theoretically the photoassociation dynamics of ultracold 85Rb atoms driven by second- and third-order phase-modulated laser fields. The interplay between the second-order and third-order terms of the phase-modulated pulse has an obvious influence on photoassociation dynamics. The different combinations of the second-order and third-order phase coefficients lead to different pulse shapes. Most of the molecular population in the excited electronic state driven only by the third-order phase pulses can be distributed in a single vibrational level. The second-order term of the phase-modulated pulse can change the instantaneous frequency, and therefore the final population is distributed on several resonant vibrational levels, instead of concentrating on a single level. Although the second- and third-order phase-modulated pulse covers more resonant vibrational levels, the total population on the resonant vibrational levels is much smaller than that controlled only by the third-order phase pulse. In particular, the third-order term of the phase-modulated pulse can weaken the ‘multiple interaction’ to some degree.
Koelsch, Patrick; Muglali, Mutlu; Rohwerder, Michael; Erbe, Andreas
2013-01-01
Vibrational sum-frequency-generation (SFG) spectroscopy experiments at electrified interfaces involve incident laser radiation at frequencies in the IR and near-IR/visible regions as well as a static electric field on the surface. Here we show that mixing the three fields present on the surface can result in third-order effects in resonant SFG signals. This was achieved for closed packed self-assembled monolayers (SAMs) with molecular groups of high optical nonlinearity and surface potentials similar to those typically applied in cyclic voltammograms. Broadband SFG spectroscopy was applied to study a hydrophobic well-ordered araliphatic SAM on a Au(111) surface using a thin-layer analysis cell for spectro-electrochemical investigations in a 100 mM NaOH electrolyte solution. Resonant contributions were experimentally separated from non-resonant contributions of the Au substrate and theoretically analyzed using a fitting function including third-order terms. The resulting ratio of third-order to second-order susceptibilities was estimated to be [Formula: see text](10(-10)) m/V. PMID:24235781
Determination of third-order elastic moduli via parameters of bulk strain solitons
NASA Astrophysics Data System (ADS)
Garbuzov, F. E.; Samsonov, A. M.; Semenov, A. A.; Shvartz, A. G.
2016-02-01
A method is proposed aimed for determination of the third-order elastic moduli (Murnaghan moduli) based on the estimation of measured parameters of bulk strain solitons in the three main waveguide configurations, a rod, a plate, and a shell. Formulas connecting the third-order moduli of the waveguide material and the parameters of a solitary strain wave (amplitude, velocity, full width at half-maximum) are derived. If the soliton parameters measured in three waveguide types manufactured from the same material are available, determination of the third-order elastic moduli is reduced to the solution of a system of three algebraic equations with a nondegenerate matrix.
Stylus profilometry of large optics
NASA Astrophysics Data System (ADS)
Wills-Moren, William J.; Leadbeater, Peter B.
1990-11-01
This paper indicates the emerging requirements for profilometry instruments for use in the fabrication and characterization of modern optical systems. Important design principles are covered, together with some of the problems which can be experienced. Examples of a number of systems recently developed are given - both stand-alone systems and those which operate in situ to the machining process.
Green, Anthony J; Space, Brian
2015-07-23
Sum frequency vibrational spectroscopy (SFVS), a second-order optical process, is interface-specific in the dipole approximation [Perry, A.; Neipert, C.; Moore, P.; Space, B. Chem. Rev. 2006, 106, 1234-1258; Richmond, G. L. Chem. Rev. 2002, 102, 2693-2724; Byrnes, S. J.; Geissler, P. L.; Shen, Y. R. Chem. Phys. Lett. 2011, 516, 115-124]. At charged interfaces, the experimentally detected signal is a combination of enhanced second-order and static-field-induced third-order contributions due to the existence of a static field. Evidence of the importance/relative magnitude of this third-order contribution is seen in the literature [Ong, S.; Zhao, X.; Eisenthal, K. B. Chem. Phys. Lett. 1992, 191, 327-335; Zhao, X.; Ong, S.; Eisenthal, K. B. Chem. Phys. Lett. 1993, 202, 513-520; Shen, Y. R. Appl. Phys. B: Laser Opt. 1999, 68, 295-300], but a molecularly detailed approach to separately calculating the second- and third-order contributions is difficult to construct. Recent work presented a novel molecular dynamics (MD)-based theory that provides a direct means to calculate the third-order contributions to SFVS spectra at charged interfaces [Neipert, C.; Space, B. J. Chem. Phys. 2006, 125, 224706], and a hyperpolarizability model for water was developed as a prerequisite to practical implementation [Neipert, C.; Space, B. Comput. Lett. 2007, 3, 431-440]. Here, these methods are applied to a highly abstracted/idealized silica/water interface, and the results are compared to experimental data for water at a fused quartz surface. The results suggest that such spectra have some quite general spectral features. PMID:25415752
NASA Astrophysics Data System (ADS)
Zuo, Yanlei; Zhou, Kainan; Wu, Zhaohui; Wang, Xiao; Xie, Na; Su, Jingqin; Zeng, Xiaoming
2016-05-01
It is necessary to eliminate third-order dispersion to acquire an ultrashort pulse of less than 30 fs. We demonstrate for the first time, to the best of our knowledge, the alignment of a petawatt-class laser compressor using the equiphase lines in the spatial and spectral interference patterns. Third-order dispersion has been completely eliminated and a Fourier-transform-limited pulsewidth of 19.6 fs has been approached.
Second- and third-order elastic coefficients in polycrystalline aluminum alloy AMg6
NASA Astrophysics Data System (ADS)
Volkov, A. D.; Kokshaiskii, A. I.; Korobov, A. I.; Prokhorov, V. M.
2015-11-01
All independent second- and third-order elastic coefficients were measured in the isotropic polycrystalline aluminum alloy AMg6 (Al-Mg-Mn system) using the Ritec RAM-5000 SNAP SYSTEM ultrasonic automated complex operating in the pulsed mode. The third-order elastic coefficients were determined using the Thurston-Bragger method from the experimentally measured velocity of shear and longitudinal elastic waves in AMg6 alloy as a function of uniaxial compression.
The actual scaling of a nominally third-order Reynolds stress
Krommes, J. A. Hammett, G. W.
2014-05-15
It is shown that a particular higher-order Reynolds stress arising from a term in the third-order gyrokinetic Hamiltonian is smaller than it nominally appears to be. However, it does not follow that all third-order terms are unimportant. The discussion is relevant to the ongoing debate about the importance of higher-order terms in the gyrokinetic theory of momentum transport.
Pulse shape measurement by a non-collinear third-order correlation technique
NASA Astrophysics Data System (ADS)
Priebe, G.; Janulewicz, K. A.; Redkorechev, V. I.; Tümmler, J.; Nickles, P. V.
2006-03-01
A third-order correlator suitable for detailed shape measurements of picosecond laser pulses has been developed. The working principle in both the single shot and the scanning mode is based on detection of the phase-matched difference frequency non-collinear generated signal in a non-linear crystal. This third-order OPA correlator was applied for the characterization of the specifically shaped picosecond laser pulses from the MBI CPA Nd: glass laser system.
Large optics for the National Ignition Facility
Baisden, P.
