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Sample records for near-field optical recording

  1. Ultrahigh-Density Storage Media for Near-Field Optical Recording

    NASA Astrophysics Data System (ADS)

    Hieda, Hiroyuki; Naito, Katsuyuki; Ishino, Takashi; Tanaka, Kuniyoshi; Sakurai, Masatoshi; Kamata, Yoshiyuki; Morita, Seiji; Kikitsu, Akira; Asakawa, Koji

    Two types of recording media possessing nano-dot structures were investigated. The media were prepared by an artificially assisted (or aligned) self-assembling (AASA) method, which includes simple nano-patterning using a nano-imprint and fine nano-patterning using self-assembling organic molecules. The AASA method were successfully applied to fabricate magnetic patterned media for opto-magnetic hybrid recordings and fluorescent organic dye media for near-field optical recording.

  2. Observation of Amorphous Recording Marks Using Reflection-Mode Near-Field Scanning Optical Microscope Supported by Optical Interference Method

    NASA Astrophysics Data System (ADS)

    Sakai, Masaru; Mononobe, Shuji; Yusu, Keiichiro; Tadokoro, Toshiyasu; Saiki, Toshiharu

    2005-09-01

    A signal enhancing technique for a reflection-mode near-field scanning optical microscope (NSOM) is proposed. Optical interference between the signal light, from an aperture at the tip of a tapered optical fiber, and the reflected light, from a metallic coating around the aperture, enhances the signal intensity. We used a rewritable high-definition digital versatile disc (HD DVD) with dual recording layers as a sample medium, and demonstrated observation of amorphous recording marks on the semitransparent (the first) recording layer. In spite of low optical contrast between the crystal region and the amorphous region on this layer, we successfully observed recording marks with good contrast.

  3. Design and control of dual servo actuator for near field optical recording system

    NASA Astrophysics Data System (ADS)

    Jeong, Jaehwa; Choi, Young-Man; Lee, Jun-Hee; Yoon, Hyoung-Kil; Gweon, Dae-Gab

    2005-12-01

    Near field recording (NFR) has been introduced as a new optical data storage method to realize higher data density beyond the diffraction limit. As the data density increases, the track pitch is remarkably reduced to about 400nm. Thus, more precise actuator is required and we propose a dual servo actuator to improve the accuracy of actuator. The proposed dual servo actuator consists of a coarse actuator and a fine actuator, multisegmented magnet array (MSMA) voice coil motor (VCM) and PMN-PT actuator. In design of VCM actuator, a novel magnetic circuit of VCM with MSMA is proposed. It can generate higher air gap flux density than the magnetic circuit of VCM with the conventional magnet array. In design of fine actuator, the fine actuator including PMN-PT single crystal instead of the conventional PZT is proposed. The displacement gain of PMN-PT fine actuator is 26 nm/V and that of PZT fine actuator is 17 nm/V. The displacement gain is increased by 53 %. To evaluate tracking performance of the manufactured dual servo actuator and to assign the proper role to each actuator, the PQ method is selected. From experiment results, the total bandwidth of the dual servo actuator is increased to 2.5kHz and the resolution is 25 nm. Comparing with the resolution of one servo actuator, 70 nm, we can find that the accuracy of actuator is remarkably improved. And the proposed dual servo actuator shows satisfactory performances to be applied to NFR and it can be applied to other future disk drives.

  4. Numerical modeling of the subwavelength phase-change recording using an apertureless scanning near-field optical microscope.

    PubMed

    Grosges, Thomas; Petit, Stéphane; Barchiesi, Dominique; Hudlet, Sylvain

    2004-11-29

    The electromagnetic field enhancement (FE) at the end of the probe of an Apertureless Scanning Near-field Optical Microscope (ASNOM) is used to write nanometric dots in a phase-change medium. The FE acts as a heat source that allows the transition from amorphous to crystalline phase in a Ge2Sb2Te5 layer. Through the 2D Finite Element Method (FEM) we predict the size of the dot as a function of both the illumination duration and the incoming power density. Numerical results are found to be in good agreement with preliminary experimental data. PMID:19488240

  5. Quantitative imaging of the optical near field.

    PubMed

    Kühler, Paul; García de Abajo, F Javier; Leiprecht, Philipp; Kolloch, Andreas; Solis, Javier; Leiderer, Paul; Siegel, Jan

    2012-09-24

    When exposing small particles on a substrate to a light plane wave, the scattered optical near field is spatially modulated and highly complex. We show, for the particular case of dielectric microspheres, that it is possible to image these optical near-field distributions in a quantitative way. By placing a single microsphere on a thin film of the photosensitive phase change material Ge(2)Sb(5)Te(5) and exposing it to a single short laser pulse, the spatial intensity modulation of the near field is imprinted into the film as a pattern of different material phases. The resulting patterns are investigated by using optical as well as high-resolution scanning electron microscopy. Quantitative information on the local optical near field at each location is obtained by calibrating the material response to pulsed laser irradiation. We discuss the influence of polarization and angle of incidence of the laser beam as well as particle size on the field distribution. The experimental results are in good quantitative agreement with a model based on a rigorous solution of Maxwell's equations. Our results have potential application to near-field optical lithography and experimental determination of near fields in complex nanostructures. PMID:23037356

  6. Nanofabrication using near-field optical probes

    PubMed Central

    McLeod, Euan; Ozcan, Aydogan

    2012-01-01

    Nanofabrication using near-field optical probes is an established technique for rapid prototyping and automated maskless fabrication of nanostructured devices. In this review, we present the primary types of near-field probes and their physical processing mechanisms. Highlights of recent developments include improved resolution by optimizing the probe shape, incorporation of surface plasmonics in probe design, broader use in biological and magnetic storage applications, and increased throughput using probe arrays as well as high speed writing and patterning. PMID:22713756

  7. Near-field compact dielectric optics

    NASA Astrophysics Data System (ADS)

    Feuermann, Daniel; Gordon, Jeffrey M.; Ng, Tuck Wah

    2006-08-01

    Aplanatic optics crafted from transparent dielectrics can approach the etendue limit for radiative transfer in pragmatic near-field systems. Illustrations are presented for the more demanding realm of high numerical aperture (NA) at the source and/or target. These light couplers can alleviate difficulties in aligning system components, and can achieve the fundamental compactness limit for optical devices that satisfy Fermat's principle.

  8. Time-resolved phase-change recording mark formation with zinc oxide near-field optical active layer

    NASA Astrophysics Data System (ADS)

    Kao, Tsung Sheng; Chen, Mu-Ku; Chen, Jia-Wern; Chen, Yi-Hao; Wu, Pei Ru; Tsai, Din Ping

    2015-09-01

    In this paper, an optical active thin film of zinc oxide (ZnOx) nano-composites exploited for the enhancement of optical signals in an ultra-high density recording scheme has been demonstrated. Via the electron microscope investigation, the results display randomly distributed crystalline nanograins in the ZnOx thin films. Optical disks with the ZnOx nanostructured thin films show that the carrier-to-noise ratio (CNR) above 25 dB can be obtained at the mark trains of 100 nm, while the optimal writing power is reduced as a function of the increasing thickness of the ZnOx films. Furthermore, by conducting a series of the optical pump-probe experiments, the optical responses of recording marks on as-deposited phase-change Ge2Sb2Te5 (as-GST) recording layers present that the highly contrast bright recording bits can be acquired with the existence of the ZnOx nanostructured thin films, providing prospective potentials in future data storage and optoelectronic devices.

  9. Near-field optical microscopy nanoarray

    NASA Astrophysics Data System (ADS)

    Semin, David J.; Ambrose, W. Patrick; Goodwin, Peter M.; Wendt, Joel R.; Keller, Richard A.

    1997-04-01

    Multiplexing near-field scanning optical microscopy (NSOM) by the use of a nanoarray with parallel imaging is studied. The fabrication, characterization, and utilization of nanoarrays with approximately 100 nm diameter apertures spaced 500 nm center-to-center is presented. Extremely uniform nanoarrays with approximately 108 apertures were fabricated by electron beam lithography and reactive ion etching. The nanoarrays were characterized by atomic force microscopy and scanning electron microscopy. In this paper we utilize these nanoarrays in a laser-illuminated microscope with parallel detection on a charge-coupled device. Detection of B-phycoerythrin molecules using near- field illumination is presented. In principle, our system can be used to obtain high lateral resolution NSOM images over a wide-field of view (e.g. 50 - 100 micrometers ) within seconds.

  10. A near-field optical microscopy nanoarray

    SciTech Connect

    Semin, D.J.; Ambrose, W.P.; Goodwin, P.M.; Kwller, A.; Wendt, J.R.

    1996-12-31

    Multiplexing near-field scanning optical microscopy (NSOM) by the use of a nanoarray with parallel imaging is studied. The fabrication, characterization, and utilization of nanoarrays with {approximately} 100 nm diameter apertures spaced 500 nm center-to- center is presented. Extremely uniform nanoarrays with {approximately} 10{sup 8} apertures were fabricated by electron beam lithography and reactive ion etching. The nanoarrays were characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). In this paper we utilize these nanoarrays in a laser-illuminated microscope with parallel detection on a charge- coupled device (CCD). Detection of B-phycoerythrin (B-PE) molecules using near-field illumination is presented. In principle, our system can be used to obtain high lateral resolution NSOM images over a wide-field of view (e.g. 50-100 {mu}m) within seconds.

  11. Novel aluminum near field transducer and highly integrated micro-nano-optics design for heat-assisted ultra-high-density magnetic recording.

    PubMed

    Miao, Lingyun; Stoddart, Paul R; Hsiang, Thomas Y

    2014-07-25

    Heat-assisted magnetic recording (HAMR) has attracted increasing attention as one of the most promising future techniques for ultra-high-density magnetic recording beyond the current limit of 1 Tb in(-2). Localized surface plasmon resonance plays an important role in HAMR by providing a highly focused optical spot for heating the recording medium within a small volume. In this work, we report an aluminum near-field transducer (NFT) based on a novel bow-tie design. At an operating wavelength of 450 nm, the proposed transducer can generate a 35 nm spot size inside the magnetic recording medium, corresponding to a recording density of up to 2 Tb in(-2). A highly integrated micro-nano-optics design is also proposed to ensure process compatibility and corrosion-resistance of the aluminum NFT. Our work has demonstrated the feasibility of using aluminum as a plasmonic material for HAMR, with advantages of reduced cost and improved efficiency compared to traditional noble metals. PMID:24981413

  12. High-Speed Gap Servo Control for Solid-Immersion-Lens-Based Near-Field Recording System with a Flexible Optical Disk

    NASA Astrophysics Data System (ADS)

    Hwang, Hyunwoo; Kim, Jung-Gon; Song, Ki Wook; Park, Kyoung-Su; Park, No-cheol; Yang, Hyunseok; Rhim, Yoon-Chul; Park, Young-Pil

    2011-09-01

    Higher data storage capacities and higher data transfer rates will be required in next-generation information storage devices. However, there is a limit to the rotational speeds of conventional disk structures. Hence, conventional disks will not be able to achieve high data transfer rates of over 250 Mbps that is required for next-generation storage devices. To increase the data transfer rate of a disk, flexible optical disks have been studied with the goal of stable rotation at a high speed, using a stabilizer to reduce disk oscillations. If a flexible optical disk is implemented in a near-field recording (NFR) system, simultaneous high data transfer rates and high-density recording should be possible. In an NFR system, it is very important to maintain the gap between the solid immersion lens (SIL) and the disk at distances below tens of nanometers. In this study, to simultaneously achieve high data storage capacity and high data transfer rate, we propose an improved gap servo control system for an SIL-based NFR system with a flexible optical disk. To enable robust control at a high rotational speed, a repetitive controller was designed and applied to the NFR servo algorithm. In both simulation and experiment, the newly designed gap servo controller stably maintained the gap distance in the SIL-based NFR system using a flexible optical disk.

  13. Novel concepts in near-field optics: from magnetic near-field to optical forces

    NASA Astrophysics Data System (ADS)

    Yang, Honghua

    Driven by the progress in nanotechnology, imaging and spectroscopy tools with nanometer spatial resolution are needed for in situ material characterizations. Near-field optics provides a unique way to selectively excite and detect elementary electronic and vibrational interactions at the nanometer scale, through interactions of light with matter in the near-field region. This dissertation discusses the development and applications of near-field optical imaging techniques, including plasmonic material characterization, optical spectral nano-imaging and magnetic field detection using scattering-type scanning near-field optical microscopy (s-SNOM), and exploring new modalities of optical spectroscopy based on optical gradient force detection. Firstly, the optical dielectric functions of one of the most common plasmonic materials---silver is measured with ellipsometry, and analyzed with the Drude model over a broad spectral range from visible to mid-infrared. This work was motivated by the conflicting results of previous measurements, and the need for accurate values for a wide range of applications of silver in plasmonics, optical antennas, and metamaterials. This measurement provides a reference for dielectric functions of silver used in metamaterials, plasmonics, and nanophotonics. Secondly, I implemented an infrared s-SNOM instrument for spectroscopic nano-imaging at both room temperature and low temperature. As one of the first cryogenic s-SNOM instruments, the novel design concept and key specifications are discussed. Initial low-temperature and high-temperature performances of the instrument are examined by imaging of optical conductivity of vanadium oxides (VO2 and V2O 3) across their phase transitions. The spectroscopic imaging capability is demonstrated on chemical vibrational resonances of Poly(methyl methacrylate) (PMMA) and other samples. The third part of this dissertation explores imaging of optical magnetic fields. As a proof-of-principle, the magnetic

  14. Dynamic near-field optical interaction between oscillating nanomechanical structures

    PubMed Central

    Ahn, Phillip; Chen, Xiang; Zhang, Zhen; Ford, Matthew; Rosenmann, Daniel; Jung, II Woong; Sun, Cheng; Balogun, Oluwaseyi

    2015-01-01

    Near-field optical techniques exploit light-matter interactions at small length scales for mechanical sensing and actuation of nanomechanical structures. Here, we study the optical interaction between two mechanical oscillators—a plasmonic nanofocusing probe-tip supported by a low frequency cantilever, and a high frequency nanomechanical resonator—and leverage their interaction for local detection of mechanical vibrations. The plasmonic nanofocusing probe provides a confined optical source to enhance the interaction between the two oscillators. Dynamic perturbation of the optical cavity between the probe-tip and the resonator leads to nonlinear modulation of the scattered light intensity at the sum and difference of their frequencies. This double-frequency demodulation scheme is explored to suppress unwanted background and to detect mechanical vibrations with a minimum detectable displacement sensitivity of 0.45 pm/Hz1/2, which is limited by shot noise and electrical noise. We explore the demodulation scheme for imaging the bending vibration mode shape of the resonator with a lateral spatial resolution of 20 nm. We also demonstrate the time-resolved aspect of the local optical interaction by recording the ring-down vibrations of the resonator at frequencies of up to 129 MHz. The near-field optical technique is promising for studying dynamic mechanical processes in individual nanostructures. PMID:26014599

  15. Dynamic near-field optical interaction between oscillating nanomechanical structures

    SciTech Connect

    Ahn, Phillip; Chen, Xiang; Zhang, Zhen; Ford, Matthew; Rosenmann, Daniel; Jung, II Woong; Sun, Cheng; Balogun, Oluwaseyi

    2015-05-27

    Near-field optical techniques exploit light-matter interactions at small length scales for mechanical sensing and actuation of nanomechanical structures. Here, we study the optical interaction between two mechanical oscillators—a plasmonic nanofocusing probe-tip supported by a low frequency cantilever, and a high frequency nanomechanical resonator—and leverage their interaction for local detection of mechanical vibrations. The plasmonic nanofocusing probe provides a confined optical source to enhance the interaction between the two oscillators. Dynamic perturbation of the optical cavity between the probe-tip and the resonator leads to nonlinear modulation of the scattered light intensity at the sum and difference of their frequencies. This double-frequency demodulation scheme is explored to suppress unwanted background and to detect mechanical vibrations with a minimum detectable displacement sensitivity of 0.45pm/Hz1/2, which is limited by shot noise and electrical noise. We explore the demodulation scheme for imaging the bending vibration mode shape of the resonator with a lateral spatial resolution of 20nm. We also demonstrate the time-resolved aspect of the local optical interaction by recording the ring-down vibrations of the resonator at frequencies of up to 129MHz. The near-field optical technique is promising for studying dynamic mechanical processes in individual nanostructures.

  16. Dynamic near-field optical interaction between oscillating nanomechanical structures

    DOE PAGESBeta

    Ahn, Phillip; Chen, Xiang; Zhang, Zhen; Ford, Matthew; Rosenmann, Daniel; Jung, II Woong; Sun, Cheng; Balogun, Oluwaseyi

    2015-05-27

    Near-field optical techniques exploit light-matter interactions at small length scales for mechanical sensing and actuation of nanomechanical structures. Here, we study the optical interaction between two mechanical oscillators—a plasmonic nanofocusing probe-tip supported by a low frequency cantilever, and a high frequency nanomechanical resonator—and leverage their interaction for local detection of mechanical vibrations. The plasmonic nanofocusing probe provides a confined optical source to enhance the interaction between the two oscillators. Dynamic perturbation of the optical cavity between the probe-tip and the resonator leads to nonlinear modulation of the scattered light intensity at the sum and difference of their frequencies. This double-frequencymore » demodulation scheme is explored to suppress unwanted background and to detect mechanical vibrations with a minimum detectable displacement sensitivity of 0.45pm/Hz1/2, which is limited by shot noise and electrical noise. We explore the demodulation scheme for imaging the bending vibration mode shape of the resonator with a lateral spatial resolution of 20nm. We also demonstrate the time-resolved aspect of the local optical interaction by recording the ring-down vibrations of the resonator at frequencies of up to 129MHz. The near-field optical technique is promising for studying dynamic mechanical processes in individual nanostructures.« less

  17. Sample heating in near-field scanning optical microscopy

    NASA Astrophysics Data System (ADS)

    Erickson, Elizabeth S.; Dunn, Robert C.

    2005-11-01

    Heating near the aperture of aluminum coated, fiber optic near-field scanning optical microscopy probes was studied as a function of input and output powers. Using the shear-force feedback method, near-field probes were positioned nanometers above a thermochromic polymer and spectra were recorded as the input power was varied. Excitation at 405 nm of a thin polymer film incorporating perylene and N-allyl-N-methylaniline leads to dual emission peaks in the spectra. The relative peak intensity is temperature sensitive leading to a ratiometric measurement, which avoids complications based solely on intensity. Using this method, we find that the proximal end of typical near-field probes modestly increase in temperature to 40-45 °C at output powers of a few nanowatts (input power of ˜0.15mW). This increases to 55-65 °C at higher output powers of 50 nW or greater (input power of ˜2-4mW). Thermal heating of the probe at higher powers leads to probe elongation, which limits the heating experienced by the sample.

  18. Near-Field Magneto-Optical Microscope

    DOEpatents

    Vlasko-Vlasov, Vitalii; Welp, Ulrich; and Crabtree, George W.

    2005-12-06

    A device and method for mapping magnetic fields of a sample at a resolution less than the wavelength of light without altering the magnetic field of the sample is disclosed. A device having a tapered end portion with a magneto-optically active particle positioned at the distal end thereof in communication with a fiber optic for transferring incoming linearly polarized light from a source thereof to the particle and for transferring reflected light from the particle is provided. The fiber optic has a reflective material trapping light within the fiber optic and in communication with a light detector for determining the polarization of light reflected from the particle as a function of the strength and direction of the magnetic field of the sample. Linearly polarized light from the source thereof transferred to the particle positioned proximate the sample is affected by the magnetic field of the sample sensed by the particle such that the difference in polarization of light entering and leaving the particle is due to the magnetic field of the sample. Relative movement between the particle and sample enables mapping.

  19. Near Field Magneto-Optical Microscope

    DOEpatents

    Vlasko-Vlasov, Vitalii K.; Welp, Ulrich; Crabtree, George W.

    2005-12-06

    A device and method for mapping magnetic fields of a sample at a resolution less than the wavelength of light without altering the magnetic field of the sample is disclosed. A device having a tapered end portion with a magneto-optically active particle positioned at the distal end thereof in communication with a fiber optic for transferring incoming linearly polarized light from a source thereof to the particle and for transferring reflected light from the particle is provided. The fiber optic has a reflective material trapping light within the fiber optic and in communication with a light detector for determining the polarization of light reflected from the particle as a function of the strength and direction of the magnetic field of the sample. Linearly polarized light from the source thereof transferred to the particle positioned proximate the sample is affected by the magnetic field of the sample sensed by the particle such that the difference in polarization of light entering and leaving the particle is due to the magnetic field of the sample. Relative movement between the particle and sample enables mapping.

  20. Nonadiabatic photodissociation process using an optical near field.

    PubMed

    Kawazoe, Tadashi; Kobayashi, Kiyoshi; Takubo, Satoru; Ohtsu, Motoichi

    2005-01-01

    We demonstrated the deposition of nanometric Zn dots using photodissociation with gas-phase diethylzinc and an optical near field under nonresonant conditions. To explain the experimental results, we proposed an exciton-phonon polariton model, and discuss the quantitative experimental dependence of the deposition rate on the optical power and photon energy based on photodissociation involving multiple-step excitation via molecular vibration modes. The physical basis of this process, which seems to violate the Franck-Condon principle, is the optically nonadiabatic excitation of the molecular vibration mode due to the steep spatial gradient of the optical near-field energy. PMID:15638622

  1. Imaging Nanoscale Electromagnetic Near-Field Distributions Using Optical Forces.

    PubMed

    Huang, Fei; Tamma, Venkata Ananth; Mardy, Zahra; Burdett, Jonathan; Wickramasinghe, H Kumar

    2015-01-01

    We demonstrate the application of Atomic Force Microscopy (AFM) for mapping optical near-fields with nanometer resolution, limited only by the AFM probe geometry. By detecting the optical force between a gold coated AFM probe and its image dipole on a glass substrate, we profile the electric field distributions of tightly focused laser beams with different polarizations. The experimentally recorded focal force maps agree well with theoretical predictions based on a dipole-dipole interaction model. We experimentally estimate the aspect ratio of the apex of gold coated AFM probe using only optical forces. We also show that the optical force between a sharp gold coated AFM probe and a spherical gold nanoparticle of radius 15 nm, is indicative of the electric field distribution between the two interacting particles. Photo Induced Force Microscopy (PIFM) allows for background free, thermal noise limited mechanical imaging of optical phenomenon over wide range of wavelengths from Visible to RF with detection sensitivity limited only by AFM performance. PMID:26073331

  2. Signal of microstrip scanning near-field optical microscope in far- and near-field zones.

    PubMed

    Morozov, Yevhenii M; Lapchuk, Anatoliy S

    2016-05-01

    An analytical model of interference between an electromagnetic field of fundamental quasi-TM(EH)00-mode and an electromagnetic field of background radiation at the apex of a near-field probe based on an optical plasmon microstrip line (microstrip probe) has been proposed. The condition of the occurrence of electromagnetic energy reverse flux at the apex of the microstrip probe was obtained. It has been shown that the nature of the interference depends on the length of the probe. Numerical simulation of the sample scanning process was conducted in illumination-reflection and illumination-collection modes. Results of numerical simulation have shown that interference affects the scanning signal in both modes. However, in illumination-collection mode (pure near-field mode), the signal shape and its polarity are practically insensible to probe length change; only signal amplitude (contrast) is slightly changed. However, changing the probe length strongly affects the signal amplitude and shape in the illumination-reflection mode (the signal formed in the far-field zone). Thus, we can conclude that even small background radiation can significantly influence the signal in the far-field zone and has practically no influence on a pure near-field signal. PMID:27140358

  3. Near-field fiber optic chemical sensors and biological applications

    NASA Astrophysics Data System (ADS)

    Tan, Weihong; Shi, Zhong-You; Thorsrud, Bjorn A.; Harris, C.; Kopelman, Raoul

    1994-03-01

    Near-field optics has been applied in the nanofabrication of subwavelength optical fiber chemical and biological sensors and their operation in chemical and biological analysis. A thousandfold miniaturization of immobilized optical fiber sensors has been achieved by a near- field photo-nanofabrication technique, which is based on nanofabricated optical fiber tips and near-field photopolymerization. This technique has been further developed by multistep near- field nanofabrication and multidye probe fabrication. Multistep nanofabrication can further miniaturize optical fiber sensors, while multidye fabrication results in multifunctional optic and excitonic probes with extremely small size. These probes emit multiwavelength photons or produce excitons of different energy levels, and may have multiple chemical or biological sensitivities. The nondestructive submicrometer sensor has demonstrated its ability to carry out static and dynamic determinations of pH in intact rat conceptuses of varying gestational ages. The ability of the sensors to measure pH changes, in real time, in the intact rat conceptus, demonstrates their potential applications for dynamic analysis in multicellular organisms and single cells. The near-field interaction of photons with matter is discussed.

  4. Nano-Scale Fabrication Using Optical-Near-Field

    NASA Astrophysics Data System (ADS)

    Yatsui, Takashi; Ohtsu, Motoichi

    This paper reviews the specific nature of nanophotonics, i.e., a novel optical nano-technology, utilizing dressed photon excited in the nano-material. As examples of nanophotnic fabrication, optical near-field etching and increased spatial homogeneity of contents in compound semiconductors is demonstrated with a self-organized manner.

  5. Near-Field Scanning Optical Microscopy and Raman Microscopy.

    NASA Astrophysics Data System (ADS)

    Harootunian, Alec Tate

    1987-09-01

    Both a one dimensional near-field scanning optical microscope and Raman microprobe were constructed. In near -field scanning optical microscopy (NSOM) a subwavelength aperture is scanned in the near-field of the object. Radiation transmitted through the aperture is collected to form an image as the aperture scans over the object. The resolution of an NSOM system is essentially wavelength independent and is limited by the diameter of the aperture used to scan the object. NSOM was developed in an effort to provide a nondestructive in situ high spatial resolution probe while still utilizing photons at optical wavelengths. The Raman microprobe constructed provided vibrational Raman information with spatial resolution equivalent that of a conventional diffraction limited microscope. Both transmission studies and near-field diffration studies of subwavelength apertures were performed. Diffraction theories for a small aperture in an infinitely thin conducting screen, a slit in a thick conducting screen, and an aperture in a black screen were examined. All three theories indicate collimation of radiation to the size to the size of the subwavelength aperture or slit in the near-field. Theoretical calculations and experimental results indicate that light transmitted through subwavelength apertures is readily detectable. Light of wavelength 4579 (ANGSTROM) was transmitted through apertures with diameters as small as 300 (ANGSTROM). These studies indicate the feasibility of constructing an NSOM system. One dimensional transmission and fluorescence NSOM systems were constructed. Apertures in the tips of metallized glass pipettes width inner diameters of less than 1000 (ANGSTROM) were used as a light source in the NSOM system. A tunneling current was used to maintain the aperture position in the near-field. Fluorescence NSOM was demonstrated for the first time. Microspectroscopic and Raman microscopic studies of turtle cone oil droplets were performed. Both the Raman vibrational

  6. Nanostructuring thin polymer films with optical near fields.

    PubMed

    Martín-Fabiani, Ignacio; Siegel, Jan; Riedel, Stephen; Boneberg, Johannes; Ezquerra, Tiberio A; Nogales, Aurora

    2013-11-13

    In the present work, we report on the application of optical near fields to nanostructuring of poly(trimethylene terephthalate) (PTT) thin films. By exposure to a single ultraviolet nanosecond laser pulse, the spatial intensity modulation of the near-field distribution created by a silica microsphere is imprinted into the films. Setting different angles of incidence of the laser, elliptical or circular periodic ring patterns can be produced with periods as small as half the laser wavelength used. These highly complex patterns show optical and topographical contrast and can be characterized by optical microscopy (OM) and atomic force microscopy (AFM). We demonstrate the key role of the laser wavelength and coherence length in achieving smooth, extended patterns in PTT by using excimer laser (193 nm) and Nd:YAG laser (266 nm) pulses. Reference experiments performed in Ge2Sb2Te5 (GST) demonstrate that nanopatterning in PTT is triggered by ablation as opposed to GST, in which nanopatterning originates from laser-induced phase change, accompanied by a small topographical contrast. The experiments presented in this work demonstrate the suitability of optical near fields for structuring polymer films, opening up new possibilities for nanopatterning and paving the way for potential applications where optical near fields and polymer nanostructures are involved. PMID:24127989

  7. Micromachined photoplastic probe for scanning near-field optical microscopy

    NASA Astrophysics Data System (ADS)

    Genolet, G.; Despont, M.; Vettiger, P.; Staufer, U.; Noell, W.; de Rooij, N. F.; Cueni, T.; Bernal, M.-P.; Marquis-Weible, F.