2015-01-12
The National Ignition Facility (NIF) laser with its 192 independent laser beams is not only the world’s largest laser, it is also the largest optical system ever built. With its 192 independent laser beams, the NIF requires a total of 7648 large-aperture (meter-sized) optics. One of the many challenges in designing and building NIF has been to carry out the research and development on optical materials, optics design, and optics manufacturing and metrology technologies needed to achieve NIF’s high output energies and precision beam quality. This paper describes the multiyear, multi-supplier, development effort that was undertaken to develop the advanced optical materials, coatings, fabrication technologies, and associated process improvements necessary to manufacture the wide range of NIF optics. The optics include neodymium-doped phosphate glass laser amplifiers; fused silica lenses, windows, and phase plates; mirrors and polarizers with multi-layer, high-reflectivity dielectric coatings deposited on BK7 substrates; and potassium di-hydrogen phosphate crystal optics for fast optical switches, frequency conversion, and polarization rotation. Also included is a discussion of optical specifications and custom metrology and quality-assurance tools designed, built, and fielded at supplier sites to verify compliance with the stringent NIF specifications. In addition, a brief description of the ongoing program to improve the operational lifetime (i.e., damage resistance) of optics exposed to high fluence in the 351-nm (3ω) is provided.
World atlas of large optical telescopes
NASA Technical Reports Server (NTRS)
Meszaros, S. P.
1979-01-01
By 1980 there will be approximately 100 large optical telescopes in the world with mirror or lens diameters of one meter (39 inches) and larger. This atlas gives information on these telescopes and shows their locations on continent-sized maps. Observatory locations considered suitable for the construction of future large telescopes are also shown.
Instability of black strings in the third-order Lovelock theory
NASA Astrophysics Data System (ADS)
Giacomini, Alex; Henríquez-Báez, Carla; Lagos, Marcela; Oliva, Julio; Vera, Aldo
2016-05-01
We show that homogeneous black strings of third-order Lovelock theory are unstable under s-wave perturbations. This analysis is done in dimension D =9 , which is the lowest dimension that allows the existence of homogeneous black strings in a theory that contains only the third-order Lovelock term in the Lagrangian. As is the case in general relativity, the instability is produced by long wavelength perturbations and it stands for the perturbative counterpart of a thermal instability. We also provide a comparative analysis of the instabilities of black strings at a fixed radius in general relativity, Gauss-Bonnet, and third-order Lovelock theories. We show that the minimum critical wavelength that triggers the instability grows with the power of the curvature defined in the Lagrangian. The maximum exponential growth during the time of the perturbation is the largest in general relativity and it decreases with the number of curvatures involved in the Lagrangian.
A note on the nonlocal boundary value problem for a third order partial differential equation
NASA Astrophysics Data System (ADS)
Belakroum, Kheireddine; Ashyralyev, Allaberen; Guezane-Lakoud, Assia
2016-08-01
The nonlocal boundary-value problem for a third order partial differential equation d/3u (t ) d t3 +A d/u (t ) d t =f (t ), 0
Mixed Convection Peristaltic Flow of Third Order Nanofluid with an Induced Magnetic Field
Noreen, Saima
2013-01-01
This research is concerned with the peristaltic flow of third order nanofluid in an asymmetric channel. The governing equations of third order nanofluid are modelled in wave frame of reference. Effect of induced magnetic field is considered. Long wavelength and low Reynolds number situation is tackled. Numerical solutions of the governing problem are computed and analyzed. The effects of Brownian motion and thermophoretic diffusion of nano particles are particularly emphasized. Physical quantities such as velocity, pressure rise, temperature, induced magnetic field and concentration distributions are discussed. PMID:24260130
Improvements in large window and optics production
NASA Astrophysics Data System (ADS)
Hallock, Bob; Messner, Bill; Hall, Chris; Supranowitz, Chris
2007-04-01
Fabrication of large optics has been a topic of discussion for decades. As early as the late 1980s, computer-controlled equipment has been used to semi-deterministically correct the figure error of large optics over a number of process iterations. Magnetorheological Finishing, MRF®, was developed and commercialized in the late 1990's to predictably and reliably allow the user to achieve deterministic results on a variety of optical glasses, ceramics and other common optical materials. Large and small optics such as primary mirrors, conformal optics and off-axis components are efficiently fabricated using this approach. More recently, specific processes, MR Fluids and equipment have been developed and implemented to enhance results when finishing large aperture sapphire windows. MRF, by virtue of its unique removal process, overcomes many of the drawbacks of a conventional polishing process. For example, lightweighted optics often exhibit a quilted pattern coincident with their pocket cell structure following conventional pad-based polishing. MRF does not induce mid-frequency errors and is capable of removing existing quilt patterns. Further, odd aperture shapes and part geometries which can represent significant challenges to conventional polish processing are simply and easily corrected with MRF tools. Similarly, aspheric optics which can often present multiple obstacles-particularly when lightweighted and off-axis-typically have a departure from best-fit sphere that is not well matched with to static pad-based polishing tools resulting in pad misfit and associated variations in removal. The conformal subaperture polishing tool inherent to the QED process works as well on typical circular apertures as it does on irregular shapes such as rectangles, petals and trapezoids for example and matches the surface perfectly at all points. Flats, spheres, aspheres and off-axis sections are easily corrected. The schedule uncertainties driven by edge roll and edge control
Higher-dimensional thin-shell wormholes in third-order Lovelock gravity
NASA Astrophysics Data System (ADS)
Mehdizadeh, Mohammad Reza; Zangeneh, Mahdi Kord; Lobo, Francisco S. N.
2015-08-01
In this paper, we explore asymptotically flat charged thin-shell wormholes of third order Lovelock gravity in higher dimensions, taking into account the cut-and-paste technique. Using the generalized junction conditions, we determine the energy-momentum tensor of these solutions on the shell, and explore the issue of the energy conditions and the amount of normal matter that supports these thin-shell wormholes. Our analysis shows that for negative second-order and positive third-order Lovelock coefficients, there are thin-shell wormhole solutions that respect the weak energy condition. In this case, the amount of normal matter increases as the third-order Lovelock coefficient decreases. We also find novel solutions which possess specific regions where the energy conditions are satisfied for the case of a positive second-order and negative third-order Lovelock coefficients. Finally, a linear stability analysis in higher dimensions around the static solutions is carried out. Considering a specific cold equation of state, we find a wide range of stability regions.
A re-averaged WENO reconstruction and a third order CWENO scheme for hyperbolic conservation laws
NASA Astrophysics Data System (ADS)
Huang, Chieh-Sen; Arbogast, Todd; Hung, Chen-Hui
2014-04-01
A WENO re-averaging (or re-mapping) technique is developed that converts function averages on one grid to another grid to high order. Nonlinear weighting gives the essentially non-oscillatory property to the re-averaged function values. The new reconstruction grid is used to obtain a standard high order WENO reconstruction of the function averages at a select point. By choosing the reconstruction grid to include the point of interest, a high order function value can be reconstructed using only positive linear weights. The re-averaging technique is applied to define two variants of a classic CWENO3 scheme that combines two linear polynomials to obtain formal third order accuracy. Such a scheme cannot otherwise be defined, due to the nonexistence of linear weights for third order reconstruction at the center of a grid element. The new scheme uses a compact stencil of three solution averages, and only positive linear weights are used. The scheme extends easily to problems in higher space dimensions, essentially as a tensor product of the one-dimensional scheme. The scheme maintains formal third order accuracy in higher dimensions. Numerical results show that this CWENO3 scheme is third order accurate for smooth problems and gives good results for non-smooth problems, including those with shocks.
Effects of focusing on third-order nonlinear processes in isotropic media. [laser beam interactions
NASA Technical Reports Server (NTRS)
Bjorklund, G. C.
1975-01-01
Third-order nonlinear processes in isotropic media have been successfully used for tripling the efficiency of high-power laser radiation for the production of tunable and fixed-frequency coherent vacuum UV radiation and for up-conversion of IR radiation. The effects of focusing on two processes of this type are studied theoretically and experimentally.
Third-order elastic constants of the alloy Fe 72Pt 28
NASA Astrophysics Data System (ADS)
Vinu, T. P.; Menon, C. S.
2004-09-01
The complete sets of second- and third-order elastic constants of the cubic Fe72Pt28 have been obtained using the strain energy density derived from interactions up to three nearest neighbours of each atom in the unit cell. The finite strain elasticity theory has been used to get the strain energy density of Fe72Pt28. The strain energy density is compared with the strain-dependent lattice energy density obtained from the continuum model approximation and the expressions for the second- and third-order elastic constants of Fe72Pt28 are given. The second-order potential parameter is deduced from the measured second-order elastic constants of Fe72Pt28 and the third-order potential parameter is estimated from the Lennard-Jones inter-atomic potential for Fe72Pt28. The inter-lattice displacements; the three independent second-order elastic constants and the six independent third-order elastic constants of Fe72Pt28 are also determined. The second-order elastic constants are compared with the experimental elastic constants of Fe72Pt28. We also study the effect of pressure on the second-order elastic constants of Fe72Pt28.
Development of large aperture composite adaptive optics
NASA Astrophysics Data System (ADS)
Kmetik, Viliam; Vitovec, Bohumil; Jiran, Lukas; Nemcova, Sarka; Zicha, Josef; Inneman, Adolf; Mikulickova, Lenka; Pavlica, Richard
2015-01-01
Large aperture composite adaptive optics for laser applications is investigated in cooperation of Institute of Plasma Physic, Department of Instrumentation and Control Engineering FME CTU and 5M Ltd. We are exploring opportunity of a large-size high-power-laser deformable-mirror production using a lightweight bimorph actuated structure with a composite core. In order to produce a sufficiently large operational free aperture we are developing new technologies for production of flexible core, bimorph actuator and deformable mirror reflector. Full simulation of a deformable-mirrors structure was prepared and validated by complex testing. A deformable mirror actuation and a response of a complicated structure are investigated for an accurate control of the adaptive optics. An original adaptive optics control system and a bimorph deformable mirror driver were developed. Tests of material samples, components and sub-assemblies were completed. A subscale 120 mm bimorph deformable mirror prototype was designed, fabricated and thoroughly tested. A large-size 300 mm composite-core bimorph deformable mirror was simulated and optimized, fabrication of a prototype is carried on. A measurement and testing facility is modified to accommodate large sizes optics.
[Zn(C 7H 3O 5N)] n · nH 2O: A third-order NLO Zn coordination polymer with spiroconjugated structure
NASA Astrophysics Data System (ADS)
Zhou, Guo-Wei; Lan, You-Zhao; Zheng, Fa-Kun; Zhang, Xin; Lin, Meng-Hai; Guo, Guo-Cong; Huang, Jin-Shun
2006-08-01
[Zn(C 7H 3O 5N)] n · nH 2O ( 1) possesses an anticlockwise windmill-like framework structure and formats spiroconjugation over the infinite molecular layer that is predicted to have large static third-order polarizability and the convergence value of γxxxx reaches 6.86 × 10 -33 esu in the case of zero input photon energy. The third-order NLO properties of 1 were investigated via Z-scan techniques at wavelength of 532 nm. It showed strong third-order NLO absorptive properties, and its n2 value was calculated to be 4.15 × 10 -11 esu. The relationship between the spiroconjugated structure and the NLO property has been discussed, which supposed to be more valuable for the NLO research.
Plasma surface figuring of large optical components
NASA Astrophysics Data System (ADS)
Jourdain, R.; Castelli, M.; Morantz, P.; Shore, P.
2012-04-01
Fast figuring of large optical components is well known as a highly challenging manufacturing issue. Different manufacturing technologies including: magnetorheological finishing, loose abrasive polishing, ion beam figuring are presently employed. Yet, these technologies are slow and lead to expensive optics. This explains why plasma-based processes operating at atmospheric pressure have been researched as a cost effective means for figure correction of metre scale optical surfaces. In this paper, fast figure correction of a large optical surface is reported using the Reactive Atom Plasma (RAP) process. Achievements are shown following the scaling-up of the RAP figuring process to a 400 mm diameter area of a substrate made of Corning ULE®. The pre-processing spherical surface is characterized by a 3 metres radius of curvature, 2.3 μm PVr (373nm RMS), and 1.2 nm Sq nanometre roughness. The nanometre scale correction figuring system used for this research work is named the HELIOS 1200, and it is equipped with a unique plasma torch which is driven by a dedicated tool path algorithm. Topography map measurements were carried out using a vertical work station instrumented by a Zygo DynaFiz interferometer. Figuring results, together with the processing times, convergence levels and number of iterations, are reported. The results illustrate the significant potential and advantage of plasma processing for figuring correction of large silicon based optical components.
A large aperture electro-optic deflector
NASA Astrophysics Data System (ADS)
Bosco, A.; Boogert, S. T.; Boorman, G. E.; Blair, G. A.
2009-05-01
An electro-optic laser beam deflector with a clear optical aperture of 8.6 mm has been designed, realized, and tested. The electro-optic material used to implement the device was a MgO:LiNbO3 crystal. The exceptionally large aperture makes the device suitable for applications where fast scanning of high power laser beams is needed. The measured deflection angle was 120 μrad/kV for a total length of electro-optic material of 90 mm. A mode quality analysis of the laser beam revealed that the M2 of the laser is affected by less than 4% during scan operation when maximum driving voltage is applied.
NASA Astrophysics Data System (ADS)
Xie, Wenfang
2014-09-01
The optical properties of a neutral donor in a ZnS/InP/ZnSe core/shell spherical quantum dot have been investigated using the variational method and the compact density-matrix approach. Two parametric potential is chosen as a confinement potential for the shell. Considering the band structure of the system it is assumed that electron is localized in InP shell. It is assumed that the impurity is located in the center of quantum dot core (ZnS). The photoionization cross section as well as the third-order nonlinear optical susceptibility of third harmonic generation has been calculated. The results show that the photoionization and the third-order nonlinear optical susceptibility of a donor in a core/shell spherical quantum dot are strongly affected by the shell thickness. We found that small applied shell thickness will lead to a significant blue shift of the peak positions in the optical spectrum. This kind of structure gives an opportunity to tune and control the photoionization and the third-order nonlinear optical susceptibility of third harmonic generation of a donor impurity by changing the shell thickness.
Optical metrology for very large convex aspheres
NASA Astrophysics Data System (ADS)
Burge, J. H.; Su, P.; Zhao, C.
2008-07-01
Telescopes with very large diameter or with wide fields require convex secondary mirrors that may be many meters in diameter. The optical surfaces for these mirrors can be manufactured to the accuracy limited by the surface metrology. We have developed metrology systems that are specifically optimized for measuring very large convex aspheric surfaces. Large aperture vibration insensitive sub-aperture Fizeau interferometer combined with stitching software give high resolution surface measurements. The global shape is corroborated with a coordinate measuring machine based on the swing arm profilometer.
Mohanasubha, R.; Chandrasekar, V. K.; Senthilvelan, M.; Lakshmanan, M.
2015-01-01
We unearth the interconnection between various analytical methods which are widely used in the current literature to identify integrable nonlinear dynamical systems described by third-order nonlinear ODEs. We establish an important interconnection between the extended Prelle–Singer procedure and λ-symmetries approach applicable to third-order ODEs to bring out the various linkages associated with these different techniques. By establishing this interconnection we demonstrate that given any one of the quantities as a starting point in the family consisting of Jacobi last multipliers, Darboux polynomials, Lie point symmetries, adjoint-symmetries, λ-symmetries, integrating factors and null forms one can derive the rest of the quantities in this family in a straightforward and unambiguous manner. We also illustrate our findings with three specific examples.
A third-order multistep time discretization for a Chebyshev tau spectral method
NASA Astrophysics Data System (ADS)
Vreman, A. W.; Kuerten, J. G. M.