    2001-10-01

    We present a hybrid probe for scanning near-field optical microscopy (SNOM), which consists of a micromachined photoplastic tip with a metallic aperture at the apex that is attached to an optical fiber, thus combining the advantages of optical fiber probes and micromachined tips. The tip and aperture are batch fabricated and assembled to a preetched optical fiber with micrometer centering precision. Rectangular apertures of 50 nm×130 nm have been produced without the need of any postprocessing. Topographical and optical imaging with a probe having an aperture of 300 nm demonstrate the great potential of the photoplastic probe for SNOM applications.

  8. Near-field fluorescence thermometry using highly efficient triple-tapered near-field optical fiber probe

    NASA Astrophysics Data System (ADS)

    Fujii, T.; Taguchi, Y.; Saiki, T.; Nagasaka, Y.

    2012-12-01

    A novel local temperature measurement method using fluorescence near-field optics thermal nanoscopy (Fluor-NOTN) has been developed. Fluor-NOTN enables nanoscale temperature measurement in situ by detecting the temperature-dependent fluorescence lifetime of CdSe quantum dots (QDs). In this paper, we report a novel triple-tapered near-field optical fiber probe that can increase the temperature measurement sensitivity of Fluor-NOTN. The performance of the proposed probe was numerically evaluated by the finite difference time domain method. Due to improvements in both the throughput and collection efficiency of near-field light, the sensitivity of the proposed probe was 1.9 times greater than that of typical double-tapered probe. The proposed shape of the triple-tapered core was successfully fabricated utilizing a geometrical model. The detected signal intensity of dried layers of QDs was greater by more than two orders than that of auto-fluorescence from the fiber core. In addition, the near-field fluorescence lifetime of the QDs and its temperature dependence were successfully measured by the fabricated triple-tapered near-field optical fiber probe. These measurement results verified the capability of the proposed triple-tapered near-field optical fiber probe to improve the collection efficiency of near-field fluorescence.

  9. Improved optical fiber probes for scanning near field optical microscopy

    NASA Astrophysics Data System (ADS)

    Wheaton, Bryan R.

    2004-12-01

    The motivation behind this work stems from a combination of my interest in atomic force microscopy (AFM) and the need to apply AFM to several areas of glass research. AFM was used as the main characterization tool in the study of near-field scanning optical microscopy (NSOM) tip formation, evaluation of phase separation in glasses and copper oxide semiconductor film formation. The use of atomic force microscopy (AFM) to evaluate the evolving tip structure of an optical fiber probe for NSOM was studied. This study demonstrates the feasibility of predicting the final tip cone angle, without taking the etching process to completion. Cone angles reported in this study ranged from 58 to 152 degrees, depending on the fiber type and etch conditions. The ability to vary the probe cone angle, and utilize AFM to evaluate the cone angle that results from a set of etch conditions, are valuable additions to the development of NSOM fiber tips. The chemical and spatial variation of phase separated morphologies in glasses can range from a few angstroms to microns, often requiring very high magnification for detection. Historically phase separated glasses have been characterized by transmission electron microscopy (TEM), a time consuming and costly technique. Atomic force microscopy (AFM) provides an inexpensive alternative to TEM and has proven to be a powerful tool in the evaluation of type, degree and scale of phase separation in glasses down to the nanometer level. AFM was used to show that the thickness and uniformity of the CuO films grown in-situ on the surface of copper containing alkali borosilicate glasses increased with time and temperature, however an upper time limit was reached in which no further thickness increases were realized. Tenorite, cuprite and copper metal films were produced depending on the heat treatment environment. XPS was utilized to confirm that copper oxide film formation during heat treatments of glasses near Tg results from the oxidation of copper

  10. Tip-enhanced near-field optical microscopy

    PubMed Central

    Mauser, Nina; Hartschuh, Achim

    2013-01-01

    Tip-enhanced near-field optical microscopy (TENOM) is a scanning probe technique capable of providing a broad range of spectroscopic information on single objects and structured surfaces at nanometer spatial resolution and with highest detection sensitivity. In this review, we first illustrate the physical principle of TENOM that utilizes the antenna function of a sharp probe to efficiently couple light to excitations on nanometer length scales. We then discuss the antenna-induced enhancement of different optical sample responses including Raman scattering, fluorescence, generation of photocurrent and electroluminescence. Different experimental realizations are presented and several recent examples that demonstrate the capabilities of the technique are reviewed. PMID:24100541

  11. Towards phonon photonics: scattering-type near-field optical microscopy reveals phonon-enhanced near-field interaction.

    PubMed

    Hillenbrand, Rainer

    2004-08-01

    Diffraction limits the spatial resolution in classical microscopy or the dimensions of optical circuits to about half the illumination wavelength. Scanning near-field microscopy can overcome this limitation by exploiting the evanescent near fields existing close to any illuminated object. We use a scattering-type near-field optical microscope (s-SNOM) that uses the illuminated metal tip of an atomic force microscope (AFM) to act as scattering near-field probe. The presented images are direct evidence that the s-SNOM enables optical imaging at a spatial resolution on a 10nm scale, independent of the wavelength used (lambda=633 nm and 10 microm). Operating the microscope at specific mid-infrared frequencies we found a tip-induced phonon-polariton resonance on flat polar crystals such as SiC and Si3N4. Being a spectral fingerprint of any polar material such phonon-enhanced near-field interaction has enormous applicability in nondestructive, material-specific infrared microscopy at nanoscale resolution. The potential of s-SNOM to study eigenfields of surface polaritons in nanostructures opens the door to the development of phonon photonics-a proposed infrared nanotechnology that uses localized or propagating surface phonon polaritons for probing, manipulating and guiding infrared light in nanoscale devices, analogous to plasmon photonics. PMID:15231334

  12. Writing 40 nm marks by using a beaked metallic plate near-field optical probe.

    PubMed

    Matsumoto, T; Anzai, Y; Shintani, T; Nakamura, K; Nishida, T

    2006-01-15

    We have developed a near-field optical probe that uses a triangular metallic plate with a three-dimensionally tapered apex as a light source for thermally assisted magnetic recording. Numerical analysis using a finite-element method shows that the size of the optical spot generated at the apex is 15 nm x 20 nm, and the efficiency (defined as the ratio between the power of the optical near field at the surface of the recording medium and that of the incident light) is 15% when the incident light is focused by a lens with a numerical aperture of 0.8. The metallic plate was fabricated on the surface of a quartz slider and used for writing marks on a phase change recording medium. The marks were observed with a scanning electron microscope, and we confirmed that marks with a diameter of 40 nm were successfully written on the medium. PMID:16441049

  13. Nonlinear nanoprobes for characterizing ultrafast optical near field

    NASA Astrophysics Data System (ADS)

    Li, Haifeng

    With the rapid development of ultrafast optics and nanophotonics, it is crucial to measure the spatiotemporal evolution of an ultrafast optical near field in nanometer spatial and femtosecond temporal resolution with minimal perturbation. Although near-field scanning optical microscopy (NSOM) can achieve nanoscale spatial resolution and various ultrashort pulse diagnostic tools can characterize femtosecond laser pulses, yet such capability to noninvasively characterize the nanoscale characteristics of femtosecond pulses in all three spatial dimensions remains elusive. In this dissertation, we developed different types of nonlinear optical probes to characterize ultrashort optical pulses. The nonlinear optical probe is composed of three parts, a silica fiber taper, a single nanowire bonded to the end of the fiber and nonlinear nanoparticles attached on the tip of the nanowire. The optical fiber taper can be readily mounted on a mechanical stage and served as a macroscopic interface for handling and positioning control. The single nanowire bridges the dimension gap between the nanocrystals and the fiber taper, and is critical for achieving large aspect ratio and hence minimizing optical scattering and perturbation. The nonlinear nanoparticles give rise to its capability to characterize ultrashort optical pulses. The unique fusion of nanoscale and nonlinear features in developed nonlinear optical probes provides the ability of probing ultrafast optical field in complex 3D microand nano- structures. The demonstration of such ability is crucial for understanding the interaction of ultrafast optical fields and nanoscale systems. The fabrication processes of the nonlinear optical probes are illustrated in detail and the optical properties of the probes are investigated. Two different types of nonlinear optical probes, two-photon fluorescent nanoprobes and Second HARmonic nanoProbes (SHARP), are fabricated. Interferometric autocorrelation measurements near the focal point

  14. Near Field Communication-based telemonitoring with integrated ECG recordings

    PubMed Central

    Morak, J.; Kumpusch, H.; Hayn, D.; Leitner, M.; Scherr, D.; Fruhwald, F.M.; Schreier, G.

    2011-01-01

    Objectives Telemonitoring of vital signs is an established option in treatment of patients with chronic heart failure (CHF). In order to allow for early detection of atrial fibrillation (AF) which is highly prevalent in the CHF population telemonitoring programs should include electrocardiogram (ECG) signals. It was therefore the aim to extend our current home monitoring system based on mobile phones and Near Field Communication technology (NFC) to enable patients acquiring their ECG signals autonomously in an easy-to-use way. Methods We prototypically developed a sensing device for the concurrent acquisition of blood pressure and ECG signals. The design of the device equipped with NFC technology and Bluetooth allowed for intuitive interaction with a mobile phone based patient terminal. This ECG monitoring system was evaluated in the course of a clinical pilot trial to assess the system’s technical feasibility, usability and patient’s adherence to twice daily usage. Results 21 patients (4f, 54 ± 14 years) suffering from CHF were included in the study and were asked to transmit two ECG recordings per day via the telemonitoring system autonomously over a monitoring period of seven days. One patient dropped out from the study. 211 data sets were transmitted over a cumulative monitoring period of 140 days (overall adherence rate 82.2%). 55% and 8% of the transmitted ECG signals were sufficient for ventricular and atrial rhythm assessment, respectively. Conclusions Although ECG signal quality has to be improved for better AF detection the developed communication design of joining Bluetooth and NFC technology in our telemonitoring system allows for ambulatory ECG acquisition with high adherence rates and system usability in heart failure patients. PMID:23616890

  15. Harmonic demodulation and minimum enhancement factors in field-enhanced near-field optical microscopy.

    PubMed

    Scarpettini, A F; Bragas, A V

    2015-01-01

    Field-enhanced scanning optical microscopy relies on the design and fabrication of plasmonic probes which had to provide optical and chemical contrast at the nanoscale. In order to do so, the scattering containing the near-field information recorded in a field-enhanced scanning optical microscopy experiment, has to surpass the background light, always present due to multiple interferences between the macroscopic probe and sample. In this work, we show that when the probe-sample distance is modulated with very low amplitude, the higher the harmonic demodulation is, the better the ratio between the near-field signal and the interferometric background results. The choice of working at a given n harmonic is dictated by the experiment when the signal at the n + 1 harmonic goes below the experimental noise. We demonstrate that the optical contrast comes from the nth derivative of the near-field scattering, amplified by the interferometric background. By modelling the far and near field we calculate the probe-sample approach curves, which fit very well the experimental ones. After taking a great amount of experimental data for different probes and samples, we conclude with a table of the minimum enhancement factors needed to have optical contrast with field-enhanced scanning optical microscopy. PMID:25231792

  16. Near-field scanning optical microscopy investigations of conjugated polymers

    NASA Astrophysics Data System (ADS)

    Dearo, Jessie Ann

    The Near-Field Scanning Optical Microscopy (NSOM) studies of novel, optically active, conjugated polymers are presented. NSOM is a relatively new technique which produces super resolution (˜50--100 nm) optical images simultaneously with topography. The conjugated polymer poly(p-phenylene vinylene) (PPV) and derivatives of PPV are organic semiconductor-like materials with interesting and unique optical properties. Derivatives of PPV have been used in LEDs and have potential in other optoelectronic devices. NSOM provides a tool for investigation of the photoluminescence, absorption/reflection, photo-dynamics and photoconductivity of films of PPV and PPV derivatives on the length scale that these properties are fundamentally defined. The NSOM experiments have revealed mesoscale domains (˜100 nm) of varying photoluminescence emission and average molecular order in drop cast films of PPV. NSOM of stretch-oriented PPV have shown domains of perpendicular molecular orientation with low photoluminescence emission. Near-field photoconductivity experiments of stretch-oriented PPV have correlated the mesoscale topography with the photoconductivity properties of the polymer. NSOM experiments of films of poly(2-methoxy, 5-(2'-(ethyl(hexyloxy)-p-phenylene vinylene) (MEH-PPV) have shown that there is mesoscale spatial inhomogeneity in the photo-oxidation process which reduces photoluminescence emission. NSOM has also been used to create nanoscale photo-patterning in MEH-PPV films. The NSOM experiments of blended films of MEH-PPV in polystyrene have shown mesoscale phase separation directly correlated to variations in the optical properties of the film. Derivatives of PPV, stretch-oriented in polyethylene, show photoluminescence intensity variations perpendicular and parallel to the stretch-direction correlated to topography features. As a complement to the NSOM studies of conjugated polymers, single polymer molecule experiments of MEH-PPV are also presented. The

  17. Imaging Analysis of Near-Field Recording Technique for Observation of Biological Specimens

    NASA Astrophysics Data System (ADS)

    Moriguchi, Chihiro; Ohta, Akihiro; Egami, Chikara; Kawata, Yoshimasa; Terakawa, Susumu; Tsuchimori, Masaaki; Watanabe, Osamu

    2006-07-01

    We present an analysis of the properties of an imaging based on a near-field recording technique in comparison with simulation results. In the system, the optical field distributions localized near the specimens are recorded as the surface topographic distributions of a photosensitive film. It is possible to observe both soft and moving specimens, because the system does not require a scanning probe to obtain the observed image. The imaging properties are evaluated using fine structures of paramecium, and we demonstrate that it is possible to observe minute differences of refractive indices.

  18. From classical to modern near-field optics and the future

    NASA Astrophysics Data System (ADS)

    Ohtsu, Motoichi

    2014-11-01

    This paper reviews the framework of classical near-field optics and recent progress in modern near-field optics. Some applications are also reviewed, including novel optical functional devices, nano-fabrication technologies, energy conversion technologies, and information processing systems. Novel theoretical models based on mathematical science are also presented, as well as an outlook for the future, hinting at the possibilities of near-field optics.

  19. Near-field optical microscopy based on microfabricated probes.

    PubMed

    Eckert, R; Freyland, J M; Gersen, H; Heinzelmann, H; Schürmann, G; Noell, W; Staufer, U; De Rooij, N F

    2001-04-01

    We demonstrate high resolution imaging with microfabricated, cantilevered probes, consisting of solid quartz tips on silicon levers. The tips are covered by a 60-nm thick layer of aluminium, which appears to be closed at the apex when investigated by transmission electron microscopy. An instrument specifically built for cantilever probes was used to record images of latex bead projection patterns in transmission as well as single molecule fluorescence. All images were recorded in constant height mode and show optical resolutions down to 32 nm. PMID:11298861

  20. Near field scanning optical microscopy of polycrystalline semiconductors

    NASA Astrophysics Data System (ADS)

    Herndon, Mary Kay

    1999-09-01

    Photovoltaic devices are commonly used for space applications and remote terrestrial power requirements. Polycrystalline solar cell devices often have much lower efficiencies than their crystalline counterparts, but because they can be fabricated much more cheaply, they can still be cost-effective when compared to single crystal devices. The long term goal of this work is to provide information that will lead to higher quality devices with improved cost efficiency. In order to do this, a better understanding of the mechanisms that take place in these materials is needed. The goal of this thesis was to improve our understanding of these devices by adapting a novel characterization technique, Near Field Scanning Optical Microscopy (NSOM), to the study of polycrystalline films. Visible light NSOM is a relatively new technique that allows for optical characterization of materials with resolution beyond the far-field diffraction limit. By using NSOM to study the physical and electrical properties of polycrystalline solar cells, individual grains can be studied and more insight can be gained as to how various properties of the thin films affect the device efficiency. For this research, an NSOM was designed and built to be versatile enough to handle the sorts of samples and measurements required for studying a variety of photovoltaic devices. As a first step, the NSOM was used to characterize single crystal GaAs solar cell devices. Measurements of topography and NSOM-induced photocurrent were obtained simultaneously on cross sections of the material, allowing the p-n junction to be probed. Because the NSOM data could be compared to an expected result, this allowed verification of the new microscope's imaging capabilities and ensured accurate data interpretation. Effects of surface recombination were detected on the cleaved edges. The NSOM was used to characterize surface quality and study the effects of surface passivation treatments. Of the polycrystalline materials

  1. High throughput optical lithography by scanning a massive array of bowtie aperture antennas at near-field

    PubMed Central

    Wen, X.; Datta, A.; Traverso, L. M.; Pan, L.; Xu, X.; Moon, E. E.

    2015-01-01

    Optical lithography, the enabling process for defining features, has been widely used in semiconductor industry and many other nanotechnology applications. Advances of nanotechnology require developments of high-throughput optical lithography capabilities to overcome the optical diffraction limit and meet the ever-decreasing device dimensions. We report our recent experimental advancements to scale up diffraction unlimited optical lithography in a massive scale using the near field nanolithography capabilities of bowtie apertures. A record number of near-field optical elements, an array of 1,024 bowtie antenna apertures, are simultaneously employed to generate a large number of patterns by carefully controlling their working distances over the entire array using an optical gap metrology system. Our experimental results reiterated the ability of using massively-parallel near-field devices to achieve high-throughput optical nanolithography, which can be promising for many important nanotechnology applications such as computation, data storage, communication, and energy. PMID:26525906

  2. High throughput optical lithography by scanning a massive array of bowtie aperture antennas at near-field

    NASA Astrophysics Data System (ADS)

    Wen, X.; Datta, A.; Traverso, L. M.; Pan, L.; Xu, X.; Moon, E. E.

    2015-11-01

    Optical lithography, the enabling process for defining features, has been widely used in semiconductor industry and many other nanotechnology applications. Advances of nanotechnology require developments of high-throughput optical lithography capabilities to overcome the optical diffraction limit and meet the ever-decreasing device dimensions. We report our recent experimental advancements to scale up diffraction unlimited optical lithography in a massive scale using the near field nanolithography capabilities of bowtie apertures. A record number of near-field optical elements, an array of 1,024 bowtie antenna apertures, are simultaneously employed to generate a large number of patterns by carefully controlling their working distances over the entire array using an optical gap metrology system. Our experimental results reiterated the ability of using massively-parallel near-field devices to achieve high-throughput optical nanolithography, which can be promising for many important nanotechnology applications such as computation, data storage, communication, and energy.

  3. Reciprocity theory of apertureless scanning near-field optical microscopy with point-dipole probes.

    PubMed

    Esslinger, Moritz; Vogelgesang, Ralf

    2012-09-25

    Near-field microscopy offers the opportunity to reveal optical contrast at deep subwavelength scales. In scanning near-field optical microscopy (SNOM), the diffraction limit is overcome by a nanoscopic probe in close proximity to the sample. The interaction of the probe with the sample fields necessarily perturbs the bare sample response, and a critical issue is the interpretation of recorded signals. For a few specific SNOM configurations, individual descriptions have been modeled, but a general and intuitive framework is still lacking. Here, we give an exact formulation of the measurable signals in SNOM which is easily applicable to experimental configurations. Our results are in close analogy with the description Tersoff and Hamann have derived for the tunneling currents in scanning tunneling microscopy. For point-like scattering probe tips, such as used in apertureless SNOM, the theory simplifies dramatically to a single scalar relation. We find that the measured signal is directly proportional to the field of the coupled tip-sample system at the position of the tip. For weakly interacting probes, the model thus verifies the empirical findings that the recorded signal is proportional to the unperturbed field of the bare sample. In the more general case, it provides guidance to an intuitive and faithful interpretation of recorded images, facilitating the characterization of tip-related distortions and the evaluation of novel SNOM configurations, both for aperture-based and apertureless SNOM. PMID:22897563

  4. Imaging of optical disc using reflection-mode scattering-type scanning near-field optical microscopy.

    PubMed

    Yamaguchi, M; Sasaki, Y; Sasaki, H; Konada, T; Horikawa, Y; Ebina, A; Umezawa, T; Horiguchi, T

    1999-01-01

    A phase-change optical disc was observed using a reflection-mode scattering-type scanning near-field optical microscope (RS-SNOM). In an a.c.-mode SNOM image, the 1.2 microm x 0.6 microm recording marks were successfully observed although the data were recorded on the groove. In contrast, no recording marks could be resolved in a d.c.-mode SNOM image. These results are in good agreement with those from a numerical simulation using the finite difference time domain method. The resolution was better than 100 nm with a.c.-mode SNOM operation and the results indicate that recording marks in phase-change optical media can be directly observed with the RS-SNOM. PMID:11388305

  5. Generalized method of eigenoscillations for near-field optical microscopy

    NASA Astrophysics Data System (ADS)

    Jiang, Bor-Yuan; Zhang, Lingfeng; Castro Neto, Antonio; Basov, Dimitri; Fogler, Michael

    2015-03-01

    Electromagnetic interaction between a sub-wavelength particle (the ``probe'') and a material surface (the ``sample'') is studied theoretically. The interaction is shown to be governed by a series of resonances (eigenoscillations), corresponding to surface polariton modes localized near the probe. The resonance parameters depend on the dielectric function and geometry of the probe, as well as the surface reflectivity of the material. Calculation of such resonances is carried out for several axisymmetric particle shapes (spherical, spheroidal, and pear-shaped). For spheroids an efficient numerical method is proposed, capable of handling cases of large or strongly momentum-dependent surface reflectivity. The method is applied to modeling near-field spectroscopy studies of various materials. For highly resonant materials such as aluminum oxide (by itself or covered with graphene) a rich structure of the simulated signal is found, including multi-peak spectra and nonmonotonic approach curves. These features have a strong dependence on physical parameters, e.g., the probe shape. For less resonant materials such as silicon oxide the dependence is weaker, and the spheroid model is generally applicable.

  6. Gold Coating of Fiber Tips in Near-Field Scanning Optical Microscopy

    NASA Technical Reports Server (NTRS)

    Vikram, Chandra S.; Witherow, William K.

    2000-01-01

    We report what is believed to be the first experimental demonstration of gold coating by a chemical baking process on tapered fiber tips used in near-field scanning optical microscopy. Many tips can be simultaneously coated.

  7. Near field optical probe for critical dimension measurements

    DOEpatents

    Stallard, Brian R.; Kaushik, Sumanth

    1999-01-01

    A resonant planar optical waveguide probe for measuring critical dimensions on an object in the range of 100 nm and below. The optical waveguide includes a central resonant cavity flanked by Bragg reflector layers with input and output means at either end. Light is supplied by a narrow bandwidth laser source. Light resonating in the cavity creates an evanescent electrical field. The object with the structures to be measured is translated past the resonant cavity. The refractive index contrasts presented by the structures perturb the field and cause variations in the intensity of the light in the cavity. The topography of the structures is determined from these variations.

  8. Near field optical probe for critical dimension measurements

    DOEpatents

    Stallard, B.R.; Kaushik, S.

    1999-05-18

    A resonant planar optical waveguide probe for measuring critical dimensions on an object in the range of 100 nm and below is disclosed. The optical waveguide includes a central resonant cavity flanked by Bragg reflector layers with input and output means at either end. Light is supplied by a narrow bandwidth laser source. Light resonating in the cavity creates an evanescent electrical field. The object with the structures to be measured is translated past the resonant cavity. The refractive index contrasts presented by the structures perturb the field and cause variations in the intensity of the light in the cavity. The topography of the structures is determined from these variations. 8 figs.

  9. Background Suppression in Near-field Optical Imaging

    PubMed Central

    Höppener, Christiane; Beams, Ryan; Novotny, Lukas

    2010-01-01

    In several recent studies, antenna-based optical microscopy (e.g. TENOM) has demonstrated its potential to resolve features as small as 10nm. Most studies are concerned with well-separated features on flat surfaces and there are only few studies that deal with samples of high feature density or even three-dimesional objects. The reason is that the external laser irradiation of the optical antenna (e.g. tip or particle) also directly irradiates the sample and therefore gives rise to a background. Here we introduce an efficient background suppression scheme that makes use of feedback modulation. The method is widely applicable and not restricted to cantilever-based scanning schemes. We apply this technique to both dense samples of dye molecules and ion channel proteins in plasma membranes and demonstrate effective background suppression and strongly improved sensitivity. The feedback modulation scheme is expected to find application for biological studies in liquid environments and for investigations of subsurface features in material science. PMID:19170554

  10. Near-Field Optical Microscopy in the Infrared Range

    NASA Astrophysics Data System (ADS)

    de Wilde, Yannick; Lemoine, Paul-Arthur; Babuty, Arthur

    The infrared covers the region of the electromagnetic spectrum with wave numbers (optical frequencies) in the range 13 000 to 10 cm-1, which corresponds to the wavelength range from 780 nm to 1 mm. Infrared frequencies, in particular those in the mid-infrared (2 < λ < 25 μm), are especially attractive for probing materials, for they provide a way of identifying and quantifying their composition and structure, or probing their electronic and thermal properties. The absorption of infrared photons excites molecular vibrations and phonons. It is maximal at those frequencies associated with the vibrational modes, which depend on the kind of molecules and functional groups involved in the vibrations, or the crystal structure. So the frequencies of the absorption maxima form a spectral fingerprint of the material. Other factors such as the electron density and interactions between electrons, in semiconductors, metals, and superconductors, affect the dielectric properties at infrared frequencies, and are studied in the field of condensed matter. Regarding thermal imaging, infrared thermography is used to observe the temperature distribution at the surface of materials. The intensity of the thermal radiation emitted by a material depends on the temperature according to Planck's law. The temperature of a material can be determined by measuring the intensity of the infrared radiation it emits, once its emissivity is known.

  11. Generalized spectral method for near-field optical microscopy

    NASA Astrophysics Data System (ADS)

    Jiang, B.-Y.; Zhang, L. M.; Castro Neto, A. H.; Basov, D. N.; Fogler, M. M.

    2016-02-01

    Electromagnetic interaction between a sub-wavelength particle (the "probe") and a material surface (the "sample") is studied theoretically. The interaction is shown to be governed by a series of resonances corresponding to surface polariton modes localized near the probe. The resonance parameters depend on the dielectric function and geometry of the probe as well as on the surface reflectivity of the material. Calculation of such resonances is carried out for several types of axisymmetric probes: spherical, spheroidal, and pear-shaped. For spheroids, an efficient numerical method is developed, capable of handling cases of large or strongly momentum-dependent surface reflectivity. Application of the method to highly resonant materials, such as aluminum oxide (by itself or covered with graphene), reveals a rich structure of multi-peak spectra and nonmonotonic approach curves, i.e., the probe-sample distance dependence. These features also strongly depend on the probe shape and optical constants of the model. For less resonant materials such as silicon oxide, the dependence is weak, so that the spheroidal model is reliable. The calculations are done within the quasistatic approximation with radiative damping included perturbatively.

  12. Phase stabilized homodyne of infrared scattering type scanning near-field optical microscopy

    SciTech Connect

    Xu, Xiaoji G.; Gilburd, Leonid; Walker, Gilbert C.

    2014-12-29

    Scattering type scanning near-field optical microscopy (s-SNOM) allows sub diffraction limited spatial resolution. Interferometric homodyne detection in s-SNOM can amplify the signal and extract vibrational responses based on sample absorption. A stable reference phase is required for a high quality homodyne-detected near-field signal. This work presents the development of a phase stabilization mechanism for s-SNOM to provide stable homodyne conditions. The phase stability is found to be better than 0.05 rad for the mid infrared light source. Phase stabilization results in improved near field images and vibrational spectroscopies. Spatial inhomogeneities of the boron nitride nanotubes are measured and compared.

  13. A quasi-optical vector near-field measurement system at terahertz band.

    PubMed

    Lou, Zheng; Hu, Jie; Zhou, Kang-Min; Miao, Wei; Shi, Sheng-Cai

    2014-06-01

    This paper describes a vector near-field measurement system at terahertz band based on a high sensitivity superconducting receiver equipped with a quasi-optical probe for high resolution near-field sensing. A novel single-receiver rather than commonly used dual-receiver configuration is adopted for vector measurement. Performances of the measurement system including stability and dynamic range are studied. Vector near-field measurement of a diagonal feedhorn at 850 GHz is presented and shows good agreement with simulation and direct far-field measurement. PMID:24985832

  14. Generation of nearly 3D-unpolarized evanescent optical near fields using total internal reflection.

    PubMed

    Hassinen, Timo; Popov, Sergei; Friberg, Ari T; Setälä, Tero

    2016-07-01

    We analyze the time-domain partial polarization of optical fields composed of two evanescent waves created in total internal reflection by random electromagnetic beams with orthogonal planes of incidence. We show that such a two-beam configuration enables to generate nearly unpolarized, genuine three-component (3D) near fields. This result complements earlier studies on spectral polarization, which state that at least three symmetrically propagating beams are required to produce a 3D-unpolarized near field. The degree of polarization of the near field can be controlled by adjusting the polarization states and mutual correlation of the incident beams. PMID:27367071

  15. Near-field study of magneto-optical samples: theoretical comparison of transversal and polar effects

    NASA Astrophysics Data System (ADS)

    Van Labeke, Daniel; Vial, A.; Barchiesi, Dominique

    1996-09-01

    The density of integration of magneto-optical devices is limited by diffraction of light. Recently some groups have proposed to use Near-Field Microscopy to overcome this limitation and some experiments have been performed both in transmission and reflection. In this paper we study theoretically magneto-optical effect in near-field. We consider a magneto-optical sample with details smaller than the wavelength. This sample is modelled as a multilayer rough structure. At least one layer has magneto-optical properties. The corrugation at the interfaces are very small compared to the optical wavelength. We do not consider the writing problem and the experiment is only modelled in the reading mode. Moreover, the magnetic properties are considered in the saturation regime. For this study we use an extension of the method that we used to describe near- field microscope with isotropic sample. The diffracted fields are determined in each layer by using a perturbative version of the Rayleigh method which leads to the resolution of a linear equation for each diffracted wave. The near- field above the sample is thus obtained by summing all the diffracted waves. We consider two geometries for the magnetization: polar effect where the magnetization is perpendicular to the sample and transversal effect where it is in the plane. We compare near-field images obtained in transmission and reflection by changing magnetization orientation. Comparisons with far-field results are also proposed.

  16. Near-field imaging and spectroscopy of hybridized plasmons (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Aeschlimann, Martin

    2015-09-01

    Understanding light-matter interactions such as the dynamic response of a metal to incident light is essential for advancing fundamental research and technological applications e.g. designing plasmonic devices such as nanoantenna directional emitters. The near-field response is determined on a length scale that is intrinsically smaller than the optical diffraction limit and so we use electrons to image the near-field distribution. We combine photoemission electron microscopy (PEEM) with a variable wavelength laser light source, an optical parametric oscillator (OPO), to perform near-field imaging and spectroscopy of whispering gallery resonator (WGR)1 arrays. These ultrahigh spatially and spectrally resolved measurements show characteristic spectral peaks and near-field mode distributions due to the excitation of different plasmon resonances. Controlling the interference between dipole and quadrupole modes allows us to direct the emission from the nanoantenna. Additionally we perform femtosecond 2-dimensional coherence spectroscopy2 on a microcavity system containing two well separated WGR nanoantennas. Hybridization of a propagating surface plasmon polariton and the localized surface plasmon in a cavity enables energy transfer between the two coupled nanoantennas. [1] E. J. R. Vessseur, F. J. García de Abajo and A. Polman Nano Letters 9 3147 (2009) [2] M. Aeschlimann et al, Science 333, 1723 (2011)

  17. Electroless silver plating for metallization of near-field optical fiber probes

    NASA Astrophysics Data System (ADS)

    Li, Chang'an; Xu, Lina; Gu, Ning

    2007-10-01

    By using mercaptopropyltrimethoxysilane (MPTS) self-assembled monolayers (SAMs), electroless silver plating is developed for the metallization of near-field optical fiber probes. This method has the advantages of controllability, no pinholes, convenience, low cost, and smooth tip surface. The metallized probes are characterized by optical microscopy, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDXS).

  18. Point-by-point near-field optical energy deposition around plasmonic nanospheres in absorbing media.

    PubMed

    Harrison, R K; Ben-Yakar, Adela

    2015-08-01

    Here we investigate the effects of absorbing media on plasmon-enhanced near-field optical energy deposition. We find that increasing absorption by the medium results in increased particle scattering at the expense of particle absorption, and that much of this increased particle scattering is absorbed by the medium close to the particle surface. We present an analytical method for evaluating the spatial distribution of near-field enhanced absorption surrounding plasmonic metal nanospheres in absorbing media using a new point-by-point method. We propose criteria to define relevant near-field boundaries and calculate the properties of the local absorption enhancement, which redistributes absorption to the near-field and decays asymptotically as a function of the distance from the particle to background levels. Using this method, we performed a large-scale parametric study to understand the effect of particle size and wavelength on the near-field absorption for gold nanoparticles in aqueous media and silicon, and identified conditions that are relevant to enhanced local infrared absorption in silicon. The presented approach provides insight into the local energy transfer around plasmonic nanoparticles for predicting near-field effects for advanced concepts in optical sensing, thin-film solar cells, nonlinear imaging, and photochemical applications. PMID:26367296

  19. Scattering-type scanning near-field optical microscopy with reconstruction of vertical interaction

    PubMed Central

    Wang, Le; Xu, Xiaoji G.

    2015-01-01

    Scattering-type scanning near-field optical microscopy provides access to super-resolution spectroscopic imaging of the surfaces of a variety of materials and nanostructures. In addition to chemical identification, it enables observations of nano-optical phenomena, such as mid-infrared plasmons in graphene and phonon polaritons in boron nitride. Despite the high lateral spatial resolution, scattering-type near-field optical microscopy is not able to provide characteristics of near-field responses in the vertical dimension, normal to the sample surface. Here, we present an accurate and fast reconstruction method to obtain vertical characteristics of near-field interactions. For its first application, we investigated the bound electromagnetic field component of surface phonon polaritons on the surface of boron nitride nanotubes and found that it decays within 20 nm with a considerable phase change in the near-field signal. The method is expected to provide characterization of the vertical field distribution of a wide range of nano-optical materials and structures. PMID:26592949

  20. Near-field imaging of optical antenna modes in the mid-infrared.

    PubMed

    Olmon, Robert L; Krenz, Peter M; Jones, Andrew C; Boreman, Glenn D; Raschke, Markus B

    2008-12-01

    Optical antennas can enhance the coupling between free-space propagating light and the localized excitation of nanoscopic light emitters or receivers, thus forming the basis of many nanophotonic applications. Their functionality relies on an understanding of the relationship between the geometric parameters and the resulting near-field antenna modes. Using scattering-type scanning near-field optical microscopy (s-SNOM) with interferometric homodyne detection, we investigate the resonances of linear Au wire antennas designed for the mid-IR by probing specific vector near-field components. A simple effective wavelength scaling is observed for single wires with lambda(eff) = lambda /(2.0+/- 0.2), specific to the geometric and material parameters used. The disruption of the coherent current oscillation by introducing a gap gives rise to an effective multipolar mode for the two near-field coupled segments. Using antenna theory and numerical electrodynamics simulations two distinct coupling regimes are considered that scale with gap width or reactive near-field decay length, respectively. The results emphasize the distinct antenna behavior at optical frequencies compared to impedance matched radio frequency (RF) antennas and provide experimental confirmation of theoretically predicted scaling laws at optical frequencies. PMID:19065168

  1. Scattering-type scanning near-field optical microscopy with reconstruction of vertical interaction.

    PubMed

    Wang, Le; Xu, Xiaoji G

    2015-01-01

    Scattering-type scanning near-field optical microscopy provides access to super-resolution spectroscopic imaging of the surfaces of a variety of materials and nanostructures. In addition to chemical identification, it enables observations of nano-optical phenomena, such as mid-infrared plasmons in graphene and phonon polaritons in boron nitride. Despite the high lateral spatial resolution, scattering-type near-field optical microscopy is not able to provide characteristics of near-field responses in the vertical dimension, normal to the sample surface. Here, we present an accurate and fast reconstruction method to obtain vertical characteristics of near-field interactions. For its first application, we investigated the bound electromagnetic field component of surface phonon polaritons on the surface of boron nitride nanotubes and found that it decays within 20 nm with a considerable phase change in the near-field signal. The method is expected to provide characterization of the vertical field distribution of a wide range of nano-optical materials and structures. PMID:26592949

  2. Scattering-type scanning near-field optical microscopy with reconstruction of vertical interaction

    NASA Astrophysics Data System (ADS)

    Wang, Le; Xu, Xiaoji G.

    2015-11-01

    Scattering-type scanning near-field optical microscopy provides access to super-resolution spectroscopic imaging of the surfaces of a variety of materials and nanostructures. In addition to chemical identification, it enables observations of nano-optical phenomena, such as mid-infrared plasmons in graphene and phonon polaritons in boron nitride. Despite the high lateral spatial resolution, scattering-type near-field optical microscopy is not able to provide characteristics of near-field responses in the vertical dimension, normal to the sample surface. Here, we present an accurate and fast reconstruction method to obtain vertical characteristics of near-field interactions. For its first application, we investigated the bound electromagnetic field component of surface phonon polaritons on the surface of boron nitride nanotubes and found that it decays within 20 nm with a considerable phase change in the near-field signal. The method is expected to provide characterization of the vertical field distribution of a wide range of nano-optical materials and structures.

  3. Sub-nanosecond time-resolved near-field scanning magneto-optical microscope.

    PubMed

    Rudge, J; Xu, H; Kolthammer, J; Hong, Y K; Choi, B C

    2015-02-01

    We report on the development of a new magnetic microscope, time-resolved near-field scanning magneto-optical microscope, which combines a near-field scanning optical microscope and magneto-optical contrast. By taking advantage of the high temporal resolution of time-resolved Kerr microscope and the sub-wavelength spatial resolution of a near-field microscope, we achieved a temporal resolution of ∼50 ps and a spatial resolution of <100 nm. In order to demonstrate the spatiotemporal magnetic imaging capability of this microscope, the magnetic field pulse induced gyrotropic vortex dynamics occurring in 1 μm diameter, 20 nm thick CoFeB circular disks has been investigated. The microscope provides sub-wavelength resolution magnetic images of the gyrotropic motion of the vortex core at a resonance frequency of ∼240 MHz. PMID:25725848

  4. Ultrafast nanoelectronics: steering electrons in infrared near-fields (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Herink, Georg; Ropers, Claus

    2015-09-01

    Plasmonic nanostructures can break the diffraction limit and confine optical fields on the nanoscale. The coupling of intense femtosecond transients to the apex of metallic nanotips enables ultrafast electron point sources which find applications in ultrafast electron microscopy and time-resolved diffraction instruments. In this contribution, we demonstrate the impact of near-field localization onto strong-field photoemission and present the control of electron trajectories via the momentary electric near-field. The photoemission dynamics at single gold and tungsten nanotips are experimentally studied over a broad range of excitation frequencies, spanning from 1 - 400 Terahertz (THz). The transition from oscillatory electron acceleration to a field-driven interaction is presented as a result of intense, long-wavelength and localized excitation. The high field enhancement at lower frequencies is demonstrated to induce localized field emission from a nanotip with moderate incident fields as provided by table-top THz sources. Such THz-induced cold field emission can be used, e.g., for the temporal tracking of optically excited hot-electron dynamics in nanostructures. Moreover, the field-driven electron acceleration in the enhanced THz near-field is employed in a pump-probe scheme to temporally map the local THz-response of the nanostructure by projecting the momentary apex near-field onto the kinetic energy of femtosecond electron pulses. Besides the electrical characterization of nanostructures at THz-frequencies, the temporally and spatially confined interaction of free electrons with ultrashort near-fields is expected to enable a novel class of ultrafast vacuum micro- and nanoelectronic devices, and first applications are presented in this talk.

  5. Towards better scanning near-field optical microscopy probes--progress and new developments.

    PubMed

    Heinzelmann, H; Freyland, J M; Eckert, R; Huser, T; Schürmann, G; Noell, W; Staufer, U; De Rooij, N F

    1999-01-01

    Several approaches are described with the aim of producing near-field optical probes with improved properties. Focused ion beam milling allows the fabrication of small apertures in a controlled fashion, resulting in probes with excellent polarization properties and increased transmission. Microfabrication processes are described that allow the production of apertures of 30-50 nm, facilitating the mass-fabrication of apertured tip structures that can be used in a combined force/near-field optical microscope. Finally, possible future developments are outlined. PMID:11388268

  6. Cancer cell imaging by stable wet near-field scanning optical microscope with resonance tracking method

    NASA Astrophysics Data System (ADS)

    Park, Kyoung-Duck; Park, Doo Jae; Jeong, Mun Seok; Choi, Geun Chang; Lee, Seung Gol; Byeon, Clare Chisu; Choi, Soo Bong

    2014-05-01

    We report on a successful topographical and optical imaging of various cancer cells in liquid and in air by using a stable wet near-field scanning optical microscope that utilizes a resonance tracking method. We observed a clear dehydration which gives rise to a decrease in the cell volume down to 51%. In addition, a micro-ball lens effect due to the round-shaped young cancer cells was observed from near-field imaging, where the refractive index of young cancer cells was deduced.

  7. Three-dimensional mapping of optical near field of a nanoscale bowtie antenna.

    PubMed

    Guo, Rui; Kinzel, Edward C; Li, Yan; Uppuluri, Sreemanth M; Raman, Arvind; Xu, Xianfan

    2010-03-01

    Ridge nanoscale aperture antennas have been shown to be a high transmission nanoscale light source. They provide a small, polarization-dependent near-field optical spot with much higher transmission efficiency than circularly-shaped apertures with similar field confinement. This provides significant motivations to understand the electromagnetic fields in the immediate proximity to the apertures. This paper describes an experimental three-dimensional optical near-field mapping of a bowtie nano-aperture. The measurements are performed using a home-built near-field scanning optical microscopy (NSOM) system. An aluminum coated Si(3)N(4) probe with a 150 nm hole at the tip is used to collect optical signals. Both contact and constant-height scan (CHS) modes are used to measure the optical intensity at different longitudinal distances. A force-displacement curve is used to determine the tip-sample separation distance allowing the optical intensities to be mapped at distances as small as 50 nm and up to micrometer level. The experimental results also demonstrate the polarization dependence of the transmission through the bowtie aperture. Numerical simulations are also performed to compute the aperture's electromagnetic near-field distribution and are shown to agree with the experimental results. PMID:20389507

  8. The thermal near-field: Coherence, spectroscopy, heat-transfer, and optical forces

    NASA Astrophysics Data System (ADS)

    Jones, Andrew C.; O'Callahan, Brian T.; Yang, Honghua U.; Raschke, Markus B.

    2013-12-01

    One of the most universal physical processes shared by all matter at finite temperature is the emission of thermal radiation. The experimental characterization and theoretical description of far-field black-body radiation was a cornerstone in the development of modern physics with the groundbreaking contributions from Gustav Kirchhoff and Max Planck. With its origin in thermally driven fluctuations of the charge carriers, thermal radiation reflects the resonant and non-resonant dielectric properties of media, which is the basis for far-field thermal emission spectroscopy. However, associated with the underlying fluctuating optical source polarization are fundamentally distinct spectral, spatial, resonant, and coherence properties of the evanescent thermal near-field. These properties have been recently predicted theoretically and characterized experimentally for systems with thermally excited molecular, surface plasmon polariton (SPP), and surface phonon polariton (SPhP) resonances. We review, starting with the early historical developments, the emergence of theoretical models, and the description of the thermal near-field based on the fluctuation-dissipation theory and in terms of the electromagnetic local density of states (EM-LDOS). We discuss the optical and spectroscopic characterization of distance dependence, magnitude, spectral distribution, and coherence of evanescent thermal fields. Scattering scanning near-field microscopy proved instrumental as an enabling technique for the investigations of several of these fundamental thermal near-field properties. We then discuss the role of thermal fields in nano-scale heat transfer and optical forces, and the correlation to the van der Waals, Casimir, and Casimir-Polder forces. We conclude with an outlook on the possibility of intrinsic and extrinsic resonant manipulation of optical forces, control of nano-scale radiative heat transfer with optical antennas and metamaterials, and the use of thermal infrared near-field

  9. Multipass laser amplification with near-field far-field optical separation

    DOEpatents

    Hagen, Wilhelm F.

    1979-01-01

    This invention discloses two classes of optical configurations for high power laser amplification, one allowing near-field and the other allowing far-field optical separation, for the multiple passage of laser pulses through one or more amplifiers over an open optical path. These configurations may reimage the amplifier or any other part of the cavity on itself so as to suppress laser beam intensity ripples that arise from diffraction and/or non-linear effects. The optical cavities combine the features of multiple passes, spatial filtering and optical reimaging and allow sufficient time for laser gain recovery.

  10. Alterations of single molecule fluorescence lifetimes in near-field optical microscopy

    SciTech Connect

    Ambrose, W.P.; Goodwin, P.M.; Keller, R.A.; Martin, J.C. )

    1994-07-15

    Fluorescence lifetimes of single Rhodamine 6G molecules on silica surfaces were measured with pulsed laser excitation, time-correlated single photon counting, and near-field scanning optical microscopy (NSOM). The fluorescence lifetime varies with the position of a molecule relative to a near-field probe. Qualitative features of lifetime decreases are consistent with molecular excited state quenching effects near metal surfaces. The technique of NSOM provides a means of altering the environment of a single fluorescent molecule and its decay kinetics in a repeatable fashion.

  11. Nanospectrofluorometry inside single living cell by scanning near-field optical microscopy

    NASA Astrophysics Data System (ADS)

    Lei, F. H.; Shang, G. Y.; Troyon, M.; Spajer, M.; Morjani, H.; Angiboust, J. F.; Manfait, M.

    2001-10-01

    Near-field fluorescence spectra with subdiffraction limit spatial resolution have been taken in the proximity of mitochondrial membrane inside breast adenocarcinoma cells (MCF7) treated with the fluorescent dye (JC-1) by using a scanning near-field optical microscope coupled with a confocal laser microspectrofluorometer. The probe-sample distance control is based on a piezoelectric bimorph shear force sensor having a static spring constant k=5 μN/nm and a quality factor Q=40 in a physiological medium of viscosity η=1.0 cp. The sensitivity of the force sensor has been tested by imaging a MCF7 cell surface.

  12. Decision making based on optical excitation transfer via near-field interactions between quantum dots

    NASA Astrophysics Data System (ADS)

    Naruse, Makoto; Nomura, Wataru; Aono, Masashi; Ohtsu, Motoichi; Sonnefraud, Yannick; Drezet, Aurélien; Huant, Serge; Kim, Song-Ju

    2014-10-01

    Optical near-field interactions between nanostructured matters, such as quantum dots, result in unidirectional optical excitation transfer when energy dissipation is induced. This results in versatile spatiotemporal dynamics of the optical excitation, which can be controlled by engineering the dissipation processes and exploited to realize intelligent capabilities such as solution searching and decision making. Here, we experimentally demonstrate the ability to solve a decision making problem on the basis of optical excitation transfer via near-field interactions by using colloidal quantum dots of different sizes, formed on a geometry-controlled substrate. We characterize the energy transfer behavior due to multiple control light patterns and experimentally demonstrate the ability to solve the multi-armed bandit problem. Our work makes a decisive step towards the practical design of nanophotonic systems capable of efficient decision making, one of the most important intellectual attributes of the human brain.

  13. Decision making based on optical excitation transfer via near-field interactions between quantum dots

    SciTech Connect

    Naruse, Makoto; Nomura, Wataru; Ohtsu, Motoichi; Aono, Masashi; Sonnefraud, Yannick; Drezet, Aurélien; Huant, Serge; Kim, Song-Ju

    2014-10-21

    Optical near-field interactions between nanostructured matters, such as quantum dots, result in unidirectional optical excitation transfer when energy dissipation is induced. This results in versatile spatiotemporal dynamics of the optical excitation, which can be controlled by engineering the dissipation processes and exploited to realize intelligent capabilities such as solution searching and decision making. Here, we experimentally demonstrate the ability to solve a decision making problem on the basis of optical excitation transfer via near-field interactions by using colloidal quantum dots of different sizes, formed on a geometry-controlled substrate. We characterize the energy transfer behavior due to multiple control light patterns and experimentally demonstrate the ability to solve the multi-armed bandit problem. Our work makes a decisive step towards the practical design of nanophotonic systems capable of efficient decision making, one of the most important intellectual attributes of the human brain.

  14. Hyperspectral optical near-field imaging: Looking graded photonic crystals and photonic metamaterials in color

    NASA Astrophysics Data System (ADS)

    Dellinger, Jean; Van Do, K.; Le Roux, Xavier; de Fornel, Frédérique; Cassan, Eric; Cluzel, Benoît

    2012-10-01

    Using a scanning near-field optical microscope operating with a hyperspectral detection scheme, we report the direct observation of the mirage effect within an on-chip integrated artificial material made of a two dimensional graded photonic crystal. The light rainbow due to the material dispersion is quantified experimentally and quantitatively compared to three dimensional plane wave assisted Hamiltonian optics predictions of light propagation.

  15. Near-field focusing of an optical wave by diffraction gratings

    NASA Astrophysics Data System (ADS)

    Geints, Yu E.; Zemlyanov, A. A.

    2016-07-01

    We report the investigation results for spatially-localised light structures (photonic nanojets) under near-field optical radiation scattering on phase diffraction gratings. Main parameters of photonic nanojets from gratings with sawtooth, rectangular and hemispherical groove profiles are obtained by numerical electrodynamic simulation. It is found that by varying a period, degree of filling, groove shape and parameters of optically contrast coating of the diffraction grating one can control the characteristics of the produced photonic jets in a wide range.

  16. Nonlinear optical tuning of photonic crystal microcavities by near-field probe

    SciTech Connect

    Vignolini, Silvia; Zani, Margherita; Riboli, Francesco; Vinattieri, Anna; Wiersma, Diederik S.; Gurioli, Massimo; Intonti, Francesca; Balet, Laurent; Li, Lianhe; Colocci, Marcello; Francardi, Marco; Gerardino, Annamaria; Fiore, Andrea

    2008-07-14

    We report on a nonlinear way to control and tune the dielectric environment of photonic crystal microcavities exploiting the local heating induced by near-field laser excitation at different excitation powers. The temperature gradient due to the optical absorption results in an index of refraction gradient which modifies the dielectric surroundings of the cavity and shifts the optical modes. Reversible tuning can be obtained either by changing the excitation power density or by exciting in different points of the photonic crystal microcavity.

  17. Analysis of optical near-field energy transfer by stochastic model unifying architectural dependencies

    SciTech Connect

    Naruse, Makoto; Akahane, Kouichi; Yamamoto, Naokatsu; Holmström, Petter; Thylén, Lars; Huant, Serge; Ohtsu, Motoichi

    2014-04-21

    We theoretically and experimentally demonstrate energy transfer mediated by optical near-field interactions in a multi-layer InAs quantum dot (QD) structure composed of a single layer of larger dots and N layers of smaller ones. We construct a stochastic model in which optical near-field interactions that follow a Yukawa potential, QD size fluctuations, and temperature-dependent energy level broadening are unified, enabling us to examine device-architecture-dependent energy transfer efficiencies. The model results are consistent with the experiments. This study provides an insight into optical energy transfer involving inherent disorders in materials and paves the way to systematic design principles of nanophotonic devices that will allow optimized performance and the realization of designated functions.

  18. Gold nanoparticle tips for optical field confinement in infrared scattering near-field optical microscopy.

    PubMed

    Wenzel, Marc Tobias; Härtling, Thomas; Olk, Phillip; Kehr, Susanne C; Grafström, Stefan; Winnerl, Stephan; Helm, Manfred; Eng, Lukas M

    2008-08-01

    We report on the implementation of metal nanoparticles as probes for scattering and apertureless near-field optical investigations in the mid-infrared (mid-IR) spectral regime. At these wavelengths, an efficient electric-field confinement is necessary and achieved here through a gold metal nanoparticle of 80 nm in diameter (Au80-MNP) acting as the optical antenna. The Au80-MNP is attached to a standard AFM cantilever used as the spatial manipulator. When approached to a sample surface while being illuminated with an infrared beam, the Au80-MNP produces a considerably improved spatial confinement of the electric field compared to an ordinary scattering AFM tip. We demonstrate here the confinement normal to the sample surface by making use of a sample-induced phonon polariton resonance in a ferroelectric lithium niobate sample. Our experimental findings are in very good agreement with the quasistatic dipole model and show improved optical resolution via well-selected antenna particles. PMID:18679508

  19. Integrating electron and near-field optics: dual vision for the nanoworld

    NASA Astrophysics Data System (ADS)

    Haegel, Nancy M.