2016-01-01
A time discretization scheme based on the third-order backward difference formula has been embedded into a Chebyshev tau spectral method for the Navier-Stokes equations. The time discretization is a variant of the second-order backward scheme proposed by Krasnov et al. (2008) [3]. High-resolution direct numerical simulations of turbulent incompressible channel flow have been performed to compare the backward scheme to the Runge-Kutta scheme proposed by Spalart et al. (1991) [2]. It is shown that the Runge-Kutta scheme leads to a poor convergence of some third-order spatial derivatives in the direct vicinity of the wall, derivatives that represent the diffusion of wall-tangential vorticity. The convergence at the wall is shown to be significantly improved if the backward scheme is applied.
NASA Astrophysics Data System (ADS)
Yan, Hao-Peng; Liu, Wen-Biao
2016-08-01
Using Parikh-Wilczek tunneling framework, we calculate the tunneling rate from a Schwarzschild black hole under the third order WKB approximation, and then obtain the expressions for emission spectrum and black hole entropy to the third order correction. The entropy contains four terms including the Bekenstein-Hawking entropy, the logarithmic term, the inverse area term, and the square of inverse area term. In addition, we analyse the correlation between sequential emissions under this approximation. It is shown that the entropy is conserved during the process of black hole evaporation, which consists with the request of quantum mechanics and implies the information is conserved during this process. We also compare the above result with that of pure thermal spectrum case, and find that the non-thermal correction played an important role.
Mitsuishi, Kazutaka; Takeguchi, Masaki; Kondo, Yukihito; Hosokawa, Fumio; Okamoto, Kimiharu; Sannomiya, Takumi; Hori, Madoka; Iwama, Takeshi; Kawazoe, Muneyuki; Furuya, Kazuo
2006-12-01
Initial results from an ultrahigh-vacuum (UHV) third-order spherical aberration (Cs) corrector for a dedicated scanning transmission electron microscopy, installed at the National Institute for Materials Science, Tsukuba, Japan, are presented here. The Cs corrector is of the dual hexapole type. It is UHV compatible and was installed on a UHV column. The Ronchigram obtained showed an extension of the sweet spot area, indicating a successful correction of the third-order spherical aberration Cs. The power spectrum of an image demonstrated that the resolution achieved was 0.1 nm. A first trial of the direct measurement of the fifth-order spherical aberration C5 was also attempted on the basis of a Ronchigram fringe measurement. PMID:19830936
Thermodynamics of asymptotically flat charged black holes in third order Lovelock gravity
Dehghani, M.H.; Shamirzaie, M.
2005-12-15
We present a new class of asymptotically flat charge static solutions in third order Lovelock gravity. These solutions present black hole solutions with two inner and outer event horizons, extreme black holes, or naked singularities provided the parameters of the solutions are chosen suitable. We find that the uncharged asymptotically flat solutions can present black holes with two inner and outer horizons. This kind of solution does not exist in Einstein or Gauss-Bonnet gravity, and it is a special effect in third order Lovelock gravity. We compute temperature, entropy, charge, electric potential, and mass of the black hole solutions, and find that these quantities satisfy the first law of thermodynamics. We also perform a stability analysis by computing the determinant of the Hessian matrix of the mass with respect to its thermodynamic variables in both the canonical and the grand-canonical ensembles, and show that there exists only an intermediate stable phase.
NASA Astrophysics Data System (ADS)
Aghababaei, Ramin; Reddy, J. N.
2009-09-01
The third-order shear deformation plate theory of Reddy [A simple higher-order theory for laminated composite plates, J. Appl. Mech. 51 (1984) 745-752] is reformulated using the nonlocal linear elasticity theory of Eringen. This theory has ability to capture the both small scale effects and quadratic variation of shear strain and consequently shear stress through the plate thickness. Analytical solutions of bending and free vibration of a simply supported rectangular plate are presented using this theory to illustrate the effect of nonlocal theory on deflection and natural frequency of the plates. Finally, the relations between nonlocal third-order, first-order and classical theories are discussed by numerical results.
Axion as a cold dark matter candidate: analysis to third order perturbation for classical axion
NASA Astrophysics Data System (ADS)
Noh, Hyerim; Hwang, Jai-chan; Park, Chan-Gyung
2015-12-01
We investigate aspects of axion as a coherently oscillating massive classical scalar field by analyzing third order perturbations in Einstein's gravity in the axion-comoving gauge. The axion fluid has its characteristic pressure term leading to an axion Jeans scale which is cosmologically negligible for a canonical axion mass. Our classically derived axion pressure term in Einstein's gravity is identical to the one derived in the non-relativistic quantum mechanical context in the literature. We present the general relativistic continuity and Euler equations for an axion fluid valid up to third order perturbation. Equations for axion are exactly the same as that of a zero-pressure fluid in Einstein's gravity except for an axion pressure term in the Euler equation. Our analysis includes the cosmological constant.
The determination of third order linear models from a seventh order nonlinear jet engine model
NASA Technical Reports Server (NTRS)
Lalonde, Rick J.; Hartley, Tom T.; De Abreu-Garcia, J. Alex
1989-01-01
Results are presented that demonstrate how good reduced-order models can be obtained directly by recursive parameter identification using input/output (I/O) data of high-order nonlinear systems. Three different methods of obtaining a third-order linear model from a seventh-order nonlinear turbojet engine model are compared. The first method is to obtain a linear model from the original model and then reduce the linear model by standard reduction techniques such as residualization and balancing. The second method is to identify directly a third-order linear model by recursive least-squares parameter estimation using I/O data of the original model. The third method is to obtain a reduced-order model from the original model and then linearize the reduced model. Frequency responses are used as the performance measure to evaluate the reduced models. The reduced-order models along with their Bode plots are presented for comparison purposes.
Divertor with a third-order null of the poloidal field
Ryutov, D. D.; Umansky, M. V.
2013-09-15
A concept and preliminary feasibility analysis of a divertor with the third-order poloidal field null is presented. The third-order null is the point where not only the field itself but also its first and second spatial derivatives are zero. In this case, the separatrix near the null-point has eight branches, and the number of strike-points increases from 2 (as in the standard divertor) to six. It is shown that this magnetic configuration can be created by a proper adjustment of the currents in a set of three divertor coils. If the currents are somewhat different from the required values, the configuration becomes that of three closely spaced first-order nulls. Analytic approach, suitable for a quick orientation in the problem, is used. Potential advantages and disadvantages of this configuration are briefly discussed.
Gillman, A.; Amadio, G.; Matouš, K.; Jackson, T. L.
2015-01-01
Obtaining an accurate higher order statistical description of heterogeneous materials and using this information to predict effective material behaviour with high fidelity has remained an outstanding problem for many years. In a recent letter, Gillman & Matouš (2014 Phys. Lett. A 378, 3070–3073. ()) accurately evaluated the three-point microstructural parameter that arises in third-order theories and predicted with high accuracy the effective thermal conductivity of highly packed material systems. Expanding this work here, we predict for the first time effective thermo-mechanical properties of granular Platonic solid packs using third-order statistical micromechanics. Systems of impenetrable and penetrable spheres are considered to verify adaptive methods for computing n-point probability functions directly from three-dimensional microstructures, and excellent agreement is shown with simulation. Moreover, a significant shape effect is discovered for the effective thermal conductivity of highly packed composites, whereas a moderate shape effect is exhibited for the elastic constants. PMID:27547103
Maxwell's second- and third-order equations of transfer for non-Maxwellian gases
NASA Technical Reports Server (NTRS)
Baganoff, D.
1992-01-01
Condensed algebraic forms for Maxwell's second- and third-order equations of transfer are developed for the case of molecules described by either elastic hard spheres, inverse-power potentials, or by Bird's variable hard-sphere model. These hardly reduced, yet exact, equations provide a new point of origin, when using the moment method, in seeking approximate solutions in the kinetic theory of gases for molecular models that are physically more realistic than that provided by the Maxwell model. An important by-product of the analysis when using these second- and third-order relations is that a clear mathematical connection develops between Bird's variable hard-sphere model and that for the inverse-power potential.