    2014-04-01

    The integration of near-field scanning optical microscopy (NSOM) with the imaging and localized excitation capabilities of electrons in a scanning electron microscope (SEM) offers new capabilities for the observation of highly resolved transport phenomena in the areas of electronic and optical materials characterization, semiconductor nanodevices, plasmonics and integrated nanophotonics. While combined capabilities for atomic force microscopy (AFM) and SEM are of obvious interest to provide localized surface topography in concert with the ease and large spatial dynamic range of SEM and dual beam imaging (e.g., in-situ AFM following focused ion beam modification), integration with near-field optical imaging capability can also provide access to localized transport phenomena beyond the reach of far-field systems. In particular, the flexibility that is achieved with the capability for independent, high resolution placement of an electron source, providing localized excitation in the form of free carriers, photons or plasmons, with scanning of the optical collecting tip allows for unique types of "dual-probe" experiments that directly image energy transfer. We review integrated near-field and electron optics systems to date, highlight applications in a variety of fields and suggest future directions.

  20. Degradation of silver near-field optical probes and its electrochemical reversal

    NASA Astrophysics Data System (ADS)

    Opilik, Lothar; Dogan, Üzeyir; Szczerbiński, Jacek; Zenobi, Renato

    2015-08-01

    Deterioration of the outstanding optical properties of elemental silver due to atmospheric corrosion compromises its use in the field of plasmonics. Therefore, more chemically inert, but more lossy, metals (e.g., gold) are often used as a compromise. Silver tips for near-field optical microscopy are only utilized by specialized laboratories with in-house tip production facilities. This article presents a time-dependent study of the effect of atmospheric corrosion on the electromagnetic enhancement of solid silver tips. It was found that chemical degradation renders them unusable for tip-enhanced Raman spectroscopy (TERS) within the first two days after production. Furthermore, we present a simple electrochemical method for recovering the enhancing effect of corroded silver tips, as well as for storing freshly prepared probes, for example, for easy shipment. The present work greatly simplifies the experimental aspects of near-field optical microscopy, which should make near-field optical techniques, and, in particular, TERS, more accessible to the scientific community.

  1. Optical Near Field Studies of Plasmonic and Optical Antennas For Sensitive and Selective Biosensing Applications

    NASA Astrophysics Data System (ADS)

    Gelfand, Ryan M.

    For biosensing applications a useful device needs at least two properties: high sensitivity and high selectivity. Optical spectroscopy offers unique advantages over other sensing techniques however one big challenge to overcome is the mismatch between wavelength and the size of biologically relevant molecules. In order to have high enough sensitivity to approach the single-molecule limit, the interaction between the light and the molecule should be strong. However, the diffraction limit of light is approximately half the incidence wavelength, on the order of 100 nm for the smallest nondestructive wavelengths. This presents a significant mismatch between the size of the molecule and the smallest focus spot of the light. The photo-excitation should be compressed more than 100 fold to interact strongly. We must use metallic antennas that convert the incidence radiation into plasmonic modes which can then be compressed well below the wavelength diffraction limit. Studying the near field characteristics of these metallic nanostructures will help us gain insight into this emerging field and allow us to better use them in developing next generation devices. We have developed different geometries of these antennas and simulated their performance using Finite Difference Time Domain software. We have concentrated our efforts in the mid-infrared because that is the natural molecular vibration frequency region and also the near infrared because at these frequencies there exists a mature industry for compact sources, detectors, and fiber optic components. Our simulations show a 6,000 fold mode compression for a bowtie antenna and a million fold compression for a plasmonic photonic crystal (ppc) antenna. The bull's-eye antenna does not have as a high a mode compression but it has a natural geometry for molecular sensing due to the central metallic disc. Experimentally, we have measured the near field of these antennas with a custom back reflection apertureless NSOM setup in both

  2. Creating optical near-field orbital angular momentum in a gold metasurface.

    PubMed

    Chen, Ching-Fu; Ku, Chen-Ta; Tai, Yi-Hsin; Wei, Pei-Kuen; Lin, Heh-Nan; Huang, Chen-Bin

    2015-04-01

    Nanocavities inscribed in a gold thin film are optimized and designed to form a metasurface. We demonstrate both numerically and experimentally the creation of surface plasmon (SP) vortex carrying orbital angular momentum in the metasurface under linearly polarized optical excitation that carries no optical angular momentum. Moreover, depending on the orientation of the exciting linearly polarized light, we show that the metasurface is capable of providing dynamic switching between SP vortex formation or SP subwavelength focusing. The resulting SP intensities are experimentally measured using a near-field scanning optical microscope and are found in excellent quantitative agreements as compared to the numerical results. PMID:25798810

  3. Hyperbolic phonon-polaritons in boron nitride for near-field optical imaging and focusing

    PubMed Central

    Li, Peining; Lewin, Martin; Kretinin, Andrey V.; Caldwell, Joshua D.; Novoselov, Kostya S.; Taniguchi, Takashi; Watanabe, Kenji; Gaussmann, Fabian; Taubner, Thomas

    2015-01-01

    Hyperbolic materials exhibit sub-diffractional, highly directional, volume-confined polariton modes. Here we report that hyperbolic phonon polaritons allow for a flat slab of hexagonal boron nitride to enable exciting near-field optical applications, including unusual imaging phenomenon (such as an enlarged reconstruction of investigated objects) and sub-diffractional focusing. Both the enlarged imaging and the super-resolution focusing are explained based on the volume-confined, wavelength dependent propagation angle of hyperbolic phonon polaritons. With advanced infrared nanoimaging techniques and state-of-art mid-infrared laser sources, we have succeeded in demonstrating and visualizing these unexpected phenomena in both Type I and Type II hyperbolic conditions, with both occurring naturally within hexagonal boron nitride. These efforts have provided a full and intuitive physical picture for the understanding of the role of hyperbolic phonon polaritons in near-field optical imaging, guiding, and focusing applications. PMID:26112474

  4. Hyperbolic phonon-polaritons in boron nitride for near-field optical imaging and focusing

    NASA Astrophysics Data System (ADS)

    Li, Peining; Lewin, Martin; Kretinin, Andrey V.; Caldwell, Joshua D.; Novoselov, Kostya S.; Taniguchi, Takashi; Watanabe, Kenji; Gaussmann, Fabian; Taubner, Thomas

    2015-06-01

    Hyperbolic materials exhibit sub-diffractional, highly directional, volume-confined polariton modes. Here we report that hyperbolic phonon polaritons allow for a flat slab of hexagonal boron nitride to enable exciting near-field optical applications, including unusual imaging phenomenon (such as an enlarged reconstruction of investigated objects) and sub-diffractional focusing. Both the enlarged imaging and the super-resolution focusing are explained based on the volume-confined, wavelength dependent propagation angle of hyperbolic phonon polaritons. With advanced infrared nanoimaging techniques and state-of-art mid-infrared laser sources, we have succeeded in demonstrating and visualizing these unexpected phenomena in both Type I and Type II hyperbolic conditions, with both occurring naturally within hexagonal boron nitride. These efforts have provided a full and intuitive physical picture for the understanding of the role of hyperbolic phonon polaritons in near-field optical imaging, guiding, and focusing applications.

  5. Hyperbolic phonon-polaritons in boron nitride for near-field optical imaging and focusing.

    PubMed

    Li, Peining; Lewin, Martin; Kretinin, Andrey V; Caldwell, Joshua D; Novoselov, Kostya S; Taniguchi, Takashi; Watanabe, Kenji; Gaussmann, Fabian; Taubner, Thomas

    2015-01-01

    Hyperbolic materials exhibit sub-diffractional, highly directional, volume-confined polariton modes. Here we report that hyperbolic phonon polaritons allow for a flat slab of hexagonal boron nitride to enable exciting near-field optical applications, including unusual imaging phenomenon (such as an enlarged reconstruction of investigated objects) and sub-diffractional focusing. Both the enlarged imaging and the super-resolution focusing are explained based on the volume-confined, wavelength dependent propagation angle of hyperbolic phonon polaritons. With advanced infrared nanoimaging techniques and state-of-art mid-infrared laser sources, we have succeeded in demonstrating and visualizing these unexpected phenomena in both Type I and Type II hyperbolic conditions, with both occurring naturally within hexagonal boron nitride. These efforts have provided a full and intuitive physical picture for the understanding of the role of hyperbolic phonon polaritons in near-field optical imaging, guiding, and focusing applications. PMID:26112474

  6. Energy modulation of nonrelativistic electrons in an optical near field on a metal microslit

    NASA Astrophysics Data System (ADS)

    Ishikawa, R.; Bae, J.; Mizuno, K.

    2001-04-01

    Energy modulation of nonrelativistic electrons with a laser beam using a metal microslit as an interaction circuit has been investigated. An optical near field is induced in the proximity of the microslit by illumination of the laser beam. The electrons passing close to the slit are accelerated or decelerated by an evanescent wave contained in the near field whose phase velocity is equal to the velocity of the electrons. The electron-evanescent wave interaction in the microslit has been analyzed theoretically and experimentally. The theory has predicted that electron energy can be modulated at optical frequencies. Experiments performed in the infrared region have verified theoretical predictions. The electron-energy changes of more than ±5 eV with a 10 kW CO2 laser pulse at the wavelength of 10.6 μm has been successfully observed for an electron beam with an energy of less than 80 keV.

  7. Near-field optical microscopy and spectroscopy of few-layer black phosphorous

    NASA Astrophysics Data System (ADS)

    Frenzel, A. J.; Tran, S.; Hinton, J. P.; Sternbach, A. J.; Yang, J.; Gillgren, N.; Lau, C. N.; Basov, D. N.

    Few-layer black phosphorous is a recent addition to the family of two-dimensional (2D) materials which exhibits strongly anisotropic transport and optical properties due to its puckered honeycomb structure. It was recently predicted that this intrinsic anisotropy should manifest in the plasmon dispersion. Additionally, tuning layer number and carrier density can control the dispersion of these collective modes. Scanning near-field optical microscopy (SNOM) has been demonstrated as a powerful method to probe electronic properties, including propagating collective modes, in layered 2D materials. We used SNOM to investigate anisotropic carrier response in few-layer black phosphorous encapsulated by hexagonal boron nitride. In addition to exploring gate-voltage tunability of the electronic response, we demonstrate effective modulation of the near-field signal by ultrafast photoexcitation.

  8. Tuning Localized Surface Plasmon Resonance in Scanning Near-Field Optical Microscopy Probes.

    PubMed

    Vasconcelos, Thiago L; Archanjo, Bráulio S; Fragneaud, Benjamin; Oliveira, Bruno S; Riikonen, Juha; Li, Changfeng; Ribeiro, Douglas S; Rabelo, Cassiano; Rodrigues, Wagner N; Jorio, Ado; Achete, Carlos A; Cançado, Luiz Gustavo

    2015-06-23

    A reproducible route for tuning localized surface plasmon resonance in scattering type near-field optical microscopy probes is presented. The method is based on the production of a focused-ion-beam milled single groove near the apex of electrochemically etched gold tips. Electron energy-loss spectroscopy and scanning transmission electron microscopy are employed to obtain highly spatially and spectroscopically resolved maps of the milled probes, revealing localized surface plasmon resonance at visible and near-infrared wavelengths. By changing the distance L between the groove and the probe apex, the localized surface plasmon resonance energy can be fine-tuned at a desired absorption channel. Tip-enhanced Raman spectroscopy is applied as a test platform, and the results prove the reliability of the method to produce efficient scattering type near-field optical microscopy probes. PMID:26027751

  9. Super-resolution imaging and detection of fluorescence from single molecules by scanning near-field optical microscopy

    NASA Astrophysics Data System (ADS)

    Meixner, Alfred J.; Zeisel, Dieter; Bopp, A. Martin; Tarrach, Guido

    1995-08-01

    Scanning near-field microscopy (SNOM or NSOM) is a versatile and attractive scanning probe technique for imaging with subdiffraction-limited spatial resolution using visible light. At least three different types of images can be recorded simultaneously of the selected sample area, such as the topography, the near-field optical transmission, and the fluorescence from excited chromophores. We have built such a microscope, especially designed for achieving the high resolution and the sensitivity needed for single molecule detection. We report on optical near- field investigations of surface structures and thin polymer films that are doped with fluorescent dye molecules. The effective aperture diameters of the fiber tips used in the SNOM experiments were determined by a photon-scanning tunneling microscopy (PSTM) giving values between 70 and 160 nm. The transmission imaging of transparent polymer phase gratings reveals the existence of different contrast mechanisms, which are either based on the inherent distance dependence of the optical near field or on the periodic change of boundary conditions for the electric field component of the light between the aperture and the sample. Furthermore, we demonstrate selective irreversible photobleaching of dye molecules at moderate concentration (10-5 M) induced locally by the subwavelength-sized probe tip. Finally, we present fluorescence images showing single molecule detection in a thin solid film. The chromophores (rhodamine 6G) were embedded at low concentration (10-7 M) in a 25-nm thin polyvinylbutyral film. A lateral resolution of 160 nm was achieved. We find that the signal strengths of the brightest fluorescent features vary considerably in a sequence of images (a typical single-molecule behavior), whereas the fluorescence background exhibits the usual photobleaching behavior of a large ensemble.

  10. Direct Measurement of Optical Force Induced by Near-Field Plasmonic Cavity Using Dynamic Mode AFM

    PubMed Central

    Guan, Dongshi; Hang, Zhi Hong; Marcet, Zsolt; Liu, Hui; Kravchenko, I. I.; Chan, C. T.; Chan, H. B.; Tong, Penger

    2015-01-01

    Plasmonic nanostructures have attracted much attention in recent years because of their potential applications in optical manipulation through near-field enhancement. Continuing experimental efforts have been made to develop accurate techniques to directly measure the near-field optical force induced by the plasmonic nanostructures in the visible frequency range. In this work, we report a new application of dynamic mode atomic force microscopy (DM-AFM) in the measurement of the enhanced optical force acting on a nano-structured plasmonic resonant cavity. The plasmonic cavity is made of an upper gold-coated glass sphere and a lower quartz substrate patterned with an array of subwavelength gold disks. In the near-field when the sphere is positioned close to the disk array, plasmonic resonance is excited in the cavity and the induced force by a 1550 nm infrared laser is found to be increased by an order of magnitude compared with the photon pressure generated by the same laser light. The experiment demonstrates that DM-AFM is a powerful tool for the study of light induced forces and their enhancement in plasmonic nanostructures. PMID:26586455

  11. Direct measurement of optical force induced by near-field plasmonic cavity using dynamic mode AFM

    SciTech Connect

    Guan, Dongshi; Hang, Zhi Hong; Marset, Zsolt; Liu, Hui; Kravchenko, Ivan I.; Chan, Ho Bun; Chan, C. T.; Tong, Penger

    2015-11-20

    Plasmonic nanostructures have attracted much attention in recent years because of their potential applications in optical manipulation through near-field enhancement. Continuing experimental efforts have been made to develop accurate techniques to directly measure the near-field optical force induced by the plasmonic nanostructures in the visible frequency range. In this work, we report a new application of dynamic mode atomic force microscopy (DM-AFM) in the measurement of the enhanced optical force acting on a nano-structured plasmonic resonant cavity. The plasmonic cavity is made of an upper gold-coated glass sphere and a lower quartz substrate patterned with an array of subwavelength gold disks. In the near-field when the sphere is positioned close to the disk array, plasmonic resonance is excited in the cavity and the induced force by a 1550 nm infrared laser is found to be increased by an order of magnitude compared with the photon pressure generated by the same laser light. Lastly, the experiment demonstrates that DM-AFM is a powerful tool for the study of light induced forces and their enhancement in plasmonic nanostructures.

  12. Direct measurement of optical force induced by near-field plasmonic cavity using dynamic mode AFM

    DOE PAGESBeta

    Guan, Dongshi; Hang, Zhi Hong; Marset, Zsolt; Liu, Hui; Kravchenko, Ivan I.; Chan, Ho Bun; Chan, C. T.; Tong, Penger

    2015-11-20

    Plasmonic nanostructures have attracted much attention in recent years because of their potential applications in optical manipulation through near-field enhancement. Continuing experimental efforts have been made to develop accurate techniques to directly measure the near-field optical force induced by the plasmonic nanostructures in the visible frequency range. In this work, we report a new application of dynamic mode atomic force microscopy (DM-AFM) in the measurement of the enhanced optical force acting on a nano-structured plasmonic resonant cavity. The plasmonic cavity is made of an upper gold-coated glass sphere and a lower quartz substrate patterned with an array of subwavelength goldmore » disks. In the near-field when the sphere is positioned close to the disk array, plasmonic resonance is excited in the cavity and the induced force by a 1550 nm infrared laser is found to be increased by an order of magnitude compared with the photon pressure generated by the same laser light. Lastly, the experiment demonstrates that DM-AFM is a powerful tool for the study of light induced forces and their enhancement in plasmonic nanostructures.« less

  13. Direct Measurement of Optical Force Induced by Near-Field Plasmonic Cavity Using Dynamic Mode AFM

    NASA Astrophysics Data System (ADS)

    Guan, Dongshi; Hang, Zhi Hong; Marcet, Zsolt; Liu, Hui; Kravchenko, I. I.; Chan, C. T.; Chan, H. B.; Tong, Penger

    2015-11-01

    Plasmonic nanostructures have attracted much attention in recent years because of their potential applications in optical manipulation through near-field enhancement. Continuing experimental efforts have been made to develop accurate techniques to directly measure the near-field optical force induced by the plasmonic nanostructures in the visible frequency range. In this work, we report a new application of dynamic mode atomic force microscopy (DM-AFM) in the measurement of the enhanced optical force acting on a nano-structured plasmonic resonant cavity. The plasmonic cavity is made of an upper gold-coated glass sphere and a lower quartz substrate patterned with an array of subwavelength gold disks. In the near-field when the sphere is positioned close to the disk array, plasmonic resonance is excited in the cavity and the induced force by a 1550 nm infrared laser is found to be increased by an order of magnitude compared with the photon pressure generated by the same laser light. The experiment demonstrates that DM-AFM is a powerful tool for the study of light induced forces and their enhancement in plasmonic nanostructures.

  14. Direct Measurement of Optical Force Induced by Near-Field Plasmonic Cavity Using Dynamic Mode AFM.

    PubMed

    Guan, Dongshi; Hang, Zhi Hong; Marcet, Zsolt; Liu, Hui; Kravchenko, I I; Chan, C T; Chan, H B; Tong, Penger

    2015-01-01

    Plasmonic nanostructures have attracted much attention in recent years because of their potential applications in optical manipulation through near-field enhancement. Continuing experimental efforts have been made to develop accurate techniques to directly measure the near-field optical force induced by the plasmonic nanostructures in the visible frequency range. In this work, we report a new application of dynamic mode atomic force microscopy (DM-AFM) in the measurement of the enhanced optical force acting on a nano-structured plasmonic resonant cavity. The plasmonic cavity is made of an upper gold-coated glass sphere and a lower quartz substrate patterned with an array of subwavelength gold disks. In the near-field when the sphere is positioned close to the disk array, plasmonic resonance is excited in the cavity and the induced force by a 1550 nm infrared laser is found to be increased by an order of magnitude compared with the photon pressure generated by the same laser light. The experiment demonstrates that DM-AFM is a powerful tool for the study of light induced forces and their enhancement in plasmonic nanostructures. PMID:26586455

  15. Improvement of tapping-mode scanning near-field optical microscope

    NASA Astrophysics Data System (ADS)

    Zhuo, Wenjiang; Li, Qin; Sun, Jialin; Xu, Jianhua; Zhao, Jun; Guo, Jihua

    2000-10-01

    The commercial crystal tuning fork glued with an optical fiber probe is used as the sensitive detecting element for the tapping-mode scanning near-field optical microscopy. Firstly, the single-mode optical fiber is etched down to a small diameter to decrease the burden of the tuning fork. Secondary, the fiber is etched for the second time to form the sharp tip with large cone angle. Thirdly, the fiber probe, with nanometric tip and high light throughput, is glued to tuning fork by Cyanoacrylate Adhesive. The measured quality factor, Q, of the tuning fork/optical fiber probe assembly prepared in this way is higher than 300. The optical signal is modulated to the frequency of the tuning fork by optical fiber probe as it is detecting the topography of sample. The high-resolution of the tapping- mode detector is proved by imaging the topography of the grating and biological cell.

  16. Analytical model for quantitative prediction of material contrasts in scattering-type near-field optical microscopy.

    PubMed

    Cvitkovic, A; Ocelic, N; Hillenbrand, R

    2007-07-01

    Nanometer-scale mapping of complex optical constants by scattering-type near-field microscopy has been suffering from quantitative discrepancies between the theory and experiments. To resolve this problem, a novel analytical model is presented here. The comparison with experimental data demonstrates that the model quantitatively reproduces approach curves on a Au surface and yields an unprecedented agreement with amplitude and phase spectra recorded on a phonon-polariton resonant SiC sample. The simple closed-form solution derived here should enable the determination of the local complex dielectric function on an unknown sample, thereby identifying its nanoscale chemical composition, crystal structure and conductivity. PMID:19547189

  17. Absorption Coefficient Imaging by Near-Field Scanning Optical Microscopy in Bacteria

    NASA Astrophysics Data System (ADS)

    de Paula, Ana M.; Chaves, Claudilene R.; Silva, Haroldo B.; Weber, Gerald

    2003-06-01

    We present a method for obtaining a position-dependent absorption coefficient from near-field scanning optical transmission microscopy. We show that the optical transmission intensity can be combined with the topography, resulting into an absorption coefficient that simplifies the analysis of different materials within a sample. The method is tested with the dye rhodamine 6G, and we show some analysis in biological samples such as bacteria Klebsiella pneumoniae and Pseudomonas aeruginosa . The calculated absorption coefficient images show important details of the bacteria, in particular for P. aeruginosa , in which membrane vesicles are clearly seen.

  18. Transverse and longitudinal characterization of electron beams using interaction with optical near-fields.

    PubMed

    Kozák, Martin; McNeur, Joshua; Leedle, Kenneth J; Deng, Huiyang; Schönenberger, Norbert; Ruehl, Axel; Hartl, Ingmar; Hoogland, Heinar; Holzwarth, Ronald; Harris, James S; Byer, Robert L; Hommelhoff, Peter

    2016-08-01

    We demonstrate an experimental technique for both transverse and longitudinal characterization of bunched femtosecond free electron beams. The operation principle is based on monitoring of the current of electrons that obtained an energy gain during the interaction with the synchronized optical near-field wave excited by femtosecond laser pulses. The synchronous accelerating/decelerating fields confined to the surface of a silicon nanostructure are characterized using a highly focused sub-relativistic electron beam. Here the transverse spatial resolution of 450 nm and femtosecond temporal resolution of 480 fs (sub-optical-cycle temporal regime is briefly discussed) achievable by this technique are demonstrated. PMID:27472587

  19. Polarization Properties in Apertureless-Type Scanning Near-Field Optical Microscopy.

    PubMed

    Ishibashi, Takayuki; Cai, Yongfu

    2015-12-01

    Polarization properties of apertureless-type scanning near-field optical microscopy (a-SNOM) were measured experimentally and were also analyzed using a finite-difference time-domain (FDTD) simulation. Our study reveals that the polarization properties in the a-SNOM are maintained and the a-SNOM works as a wave plate expressed by a Jones matrix. The measured signals obtained by the lock-in detection technique could be decomposed into signals scattered from near-field region and background signals reflected by tip and sample. Polarization images measured by a-SNOM with an angle resolution of 1° are shown. FDTD analysis also reveals the polarization properties of light in the area between a tip and a sample are p-polarization in most of cases. PMID:26415540

  20. Surface-polariton propagation for scanning near-field optical microscopy application.

    PubMed

    Keilmann, F

    1999-01-01

    Surface plasmon-, phonon- and exciton-polaritons exist on specific materials in specific spectral regions. We assess the properties of such travelling surface-bound electromagnetic waves relevant for scanning near-field optical microscopy applications, i.e. the tightness of surface binding, the attenuation, the phase velocity and the coupling with free-space electromagnetic waves. These quantities can be directly determined by photographic imaging of surface plasmon- and surface phonon-polaritons, in both the visible and mid-infared regions. Focusing of mid-infrared surface plasmons is demonstrated. Surface waveguides to transport and focus photons to the tip of a scanning near-field probe are outlined. PMID:11388308

  1. Optical security based on near-field processes at the nanoscale

    NASA Astrophysics Data System (ADS)

    Naruse, Makoto; Tate, Naoya; Ohtsu, Motoichi

    2012-09-01

    Optics has been playing crucial roles in security applications ranging from authentication and watermarks to anti-counterfeiting. However, since the fundamental physical principle involves optical far-fields, or propagating light, diffraction of light causes severe difficulties, for example in device scaling and system integration. Moreover, conventional security technologies in use today have been facing increasingly stringent demands to safeguard against threats such as counterfeiting of holograms, requiring innovative physical principles and technologies to overcome their limitations. Nanophotonics, which utilizes interactions between light and matter at the nanometer scale via optical near-field interactions, can break through the diffraction limit of conventional propagating light. Moreover, nanophotonics has some unique physical attributes, such as localized optical energy transfer and the hierarchical nature of optical near-field interactions, which pave the way for novel security functionalities. This paper reviews the physical principles and describes some experimental demonstrations of systems based on nanophotonics with respect to security applications such as tamper resistance against non-invasive and invasive attacks, hierarchical information retrieval, hierarchical holograms, authentication, and traceability.

  2. Power delivery and self-heating in nanoscale near field transducer for heat-assisted magnetic recording.

    PubMed

    Zhou, Nan; Traverso, Luis M; Xu, Xianfan

    2015-03-27

    To keep increasing the storage density in next-generation hard disk drives, heat-assisted magnetic recording is being developed where a nanoscale near field transducer (NFT) locally and temporally heats a sub-diffraction-limited region in the recording medium to reduce the magnetic coercivity. This allows the use of very small grain in the medium while still maintaining data thermal stability. Plasmonic nanostructures made of apertures or antennas are good candidates for NFTs because of their capability of subwavelength light manipulation in optical frequencies. The NFT must simultaneously deliver enough power to the recording medium with as small as possible incident laser power to reduce self-heating in the NFT, which could cause thermal expansion and materials failure that lead to degradation of the overall hard drive performance. In this work, we study the effect of optical properties on the power delivery efficiency of nanoscale bowtie aperture antennas, with the presence of a recording media stack. Heat dissipation and temperature rise in the NFT are also computed to investigate their dependence on materials' properties. The possibility of using alternative plasmonic materials for delivering higher power and/or reducing heating in NFTs is discussed. PMID:25759907

  3. Optical near-field investigations of individual single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Hartschuh, Achim

    2009-03-01

    Optical excitation of semiconducting nanotubes creates excitons that determine nearly all light-based applications. Near-field photoluminescence (PL) and Raman imaging with a spatial resolution better than 15 nm was used to probe the spectroscopic properties of excitonic states along single nanotubes on substrates [1,2]. The PL intensity was found to decrease towards the nanotube ends on a length scale of few 10 nm probably caused by exciton transport to localized end states followed by efficient non-radiative recombination. DNA-wrapping of nanotubes results in pronounced emission energy variations on a length scale of few 10 nm indicating the potential of the material for nanoscale sensing applications [3]. Inter-nanotube energy transfer was studied for different pairs of semiconducting nanotubes forming bundles and crossings [4]. Efficient transfer is found to be limited to a few nanometres because of competing fast non-radiative relaxation and can be explained in terms of electromagnetic near-field coupling. We also report on our recent experimental results on time-resolved near-field PL measurements, electrically gated nanotubes and the PL of nanotubes on metal surfaces. [4pt] References: [0pt] [1] A. Hartschuh, Angew. Chem. Int. Ed. 47, 8178 (2008). [0pt] [2] I. O. Maciel et. al, Nature Mat. 7, 878 (2008). [0pt] [3] H. Qian et. al, Nano Lett. 8, 2706 (2008). [0pt] [4] H. Qian et. al, Nano Lett. 8, 1363 (2008).