Wave-dispersed third-order nonlinear optical properties of C 60 thin films
NASA Astrophysics Data System (ADS)
Kajzar, F.; Taliani, C.; Danieli, R.; Rossini, S.; Zamboni, R.
1994-01-01
Results of wave-dispersed third harmonic generation measurements in sublimed C 60 thin films are reported and discussed within a three-level model. Two strong resonant enhancements in cubic susceptibility χ (3)(-3ω; ω, ω, ω) are observed. The first one, occurring at a fundamental wavelength of 1.3 μm with a χ (3)(-3ω; ω, ω, ω) maximum value of 6.1×10 -11 esu, is interpreted in terms of a two-photon resonance with the one-photon forbidden electronic T 1g level. The second resonance at 1.064 μm, with a maximum value of χ (3)(-3ω; ω, ω, ω)=8.2×10 -11 esu is interpreted as a three-photon resonance with the lowest one-photon allowed T 1u electronic level.
NASA Astrophysics Data System (ADS)
Nagai, Hiroshi; Nakano, Masayoshi; Yoneda, Kyohei; Fukui, Hitoshi; Minami, Takuya; Bonness, Sean; Kishi, Ryohei; Takahashi, Hideaki; Kubo, Takashi; Kamada, Kenji; Ohta, Koji; Champagne, Benoît; Botek, Edith
2009-08-01
Using hybrid density functional theory methods, we investigate the second hyperpolarizabilities ( γ) of hexagonal shaped finite graphene fragments, which are referred to as hexagonal graphene nanoflakes (HGNFs), with two types of edge shapes: zigzag (Z) and armchair (A) edges. It is found that Z-HGNF, which gives intermediate diradical characters ( y), exhibits about 3.3 times larger orthogonal components of γ ( γ xxxx = γ yyyy in this case) than A-HGNF, which gives zero y value (closed-shell system). The γ density analysis reveals that this enhancement originates in the significant contribution of γ densities on edge regions in Z-HGNF. These observations strongly indicate that Z-HGNF is a promising candidate of open-shell singlet NLO systems.
Third-order accurate entropy-stable schemes for initial-boundary-value conservation laws
NASA Astrophysics Data System (ADS)
Svärd, Magnus
2012-08-01
We consider initial-boundary-value conservation laws with the objective to obtain high-order approximations. We study two different approaches to obtain third-order accuracy, local entropy stability and a global bound on the entropy. The results are applicable to, for example the Euler equations of gas dynamics, for which we present numerical results demonstrating the robustness and accuracy of the scheme.
Transformation properties and third-order aberrations of thin dynamic χ(2) holograms
NASA Astrophysics Data System (ADS)
Miloglyadov, E. V.; Stasel'ko, D. I.
2016-07-01
The results of a theoretical study of the transformation properties of thin dynamic χ(2) holograms for all frequency mixing versions are generalized, and a general pattern of transformations of reconstructed images (recorded and read at different frequencies) is developed. The principles of ray geometric construction of reconstructed images are determined. The theory of thin dynamic χ(2) holograms is extended to the range of third-order aberrations.
Third-order 2N-storage Runge-Kutta schemes with error control
NASA Technical Reports Server (NTRS)
Carpenter, Mark H.; Kennedy, Christopher A.
1994-01-01
A family of four-stage third-order explicit Runge-Kutta schemes is derived that requires only two storage locations and has desirable stability characteristics. Error control is achieved by embedding a second-order scheme within the four-stage procedure. Certain schemes are identified that are as efficient and accurate as conventional embedded schemes of comparable order and require fewer storage locations.
NASA Astrophysics Data System (ADS)
Gariel, J.; Marcilhacy, G.; Santos, N. O.
2008-02-01
We extend the method of separation of variables, studied by Léauté and Marcilhacy [Ann. Inst. Henri Poincare, Sect. A 331, 363 (1979)], to obtain transcendent solutions of the field equations for stationary axisymmetric systems. These solutions depend on transcendent functions satisfying a third order differential equation. For some solutions this equation satisfies the necessary conditions, but not sufficient, to have fixed critical points.
Subpiosecond Third Order Nonlinear Response in Polythiophene and Thiopene Based Thin Films
NASA Technical Reports Server (NTRS)
Harris, D.; Royer, E.; Dorsinville, R.
1995-01-01
Ultrafast relaxation kinetics of the third order nonlinear susceptibility of polythiophene and polycondensed thiophene-based polymer was determined by the forward degenerate four-wave mixing technique. Deep into the absorption band the nonlinear response shows only a fast component (less than 900 fs at 587 nm) while at the edge of the absorption band at 642 nm a much slower and complex decay was measured.
Chaotic attractors based on unstable dissipative systems via third-order differential equation
NASA Astrophysics Data System (ADS)
Campos-Cantón, E.
2016-07-01
In this paper, we present an approach how to yield 1D, 2D and 3D-grid multi-scroll chaotic systems in R3 based on unstable dissipative systems via third-order differential equation. This class of systems is constructed by a switching control law(SCL) changing the equilibrium point of an unstable dissipative system. The switching control law that governs the position of the equilibrium point varies according to the number of scrolls displayed in the attractor.
Dynamic properties and third order diffusion coefficients of ions in electrostatic fields
NASA Astrophysics Data System (ADS)
Koutselos, Andreas D.
1997-05-01
Velocity correlation functions and third order diffusion coefficients of ions moving in a buffer gas under the influence of an electrostatic field are determined via molecular dynamics simulation. For the closed shell system of K+ in Ar using a universal interaction model potential, the general form of the third order correlation functions is found to be monotonically decaying in time except in the cases of <ΔvZ(0)ΔvX(t)2>, <ΔvZ(0)ΔvY(t)2>, and <ΔvZ(0)ΔvZ(t)2>, with Δv(t)=v(t) -
NASA Astrophysics Data System (ADS)
Rahmani, O.; Jandaghian, A. A.
2015-06-01
In this paper, a general third-order beam theory that accounts for nanostructure-dependent size effects and two-constituent material variation through the nanobeam thickness, i.e., functionally graded material (FGM) beam is presented. The material properties of FG nanobeams are assumed to vary through the thickness according to the power law. A detailed derivation of the equations of motion based on Eringen nonlocal theory using Hamilton's principle is presented, and a closed-form solution is derived for buckling behavior of the new model with various boundary conditions. The nonlocal elasticity theory includes a material length scale parameter that can capture the size effect in a functionally graded material. The proposed model is efficient in predicting the shear effect in FG nanobeams by applying third-order shear deformation theory. The proposed approach is validated by comparing the obtained results with benchmark results available in the literature. In the following, a parametric study is conducted to investigate the influences of the length scale parameter, gradient index, and length-to-thickness ratio on the buckling of FG nanobeams and the improvement on nonlocal third-order shear deformation theory comparing with the classical (local) beam model has been shown. It is found out that length scale parameter is crucial in studying the stability behavior of the nanobeams.
Relationship between second- and third-order acoustic nonlinear parameters in relative measurement.
Ren, Gang; Kim, Jongboem; Jhang, Kyung-Young
2015-02-01
The higher-order acoustic nonlinear parameters are considered effective damage indices in the field of nondestructive evaluation (NDE). They are defined by using the displacement amplitudes of the fundamental frequency and the harmonics, which are called the absolute nonlinear parameters. Generally, however, it is difficult to measure the very small displacement amplitudes of high-frequency harmonics. Therefore, the simplified parameters using the detected wave signal amplitudes, which are known as the relative nonlinear parameters, have been widely used, although their applications are limited to the relative comparison of before and after damage of a single material under consistent experimental circumstances. In this paper, in order to make clear the concept of relative parameter, we presented first that the relative ratio of the simplified parameters is identical to that of the absolute parameters when the detected signal amplitudes are linearly proportional to the actual displacement amplitudes with respect to the fundamental frequency and the harmonics. In addition, the new relationship between the relative ratio of simplified second-order parameter and the relative ratio of simplified third-order parameter was derived from the relationship between the absolute second- and third-order parameters. This new relationship was successfully verified based on experimental results obtained from Al 6061-T6 processed for different heat treatment times, where it was confirmed in advance that the PZT detection signal amplitudes at the fundamental frequency and its second- and third-order harmonics were linearly proportional to the displacement amplitudes. PMID:25455194
Compensation of nonlinear phase shifts with third-order dispersion in short-pulse fiber amplifiers.