  4. Toward Nanometer-Scale Optical Photolithography: Utilizing the Near-Field of Bowtie Optical Nanoantennas

    PubMed Central

    Sundaramurthy, Arvind; Kino, Gordon S.; Schuck, P. James; Conley, Nicholas R.; Fromm, David P.; Moerner, W. E.

    2006-01-01

    Optically resonant metallic bowtie nanoantennas are utilized as fabrication tools for the first time, resulting in the production of polymer resist nanostructures <30 nm in diameter at record low incident multiphoton energy densities. The nanofabrication is accomplished via nonlinear photopolymerization, which is initiated by the enhanced, confined optical fields surrounding the nanoantenna. The position, size, and shape of the resist nanostructures directly correlate with rigorous finite-difference time-domain computations of the field distribution, providing a nanometer-scale measurement of the actual field confinement offered by single optical nanoantennas. In addition, the size of the photoresist regions yields strong upper bounds on photoacid diffusion and resist resolution in SU-8, demonstrating a technique that can be generalized to the study of many current and yet-to-be-developed photoresist systems. PMID:16522022

  5. Conference Paper NFO-7:7th International Conference on Near-Field Optics and Related Technologies

    SciTech Connect

    Prof.Dr. Lukas Novotny

    2004-10-18

    The seventh conference in the NFO conference series, held here in Rochester, provided to be the principal forum for advances in sub-wavelength optics, near-field optical microscopy, local field enhancement, instrumental developments and the ever-increasing range of applications. This conference brought together the diverse scientific communities working on the theory and application of near-field optics (NFO) and related techniques.

  6. A single beam near-field laser trap for optical stretching, folding and rotation of erythrocytes

    NASA Astrophysics Data System (ADS)

    Gu, Min; Kuriakose, Smitha; Gan, Xiaosong

    2007-02-01

    To understand the fundamental mechanical and viscoelastic properties of RBCs, one needs laser tweezers in which cells can not only be trapped, but also be stretched, folded, and rotated. Stretching, folding and rotating an RBC is particularly important in order to reveal the shear elasticity of the RBC membrane. Here we show a single beam near-field laser trapping technique under focused evanescent wave illumination for optical stretching, folding and rotation of a single RBC. This multifunctional manipulation method will provide a new platform for measuring cell properties such as the membrane elasticity, viscoelasticity and deformability.

  7. Image formation properties and inverse imaging problem in aperture based scanning near field optical microscopy.

    PubMed

    Schmidt, S; Klein, A E; Paul, T; Gross, H; Diziain, S; Steinert, M; Assafrao, A C; Pertsch, T; Urbach, H P; Rockstuhl, C

    2016-02-22

    Aperture based scanning near field optical microscopes are important instruments to study light at the nanoscale and to understand the optical functionality of photonic nanostructures. In general, a detected image is affected by both the transverse electric and magnetic field components of light. The discrimination of the individual field components is challenging as these four field components are contained within two signals in the case of a polarization resolved measurement. Here, we develop a methodology to solve the inverse imaging problem and to retrieve the vectorial field components from polarization and phase resolved measurements. Our methodology relies on the discussion of the image formation process in aperture based scanning near field optical microscopes. On this basis, we are also able to explain how the relative contributions of the electric and magnetic field components within detected images depend on the chosen probe. We can therefore also describe the influence of geometrical and material parameters of individual probes within the image formation process. This allows probes to be designed that are primarily sensitive either to the electric or magnetic field components of light. PMID:26907063

  8. High-sensitivity piezoelectric tube sensor for shear-force detection in scanning near-field optical microscopy

    NASA Astrophysics Data System (ADS)

    Lindfors, K.; Kapulainen, M.; Ryytty, P.; Kaivola, M.

    2004-11-01

    An easy-to-implement non-optical shear-force detection setup for tip-sample distance regulation in scanning near-field optical microscopy is demonstrated. The detection method is based on attaching the near-field probe to a piezoelectric tube resulting in excellent mechanical contact between tip and detector. The main advantages of the method are good signal-to-background contrast and thus potential for high sensitivity. The method is demonstrated by obtaining approach curves of silicon surfaces. The suitability for optical experiments is further shown by measuring the near-field intensity distribution of the emission of a semiconductor laser.

  9. Optical forces on a Rayleigh dielectric particle in a patterned near-field landscape

    NASA Astrophysics Data System (ADS)

    Zelenina, Anna; Quidant, Romain; Petrov, Dmitri; Badenes, Goncal

    2005-07-01

    The trapping of micro-objects by optical radiation forces, so-called optical tweezers, has become widely used in physical, chemical and biological experiments where accurate and non-invasive manipulation is required. Recent advances in beam shaping render it possible for instance to rotate or to dynamically manipulate independently several elements. Today, one of the remaining challenges of conventional optical tweezers is the direct manipulation of systems with sizes belonging to the sub-wavelength or Rayleigh regime. Indeed, the diffraction limit prevents in that case from achieving a commensurable trapping volume and thus does not allow for minimizing the fluctuations in position of the trapped object due to its strong Brownian motion. In order to overcome this limitation, it has been proposed to use evanescent fields instead of the usual propagating fields. Recent advances in optics of noble metal nano-structures have recently provided new configurations to achieve nano-optical tweezers. Especially, tightly localized modes resulting from the coupling between resonant noble metal nanostructures may offer the gradient forces able to trap and manipulate Rayleigh objects. In this work, we calculate the radiation forces exerted on a nanometric dielectric sphere when exposed to a patterned optical near-field landscape at an interface decorated with resonant gold nanostructures. By comparing their magnitude with other forces that affect the movement of the particle, we discuss the practical ability of our configuration for multiple parallel optical manipulation.

  10. Effect of condensed water on scanning near-field optical microscope measurement

    NASA Astrophysics Data System (ADS)

    Douas, M.; Serena, P. A.; Marqués, M. I.

    2013-11-01

    The relevance of the scanning near-field optical microscope (SNOM), for near-field characterization, is often shaded by the appearance of artifacts, especially when geometrical characterization is intended. Artifacts are related to many features such as the feedback system or the scanning mode. For non-vacuum environmental conditions, artifact sources may be related to tip geometry and the pollutants attached, either on the tip or on the studied surfaces, altering the optical image. As an environmental element, water vapor could be treated as a source for artifacts, but could also be used as a tool for chemical characterization of hydrophilic patches. Spontaneous meniscus formation between hydrophilic surfaces, such as the tip and the sample, may guide light from the tip to the sample, enhancing the transmitted signal. This study focuses on the effects that water condensation at the nanoscale has on the signals achieved by SNOM, combining two computational methods (Monte Carlo and finite difference time domain) in order to deal with light propagation through heterogeneous media and water condensation.

  11. Mapping electron-beam-injected trapped charge with scattering scanning near-field optical microscopy.

    PubMed

    Tranca, Denis E; Sánchez-Ortiga, Emilio; Saavedra, Genaro; Martínez-Corral, Manuel; Tofail, Syed A M; Stanciu, Stefan G; Hristu, Radu; Stanciu, George A

    2016-03-01

    Scattering scanning near-field optical microscopy (s-SNOM) has been demonstrated as a valuable tool for mapping the optical and optoelectronic properties of materials with nanoscale resolution. Here we report experimental evidence that trapped electric charges injected by an electron beam at the surface of dielectric samples affect the sample-dipole interaction, which has direct impact on the s-SNOM image content. Nanoscale mapping of the surface trapped charge holds significant potential for the precise tailoring of the electrostatic properties of dielectric and semiconductive samples, such as hydroxyapatite, which has particular importance with respect to biomedical applications. The methodology developed here is highly relevant to semiconductor device fabrication as well. PMID:26974112

  12. Double-resonance probe for near-field scanning optical microscopy

    NASA Astrophysics Data System (ADS)

    Cherkun, A. P.; Serebryakov, D. V.; Sekatskii, S. K.; Morozov, I. V.; Letokhov, V. S.

    2006-03-01

    A surface-contact transducer is developed for scanning probe microscopes, whose operating principle is based on the coincidence between the resonance frequency of a 32kHz quartz tuning fork and that of the probe attached to it. This allows the transducer to have a high quality factor and, if the vibration amplitude of the probe tip exceeds that of the tuning fork prongs, materially improves its force sensitivity. The resonance transducer proposed by us has an experimentally verified force sensitivity of 8pN (rms) in the 300Hz frequency band, which is of the same order of magnitude as the sensitivity of atomic force microscope (AFM) cantilever sensors. The manufacture of such transducers equipped with optical-fiber probes for near-field scanning optical microscopy and with tungsten probes for AFM is described as an example.

  13. Selective trapping or rotation of isotropic dielectric microparticles by optical near field in a plasmonic archimedes spiral.

    PubMed

    Tsai, Wei-Yi; Huang, Jer-Shing; Huang, Chen-Bin

    2014-02-12

    We demonstrate selective trapping or rotation of optically isotropic dielectric microparticles by plasmonic near field in a single gold plasmonic Archimedes spiral. Depending on the handedness of circularly polarized excitation, plasmonic near fields can be selectively engineered into either a focusing spot for particle trapping or a plasmonic vortex for particle rotation. Our design provides a simple solution for subwavelength optical manipulation and may find applications in micromechanical and microfluidic systems. PMID:24392638

  14. Two-dimensional refractive index profiling of optical fibers by modified refractive near-field technique

    NASA Astrophysics Data System (ADS)

    El Sayed, A.; Pilz, Soenke; Ryser, Manuel; Romano, Valerio

    2016-02-01

    The refractive index distribution in the core-cladding region of an optical fiber plays an important role in determining the transmission and dispersion properties of the waveguide. The refracted near-field technique (RNF) is among the most widespread techniques used for measuring the refractive index profile of optical fibers and is based on illuminating the end-facet of a fiber with a focused beam whose vertex angle greatly exceeds the acceptance angle of the fiber, which is immersed in an index matching liquid. What one observes are then the refracted unguided rays rather than the guided rays. Nevertheless, the standard refracted near-field technique cannot be applied to a wide range of optical fibers e.g. if their shapes are not axially symmetric. In this work we demonstrate a modified method which allows 2-D imaging of the refractive index profile and thereby overcoming the axial symmetric limitation of the standard RNF. The new system is operating at 630 nm and based on the same principle of the RNF, but the optical path is reversed so that the light at the fiber end-facet is collected by an objective lens and detected by a CCD camera. The method does not require scanning over the fiber end-facet. Thus the system is faster and less sensitive to vibrations and external conditions compared to the standard RNF, furthermore it allows averaging to improve the signal to noise ratio. The spatial resolution of the system is determined by the numerical aperture of the objective and by the resolution of the CCD camera. To calibrate the setup, a reference multi-step index fiber provided by National Physical Laboratory was used.

  15. Optical Characterization of Component Wear and Near-Field Plasma of the Hermes Thruster

    NASA Technical Reports Server (NTRS)

    Williams, George J., Jr.; Kamhawi, Hani

    2015-01-01

    Optical emission spectral (OES) data are presented which correlate trends in sputtered species and the near-field plasma with the Hall-Effect Rocket with Magnetic Shielding (HERMeS) thruster operating condition. The relative density of singly-ionized xenon (Xe II) is estimated using a collisional-radiative model. OES data were collected at three radial and several axial locations downstream of the thruster's exit plane. These data were deconvolved to show the structure for the near-field plasma as a function of thruster operating condition. The magnetic field is shown to have a much greater affect on plasma structure than the discharge voltage with the primary ionization/acceleration zone boundary being similar for all nominal operating voltages at constant power. OES measurement of sputtered boron shows that the HERMeS thruster is magnetically shielded across its operating envelope. Preliminary assessment of carbon sputtered from the keeper face suggest it increases significantly with operating voltage, but the uncertainty associated with these measurements is very high.

  16. Quantitative Imaging of Rapidly Decaying Evanescent Fields Using Plasmonic Near-Field Scanning Optical Microscopy

    PubMed Central

    Zhang, Zhen; Ahn, Phillip; Dong, Biqin; Balogun, Oluwaseyi; Sun, Cheng

    2013-01-01

    Non-propagating evanescent fields play an important role in the development of nano-photonic devices. While detecting the evanescent fields in far-field can be accomplished by coupling it to the propagating waves, in practice they are measured in the presence of unwanted propagating background components. It leads to a poor signal-to-noise ratio and thus to errors in quantitative analysis of the local evanescent fields. Here we report on a plasmonic near-field scanning optical microscopy (p-NSOM) technique that incorporates a nanofocusing probe for adiabatic focusing of propagating surface plasmon polaritons at the probe apex, and for enhanced coupling of evanescent waves to the far-field. In addition, a harmonic demodulation technique is employed to suppress the contribution of the background. Our experimental results show strong evidence of background free near-field imaging using the new p-NSOM technique. Furthermore, we present measurements of surface plasmon cavity modes, and quantify their contributing sources using an analytical model. PMID:24076563

  17. Nanoscale optical and electrical characterizations of ZnO nanostructures by near-field microscopy

    NASA Astrophysics Data System (ADS)

    Bercu, Bogdan; Giraudet, Louis; Molinari, Michael

    2014-03-01

    The interest in the recent years for nanostructure studies has led to the development of a wide palette of characterization techniques such as the electrical modes in scanning probe microscopy (STM, EFM, KPFM...). Optical characterization at nanoscale remains nevertheless a challenge especially for wide gap semiconductors where high energy is required. In this presentation, we will present our work focusing in the development and the improvement of near-field microscopy techniques to investigate nanoscale properties of ZnO nanostructures and related semiconducting objects. For the optical characterization, cathodoluminescence (CL) studies present many advantages over the classical photoluminescence experiments for ZnO analysis. This contribution presents the development of a scanning near-field cathodoluminescence microscope where a bimorph piezoelectric cantilever is simultaneously used for both actuation and oscillation amplitude detection. Operated inside a scanning electron microscope (SEM) it offers the possibility of performing simultaneous topography and cathodoluminescence charting of the sample surface additionally to the SEM imaging with a resolution in the order of several tenths of nanometers. Different measurements of ZnO nanostructures and related objects will be presented to show the potentiality of our optical characterization setup. Complementary STEM-CL measurements at higher beam energy were performed on the ZnO nanowires confirming the good quality of the investigated nanostructures. As for the electrical characterization, we will focus on the local surface potential mapping of ZnO nanowires used for photoconduction using Kelvin Probe Force Microscopy. While ZnO nanowire photoconduction gains as high as 1010 in the UV region were reported, several issues come into play when it comes to making a precise measurement of a single nanowire. An important issue is the good quality of the injecting contacts on the nanowire and the reproducibility of its

  18. Simulation of near-field scanning optical microscopy using a plasmonic gap probe

    NASA Astrophysics Data System (ADS)

    Tanaka, Kazuo; Tanaka, Masahiro; Katayama, Kiyofumi

    2006-10-01

    Imaging by near-field scanning optical microscopy (NSOM) with a plasmonic gap probe (PGP) is simulated to confirm the operation of the recently proposed PGP. The simulations demonstrate that the probe works in illumination, collection-reflection and collection mode, and that is it not necessary to vibrate the probe tip in order to remove background noise. The resolution of the scanned image is also shown to be approximately equal to the diameter of the probe tip. Furthermore, the throughput of the probe is much higher than conventional aperture probes providing similar resolution. The proposed probe thus has the advantages of both aperture probes and scattering probes, and is expected to have excellent characteristics for use as a scanning probe for NSOM.

  19. Desktop near-field thermal-lens microscope for thermo-optical detection in microfluidics.

    PubMed

    Smirnova, Adelina; Proskurnin, Mikhail A; Mawatari, Kazuma; Kitamori, Takehiko

    2012-09-01

    A new compact near-field desktop-sized diode laser thermal-lens microscope for analysis in microfluidics was proposed. A novel beam-alignment and detection systems provided high signal stability and, along with reduced number of optical elements rendered the instrument portable. The detection of nonfluorescent model species (Fe(II)-bathophenanthroline chelate) in water showed good linearity in the range of 5 × 10(-9) to 1 × 10(-4) M, and the limit of detection was 3.5 × 10(-9) M, which corresponded to 3.5 × 10(-7) absorbance units and provided a 20-fold enhancement in sensitivity compared with existing schematic. PMID:22965721

  20. Widely tuneable scattering-type scanning near-field optical microscopy using pulsed quantum cascade lasers

    SciTech Connect

    Yoxall, Edward Rahmani, Mohsen; Maier, Stefan A.; Phillips, Chris C.; Navarro-Cía, Miguel

    2013-11-18

    We demonstrate the use of a pulsed quantum cascade laser, wavelength tuneable between 6 and 10 μm, with a scattering-type scanning near-field optical microscope (s-SNOM). A simple method for calculating the signal-to-noise ratio (SNR) of the s-SNOM measurement is presented. For pulsed lasers, the SNR is shown to be highly dependent on the degree of synchronization between the laser pulse and the sampling circuitry; in measurements on a gold sample, the SNR is 26 with good synchronization and less than 1 without. Simulations and experimental s-SNOM images, with a resolution of 100 nm, corresponding to λ/80, and an acquisition time of less than 90 s, are presented as proof of concept. They show the change in the field profile of plasmon-resonant broadband antennas when they are excited with wavelengths of 7.9 and 9.5 μm.

  1. Evolution of Biomass Burning Aerosol Optical Properties in the Near Field

    NASA Astrophysics Data System (ADS)

    Sedlacek, A. J., III; Arnott, W. P.; Chand, D.; Fortner, E.; Freedman, A.; Kleinman, L. I.; Onasch, T. B.; Shilling, J. E.; Springston, S. R.

    2014-12-01

    Biomass burning (BB) events are known to produce chemically rich environments that can impact the evolution of primary aerosols and influence secondary aerosols production rates. With their increasing in frequency, BB events are expected to exert an ever-increasing impact on climate due to aerosol radiative forcing processes. One area that is still poorly understood is the evolution of these smoke aerosols in the near field. Recent literature suggests that BB aerosols undergo a rapid evolution near their source that is then followed by a slower aging phase. During the summer of 2013, the Department of Energy-sponsored an aircraft field campaign called the Biomass Burning Observation Project (BBOP) that specifically targeted the evolution of smoke aerosols in the near field (< 2 hours). Results examining the evolution of BB optical and microphysical properties will be presented. To probe these properties, the BBOP field campaign deployed a Single Particle Soot Photometer (SP2) to probe the mixing state of refractory black carbon (rBC) and a Soot Particle Aerosol Mass Spectrometer (SP-AMS) to investigate the composition of both non-refractory and rBC-containing particles. Aerosol optical properties were measured in situ using a 355 nm Photoacoustic spectrometer (PAS), a 532 nm photo thermal interferometer (PTI), a 630 nm cavity Attenuation Phase Shifted (CAPS) spectrometer, a 3-λ nephelometer, and a 3-λ PSAP. The BBOP study represented the maiden aircraft deployment for the SP-AMS, the 355 nm PAS and 532 nm PTI. Discussion will be on the near-field evolution of particle mixing state and morphology, chemical composition, and microphysical processes that determine aerosol size distributions and single scattering albedo (SSA) of light absorbing aerosols. In the cases studied, increases in the coating thickness of refractive black carbon (rBC) particles, organic aerosol/rBC ratio, scattering/CO ratio, and aerosol size distributions have been observed. Results will be

  2. Far- and near-field optical properties of gold nanoparticle ensembles

    SciTech Connect

    Nedyalkov, N N; Dikovska, A O; Dimitrov, I; Nikov, Ru; Atanasov, P A; Toshkova, R A; Gardeva, E G; Yossifova, L S; Alexandrov, M T

    2012-12-31

    The optical properties of gold nanoparticle clusters are presented from the point of view of their applications in biophotonics, where the absorption and scattering spectra are crucial. Generalised multiparticle Mie theory and finite difference time domain (FDTD) technique are used for theoretical description of the far- and nearfield optical properties of two dimensional nanoparticle ensembles. The system under consideration consists of spherical gold nanoparticles from 20 to 200 nm in diameter, forming 2D clusters in water. The properties of the far-field absorption and scattering spectra as a function of the cluster size, particle dimensions, and interparticle distance are investigated for ordered hexagonal structure of the particle arrays. It is found that the absorption efficiency can be shifted to the IR spectral range by increasing array size and decreasing interparticle distance. The increase in the array size also results in enhancement of the scattering efficiency while the absorption is reduced. The near-field intensity distribution is inhomogeneous over the array, as formation of zones with intensity enhancement of about two orders of magnitude is observed in specific areas. The optical properties of an ensemble whose configuration is reproduced from real experiments of gold nanoparticle deposition onto cancer cells are also presented. The results obtained can be used in designing of nanoparticle arrays with applications in biophotonics, bioimaging and photothermal therapy. (nanosystems)

  3. Near-Field Scanning Optical Microscopy for High-Resolution Membrane Studies

    PubMed Central

    Huckabay, Heath A.; Armendariz, Kevin P.; Newhart, William H.; Wildgen, Sarah M.; Dunn, Robert C.

    2012-01-01

    The desire to directly probe biological structures on the length scales that they exist has driven the steady development of various high-resolution microscopy techniques. Among these, optical microscopy and, in particular, fluorescence-based approaches continue to occupy dominant roles in biological studies given their favorable attributes. Fluorescence microscopy is both sensitive and specific, is generally noninvasive toward biological samples, has excellent temporal resolution for dynamic studies, and is relatively inexpensive. Light-based microscopies can also exploit a myriad of contrast mechanisms based on spectroscopic signatures, energy transfer, polarization, and lifetimes to further enhance the specificity or information content of a measurement. Historically, however, spatial resolution has been limited to approximately half the wavelength due to the diffraction of light. Near-field scanning optical microscopy (NSOM) is one of several optical approaches currently being developed that combines the favorable attributes of fluorescence microscopy with superior spatial resolution. NSOM is particularly well suited for studies of both model and biological membranes and application to these systems is discussed. PMID:23086886

  4. Optical gecko toe: Optically controlled attractive near-field forces between plasmonic metamaterials and dielectric or metal surfaces

    NASA Astrophysics Data System (ADS)

    Zhang, J.; MacDonald, K. F.; Zheludev, N. I.

    2012-05-01

    On the mesoscopic scale, electromagnetic forces are of fundamental importance to an enormously diverse range of systems, from optical tweezers to the adhesion of gecko toes. Here we show that a strong light-driven force may be generated when a plasmonic metamaterial is illuminated in close proximity to a dielectric or metal surface. This near-field force can exceed radiation pressure and Casimir forces to provide an optically controlled adhesion mechanism mimicking the gecko toe: At illumination intensities of just a few tens of nW/μm2 it is sufficient to overcome the Earth's gravitational pull.

  5. Optical resonance-enhanced absorption-based near-field immunochip biosensor for allergen detection.

    PubMed

    Maier, Irene; Morgan, Michael R A; Lindner, Wolfgang; Pittner, Fritz

    2008-04-15

    An optical immunochip biosensor has been developed as a rapid method for allergen detection in complex food matrixes, and its application evaluated for the detection of the egg white allergens, ovalbumin and ovomucoid. The optical near-field phenomenon underlying the basic principle of the sensor design is called resonance-enhanced absorption (REA), which utilizes gold nanoparticles (Au NPs) as signal transducers in a highly sensitive interferometric setup. Using this approach, a novel, simple, and rapid colorimetric solid-phase immunoassay on a planar chip substrate was realized in direct and sandwich assay formats, with a detection system that does not require any instrumentation for readout. Semiquantitative immunochemical responses are directly visible to the naked eye of the analyst. The biosensor shows concentration-dependent color development by capturing antibody-functionalized Au NPs on allergen-coated chips and has a detection limit of 1 ng/mL. To establish a rapid method, we took advantage of the physicochemical microenvironment of the Au NP-antibody bioconjugate to be bound directly over an interacting poly(styrene-methyl methacrylate) interlayer by an immobilized antigen. In the direct assay format, a coating time with allergen of only 5 min under "soft" nondenaturing conditions was sufficient for accurate reproducibility and sensitivity. In conclusion, the REA-based immunochip sensor is easy to fabricate, is reproducible and selective in its performance, has minimal technical requirements, and will enable high-throughput screening of affinity binding interactions in technological and medical applications. PMID:18358010

  6. Imaging biological molecules with single molecule sensitivity using near-field scanning optical microscopy

    SciTech Connect

    Ambrose, W.P.; Affleck, R.L.; Goodwin, P.M.; Keller, R.A.; Martin, J.C.; Petty, J.T.; Schecker, J.A.; Wu, Ming

    1995-12-01

    We have developed a near-field scanning optical microscope with the sensitivity to detect single fluorescent molecules. Our microscope is based on scanning a sample under a tapered and metal coated fiber optic probe and has an illumination-aperture diameter as small as 100 nm. The microscope simultaneously acquires a shear force image with a height noise of {approximately} 1 nm. We have used this system to demonstrate the detection of single molecules of Rhodamine-6G on silica. In this paper, we explore the use of NSOM for investigations of biological molecules. We have prepared and imaged double-stranded DNA intercalated with thiazole orange homodimer (TOTO); single chromosomes stained with propidium iodide; and {beta}-phycoerythrin proteins on dry, borosilicate-glass surfaces. At very dilute coverages, isolated fluorescent spots are observed for the un-intercalated TOTO dye and for {beta}-phycoerythrin. These fluorescent spots exhibit-emission intensity fluctuations and abrupt bleaching transitions, similar to the intensity behavior observed previously for single Rhodamine 6G molecules on silica.