Zhou, Shian; Kuznetsova, Lyuba; Chong, Andy; Wise, Frank
2005-06-27
We show that nonlinear phase shifts and third-order dispersion can compensate each other in short-pulse fiber amplifiers. This compen-sation can be exploited in any implementation of chirped-pulse amplification, with stretching and compression accomplished with diffraction gratings, single-mode fiber, microstructure fiber, fiber Bragg gratings, etc. In particular, we consider chirped-pulse fiber amplifiers at wavelengths for which the fiber dispersion is normal. The nonlinear phase shift accumulated in the amplifier can be compensated by the third-order dispersion of the combination of a fiber stretcher and grating compressor. A numerical model is used to predict the compensation, and experimental results that exhibit the main features of the calculations are presented. In the presence of third-order dispersion, an optimal nonlinear phase shift reduces the pulse duration, and enhances the peak power and pulse contrast compared to the pulse produced in linear propagation. Contrary to common belief, fiber stretchers can perform as well or better than grating stretchers in fiber amplifiers, while offering the major practical advantages of a waveguide medium. PMID:19498473
Optical design for large depth of field
NASA Astrophysics Data System (ADS)
Shen, Yang; Wang, Hu; Yue, Pan; Xue, Yaoke; Liu, Jie; Ye, Shuifu
2016-01-01
Optical system with large depth of field and large field of view has been designed. To enforce optical system with focal length of 6 mm to imaging the object with object length of 200mmm-1200mm, accord to the equation of depth of field, in case of the CCD sensor with pixel of 5.5umx 5.5um square area, the entrance pupil diameter to ideal imaging will be 0.423mm. To enlarge the modulation transfer function (MTF) at spatial frequency of 90 lp/mm, the entrance pupil diameter is enlarged to 1mm.After design and optimization, with field of view of 80°, within object length of 200mm - 1200mm, the optical system can imaging well, the modulation transfer function (MTF) at spatial frequency of 90lp/mm is larger than 0.1, the distortion of full field of viewed is less than 3%.The optical system can be widely used in machine vision, surveillance cameras, etc.
Large area damage testing of optics
Sheehan, L.; Kozlowski, M.; Stolz, C.
1996-04-26
The damage threshold specifications for the National Ignition Facility will include a mixture of standard small-area tests and new large-area tests. During our studies of laser damage and conditioning processes of various materials we have found that some damage morphologies are fairly small and this damage does not grow with further illumination. This type of damage might not be detrimental to the laser performance. We should therefore assume that some damage can be allowed on the optics, but decide on a maximum damage allowance of damage. A new specification of damage threshold termed {open_quotes}functional damage threshold{close_quotes} was derived. Further correlation of damage size and type to system performance must be determined in order to use this measurement, but it is clear that it will be a large factor in the optics performance specifications. Large-area tests have verified that small-area testing is not always sufficient when the optic in question has defect-initiated damage. This was evident for example on sputtered polarizer and mirror coatings where the defect density was low enough that the features could be missed by standard small- area testing. For some materials, the scale-length at which damage non-uniformities occur will effect the comparison of small-area and large-area tests. An example of this was the sub-aperture tests on KD*P crystals on the Beamlet test station. The tests verified the large-area damage threshold to be similar to that found when testing a small-area. Implying that for this KD*P material, the dominate damage mechanism is of sufficiently small scale-length that small-area testing is capable of determining the threshold. The Beamlet test station experiments also demonstrated the use of on-line laser conditioning to increase the crystals damage threshold.
Large-scale polarimetry of large optical galaxies
NASA Astrophysics Data System (ADS)
Sholomitskii, G. B.; Maslov, I. A.; Vitrichenko, E. A.
1999-11-01
We present preliminary results of wide-field visual CCD polarimetry for large optical galaxies through a concentric multisector radial-tangential polaroid analyzer mounted at the intermediate focus of a Zeiss-1000 telescope. The mean degree of tangential polarization in a 13-arcmin field, which was determined by processing images with imprinted ``orthogonal'' sectors, ranges from several percent (M 82) and 0.51% (the spirals M 51, M 81) to lower values for elliptical galaxies (M 49, M 87). It is emphasized that the parameters of large-scale polarization can be properly determined by using physical models for galaxies; inclination and azimuthal dependences of the degree of polarization are given for spirals.
NASA Astrophysics Data System (ADS)
Rehbein, S.; Guttmann, P.; Werner, S.; Schneider, G.
2011-09-01
The Helmholtz-Zentrum Berlin (HZB) operates a transmission x-ray microscope (TXM) in the soft x-ray photon energy range with an energy resolution up to E/ΔE = 104 [1]. An approach to achieve ultrahigh spatial resolution with conventional, standard zone plate optics is to employ higher orders of diffraction of the zone plate objective [2]. In this paper, we demonstrate that 11-nm lines and spaces of a multilayer test structure are clearly resolved by the x-ray microscope using the third order of diffraction of a zone plate objective with 20-nm outermost zone width. The disadvantage of high-order imaging is an about one order of magnitude lower diffraction efficiency of the used zone plates employed in the third order compared to the first order of diffraction. In addition, the measured background signal in the TXM images is no longer negligible. Therefore, we worked on the fabrication of zone plates with sub-20-nm outermost zone width to increase the spatial resolution in the first order of diffraction. A new high-resolution 100-keV e-beam lithography system from VISTEC, which was recently installed at the Helmholtz-Zentrum Berlin, makes these developments possible. Initial results on zone plates with an outermost zone width down to 15 nm exposed with the new e-beam system are presented. Furthermore, the contrast transfer function of the transmission x-ray microscope operating in partial coherence mode is measured by using the first and third diffraction order of the zone plate objective.
Rehbein, S.; Guttmann, P.; Werner, S.; Schneider, G.
2011-09-09
The Helmholtz-Zentrum Berlin (HZB) operates a transmission x-ray microscope (TXM) in the soft x-ray photon energy range with an energy resolution up to E/{Delta}E = 10{sup 4}. An approach to achieve ultrahigh spatial resolution with conventional, standard zone plate optics is to employ higher orders of diffraction of the zone plate objective. In this paper, we demonstrate that 11-nm lines and spaces of a multilayer test structure are clearly resolved by the x-ray microscope using the third order of diffraction of a zone plate objective with 20-nm outermost zone width. The disadvantage of high-order imaging is an about one order of magnitude lower diffraction efficiency of the used zone plates employed in the third order compared to the first order of diffraction. In addition, the measured background signal in the TXM images is no longer negligible. Therefore, we worked on the fabrication of zone plates with sub-20-nm outermost zone width to increase the spatial resolution in the first order of diffraction. A new high-resolution 100-keV e-beam lithography system from VISTEC, which was recently installed at the Helmholtz-Zentrum Berlin, makes these developments possible. Initial results on zone plates with an outermost zone width down to 15 nm exposed with the new e-beam system are presented. Furthermore, the contrast transfer function of the transmission x-ray microscope operating in partial coherence mode is measured by using the first and third diffraction order of the zone plate objective.