  7. Near-field characteristics of broad area diode lasers during catastrophic optical damage failure

    NASA Astrophysics Data System (ADS)

    Hempel, Martin; Tomm, Jens W.; Baeumler, Martina; Konstanzer, Helmer; Mukherjee, Jayanta; Elsaesser, Thomas

    2012-06-01

    One of the failure mechanisms preventing diode lasers in reaching ultra high optical output powers is the catastrophic optical damage (COD). It is a sudden degradation mechanism which impairs the device functionality completely. COD is caused by a positive feedback loop of absorbing laser light and increasing temperature at a small portion of the active material, leading to a thermal runaway on a nanosecond timescale. We analyze commercial gain-guided AlGaAs/GaAs quantum well broad area diode lasers in single pulse step tests. The near-field emission on the way to and at the COD is resolved on a picosecond time scale by a streak-camera combined with a microscope. In the final phase of the step tests the COD is occurring at ~50 times threshold current. The growth of the COD defect site is monitored and defect propagation velocities between 30 and 190 μm/μs are determined. The final shape of the damage is verified by opening the device and taking a micro-photoluminescence map of the active layer.

  8. Self-Cleaning Effect of Solid Immersion Lens Using Photocatalyst TiO2 Film for Near-Field Recording

    NASA Astrophysics Data System (ADS)

    Hong, Hyun-Guk; Kim, Young-Joo

    2008-07-01

    A novel approach using the self-cleaning effect of photocatalyst TiO2 film was proposed and studied experimentally to solve the critical contamination issues in solid immersion lens (SIL) based near-field recording (NFR). To evaluate the feasibility of the self-cleaning approach, the surface of a hemispherical (half-ball) SIL and a glass disk were coated with TiO2 film which constituted the final layer of an antireflection (AR) coating for better optical transmittance. The hydrophilic property of the TiO2-coated SIL and disk was confirmed by the contact angle measurement with deionized water after thermal treatment to form an anatase structure and by the irradiation of UV light. To determine the effectiveness of the self-cleaning effect, a removal test was conducted with different contaminants such as a fingerprint and laser toner particles. The effects of the wavelength and intensity of UV light were tested over a range of irradiation times. The air flow during the rotation of the disk was also helpful for removing the contaminants. From the experimental results, it was confirmed that the self-cleaning effect of photocatalyst TiO2 film is very effective for removing organic contaminants from the surfaces of an SIL and disk, which means that this approach can be applied to SIL-based NFR systems.

  9. Modeling the Optical Response to a Near-Field Probe Tip from a Generalized Multilayer Thin Film

    NASA Astrophysics Data System (ADS)

    Lawrence, A. J.

    The contrast mechanism in Kerr imaging is the apparent angle through which the plane of polarization is rotated upon reflection from a magnetic surface. This can be calculated for a well characterized surface given the polarization state of the incident light. As in traditional optical microscopy, the spatial resolution is limited by diffraction to roughly half the wavelength of the illumination light. The diffraction limit can be circumvented through the use of near-field scanning optical microscopy, in which the illumination source is an evanescent field at the tip of a tapered optical fiber. A novel probe design for near-field optical imaging in reflection mode will be proposed, and experimental work on the development of a near-field Kerr microscope performed up to this point will be presented. The complication in merging these two techniques arises from the complex polarization profile of the evanescent field. This profile can be characterized for a given probe geometry with the use of electromagnetic field modeling software, allowing for subsequent modeling of the polarization profile of the optical response. An algorithm for predicting the optical response to a near-field probe tip from a generalized multilayer thin-film is presented.

  10. Indirect interband transition induced by optical near fields with large wave numbers

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Maiku; Nobusada, Katsuyuki

    2016-05-01

    Optical near fields (ONFs) have Fourier components with large wave numbers that are two or three orders of magnitude larger than those of far-field propagating light owing to their nonuniformity in space. By utilizing these large wave numbers, the ONF is expected to induce an indirect interband transition between Bloch states having different wave numbers and directly generate an electron-hole pair without electron-phonon coupling. We perform time-dependent dynamics calculations of a one-dimensional periodic potential with an indirect band-gap structure and demonstrate that the ONF definitely induces an indirect interband transition. Instead of using the general Bloch boundary condition, which is usually imposed in conventional band structure calculations, we adopt an alternative boundary condition, the Born-von Kármán boundary condition, to appropriately treat indirect interband transitions. The calculated absorption spectra for the far-field and ONF excitations show different absorption edges and spectral patterns. We argue that this difference can be experimentally measured as evidence of the effects of the large wave numbers of the ONF.

  11. Highly efficient plasmonic tip design for plasmon nanofocusing in near-field optical microscopy.

    PubMed

    Umakoshi, Takayuki; Saito, Yuika; Verma, Prabhat

    2016-03-14

    Near-field scanning optical microscopy (NSOM) combined with plasmon nanofocusing is a powerful nano-analytical tool due to its attractive feature of efficient background suppression as well as light energy compression to the nanoscale. In plasmon nanofocusing-based NSOM, the metallic tip plays an important role in inducing plasmon nanofocusing. It is, however, very challenging to control plasmonic properties of tips for plasmon nanofocusing with existing tip fabrication methods, even though the plasmonic properties need to be adjusted to experimental environments such as the sample or excitation wavelength. In this study, we propose an efficient tip design and fabrication which enable one to actively control plasmonic properties for efficient plasmon nanofocusing. Because our method offers flexibility in the material and structure of tips, one can easily modify the plasmonic properties depending on the requirements. Importantly, through optimization of the plasmonic properties, we achieve almost 100% reproducibility in plasmon nanofocusing in our experiments. This new approach of tip fabrication makes plasmon nanofocusing-based NSOM practical and reliable, and opens doors for many scientists working in related fields. PMID:26892672

  12. Potential Challenges in Near-Field Scanning Optical Microscopy for Space Applications

    NASA Technical Reports Server (NTRS)

    Vikram, C. S.; Witherow, W.

    2000-01-01

    Near-field scanning optical microscopy is a relatively new but very powerful technique for obtaining several metrological parameters at nanometer range spatial resolution. It is logical to think deploying it into space applications like diagnostics of protein crystal growth under microgravity conditions. One may attempt to deploy existing instrumentation and expect some results. However, the existing technology and commercial instrumentation is tailored to ground based laboratory situations. Even in those laboratory conditions, the role of fluids (common in crystal growth), rough objects (such as a crystal under growth), etc. on the instrumentation is only recently being investigated. These aspects combined with effects of reduced gravity environment are going to make the problem more complex. These technological challenges must be tackled for meaningful system operation in space. Since the microscopy concept has not been attempted so far in space, all of the actual problems are unknown. Nevertheless, based on current literature, some possible problems and potential solutions are described here. One may use the discussion for system modification/optimization during initial use of this kind of microscopy in space.

  13. Highly efficient plasmonic tip design for plasmon nanofocusing in near-field optical microscopy

    NASA Astrophysics Data System (ADS)

    Umakoshi, Takayuki; Saito, Yuika; Verma, Prabhat

    2016-03-01

    Near-field scanning optical microscopy (NSOM) combined with plasmon nanofocusing is a powerful nano-analytical tool due to its attractive feature of efficient background suppression as well as light energy compression to the nanoscale. In plasmon nanofocusing-based NSOM, the metallic tip plays an important role in inducing plasmon nanofocusing. It is, however, very challenging to control plasmonic properties of tips for plasmon nanofocusing with existing tip fabrication methods, even though the plasmonic properties need to be adjusted to experimental environments such as the sample or excitation wavelength. In this study, we propose an efficient tip design and fabrication which enable one to actively control plasmonic properties for efficient plasmon nanofocusing. Because our method offers flexibility in the material and structure of tips, one can easily modify the plasmonic properties depending on the requirements. Importantly, through optimization of the plasmonic properties, we achieve almost 100% reproducibility in plasmon nanofocusing in our experiments. This new approach of tip fabrication makes plasmon nanofocusing-based NSOM practical and reliable, and opens doors for many scientists working in related fields.

  14. Concurrent polarization retrieval in multi-heterodyne scanning near-field optical microscopy: validation on silicon form-birefringent grating.

    PubMed

    Yu, L; Sfez, T; Paeder, V; Stenberg, P; Nakagawa, W; Kuittinen, M; Herzig, H P

    2012-10-01

    We demonstrate a concurrent polarization-retrieval algorithm based on a multi-heterodyne scanning near-field optical microscopy (MH-SNOM) measurement system. This method relies on calibration of the polarization properties of the MH-SNOM using an isotropic region of the sample in the vicinity of the nanostructures of interest. We experimentally show the effectiveness of the method on a silicon form-birefringent grating (FBG) with significant polarization diversity. Three spatial dimensional near-field measurements are in agreement with theoretical predictions obtained with rigorous coupled-wave analysis (RCWA). Pseudo-far-field measurements are performed to obtain the effective refractive index of the FBG, emphasizing the validity of the proposed method. This reconstruction algorithm makes the MH-SNOM a powerful tool to analyze concurrently the polarization-dependent near-field optical response of nanostructures with sub wavelength resolution as long as a calibration area is available in close proximity. PMID:23188273

  15. Optimization and maximum potential of optical antennae in near-field enhancement.

    PubMed

    Chen, PingPing; Liu, Ju; Wang, Li; Jin, Kuijuan; Yin, Yan; Li, ZhiYuan

    2015-06-20

    We investigate four types of gold nanoantennae (the monopole, the dipole, the cone-shaped, and the cone-bowtie antenna), under a fixed working wavelength. The finite-difference time-domain (FDTD) simulations show that the near-field enhancement values do not increase monotonously when the antennae sizes decrease, and optimization conditions vary with the antenna shapes. We also propose a distributed dipole ring model to analytically calculate the near field. The size condition for the strongest enhancement is the compromising result of the total radiated energy and the near-field distribution factor. Assuming the cone-bowtie antenna is the best for high enhancement, the maximum potential in near-field enhancement is 2×10(5) for a linear signal or 4×10(10) for typical nonlinear signals. PMID:26193035

  16. The study of quasi-optical system used in a passive near-field tetrahertz imaging system

    NASA Astrophysics Data System (ADS)

    Wang, Zhuo; Zhu, Wei-wen; Zhang, Wen-si; Zhang, Cheng-jiang; Ding, Qing; Bi, Xian-ting; Wu, Jui-feng

    2013-08-01

    Passive terahertz imaging technology, which provided blackbody thermal imaging, showed great potential for security applications during the last years. Different research teams in different countries spent a great effort on it for obvious reasons, and first commercial passive THz human imaging system was available. Yet, development of passive THz-imaging system was always limited by the frame rate, spatial resolution and detector cell of it. In this paper, we presented the concept and experimental set-up for a quasi-optical system used in a near-field 0.14THz passive terahertz imaging system. The quasi-optical system was composed of a double-mirror beam-waveguide system and a special feed-horns array. The design of quasi-optical system was based on near-field Gauss optics theory. The double-mirror beam waveguide system was made up of an off-axis ellipsoid mirror and a flat mirror. The influence of angle-scanning of quasi-optics system in near-field THz-imaging was investigated theoretically. Meanwhile, a spatial sparse array-arrangement of feed-horns was applied in quasi-optics system, that the adjacent feed-horns were stagger in the horizontal direction. The influence of this special feed-horns array arrangement on the near-field imaging was also discussed in theory. The quasi-optical system met the requirements of the near-field imaging. The problem of low frame rate of traditional sparse array arrangement was solved by this special array arrangement. And the spatial imaging range of the passive imaging system was also increased. The experimental results of this terahertz imaging system were consistent with our earlier theoretical results. When the detective distance was 3-5m, the experimental spatial resolution of near-field THz imaging was 5cm, and a 5Hz of frame rate was obtained. The quasi-optics system had demonstrated its ability to scan persons and various kinds of objects. We hoped a commercial, user-friendly terahertz imaging system, which could be used

  17. Nano-optical conveyor belt, part II: Demonstration of handoff between near-field optical traps.

    PubMed

    Zheng, Yuxin; Ryan, Jason; Hansen, Paul; Cheng, Yao-Te; Lu, Tsung-Ju; Hesselink, Lambertus

    2014-06-11

    Optical tweezers have been widely used to manipulate biological and colloidal material, but the diffraction limit of far-field optics makes focused beams unsuitable for manipulating nanoscale objects with dimensions much smaller than the wavelength of light. While plasmonic structures have recently been successful in trapping nanoscale objects with high positioning accuracy, using such structures for manipulation over longer range has remained a significant challenge. In this work, we introduce a conveyor belt design based on a novel plasmonic structure, the resonant C-shaped engraving (CSE). We show how long-range manipulation is made possible by means of handoff between neighboring CSEs, and we present a simple technique for controlling handoff by rotating the polarization of laser illumination. We experimentally demonstrate handoff between a pair of CSEs for polystyrene spheres 200, 390, and 500 nm in diameter. We then extend this technique and demonstrate controlled particle transport down a 4.5 μm long "nano-optical conveyor belt." PMID:24807058

  18. High-resolution apertureless near-field optical imaging using gold nanosphere probes.

    PubMed

    Kim, Zee Hwan; Leone, Stephen R

    2006-10-12

    An apertureless near-field scanning optical microscope (ANSOM) that utilizes the enhanced field around a gold nanosphere, which is attached to the end of an atomic force microscope (AFM) tip, is used to image the local dielectric constant of the patterned metallic surfaces and local electric field around plasmonic nanosphere samples. A colloidal gold nanosphere (approximately 50 nm diameter) is linked to the extremity of the conventional etched-silicon probe. The scattering of laser radiation (633 or 532 nm) is modulated by the oscillating nanosphere-functionalized silicon tip, and the scattered radiation is detected. The approach curve (scattering intensity as a function of the tip-sample distance), the polarization dependence (scattering intensity as a function of the excitation polarization direction), and ANSOM image contrast confirm that the spherical nanosphere attached to the silicon tip acts as a point dipole that interacts with the sample surface via a dipole-dipole coupling, in which the dipole created by the field at the tip interacts with its own image dipole in the sample. The image obtained with the nanoparticle functionalized tip provides a dielectric map of the sample surface with a spatial resolution better than 80 nm. In addition, we show that the functionalized tip is capable of imaging the local electric field distribution above the plasmonic nanosphere samples. Overall, the result shows that high-resolution ANSOM is possible without the aid of the lightning-rod effect. With an improved tip-fabrication method, we believe that the method can provide a versatile high-resolution chemical imaging that is not available from usual forms of ANSOM. PMID:17020365

  19. Fluorescence detection of single molecules using pulsed near-field optical excitation and time correlated photon counting

    SciTech Connect

    Ambrose, W.P.; Goodwin, P.M.; Martin, J.C.; Keller, R.A.

    1994-03-01

    Pulsed excitation, time correlated single photon counting and time gated detection are used in near-field optical microscopy to enhance fluorescence images and measure the fluorescence lifetimes of single molecules of Rhodamine 6G on silica surfaces. Time gated detection is used to reject prompt scattered background and to improve the image signal to noise ratio. The excited state lifetime of a single Rhodamine 6G molecule is found to depend on the position of the near-field probe. We attribute the lifetime variations to spontaneous emission rate alterations by the fluorescence reflected from and quenching by the aluminum coated probe.

  20. An Alternative Tapping Scanning Near-Field Optical Microscope Setup Enabling the Study of Biological Systems in Liquid Environment

    NASA Astrophysics Data System (ADS)

    Girasole, M.; Longo, G.; Cricenti, A.

    2006-03-01

    A new aperture scanning near-field optical microscope operating in the intermittent contact mode using a non-bent optical fiber is introduced. The microscope was built modifying a classical scanning near-field optical microscope (SNOM) unit introducing a patented probe-holder (MTP) which contains a piezo-motor and a bimorph-transductor. The main advantages of the present set-up in terms of stability, versatility, optical resolution, and quality of the collected signals are described. The instrument works properly while exerting a minimum perturbation on the sample thus overcoming the major drawbacks of different SNOM-based imaging modes and allowing to study very delicate samples including living cells in physiological environment.

  1. Fabrication of a Near-Field Optical Fiber Probe Based on Electroless Nickel Plating under Ultrasonic Irradiation

    NASA Astrophysics Data System (ADS)

    Mononobe, Shuji; Saito, Yuichi; Ohtsu, Motoichi; Honma, Hideo

    2004-05-01

    We present a method of fabricating a near-field optical probe with a nickel film whose thickness gradually decreases to a few tens of nanometers toward the apex. This method involves etching an optical fiber and electroless nickel plating with ultrasonic agitation. Using 1 MHz ceramic transducers, we have reproducibly fabricated the probe with a tip diameter of less than 40 nm. This reproducibility is high compared to those for Langevin-type transducers.

  2. A Study on Enhancing Data Storage Capacity and Mechanical Reliability of Solid Immersion Lens-Based Near-Field Recording System

    NASA Astrophysics Data System (ADS)

    Park, No-Cheol; Yang, Hyun-Seok; Rhim, Yoon-Cheol; Park, Young-Pil

    2008-08-01

    In this study, several technical issues on solid immersion lens (SIL)-based near-field recording (NFR) are explored, namely, to enhance storage capacity and to guarantee mechanical reliability of the device. For the purpose of enhancing the storage capacity of the NFR system, two optical configurations using radial polarization and dual recording layers are proposed. Through a feasibility analysis of the proposed optical configuration with radial polarization, it was determined that illumination of radial polarization is not a suitable solution to achieve higher areal density. To apply highly focusing characteristics of incidence of radial polarized light to cover-layer protected data storage, an annular pupil filtering method was introduced. Complete field analysis of the proposed dual layered NFR optics verified its feasibility, and the assembly of the SIL of the proposed model was successfully achieved. In addition, to improve mechanical reliability of the SIL-based NFR system, improved near-field (NF) air-gap servo methods and air flow analysis around the low part of the SIL have been evaluated. With improved NF gap servo methods using an error-based disturbance observer (EDOB) on a base air-gap controller, residual gap errors were markebly reduced by 26.26% while controlling the NF air-gap to 30 nm. Air flow near the head media interface was visualized and an undesirable effect of backward flow climbing from the bottom surface of the SIL was ovserved.

  3. Imaging of green fluorescent protein in live plant by scanning near-field optical microscopy

    NASA Astrophysics Data System (ADS)

    Xu, Jianhua; Chen, Tao; Sun, Jialin; Guo, Jihua; Zhao, Jun

    2002-04-01

    An auxin/IAA induced in vivo green fluorescent protein (GFP) in a living plant Arabidopsis root has been studied by a scanning near-field microscope in transmission mode. The promising near-field images of the inducible GFPs at sub- surface of a plant cell suggest that they may locate proximity to the cell wall, i.e. both sides of and in the cytoplasm membrane. The clear and faint fluorescent spots with 1-3 micrometers showed that the proteins localized nearer and farther to the cell wall, respectively. All GFP molecules gathered together in a cell, and no individual GFP was observed in the experiment.

  4. Optical singularities and power flux in the near-field region of planar evanescent-field superlenses.

    PubMed

    Perez-Molina, Manuel; Carretero, L; Acebal, P; Blaya, S

    2008-11-01

    We rigorously analyze the optical singularities and power flux in the near-field region of the novel superlenses reported in [Science317, 927 (2007)] For this purpose, we derive near-field expressions and a general criterion to classify the optical singularities in the vacuum, which are valid when the (s- or p-polarized) electromagnetic fields are generated by any planar field distribution with Cartesian or azimuthal symmetry. Such general results are particularized to the superlenses [Science317, 927 (2007)], for which we identify a sequence of optical vortices and saddles that arise from evanescent-field interference. While the saddles are always located around the focal region, the vortex locations depend on the source field. The features of the topological connection between vortices and saddles are also discussed. PMID:18978868

  5. Low Temperature Apertureless Near-field Scanning Optical Microscope for Optical Spectroscopy of Single Ge/Si Quantum Dots

    NASA Astrophysics Data System (ADS)

    Zhu, Henry; Patil, N. G.; Levy, Jeremy

    2001-03-01

    A low-temperature apertureless near-field scanning optical microscope has been designed and constructed for the purpose of investigating the optical properties of individual Ge/Si quantum dots. The microscope fits in the 37 mm bore of a Helium vapor magneto-optic cryostat, allowing operations down to liquid helium temperatures in magnetic fields up to 8 Tesla. An in situ microscope objective focuses light onto the sample, which is scanned in the three spatial directions using a compact modular stage. An AFM/STM tip resides on the top; feedback is achieved using a quartz tuning fork oscillator. Both tip and objective are attached to inertial sliding motors that can move in fine (10 nm) steps to achieve touchdown and focus. A femtosecond optical parametric oscillator is used to excite carriers in the quantum dots both resonantly and non-resonantly; scattered luminescence from the AFM/STM tip is collected and analyzed spectrally using a 1/2 meter imaging spectrometer and a LN_2-cooled InGaAs array. We gratefully acknowledge NSF (DMR-9701725, IMR-9802784) and DARPA (DAAD-16-99-C1036) for financial support of this work.

  6. Optical and mechanical detection of near-field light by atomic force microscopy using a piezoelectric cantilever

    NASA Astrophysics Data System (ADS)

    Satoh, Nobuo; Kobayashi, Kei; Watanabe, Shunji; Fujii, Toru; Matsushige, Kazumi; Yamada, Hirofumi

    2016-08-01

    In this study, we developed an atomic force microscopy (AFM) system with scanning near-field optical microscopy (SNOM) using a microfabricated force-sensing cantilever with a lead zirconate titanate (PZT) thin film. Both optical and mechanical detection techniques were adopted in SNOM to detect scattered light induced by the interaction of the PZT cantilever tip apex and evanescent light, and SNOM images were obtained for each detection scheme. The mechanical detection technique did allow for a clear observation of the light scattered from the PZT cantilever without the interference observed by the optical detection technique, which used an objective lens, a pinhole, and a photomultiplier tube.

  7. Application of evolution strategies for the solution of an inverse problem in near-field optics.

    PubMed

    Macías, Demetrio; Vial, Alexandre; Barchiesi, Dominique

    2004-08-01

    We introduce an inversion procedure for the characterization of a nanostructure from near-field intensity data. The method proposed is based on heuristic arguments and makes use of evolution strategies for the solution of the inverse problem as a nonlinear constrained-optimization problem. By means of some examples we illustrate the performance of our inversion method. We also discuss its possibilities and potential applications. PMID:15330475

  8. Short-range order and near-field effects on optical scattering and structural coloration

    SciTech Connect

    Liew, S.F.; Forster, J.; Noh, H.; Schreck, C.F.; Saranathan, V.; Lu, X.; Yang, L.; Prum, Richard O.; O’Hern, C.S.; Dufresne, E.R.; Cao, H.

    2012-03-26

    We have investigated wavelength-dependent light scattering in biomimetic structures with short-range order. Coherent backscattering experiments are performed to measure the transport mean free path over a wide wavelength range. Overall scattering strength is reduced significantly due to short-range order and near-field effects. Our analysis explains why single scattering of light is dominant over multiple scattering in similar biological structures and is responsible for color generation.

  9. Short-range Order and Near-field Effects on Optical Scattering and Structural Coloration

    SciTech Connect

    S Liew; J Forster; H Noh; C Schreck; V Saranathan; X Lu; L Yang; E Dufresne; H Cao; et al.

    2011-12-31

    We have investigated wavelength-dependent light scattering in biomimetic structures with short-range order. Coherent backscattering experiments are performed to measure the transport mean free path over a wide wavelength range. Overall scattering strength is reduced significantly due to short-range order and near-field effects. Our analysis explains why single scattering of light is dominant over multiple scattering in similar biological structures and is responsible for color generation.

  10. Imaging of quantum Hall edge states under quasiresonant excitation by a near-field scanning optical microscope

    SciTech Connect

    Ito, H.; Shibata, Y.; Mamyoda, S.; Ootuka, Y.; Nomura, S.; Kashiwaya, S.; Yamaguchi, M.; Akazaki, T.; Tamura, H.

    2013-12-04

    A high resolution mapping of quantum Hall edge states has been performed by locally creating electrons with small excess energies with a near-field scanning optical microscope in a dilution refrigerator. We have observed fine structures parallel to the edge in photovoltage signals, which appear only at low temperature. The observed fine structures near sample edges have been seen to shift inward with increase in magnetic field in accordance with Chklovskii Shklovskii, and Glazman model.

  11. Dynamics of a piezoelectric tuning fork/optical fiber assembly in a near-field scanning optical microscope

    NASA Astrophysics Data System (ADS)

    Shelimov, Konstantin B.; Davydov, Dmitri N.; Moskovits, Martin

    2000-02-01

    Factors leading to a decrease in the resonance quality (the Q factor) of quartz microtuning fork/optical fiber assemblies used as sensing elements in near-field scanning optical microscopes were considered using a simple elastomechanical analysis. Experiments to test the predictions of the analysis were carried out and strategies for recovering high Q factors were proposed and tested. Three major factors affecting the magnitude of the Q factor are discussed. The first is the stiffness imparted to the tine of the microtuning fork by the optical fiber attached to it; the second is the location of the attachment point of the fiber along the tine; the third is the resonant vibrational excitation of the fiber tip which acts as an energy dissipative channel. For tapping mode operation using a standard 125 μm diameter fiber, the large longitudinal stiffness of the fiber results in a dramatic Q-factor degradation. This effect can be overcome by reducing the diameter of the fiber cladding, d, and by slightly bending the fiber. Under these conditions, bending rather than longitudinal stretching dominates the fiber dynamics. The effective bending force constant for a thinned fiber is predicted to be proportional to d4. A sharp upturn in the Q factor is observed for d⩽25 μm, consistent with this prediction. The effective stiffness and mass of the fiber are also expected to scale approximately as x3, where x is the distance from the point of attachment of the fiber to the fork's base. Hence, the Q factor can be improved further by attaching the fiber closer to the tuning fork's base. Vibrational coupling between the tuning fork and the probe tip can result in a substantial Q-factor degradation for tips of a certain size. By taking these insights into consideration, we were able to construct tapping mode tuning fork/optical fiber assemblies with Q factors of up to 9000.

  12. Near-field phase-change recording using a GaN laser diode

    NASA Astrophysics Data System (ADS)

    Kishima, Koichiro; Ichimura, Isao; Yamamoto, Kenji; Osato, Kiyoshi; Kuroda, Yuji; Iida, Atsushi; Saito, Kimihiro

    2000-09-01

    We developed a 1.5-Numerical-Aperture optical setup using a GaN blue-violet laser diode. We used a 1.0 mm-diameter super-hemispherical solid immersion lens, and optimized a phase-change disk structure including the cover layer by the method of MTF simulation. The disk surface was polished by tape burnishing technique. An eye-pattern of (1-7)-coded data at the linear density of 80 nm/bit was demonstrated on the phase-change disk below a 50 nm gap height, which was realized through our air-gap servo mechanism.

  13. Solvothermally Synthesized Sb2Te3 Platelets Show Unexpected Optical Contrasts in Mid-Infrared Near-Field Scanning Microscopy.