Large directional optical anisotropy in multiferroic ferroborate
NASA Astrophysics Data System (ADS)
Kuzmenko, A. M.; Dziom, V.; Shuvaev, A.; Pimenov, Anna; Schiebl, M.; Mukhin, A. A.; Ivanov, V. Yu.; Gudim, I. A.; Bezmaternykh, L. N.; Pimenov, A.
2015-11-01
One of the most fascinating and counterintuitive recent effects in multiferroics is directional anisotropy, the asymmetry of light propagation with respect to the direction of propagation. In such case the absorption in a material can be different for opposite directions. Besides absorption, different velocities of light for different directions of propagation may be also expected, which is termed directional birefringence. In this work, we demonstrate large directional anisotropy in multiferroic samarium ferroborate. The effect is observed for linear polarization of light in the range of millimeter wavelengths, and it survives down to low frequencies. The dispersion and absorption close to the electromagnon resonance can be controlled by external magnetic field and are fully suppressed in one direction. By changing the geometry of the external field, samarium ferroborate shows giant optical activity, which makes this material a universal tool for optical control: with a magnetic field as an external parameter it allows switching between two functionalities: polarization rotation and directional anisotropy.
Optical metrology devices for high-power laser large optics
NASA Astrophysics Data System (ADS)
Daurios, J.; Bouillet, S.; Gaborit, G.; Poncetta, J. C.
2007-06-01
High power laser systems such as the LMJ laser or the LIL laser, its prototype, require large optical components with very strict and various specifications. Technologies used for the fabrication of these components are now usually compatible of such specifications, but need the implementation at the providers' sites of different kind of metrology like interferometry, photometry, surface inspection, etc., systematically performed on the components. So, during the production for the LIL and now for the LMJ, CEA has also equipped itself with a wide range of specific metrology devices used to verify the effective quality of these large optics. These various systems are now used to characterize and validate the LMJ vendors' processes or to perform specific controls dedicated to analyzes which are going further than the simple "quality control" of the component (mechanical mount effect, environment effect, ageing effect,...). After a short introduction on the LMJ laser and corresponding optical specifications for components, we will focus on different metrology devices concerning interferometry and photometry measurements or surface inspection. These systems are individually illustrated here by the mean of different results obtained during controls done in the last few years.
Pulse compression to 14 fs by third-order dispersion control in a hybrid grating-prism compressor.
Zeytunyan, Aram; Yesayan, Garegin; Mouradian, Levon
2013-11-10
A pulse compressor consisting of a fiber and a compact hybrid grating-prism dispersive delay line (DDL) is used to compress readily-available 140-fs pulses from a Ti:sapphire laser. We generate broadband pulses of up to 75 THz FWHM bandwidth in normally-dispersive single-mode conventional and photonic crystal fibers, with a potential of compression to 6 fs. Pulse dechirping in our hybrid DDL through second- and third-order dispersion (TOD) compensation results in 10× compression to 14 fs, limited by the bandwidth of the DDL transfer function and higher-order dispersion. The large tunability of the TOD of the hybrid DDL is shown. PMID:24216734
Large aperture adaptive optics for intense lasers
NASA Astrophysics Data System (ADS)
Deneuville, François; Ropert, Laurent; Sauvageot, Paul; Theis, Sébastien
2015-05-01
ISP SYSTEM has developed a range of large aperture electro-mechanical deformable mirrors (DM) suitable for ultra short pulsed intense lasers. The design of the MD-AME deformable mirror is based on force application on numerous locations thanks to electromechanical actuators driven by stepper motors. DM design and assembly method have been adapted to large aperture beams and the performances were evaluated on a first application for a beam with a diameter of 250mm at 45° angle of incidence. A Strehl ratio above 0.9 was reached for this application. Simulations were correlated with measurements on optical bench and the design has been validated by calculation for very large aperture (up to Ø550mm). Optical aberrations up to Zernike order 5 can be corrected with a very low residual error as for actual MD-AME mirror. Amplitude can reach up to several hundreds of μm for low order corrections. Hysteresis is lower than 0.1% and linearity better than 99%. Contrary to piezo-electric actuators, the μ-AME actuators avoid print-through effects and they permit to keep the mirror shape stable even unpowered, providing a high resistance to electro-magnetic pulses. The MD-AME mirrors can be adapted to circular, square or elliptical beams and they are compatible with all dielectric or metallic coatings.
Third-order TRANSPORT: A computer program for designing charged particle beam transport systems
Carey, D.C.; Brown, K.L.; Rothacker, F.
1995-05-01
TRANSPORT has been in existence in various evolutionary versions since 1963. The present version of TRANSPORT is a first-, second-, and third-order matrix multiplication computer program intended for the design of static-magnetic beam transport systems. This report discusses the following topics on TRANSPORT: Mathematical formulation of TRANSPORT; input format for TRANSPORT; summaries of TRANSPORT elements; preliminary specifications; description of the beam; physical elements; other transformations; assembling beam lines; operations; variation of parameters for fitting; and available constraints -- the FIT command.
Triska, F.J.; Kennedy, V.C.; Avanzino, R.J.; Zellweger, G.W.; Bencala, K.E.
1989-01-01
Chloride and nitrate were coinjected into the surface waters of a third-order stream for 20 d to exmaine solute retention, and the fate of nitrate during subsurface transport. A series of wells (shallow pits) 0.5-10 m from the adjacent channel were sampled to estimate the lateral interflow of water. Two subsurface return flows beneath the wetted channel were also examined. Results indicated that the capacity of the hyporheic zone for transient solute storage and as potential biological habitat varies with channel morphology, bed roughness, and permeability. A conceptual model that considers the groundwater-stream water interface as the fluvial boundary is proposed. -from Authors
Third-order elastic constants of diamond determined from experimental data
NASA Astrophysics Data System (ADS)
Winey, J. M.; Hmiel, A.; Gupta, Y. M.
2016-06-01
The pressure derivatives of the second-order elastic constants (SOECs) of diamond were determined by analyzing previous sound velocity measurements under hydrostatic stress [McSkimin and Andreatch, J. Appl. Phys., vol. 43, 1972, pp. 2944] [4]. Our analysis corrects an error in the previously reported results. Using the corrected pressure derivatives, together with published data for the nonlinear elastic response of shock-compressed diamond [Lang and Gupta, Phys. Rev. Lett., vol. 106, 2011, pp. 125502] [3], a complete and corrected set of third-order elastic constants (TOECs) is presented that differs significantly from TOECs published previously.
X-ray third-order nonlinear dynamical diffraction in a crystal
Balyan, M. K.
2015-12-15
The dynamic diffraction of an X-ray wave in a crystal with a third-order nonlinear response to external field strength has been theoretically investigated. General equations for the wave propagation in crystal and nonlinear Takagi equations for both ideal and deformed crystals are derived. Integrals of motion are determined for the nonlinear problem of dynamic diffraction. The results of the numerical calculations of reflectivity in the symmetric Laue geometry for an incident plane wave and the intensity distributions on the output crystal surface for a point source are reported as an example.
On scaling properties of crossing the third-order resonance in particle accelerator
Lee, S.Y.; Pang, X.; Jing, Y.; Luo, T.; Ng, K.Y.; /Fermilab
2011-12-01
We study effects of charged particle beams crossing a third-order resonance in an accelerator. The distortion of invariant torus during the resonance crossing is used to set 20% emittance growth or 2.5% of trap fraction as the critical resonance strength. We find a simple scaling law for the critical resonance strength vs the tune ramp rate and the initial emittance. The scaling law can be derived by solving Hamilton's equation of motion with stationary phase condition. Such scaling law can be used to evaluate the performance in high power accelerators, such as the FFAG and cyclotron.
Effect of vorticity on second- and third-order statistics of passive scalar gradients.
Gonzalez, Michel
2002-05-01
The influence of vorticity on second- and third-order moments of the spatial derivatives of a forced, passive scalar field has been studied in the framework of a simplified problem; the analysis is restricted to dominating rotation and molecular diffusion is represented by a linear model. The results reveal that, in the case of a passive scalar experiencing forcing in an isotropic medium, both vorticity and diffusion counteract anisotropy imposed on the scalar field. Anisotropy at the level of second-order moments appears to be destroyed essentially by the action of vorticity. PMID:12059703
Large extinction ratio optical electrowetting shutter.
Montoya, Ryan D; Underwood, Kenneth; Terrab, Soraya; Watson, Alexander M; Bright, Victor M; Gopinath, Juliet T
2016-05-01
A large extinction ratio optical shutter has been demonstrated using electrowetting liquids. The device is based on switching between a liquid-liquid interface curvature that produces total internal reflection and one that does not. The interface radius of curvature can be tuned continuously from 9 mm at 0 V to -45 mm at 26 V. Extinction ratios from 55.8 to 66.5 dB were measured. The device shows promise for ultracold chip-scale atomic clocks. PMID:27137579
Chen, Yong; Yan, Zhenya
2016-01-01
Solitons are of the important significant in many fields of nonlinear science such as nonlinear optics, Bose-Einstein condensates, plamas physics, biology, fluid mechanics, and etc. The stable solitons have been captured not only theoretically and experimentally in both linear and nonlinear Schrödinger (NLS) equations in the presence of non-Hermitian potentials since the concept of the parity-time -symmetry was introduced in 1998. In this paper, we present novel bright solitons of the NLS equation with third-order dispersion in some complex -symmetric potentials (e.g., physically relevant -symmetric Scarff-II-like and harmonic-Gaussian potentials). We find stable nonlinear modes even if the respective linear -symmetric phases are broken. Moreover, we also use the adiabatic changes of the control parameters to excite the initial modes related to exact solitons to reach stable nonlinear modes. The elastic interactions of two solitons are exhibited in the third-order NLS equation with -symmetric potentials. Our results predict the dynamical phenomena of soliton equations in the presence of third-order dispersion and -symmetric potentials arising in nonlinear fiber optics and other physically relevant fields. PMID:27002543
Chen, Yong; Yan, Zhenya
2016-01-01
Solitons are of the important significant in many fields of nonlinear science such as nonlinear optics, Bose-Einstein condensates, plamas physics, biology, fluid mechanics, and etc. The stable solitons have been captured not only theoretically and experimentally in both linear and nonlinear Schrödinger (NLS) equations in the presence of non-Hermitian potentials since the concept of the parity-time -symmetry was introduced in 1998. In this paper, we present novel bright solitons of the NLS equation with third-order dispersion in some complex -symmetric potentials (e.g., physically relevant -symmetric Scarff-II-like and harmonic-Gaussian potentials). We find stable nonlinear modes even if the respective linear -symmetric phases are broken. Moreover, we also use the adiabatic changes of the control parameters to excite the initial modes related to exact solitons to reach stable nonlinear modes. The elastic interactions of two solitons are exhibited in the third-order NLS equation with -symmetric potentials. Our results predict the dynamical phenomena of soliton equations in the presence of third-order dispersion and -symmetric potentials arising in nonlinear fiber optics and other physically relevant fields. PMID:27002543
NASA Astrophysics Data System (ADS)
Chen, Yong; Yan, Zhenya
2016-03-01
Solitons are of the important significant in many fields of nonlinear science such as nonlinear optics, Bose-Einstein condensates, plamas physics, biology, fluid mechanics, and etc. The stable solitons have been captured not only theoretically and experimentally in both linear and nonlinear Schrödinger (NLS) equations in the presence of non-Hermitian potentials since the concept of the parity-time -symmetry was introduced in 1998. In this paper, we present novel bright solitons of the NLS equation with third-order dispersion in some complex -symmetric potentials (e.g., physically relevant -symmetric Scarff-II-like and harmonic-Gaussian potentials). We find stable nonlinear modes even if the respective linear -symmetric phases are broken. Moreover, we also use the adiabatic changes of the control parameters to excite the initial modes related to exact solitons to reach stable nonlinear modes. The elastic interactions of two solitons are exhibited in the third-order NLS equation with -symmetric potentials. Our results predict the dynamical phenomena of soliton equations in the presence of third-order dispersion and -symmetric potentials arising in nonlinear fiber optics and other physically relevant fields.
Optical encryption for large-sized images
NASA Astrophysics Data System (ADS)
Sanpei, Takuho; Shimobaba, Tomoyoshi; Kakue, Takashi; Endo, Yutaka; Hirayama, Ryuji; Hiyama, Daisuke; Hasegawa, Satoki; Nagahama, Yuki; Sano, Marie; Oikawa, Minoru; Sugie, Takashige; Ito, Tomoyoshi
2016-02-01
We propose an optical encryption framework that can encrypt and decrypt large-sized images beyond the size of the encrypted image using our two methods: random phase-free method and scaled diffraction. In order to record the entire image information on the encrypted image, the large-sized images require the random phase to widely diffuse the object light over the encrypted image; however, the random phase gives rise to the speckle noise on the decrypted images, and it may be difficult to recognize the decrypted images. In order to reduce the speckle noise, we apply our random phase-free method to the framework. In addition, we employ scaled diffraction that calculates light propagation between planes with different sizes by changing the sampling rates.
Traversable wormholes satisfying the weak energy condition in third-order Lovelock gravity
NASA Astrophysics Data System (ADS)
Zangeneh, Mahdi Kord; Lobo, Francisco S. N.; Dehghani, Mohammad Hossein
2015-12-01
In this paper, we consider third-order Lovelock gravity with a cosmological constant term in an n -dimensional spacetime M4×Kn -4, where Kn -4 is a constant curvature space. We decompose the equations of motion to four and higher dimensional ones and find wormhole solutions by considering a vacuum Kn -4 space. Applying the latter constraint, we determine the second- and third-order Lovelock coefficients and the cosmological constant in terms of specific parameters of the model, such as the size of the extra dimensions. Using the obtained Lovelock coefficients and Λ , we obtain the four-dimensional matter distribution threading the wormhole. Furthermore, by considering the zero tidal force case and a specific equation of state, given by ρ =(γ p -τ )/[ω (1 +γ )], we find the exact solution for the shape function which represents both asymptotically flat and nonflat wormhole solutions. We show explicitly that these wormhole solutions in addition to traversibility satisfy the energy conditions for suitable choices of parameters and that the existence of a limited spherically symmetric traversable wormhole with normal matter in a four-dimensional spacetime implies a negative effective cosmological constant.
Regenerator performance in a Vuilleumier refrigerator compared with a third-order numerical model
NASA Technical Reports Server (NTRS)
Bradley, P. E.; Radebaugh, Ray; Gary, John
1991-01-01
A three-stage Vuilleumier refrigerator was used to measure the performance of various third stage regenerators. The refrigerator operates between 2.5 and 5.0 Hz and, depending on the material used in the third stage regenerator, achieves temperatures of 8 to 20 K at the cold end of the third stage. This paper presents a comparison of regenerator performance for four regenerator materials: 229 micron diameter spheres of Pb(+)5 pct Sb, 229 micron diameter spheres of brass, 216 micron irregularly-shaped GdRh powder, and a mixture of 229 microns and 762 microns diameter spheres of Pb(+5) pct Sb. The experimental results are compared with a first-order model that neglects the void volume within the regenerator and with a third-order model that considers the effect of pressure oscillations in the regenerator void volume. Experimental results indicate that regenerator losses are dominated by the pressure oscillation in the void volume rather than the mass flow through the temperature gradient in the regenerator. These results are consistent with the third-order numerical model. This model shows that the heat capacity of the gas in the void space as well as the heat capacity of the matrix influences the regenerator performance.