    PubMed

    Hauer, Benedikt; Saltzmann, Tobias; Simon, Ulrich; Taubner, Thomas

    2015-05-13

    We report nanoscale-resolved optical investigations on the local material properties of Sb2Te3 hexagonal platelets grown by solvothermal synthesis. Using mid-infrared near-field microscopy, we find a highly symmetric pattern, which is correlated to a growth spiral and which extends over the entire platelet. As the origin of the optical contrast, we identify domains with different densities of charge carriers. On Sb2Te3 samples grown by other means, we did not find a comparable domain structure. PMID:25868047

  14. E-beam lithography and optical near-field lithography: new prospects in fabrication of various grating structures

    NASA Astrophysics Data System (ADS)

    Kley, Ernst-Bernhard; Clausnitzer, Tina

    2003-12-01

    Today"s technologies available for the fabrication of micro structured optical elements are well developed for defined classes of structures. Techniques for very complex optical functions or for combinations of optical functions together with others are more or less in the level of research or labs. A promising approach for complex grating fabrication is the use of optical near field holography (NFH) and e-beam writing for unification of the advantages. The paper wants to show the potential of both techniques itself as well as the potential that arises from their teamwork. The paper demonstrates one and two dimensional gratings, chirped and unidirectional gratings fabricated by NFH using e-beam written masks. It shows also possibilities for the fabrication of gratings on binary, multilevel and continuous optical profiles.

  15. Characterization of the near-field and convectional transport behavior of micro and nanoparticles in nanoscale plasmonic optical lattices.

    PubMed

    Yang, Tsang-Po; Yossifon, Gilad; Yang, Ya-Tang

    2016-05-01

    Here, we report the characterization of the transport of micro- and nanospheres in a simple two-dimensional square nanoscale plasmonic optical lattice. The optical potential was created by exciting plasmon resonance by way of illuminating an array of gold nanodiscs with a loosely focused Gaussian beam. This optical potential produced both in-lattice particle transport behavior, which was due to near-field optical gradient forces, and high-velocity (∼μm/s) out-of-lattice particle transport. As a comparison, the natural convection velocity field from a delocalized temperature profile produced by the photothermal heating of the nanoplasmonic array was computed in numerical simulations. This work elucidates the role of photothermal effects on micro- and nanoparticle transport in plasmonic optical lattices. PMID:27226813

  16. Observation of nonlinear bands in near-field scanning optical microscopy of a photonic-crystal waveguide

    SciTech Connect

    Singh, A.; Huisman, S. R.; Ctistis, G. Mosk, A. P.; Pinkse, P. W. H.; Korterik, J. P.; Herek, J. L.

    2015-01-21

    We have measured the photonic bandstructure of GaAs photonic-crystal waveguides with high resolution in energy as well as in momentum using near-field scanning optical microscopy. Intriguingly, we observe additional bands that are not predicted by eigenmode solvers, as was recently demonstrated by Huisman et al. [Phys. Rev. B 86, 155154 (2012)]. We study the presence of these additional bands by performing measurements of these bands while varying the incident light power, revealing a non-linear power dependence. Here, we demonstrate experimentally and theoretically that the observed additional bands are caused by a waveguide-specific near-field tip effect not previously reported, which can significantly phase-modulate the detected field.

  17. Observation of nonlinear bands in near-field scanning optical microscopy of a photonic-crystal waveguide

    NASA Astrophysics Data System (ADS)

    Singh, A.; Ctistis, G.; Huisman, S. R.; Korterik, J. P.; Mosk, A. P.; Herek, J. L.; Pinkse, P. W. H.

    2015-01-01

    We have measured the photonic bandstructure of GaAs photonic-crystal waveguides with high resolution in energy as well as in momentum using near-field scanning optical microscopy. Intriguingly, we observe additional bands that are not predicted by eigenmode solvers, as was recently demonstrated by Huisman et al. [Phys. Rev. B 86, 155154 (2012)]. We study the presence of these additional bands by performing measurements of these bands while varying the incident light power, revealing a non-linear power dependence. Here, we demonstrate experimentally and theoretically that the observed additional bands are caused by a waveguide-specific near-field tip effect not previously reported, which can significantly phase-modulate the detected field.

  18. Optical far- and near-field femtosecond laser ablation of Si for nanoscale chemical analysis

    SciTech Connect

    Zormpa, Vasileia; Mao, Xianglei; Russo, Richard E.

    2010-02-02

    Extending spatial resolution in laser-based chemical analysis to the nanoscale becomes increasingly important as nanoscience and nanotechnology develop. Implementation of femtosecond laser pulses arises as a basic strategy for increasing resolution since it is associated with spatially localized material damage. In this work we study femtosecond laser far- and near-field processing of silicon (Si) at two distinct wavelengths (400 and 800 nm), for nanoscale chemical analysis. By tightly focusing femtosecond laser beams in the far-field we were able to produce sub-micrometer craters. In order to further reduce the crater size, similar experiments were performed in the near-field through sub-wavelength apertures, resulting to the formation of sub-30 nm craters. Laser Induced Breakdown Spectroscopy (LIBS) was used for chemical analysis with a goal to identify the minimum crater size from which spectral emission could be measured. Emission from sub-micrometer craters (full-with-at-half-maximum) was possible, which are among the smallest ever reported for femtosecond LIBS.

  19. Photoplastic near-field optical probe with sub-100 nm aperture made by replication from a nanomould.

    PubMed

    Kim, G M; Kim, B J; Ten Have, E S; Segerink, F; Van Hulst, N F; Brugger, J

    2003-03-01

    Polymers have the ability to conform to surface contours down to a few nanometres. We studied the filling of transparent epoxy-type EPON SU-8 into nanoscale apertures made in a thin metal film as a new method for polymer/metal near-field optical structures. Mould replica processes combining silicon micromachining with the photo-curable SU-8 offer great potential for low-cost nanostructure fabrication. In addition to offering a route for mass production, the transparent pyramidal probes are expected to improve light transmission thanks to a wider geometry near the aperture. By combining silicon MEMS, mould geometry tuning by oxidation, anti-adhesion coating by self-assembled monolayer and mechanical release steps, we propose an advanced method for near-field optical probe fabrication. The major improvement is the possibility to fabricate nanoscale apertures directly on wafer scale during the microfabrication process and not on free-standing tips. Optical measurements were performed with the fabricated probes. The full width half maximum after a Gaussian fit of the intensity profile indicates a lateral optical resolution of approximately 60 nm. PMID:12641773

  20. Characterization of surface and sub-surface defects in optical materials using the near field evanescent wave

    SciTech Connect

    Yan, M.; Oberhelman, S.; Wang, L.; Siekhaus, W.; Kozlowski, M.

    1998-12-31

    Optical properties of sub-micron defects at and near the surface are of interest in many applications, e.g. in high power laser systems where initiation of laser induced damage is a critical issue. In-situ scanning atomic force microscopy (AFM) has been used previously to establish a direct correlation between a particular structural surface inhomogeneity (such as a nodular defect in coatings) and the initiation of local laser damage at that inhomogeneity. Near field scanning optical microscopy (NSOM) make it now possible to provide information on both morphology and optical properties of localized defects at and near the surface. The authors have measured the amplitude variation of the near field evanescent wave around nodular defects and sub-surface inclusions in optical coatings and thus detected local laser field intensification. The observed intensity variation of the evanescent wave agrees with theoretical calculations of laser amplification around the inclusion. These findings support the theory that laser damage may be induced by local electrical field enhancement associated with micron and sub-micron defects.

  1. Two-photon absorption induced by electric field gradient of optical near-field and its application to photolithography

    SciTech Connect

    Yamaguchi, Maiku; Kawazoe, Tadashi; Yatsui, Takashi; Nobusada, Katsuyuki

    2015-05-11

    An electric field gradient is an inherent property of the optical near-field (ONF). We investigated its effect on electron excitation in a quantum dot via model calculations combining a density matrix formalism and a classical Lorentz model. The electric field gradient of the ONF was found to cause two-photon absorption by an unusual mechanism. Furthermore, the absorption exhibits a nonmonotonic dependence on the spatial arrangement of the nanosystem, completely different from that of conventional two-photon absorption induced by an intense electric field. The present two-photon absorption process was verified in a previous experimental observation by reinterpreting the results of ONF photolithography.

  2. Development of new apertureless near-field scanning optical microscope tip using finite-differential time-domain calculation

    NASA Astrophysics Data System (ADS)

    Kodama, Takashi; Ohtani, Hiroyuki

    2006-12-01

    We calculated the electric field enhancement factor of the apertureless near-field scanning optical microscope (ANSOM) tip using the finite-differential time-domain method. The results revealed that the enhancement factor of the silver tip remarkably decreased as the rounded tip radius increased. On the other hand, aggregated silver nanoparticles resulted in a strong field enhancement. Therefore, we developed a silver nanoparticles immobilized tip for the ANSOM probe and attempted to measure the surface enhanced Raman scattering spectrum of carbon onion molecules using it. We successfully detected the Raman spectra of individual carbon onions with a high sensitivity.

  3. Background-free imaging of plasmonic structures with cross-polarized apertureless scanning near-field optical microscopy.

    PubMed

    Esslinger, M; Dorfmüller, J; Khunsin, W; Vogelgesang, R; Kern, K

    2012-03-01

    We present advances in experimental techniques of apertureless scanning near-field optical microscopy (aSNOM). The rational alignment procedure we outline is based upon a phase singularity that occurs while scanning polarizers around the nominal cross-polarized configuration of s-polarized excitation and p-polarized detection. We discuss the theoretical origin of this topological feature of the setup, which is robust against small deviations, such as minor tip misalignment or shape variations. Setting the polarizers to this singular configuration point eliminates all background signal, allowing for reproducible plasmonic eigenmode mapping with optimal signal-to-noise ratio. PMID:22462926

  4. Variable Temperature SiO2 Stripes Spectroscopy Taken by Customized Scattering Type Scanning Near-field Optical Microscopy

    NASA Astrophysics Data System (ADS)

    Li, Chaoran

    Variable temperature scattering-type scanning near-field optical microscopy is the system we built up from basis to explore the phase transition under low temperature. It has advantages of be able to take topography and spectroscopy simultaneously. What the SNOM system measures is the reflective effivient, it is determinde by the dielectric value of the sample, which is an intrinsic chemical propertiy. In this experiment, we taken spectroscopy of a sample with silicon dioxide stripes doped on the silicon substrate, get the contrast of silicon/silison dioxide, which is accord to the prediction of two models. Furthermore, the different contrast under various temperature reveals the temperature dependent dielectric function.

  5. Near-field enhanced optical tweezers utilizing femtosecond-laser nanostructured substrates

    SciTech Connect

    Kotsifaki, D. G. Kandyla, M.; Lagoudakis, P. G.

    2015-11-23

    We present experimental evidence of plasmonic-enhanced optical tweezers, of polystyrene beads in deionized water in the vicinity of metal-coated nanostructures. The optical tweezers operate with a continuous wave near-infrared laser. We employ a Cu/Au bilayer that significantly improves dissipation of heat generated by the trapping laser beam and avoid de-trapping from heat convection currents. We investigate the improvement of the optical trapping force and the effective trapping quality factor, and observe an exponential distance dependence of the trapping force from the nanostructures, indicative of evanescent plasmonic enhancement.

  6. Near-field enhanced optical tweezers utilizing femtosecond-laser nanostructured substrates

    NASA Astrophysics Data System (ADS)

    Kotsifaki, D. G.; Kandyla, M.; Lagoudakis, P. G.

    2015-11-01

    We present experimental evidence of plasmonic-enhanced optical tweezers, of polystyrene beads in deionized water in the vicinity of metal-coated nanostructures. The optical tweezers operate with a continuous wave near-infrared laser. We employ a Cu/Au bilayer that significantly improves dissipation of heat generated by the trapping laser beam and avoid de-trapping from heat convection currents. We investigate the improvement of the optical trapping force and the effective trapping quality factor, and observe an exponential distance dependence of the trapping force from the nanostructures, indicative of evanescent plasmonic enhancement.

  7. Optical fiber characterization: Backscatter, time domain bandwidth, refracted from near field and interlaboratory comparisons, volume 1

    NASA Astrophysics Data System (ADS)

    Danielson, B. L.; Day, G. W.; Franzen, D. L.; Kim, E. M.; Young, M.

    1982-09-01

    Optical fiber waveguide measurements are described. Systems to determine the backscatter, bandwidth, and index profile are covered in detail. Measurement comparisons between laboratories are given for fiber attenuation, bandwidth, numerical aperture, and core diameter.

  8. Near-field optical patterning and structuring based on local-field enhancement at the extremity of a metal tip.

    PubMed

    Royer, Pascal; Barchiesi, Dominique; Lerondel, Gilles; Bachelot, Renaud

    2004-04-15

    We present a particular approach and the associated results allowing the nanostructuration of a thin photosensitive polymer film. This approach based on a scanning near-field optical microscopy configuration uses the field-enhancement (FE) effect, a so-called lightning-rod effect appearing at the extremity of a metallic tip when illuminated with an incident light polarized along the tip axis. The local enhancement of the electromagnetic field straight below the tip's apex is observed directly through a photoisomerization reaction, inducing the growth of a topographical nanodot characterized in situ by atomic-force microscopy using the same probe. From a survey of the literature, we first review the different experimental approaches offered to nanostructure materials by near-field optical techniques. We describe more particularly the FE effect approach. An overview of the theoretical approach of this effect is then given before presenting some experimental results so as theoretical results using the finite-element method. These results show the influence on the nanostructuration of the polymer of a few experimental parameters such as the polarization state, the illumination mode and the tip's geometry. Finally, the potentiality of this technique for some applications in the field of lithography and high-density data storage is shown via the fabrication of nano-patterns. PMID:15306496

  9. Analysis of near-field method for optical data storage using microstrip probe under illumination and illumination-collection mode

    NASA Astrophysics Data System (ADS)

    Morozov, Yevhenii; Kryuchyn, Andriy A.; Petrov, Viacheslav V.; Lapchuk, Anatoliy S.

    2014-09-01

    Results of numerical simulation of near-field optical data storage using microstrip probe are presented. Simulation is carried out on the basis of the finite-difference time-domain method. Features of the information reading process from the ROM and RW (based on the phase transmissions of Ge2Sb2Te5 film) formats of optical discs under illumination and illumination-collection mode are analyzed and considered. Mathematical modeling has shown that the signal from the ROM-format disc under illumination mode, despite the fact that the probe has a significant far-field transmission coefficient, has a large crosstalk and small spatial resolution (significantly worse than a size of probe aperture). Unlike illumination mode, signal under illumination-collection mode (pure near-field method) has a resolution close to the size of the aperture, good amplitude and contrast, as well as relatively low crosstalk. However, information reading under illumination-collection mode from RW-format disc is not able to get the same good quality signal. Therefore the further optimization of the method is required to improve the signal quality of RW format.

  10. Optical near field phenomena in planar and structured organic solar cells

    NASA Astrophysics Data System (ADS)

    Niggemann, M.; Ziegler, T.; Glatthaar, M.; Riede, M.; Zimmermann, B.; Gombert, A.

    2006-04-01

    One key problem in optimizing organic solar cells is to maximize the absorption of incident light and to keep the charge carrier transport paths as short as possible in order to minimize transport losses. The large versatility of organic semiconductors and compositions requires specific optimization of each system. We investigate two model systems, the MDMO-PPV:PCBM blend and the P3HT:PCBM blend. Due to the small thickness of the functional layers in the order of several ten nanometers, coherent optics has to be considered and therefore interference effects play a dominant role. The influence of the thickness of the photoactive layer on the light absorption is investigated and compared with experimental data. The potential of an optical spacer which is introduced between the aluminium electrode and the photoactive layer to enhance the light harvesting is evaluated by optical modelling. Optical modelling becomes more complex for novel solar cell architectures based on nanostructured substrates. Exemplary optical simulations are presented for a nanoelectrode solar cell architecture.

  11. Near-field scanning optical microscopy cross-sectional measurements of crystalline GaAs solar cells

    SciTech Connect

    Herndon, M. K.; Bradford, W. C.; Collins, R. T.; Hawkins, B. E.; Kuech, T. F.; Friedman, D. J.; Kurtz, S. R.

    2000-07-03

    Near-field scanning optical microscopy (NSOM) was used to study cleaved edges of GaAs solar cell devices. Using visible light for excitation, the NSOM acquired spatially resolved traces of the photocurrent response across the various layers in the device. For excitation energies well above the band gap, carrier recombination at the cleaved surface had a strong influence on the photocurrent signal. Decreasing the excitation energy, which increased the optical penetration depth, allowed the effects of surface recombination to be separated from collection by the pn junction. Using this approach, the NSOM measurements directly observed the effects of a buried minority carrier reflector/passivation layer. (c) 2000 American Institute of Physics.

  12. Near-field penetrating optical microscopy: A live cell nanoscale refractive index measurement technique for quantification of internal macromolecular density

    PubMed Central

    Strasser, Samantha Dale; Shekhawat, Gajendra; Rogers, Jeremy D.; Dravid, Vinayak P.; Taflove, Allen; Backman, Vadim

    2012-01-01

    Quantification of intracellular nanoscale macromolecular density distribution is a fundamental aspect to understanding cellular processes. We report a near-field penetrating optical microscopy (NPOM) technique to directly probe the internal nanoscale macromolecular density of biological cells through quantification of intracellular refractive index (RI). NPOM inserts a tapered optical fiber probe to successive depths into an illuminated sample. A 50 nm diameter probe-tip collects signal that exhibits a linear relationship with the sample RI at a spatial resolution of approximately 50 nm for biologically relevant measurements, one order-of-magnitude finer than the Abbe diffraction limit. Live and fixed cell data illustrate the mechanical ability of a 50 nm probe to penetrate biological samples. PMID:22344088

  13. Near-field penetrating optical microscopy: a live cell nanoscale refractive index measurement technique for quantification of internal macromolecular density.

    PubMed

    Strasser, Samantha Dale; Shekhawat, Gajendra; Rogers, Jeremy D; Dravid, Vinayak P; Taflove, Allen; Backman, Vadim

    2012-02-15

    Quantification of intracellular nanoscale macromolecular density distribution is a fundamental aspect to understanding cellular processes. We report a near-field penetrating optical microscopy (NPOM) technique to directly probe the internal nanoscale macromolecular density of biological cells through quantification of intracellular refractive index (RI). NPOM inserts a tapered optical fiber probe to successive depths into an illuminated sample. A 50 nm diameter probe tip collects signal that exhibits a linear relationship with the sample RI at a spatial resolution of approximately 50 nm for biologically relevant measurements, one order of magnitude finer than the Abbe diffraction limit. Live and fixed cell data illustrate the mechanical ability of a 50 nm probe to penetrate biological samples. PMID:22344088

  14. Use of the sampling theorem to speed up near-field physical optics scattering calculations

    NASA Technical Reports Server (NTRS)

    Cramer, P. W.; Imbriale, W. A.

    1994-01-01

    Physical optics scattering calculations performed on the DSN 34-m beam-waveguide antennas at Ka-band (32 GHz) require approximately 12 hr of central processing unit time on a Cray Y-MP2 computer. This is excessive in terms of resource utilization and turnaround time. Typically, the calculations involve five surfaces, and the calculations are done two surfaces at a time. The sampling theorem is used to reduce the number of current values that must be calculated over the second surface by performing a physical optics integration over the first surface. The additional number of current values required on the second surface by subsequent physical optics integrations is obtained by interpolation over the original current values. Time improvements on the order of a factor of 2 to 4 were obtained for typical scattering pairs.

  15. Optical properties of microfabricated fully-metal-coated near-field probes in collection mode.

    PubMed

    Descrovi, Emiliano; Vaccaro, Luciana; Aeschimann, Laure; Nakagawa, Wataru; Staufer, Urs; Herzig, Hans-Peter

    2005-07-01

    A study of the optical properties of microfabricated, fully-metal-coated quartz probes collecting longitudinal and transverse optical fields is presented. The measurements are performed by raster scanning the focal plane of an objective, focusing azimuthally and radially polarized beams by use of two metal-coated quartz probes with different metal coatings. A quantitative estimation of the collection efficiencies and spatial resolutions in imaging both longitudinal and transverse fields is made. Longitudinally polarized fields are collected with a resolution approximately 1.5 times higher as compared with transversely polarized fields, and this behavior is almost independent of the roughness of the probe's metal coating. Moreover, the coating roughness is a critical parameter in the relative collection efficiency of the two field orientations. PMID:16053165

  16. Simulation of near-field and far-field optical properties of electromagnetically coupled multi-layered nanoparticles

    NASA Astrophysics Data System (ADS)

    Xu, Hongxing; Käll, Mikael

    2001-03-01

    Recent studies of nanoparticle-oligonucleotide conjugates^1 and “hot sites” in single-molecule surface-enhanced Raman scattering (SERS)^2 have highlighted the importance of clustering effects for the optical properties of metal nanoparticles. However, many applications in the life-sciences require coated nanoparticles, e.g. in order to induce biocompatibility or biorecognition. Such a coating will change the optical properties of the nanoparticle system. We here describe a calculational procedure that can be used to model the optical response of clusters composed of shelled spherical nanoparticles. Both far-field (e.g. extinction cross section) and near-field (e.g. SERS effect) optical properties can be evaluated. We will discuss how the wavelength dependent optical properties are influenced by core nanoparticle size and composition; surrounding medium; shell thickness and dielectric constant, and interparticle separation distance. ^1R. Elghanian et al., Science, 277, 1078 (1997); ^2H. Xu et al., Phys. Rev. Lett., 83, 4357 (1999) and Phys. Rev. E, 62, 4318 (2000)

  17. Simulations of near-field and far-field optical properties of electromagnetically coupled multi-layered nanoparticles

    NASA Astrophysics Data System (ADS)

    Xu, Hongxing

    2004-03-01

    Recent studies of nanoparticle-oligonucleotide conjugates[1] and "hot sites" in single-molecule surface-enhanced Raman scattering(SERS)[2] have highlighted the importance of clustering effects for the optical properties of metal nanoparticles. However, many applications in the life-sciences require coated nanoparticles, e.g. in order to induce biocompatibility or biorecognition. Such a coating will change the optical properties of nanoparticle system. We here describe a recursive method based on the extended Mie theory, which can be used to model the optical response clusters of shelled spherical nanoparticles. Both far-field (e.g. extinction cross section) and near-field (e.g. SERS effect) optical properties can be evaluated. We will discuss how the wavelength dependent optical properties are influenced by core nanoparticle size and composition; surrounding medium; shell thickness and dielectric constant, and interparticle separation distance. [1]R. Elghanian et al., Science, 277, 1078(1997); [2]H. Xu et al., Phys. Rev. Lett., 83, 4357(1999) and Phys. Rev. E, 62, 4318(2000)

  18. Bayesian exploration of coseismic seafloor deformation process during the 2011 Tohoku-Oki earthquake using near-field tsunami records

    NASA Astrophysics Data System (ADS)

    Jiang, J.; Simons, M.

    2014-12-01

    The diverse range of data for the 2011 Mw 9.0 Tohoku-oki earthquake are unprecedented. However, several models using joint data sets still disagree on the estimated slip distribution due to (1) choice of fault geometry and elastic structure; (2) choice of regularization scheme in optimization approaches; (3) lack or under-estimation of model prediction error due to imperfect forward modeling. Some important questions therefore remain unresolved, e.g., what is the profile of fault slip as one approaches the trench, and how much of the co-seismic signals is recorded in seafloor geodetic measurements. To obtain robust and detailed features of the co-seismic process, we present an approach to invert for the seafloor deformation field using only tsunami waveforms recorded by near-field stations, including GPS buoys, ocean bottom pressure gauges, cable pressure gauges and open ocean DART buoys. In addition to observational error, we incorporate model prediction error by considering the uncertainty in dispersion characteristics of tsunami propagation simulations. We adopt an analytical Bayesian approach to derive the posterior distributions for the coseismic seafloor deformation with minimal a priori assumptions. The analytical approach provides fast and robust characterization of coseismic seafloor deformation using the first arrivals of tsunami waveforms with potential for real-time applications. Our models show that large seafloor uplift is required at the trench, with maximum seafloor uplift occurring about 50 km from the trench. The actual fault slip depends on the assumed elastic structure and fault geometry; in the case of a homogeneous half-space and simplified fault geometry, slip decreases towards the trench. This method also provides direct comparisons with seafloor geodetic measurements and a quantitative estimation of the respective contributions from co- and post-seismic processes.

  19. Linear-phase approximation in the triangular facet near-field physical optics computer program

    NASA Technical Reports Server (NTRS)

    Imbriale, W. A.; Hodges, R. E.

    1990-01-01

    Analyses of reflector antenna surfaces use a computer program based on a discrete approximation of the radiation integral. The calculation replaces the actual surface with a triangular facet representation; the physical optics current is assumed to be constant over each facet. Described here is a method of calculation using linear-phase approximation of the surface currents of parabolas, ellipses, and shaped subreflectors and compares results with a previous program that used a constant-phase approximation of the triangular facets. The results show that the linear-phase approximation is a significant improvement over the constant-phase approximation, and enables computation of 100 to 1,000 lambda reflectors within a reasonable time on a Cray computer.

  20. Photodissociation path in H2 + induced by nonuniform optical near fields: Two-step excitation via vibrationally excited states

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Maiku; Nobusada, Katsuyuki

    2016-02-01

    In this paper, effects of the spatial nonuniformity of an optical near field (ONF) on the molecular photodissociation process are presented. The dissociation dynamics of H2 + was theoretically investigated by solving a non-Born-Oppenheimer Schrödinger equation. It was found that in addition to two dissociation mechanisms, which are one-photon and three-photon processes induced by uniform laser light excitation, the nonuniform ONF opens another dissociation path: two-step excitation mediated by vibrationally excited states. The nonuniformity of the ONF causes a transition between vibrational states that is forbidden according to conventional selection rules, leading to the dissociation path. The dependences of photodissociation on the intensity and nonuniformity of the ONF were calculated and the results validated the two-step dissociation mechanism.

  1. Second International Conference on Near-Field Optical Analysis: Photodynamic Therapy and Photobiology Effects

    NASA Technical Reports Server (NTRS)

    Bulgher, Debra L. (Editor); Morrison, Dennis

    2002-01-01

    The International NASA/DARPA Photobiology Conference held at the Johnson Space Center in Houston/TX demonstrated where low level laser therapy (LLLT), respectively low intensity light activated biostimulation (LILAB) and nanotechnological applications employing photobiomodulation techniques will presumably go in the next ten years. The conference was a continuation of the 1st International Conference on Nearfield Optical Analysis organized by Andrei Sommer (ENSOMA Lab, University of Ulm, Germany) in November 2000 at Castle Reisenburg, Germany, which started with a group of ten scientists from eight different countries. The 1st conference was co-sponsored by the American Chemical Society to evaluate the molecular mechanism of accelerated and normal wound healing processes. The 2nd conference was co-sponsored by DARPA, NASA-JSC and the Medical College of Wisconsin. Despite the short time between events, the 2nd conference hosted 40 international experts form universities, research institutes, agencies and the industry. The materials published here are expected to become milestones forming a novel platform in biomedical photobiology. The multidisciplinary group of researchers focused on LLLT/LILAB-applications under extreme conditions expected to have beneficial effects particularly in space, on submarines, and under severe battlefield conditions. The group also focused on novel technologies with possibilities allowing investigating the interaction of light with biological systems, molecular mechanisms of wound healing, bone regeneration, nerve regeneration, pain modulation, as well as biomineralization and biofilm formulation processes induced by nanobacteria.

  2. Polarization-sensitive characterization of the propagating plasmonic modes in silver nanowire waveguide on a glass substrate with a scanning near-field optical microscope.

    PubMed

    Venugopalan, Priyamvada; Zhang, Qiming; Li, Xiangping; Gu, Min

    2013-07-01

    In this paper, we report on the experimental investigation of the polarization properties of the plasmonic modes along a silver nanowire waveguide on a glass substrate. Two orthogonal polarization light components at the distal end of the nanowire are observed in the far-field. The near-field mapping with a scanning near-field optical microscopic probe exhibiting an in-plane polarization sensitivity reveals the two polarization components of the propagating plasmonic modes along the nanowire. PMID:23842310

  3. Effects of Optical Combiner and IPD Change for Convergence on Near-Field Depth Perception in an Optical See-Through HMD.

    PubMed

    Lee, Sangyoon; Hu, Xinda; Hua, Hong

    2016-05-01

    Many error sources have been explored in regards to the depth perception problem in augmented reality environments using optical see-through head-mounted displays (OST-HMDs). Nonetheless, two error sources are commonly neglected: the ray-shift phenomenon and the change in interpupillary distance (IPD). The first source of error arises from the difference in refraction for virtual and see-through optical paths caused by an optical combiner, which is required of OST-HMDs. The second occurs from the change in the viewer's IPD due to eye convergence. In this paper, we analyze the effects of these two error sources on near-field depth perception and propose methods to compensate for these two types of errors. Furthermore, we investigate their effectiveness through an experiment comparing the conditions with and without our error compensation methods applied. In our experiment, participants estimated the egocentric depth of a virtual and a physical object located at seven different near-field distances (40∼200 cm) using a perceptual matching task. Although the experimental results showed different patterns depending on the target distance, the results demonstrated that the near-field depth perception error can be effectively reduced to a very small level (at most 1 percent error) by compensating for the two mentioned error sources. PMID:27045910

  4. Imaging cervical cytology with scanning near-field optical microscopy (SNOM) coupled with an IR-FEL.

    PubMed

    Halliwell, Diane E; Morais, Camilo L M; Lima, Kássio M G; Trevisan, Julio; Siggel-King, Michele R F; Craig, Tim; Ingham, James; Martin, David S; Heys, Kelly A; Kyrgiou, Maria; Mitra, Anita; Paraskevaidis, Evangelos; Theophilou, Georgios; Martin-Hirsch, Pierre L; Cricenti, Antonio; Luce, Marco; Weightman, Peter; Martin, Francis L

    2016-01-01

    Cervical cancer remains a major cause of morbidity and mortality among women, especially in the developing world. Increased synthesis of proteins, lipids and nucleic acids is a pre-condition for the rapid proliferation of cancer cells. We show that scanning near-field optical microscopy, in combination with an infrared free electron laser (SNOM-IR-FEL), is able to distinguish between normal and squamous low-grade and high-grade dyskaryosis, and between normal and mixed squamous/glandular pre-invasive and adenocarcinoma cervical lesions, at designated wavelengths associated with DNA, Amide I/II and lipids. These findings evidence the promise of the SNOM-IR-FEL technique in obtaining chemical information relevant to the detection of cervical cell abnormalities and cancer diagnosis at spatial resolutions below the diffraction limit (≥0.2 μm). We compare these results with analyses following attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy; although this latter approach has been demonstrated to detect underlying cervical atypia missed by conventional cytology, it is limited by a spatial resolution of ~3 μm to 30 μm due to the optical diffraction limit. PMID:27406404

  5. Feasibility demonstration of a massively parallelizable optical near-field sensor for sub-wavelength defect detection and imaging

    NASA Astrophysics Data System (ADS)

    Mostafavi, Mahkamehossadat; Diaz, Rodolfo E.

    2016-05-01

    To detect and resolve sub-wavelength features at optical frequencies, beyond the diffraction limit, requires sensors that interact with the electromagnetic near-field of those features. Most instruments operating in this modality scan a single detector element across the surface under inspection because the scattered signals from a multiplicity of such elements would end up interfering with each other. However, an alternative massively parallelized configuration, capable of interrogating multiple adjacent areas of the surface at the same time, was proposed in 2002. Full physics simulations of the photonic antenna detector element that enables this instrument, show that using conventional red laser light (in the 600 nm range) the detector magnifies the signal from an 8 nm particle by up to 1.5 orders of magnitude. The antenna is a shaped slot element in a 60 nm silver film. The ability of this detector element to resolve λ/78 objects is confirmed experimentally at radio frequencies by fabricating an artificial material structure that mimics the optical permittivity of silver scaled to 2 GHz, and “cutting” into it the slot antenna. The experimental set-up is also used to demonstrate the imaging of a patterned surface in which the critical dimensions of the pattern are λ/22 in size.

  6. Imaging cervical cytology with scanning near-field optical microscopy (SNOM) coupled with an IR-FEL

    PubMed Central

    Halliwell, Diane E.; Morais, Camilo L. M.; Lima, Kássio M. G.; Trevisan, Julio; Siggel-King, Michele R. F.; Craig, Tim; Ingham, James; Martin, David S.; Heys, Kelly A.; Kyrgiou, Maria; Mitra, Anita; Paraskevaidis, Evangelos; Theophilou, Georgios; Martin-Hirsch, Pierre L.; Cricenti, Antonio; Luce, Marco; Weightman, Peter; Martin, Francis L.

    2016-01-01

    Cervical cancer remains a major cause of morbidity and mortality among women, especially in the developing world. Increased synthesis of proteins, lipids and nucleic acids is a pre-condition for the rapid proliferation of cancer cells. We show that scanning near-field optical microscopy, in combination with an infrared free electron laser (SNOM-IR-FEL), is able to distinguish between normal and squamous low-grade and high-grade dyskaryosis, and between normal and mixed squamous/glandular pre-invasive and adenocarcinoma cervical lesions, at designated wavelengths associated with DNA, Amide I/II and lipids. These findings evidence the promise of the SNOM-IR-FEL technique in obtaining chemical information relevant to the detection of cervical cell abnormalities and cancer diagnosis at spatial resolutions below the diffraction limit (≥0.2 μm). We compare these results with analyses following attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy; although this latter approach has been demonstrated to detect underlying cervical atypia missed by conventional cytology, it is limited by a spatial resolution of ~3 μm to 30 μm due to the optical diffraction limit. PMID:27406404

  7. Feasibility demonstration of a massively parallelizable optical near-field sensor for sub-wavelength defect detection and imaging

    PubMed Central

    Mostafavi, Mahkamehossadat; Diaz, Rodolfo E.

    2016-01-01

    To detect and resolve sub-wavelength features at optical frequencies, beyond the diffraction limit, requires sensors that interact with the electromagnetic near-field of those features. Most instruments operating in this modality scan a single detector element across the surface under inspection because the scattered signals from a multiplicity of such elements would end up interfering with each other. However, an alternative massively parallelized configuration, capable of interrogating multiple adjacent areas of the surface at the same time, was proposed in 2002. Full physics simulations of the photonic antenna detector element that enables this instrument, show that using conventional red laser light (in the 600 nm range) the detector magnifies the signal from an 8 nm particle by up to 1.5 orders of magnitude. The antenna is a shaped slot element in a 60 nm silver film. The ability of this detector element to resolve λ/78 objects is confirmed experimentally at radio frequencies by fabricating an artificial material structure that mimics the optical permittivity of silver scaled to 2 GHz, and “cutting” into it the slot antenna. The experimental set-up is also used to demonstrate the imaging of a patterned surface in which the critical dimensions of the pattern are λ/22 in size. PMID:27185385

  8. Feasibility demonstration of a massively parallelizable optical near-field sensor for sub-wavelength defect detection and imaging.

    PubMed

    Mostafavi, Mahkamehossadat; Diaz, Rodolfo E

    2016-01-01

    To detect and resolve sub-wavelength features at optical frequencies, beyond the diffraction limit, requires sensors that interact with the electromagnetic near-field of those features. Most instruments operating in this modality scan a single detector element across the surface under inspection because the scattered signals from a multiplicity of such elements would end up interfering with each other. However, an alternative massively parallelized configuration, capable of interrogating multiple adjacent areas of the surface at the same time, was proposed in 2002. Full physics simulations of the photonic antenna detector element that enables this instrument, show that using conventional red laser light (in the 600 nm range) the detector magnifies the signal from an 8 nm particle by up to 1.5 orders of magnitude. The antenna is a shaped slot element in a 60 nm silver film. The ability of this detector element to resolve λ/78 objects is confirmed experimentally at radio frequencies by fabricating an artificial material structure that mimics the optical permittivity of silver scaled to 2 GHz, and "cutting" into it the slot antenna. The experimental set-up is also used to demonstrate the imaging of a patterned surface in which the critical dimensions of the pattern are λ/22 in size. PMID:27185385

  9. Local optical absorption spectra of h-BN–MoS2 van der Waals heterostructure revealed by scanning near-field optical microscopy

    NASA Astrophysics Data System (ADS)

    Nozaki, Junji; Kobayashi, Yu; Miyata, Yasumitsu; Maniwa, Yutaka; Watanabe, Kenji; Taniguchi, Takashi; Yanagi, Kazuhiro

    2016-06-01

    Van der Waals (vdW) heterostructures, in which different two-dimensional layered materials are stacked, can exhibit unprecedented optical properties. Development of a technique to clarify local optical properties of vdW heterostructures is of great importance for the correct understanding of their backgrounds. Here, we examined local optical absorption spectra of h-BN–MoS2 vdW heterostructures by scanning near-field microscopy measurements with a spatial resolution of 100 nm. In an as-grown sample, there was almost no site dependence of their optical absorption spectra. However, in a degraded sample where defects and deformations were artificially induced, a significant site-dependence of optical absorption spectra was observed.

  10. Writing and reading methodology for biochips with sub-100-nm chemical patterns based on near-field scanning optical microscopy.

    PubMed

    Kobayashi, Yasuhiro; Sakai, Masaru; Ueda, Akio; Maruyama, Kenichi; Saiki, Toshiharu; Suzuki, Koji

    2008-05-01

    This paper demonstrates a writing and reading methodology, which allows both to create and to detect sub-100-nm carboxyl-terminated patterns on light-transmissive quartz substrates by the same instrumental system. Such a technique, capable of creating carboxyl-terminated nanopatterns, offers several benefits for the miniaturization of biochips, since the carboxyl-terminated nanopatterns allow the easy immobilization of biomolecules by amide bond formation. As a consequence, increasingly miniaturized biochips require suitable analytical methods for the detection of nanopatterns. In our approach, carboxyl-terminated nanopatterns of down to 80 nm width were created using a photolabile silane coupling agent and a UV laser coupled to a near-field scanning optical microscope (NSOM). The same NSOM system was then used in a next step to detect the fabricated carboxyl-terminated nanopatterns after modification with a fluorescent label. Furthermore, as a first step towards biochip applications, the successful immobilization of several biomolecules, such as streptavidin, IgG and DNA on carboxyl-terminated nanopatterns was demonstrated. We have shown that our approach has the potential to lead to a new bioanalytical method, which enables one to write and to read biochips on a sub-100-nm scale by the same system. PMID:18469460

  11. Electro-Optical Sensor Fabricated Using a Bulk Cleavage Technique and Its Characteristics for Near-Field Intra-Body Communication

    NASA Astrophysics Data System (ADS)

    Furuya, Akinori; Sasaki, Ai-ichiro; Morimura, Hiroki; Aihara, Kimihisa; Shinagawa, Mitsuru

    2013-09-01

    This paper describes how to obtain a low cost electro-optical (EO) sensor module for the mass production of near-field intra-body communication devices. In this study, we used a bulk cleavage technique to fabricate EO modulators without the need for any optical polishing or washing processes, and clarified the feasibility of assembling optical components using only a passive alignment technique with a compact housing.

  12. Near-field-induced optical force on a metal particle and C{sub 60}: Real-time and real-space electron dynamics simulation

    SciTech Connect

    Iwasa, Takeshi; Nobusada, Katsuyuki

    2010-10-15

    Optical forces induced by a near field are calculated for a 1-mm-sized metal particle mimicked by a jellium model and for C{sub 60} in the framework of real-time and real-space time-dependent density-functional theory combined with a nonuniform light-matter interaction formalism, fully taking account of multipole interaction. A highly localized near field nonuniformly polarizes these molecules. The locally induced polarization charges in the molecules are partly canceled by the screening charges. The polarization and screening charges generally contribute to the attractive and repulsive forces, respectively, and a sensible balance between these charges results in several peaks in the optical force as a function of the frequency of the near field. The resonance excitation does not necessarily maximally induce the net force, and the force exerted on the molecules strongly depends on the details of their electronic structures. The optical force is larger in the metal particle than in C{sub 60}. We also found that the optical force depends linearly on the intensity of the near field.

  13. Observation of amplitude and phase in ridge and photonic crystal waveguides operating at 1.55 microm by use of heterodyne scanning near-field optical microscopy.

    PubMed

    Tortora, P; Abashin, M; Märki, I; Nakagawa, W; Vaccaro, L; Salt, M; Herzig, H P; Levy, U; Fainman, Y

    2005-11-01

    We apply heterodyne scanning near-field optical microscopy (SNOM) to observe with subwavelength resolution the amplitude and phase of optical fields propagating in several microfabricated waveguide devices operating around the 1.55 microm wavelength. Good agreement between the SNOM measurements and predicted optical mode propagation characteristics in standard ridge waveguides demonstrates the validity of the method. In situ observation of the subwavelength-scale distribution and propagation of optical fields in straight and 90 degrees bend photonic crystal waveguides facilitates a more detailed understanding of the optical performance characteristics of these devices and illustrates the usefulness of the technique for investigating nanostructured photonic devices. PMID:16279458

  14. Effects of Configuration of Optical Combiner on Near-Field Depth Perception in Optical See-Through Head-Mounted Displays.

    PubMed

    Lee, Sangyoon; Hua, Hong

    2016-04-01

    The ray-shift phenomenon means the apparent distance shift in the display image plane between virtual and physical objects. It is caused by the difference in the refraction of virtual display and see-through optical paths derived from optical combiners that are necessary to provide a see-through capability in optical see-through head-mounted displays. In this work, through a human-subject experiment, we investigated the effects of ray-shift phenomenon induced by the optical combiner on depth perception for near-field distances (40 cm-100 cm). In our experiment, we considered three different configurations of optical combiner: horizontal-tilt and vertical-tilt configurations (using plate beamsplitters horizontally and vertically tilted by 45°, respectively), and non-tilt configuration (using rectangular solid waveguides). Participants' depth perception errors in these configurations were compared with those in an ordinary condition (i.e., the condition where physical objects are directly shown without the displays) and theoretically estimated ones. According to the experimental results, the measured percentage depth perception errors were similar to the theoretically estimated ones, where the amount of estimated percentage depth errors was greater than 0.3%. Furthermore, the participants showed significantly larger depth perception errors in the horizontal-tilt configuration than in an ordinary condition, while no large errors were found in the vertical-tilt configuration. In the non-tilt configuration, the results were dependent on the thickness of optical combiner and target distance. PMID:26780807

  15. Nanospot soldering polystyrene nanoparticles with an optical fiber probe laser irradiating a metallic AFM probe based on the near-field enhancement effect.

    PubMed

    Cui, Jianlei; Yang, Lijun; Wang, Yang; Mei, Xuesong; Wang, Wenjun; Hou, Chaojian

    2015-02-01

    With the development of nanoscience and nanotechnology for the bottom-up nanofabrication of nanostructures formed from polystyrene nanoparticles, joining technology is an essential step in the manufacturing and assembly of nanodevices and nanostructures in order to provide mechanical integration and connection. To study the nanospot welding of polystyrene nanoparticles, we propose a new nanospot-soldering method using the near-field enhancement effect of a metallic atomic force microscope (AFM) probe tip that is irradiated by an optical fiber probe laser. On the basis of our theoretical analysis of the near-field enhancement effect, we set up an experimental system for nanospot soldering; this approach is carried out by using an optical fiber probe laser to irradiate the AFM probe tip to sinter the nanoparticles, providing a promising technical approach for the application of nanosoldering in nanoscience and nanotechnology. PMID:25582678

  16. Development of a shear-force scanning near-field cathodoluminescence microscope for characterization of nanostructures' optical properties.

    PubMed

    Bercu, N B; Troyon, M; Molinari, M

    2016-09-01

    An original scanning near-field cathodoluminescence microscope for nanostructure characterization has been developed and successfully tested. By using a bimorph piezoelectric stack both as actuator and detector, the developed setup constitutes a real improvement compared to previously reported SEM-based solutions. The technique combines a scanning probe and a scanning electron microscope in order to simultaneously offer near-field cathodoluminescence and topographic images of the sample. Share-force topography and cathodoluminescence measurements on GaN, SiC and ZnO nanostructures using the developed setup are presented showing a nanometric resolution in both topography and cathodoluminescence images with increased sensitivity compared to classical luminescence techniques. PMID:27125561

  17. Remote optical sensing on the nanometer scale with a bowtie aperture nano-antenna on a fiber tip of scanning near-field optical microscopy

    SciTech Connect

    Atie, Elie M.; Xie, Zhihua; El Eter, Ali; Salut, Roland; Baida, Fadi I.; Grosjean, Thierry; Nedeljkovic, Dusan; Tannous, Tony

    2015-04-13

    Plasmonic nano-antennas have proven the outstanding ability of sensing chemical and physical processes down to the nanometer scale. Sensing is usually achieved within the highly confined optical fields generated resonantly by the nano-antennas, i.e., in contact to the nanostructures. In this paper, we demonstrate the sensing capability of nano-antennas to their larger scale environment, well beyond their plasmonic confinement volume, leading to the concept of “remote” (non contact) sensing on the nanometer scale. On the basis of a bowtie-aperture nano-antenna (BNA) integrated at the apex of a SNOM (Scanning Near-field Optical Microscopy) fiber tip, we introduce an ultra-compact, moveable, and background-free optical nanosensor for the remote sensing of a silicon surface (up to distance of 300 nm). Sensitivity of the BNA to its large scale environment is high enough to expect the monitoring and control of the spacing between the nano-antenna and a silicon surface with sub-nanometer accuracy. This work paves the way towards an alternative class of nanopositioning techniques, based on the monitoring of diffraction-free plasmon resonance, that are alternative to nanomechanical and diffraction-limited optical interference-based devices.

  18. Detection of an infrared near-field optical signal by attaching an infrared-excitable phosphor to the end of a photocantilever.

    PubMed

    Tanaka, Y; Fukuzawa, K; Ohwaki, J

    1999-01-01

    To improve the signal-to-noise ratio of near-field scanning optical microscopy, we propose attaching an infrared-excitable phosphor (IEP) to a photocantilever. One source of noise is the light scattered from locations on the sample surface other than that of the probe tip. By detecting only the light scattered from the tip, we can obtain a near-field optical signal without noise. We attached an IEP particle to a photocantilever to convert infrared light to visible light and we used 1550-nm infrared illumination, so the light scattered from the sample was only infrared. The silicon photodiode of the photocantilever is 10(6) times less sensitive to infrared light than to visible light. As a result, only the converted visible light from the IEP particle, i.e. the signal containing the near-field optical information from the tip, was detected. We verified that the photocantilever detected the signal in the evanescent light produced by infrared illumination and that the detected signal was the light converted by the IEP. The experimental results show the feasibility of detecting infrared light and not the background light through the use of the IEP. PMID:11388267

  19. Tip-enhanced near-field optical microscope with side-on and ATR-mode sample excitation for super-resolution Raman imaging of surfaces

    NASA Astrophysics Data System (ADS)

    Heilman, A. L.; Gordon, M. J.

    2016-06-01

    A tip-enhanced near-field optical microscope with side-on and attenuated total reflectance (ATR) excitation and collection is described and used to demonstrate sub-diffraction-limited (super-resolution) optical and chemical characterization of surfaces. ATR illumination is combined with an Au optical antenna tip to show that (i) the tip can quantitatively transduce the optical near-field (evanescent waves) above the surface by scattering photons into the far-field, (ii) the ATR geometry enables excitation and characterization of surface plasmon polaritons (SPPs), whose associated optical fields are shown to enhance Raman scattering from a thin layer of copper phthalocyanine (CuPc), and (iii) SPPs can be used to plasmonically excite the tip for super-resolution chemical imaging of patterned CuPc via tip-enhanced Raman spectroscopy (TERS). ATR-illumination TERS is also quantitatively compared with the more conventional side-on illumination scheme. In both cases, spatial resolution was better than 40 nm and tip on/tip off Raman enhancement factors were >6500. Furthermore, ATR illumination was shown to provide similar Raman signal levels at lower "effective" pump powers due to additional optical energy delivered by SPPs to the active region in the tip-surface gap.

  20. Fabrication and characterization of a silicon cantilever probe with an integrated quartz-glass (fused-silica) tip for scanning near-field optical microscopy.

    PubMed

    Schürmann, G; Noell, W; Staufer, U; de Rooij, N F; Eckert, R; Freyland, J M; Heinzelmann, H

    2001-10-01

    A cantilever-based probe is introduced for use in scanning near-field optical microscopy (SNOM) combined with scanning atomic-force microscopy (AFM). The probes consist of silicon cantilevers with integrated 25-mum-high fused-silica tips. The probes are batch fabricated by microfabrication technology. Transmission electron microscopy reveals that the transparent quartz tips are completely covered with an opaque aluminum layer before the SNOM measurement. Static and dynamic AFM imaging was performed. SNOM imaging in transmission mode of single fluorescent molecules shows an optical resolution better than 32 nm. PMID:18364783

  1. Near-field ground motion of the 2002 Denali fault, Alaska, earthquake recorded at pump station 10

    USGS Publications Warehouse

    Ellsworth, W.L.; Celebi, M.; Evans, J.R.; Jensen, E.G.; Kayen, R.; Metz, M.C.; Nyman, D.J.; Roddick, J.W.; Spudich, P.; Stephens, C.D.

    2004-01-01

    A free-field recording of the Denali fault earthquake was obtained by the Alyeska Pipeline Service Company 3 km from the surface rupture of the Denali fault. The instrument, part of the monitoring and control system for the trans-Alaska pipeline, was located at Pump Station 10, approximately 85 km east of the epicenter. After correction for the measured instrument response, we recover a seismogram that includes a permanent displacement of 3.0 m. The recorded ground motion has relatively low peak acceleration (0.36 g) and very high peak velocity (180 cm/s). Nonlinear soil response may have reduced the peak acceleration to this 0.36 g value. Accelerations in excess of 0.1 g lasted for 10 s, with the most intense motion occurring during a 1.5-s interval when the rupture passed the site. The low acceleration and high velocity observed near the fault in this earthquake agree with observations from other recent large-magnitude earthquakes. ?? 2004, Earthquake Engineering Research Institute.

  2. Revealing nanoscale optical properties and morphology in perfluoropentacene films by confocal and tip-enhanced near-field optical microscopy and spectroscopy.

    PubMed

    Wang, Xiao; Broch, Katharina; Schreiber, Frank; Meixner, Alfred J; Zhang, Dai

    2016-06-21

    Combining high resolution optical microscopy and spectroscopy, we propose a novel, generally applicable and highly sensitive method for determining the local morphology in organic semiconductor thin films (e.g. perfluoropentacene (PFP)). An azimuthally or radially polarized doughnut mode (APDM or RPDM) laser beam is focused by a high numerical aperture parabolic-mirror to excite a diffraction limited volume of the PFP film with an electric field polarized either exclusively in-plane or dominantly out-of-plane (relative to the substrate). We find two distinct morphologies of thin PFP films: molecular aggregates and crystalline terraces. The well-defined dipole emission patterns observed from the molecular aggregates strongly suggest the presence of localized excitations. For both laser modes, we observe that for the PFP aggregates, the photoluminescence (PL) emission from the main electronic transition is blue-shifted by about 10 meV, as compared to that from the molecular terraces. For the C-C bending modes, the B3g at 1581 cm(-1) (ν1) and the Ag at 1316 cm(-1) (ν0), we observe a decrease of the intensity ratio (Iν1/Iν0) from 0.6 (terrace) to 0.15 (aggregate). Furthermore, the intensity ratios (IAPDM/IRPDM) of ν1 excited by different polarizations increase from 0.12 (terrace) to 0.73 (aggregate). These results indicate that the PFP molecules orient rather parallel to the substrate in the aggregates, whilst more upright in the terraces. Benefiting from the nanometer scale optical resolution offered by the tip-enhanced near-field optical method, we observe clear optical contrasts between the molecular aggregate and the terrace as well as individual layers within a terrace. Tip-enhanced optical spectra locally taken from the molecular terrace and the aggregate show similar blue-shift of the main PL peak and change in the Raman intensity with different polarizations as from the far-field assemble-measurements, which further confirms the different molecular

  3. Optical sedimentation recorder

    DOEpatents

    Bishop, James K.B.

    2014-05-06

    A robotic optical sedimentation recorder is described for the recordation of carbon flux in the oceans wherein both POC and PIC particles are captured at the open end of a submersible sampling platform, the captured particles allowed to drift down onto a collection plate where they can be imaged over time. The particles are imaged using three separate light sources, activated in sequence, one source being a back light, a second source being a side light to provide dark field illumination, and a third source comprising a cross polarized light source to illuminate birefringent particles. The recorder in one embodiment is attached to a buoyancy unit which is capable upon command for bringing the sedimentation recorder to a programmed depth below the ocean surface during recordation mode, and on command returning the unit to the ocean surface for transmission of recorded data and receipt of new instructions. The combined unit is provided with its own power source and is designed to operate autonomously in the ocean for extended periods of time.

  4. Local detection efficiency of a NbN superconducting single photon detector explored by a scattering scanning near-field optical microscope.

    PubMed

    Wang, Qiang; Renema, Jelmer J; Engel, Andreas; van Exter, Martin P; de Dood, Michiel J A

    2015-09-21

    We propose an experiment to directly probe the local response of a superconducting single photon detector using a sharp metal tip in a scattering scanning near-field optical microscope. The optical absorption is obtained by simulating the tip-detector system, where the tip-detector is illuminated from the side, with the tip functioning as an optical antenna. The local detection efficiency is calculated by considering the recently introduced position-dependent threshold current in the detector. The calculated response for a 150 nm wide detector shows a peak close to the edge that can be spatially resolved with an estimated resolution of ∼ 20 nm, using a tip with parameters that are experimentally accessible. PMID:26406688

  5. Combining near-field hyperspectral imaging and far-field spectral-angular distribution to develop mid-field white LED optical models with spatial color deviation.

    PubMed

    Lee, Tsung-Xian; Lu, Tsung-Lin; Chen, Bo-Song

    2016-07-11

    The integration of spatial distribution of light intensity and color in the midfield is instrumental for LED optical design. On the basis of this rationale, we proposed an accurate and convenient method for developing white LED optical models. Near-field hyperspectral images and far-field spectral-angular distributions were integrated to illustrate changes in spatial light intensity and color distribution in the mid-field, to the exclusion of the absorption, conversion, and scattering of phosphors. The corresponding optical models were developed for three LED samples under different packaging conditions. Their normalized cross-correlation values for spatial light intensity and correlated-color-temperature distribution between simulation and measurement averaged as high as 0.995 and 0.99 respectively, which validated the accuracy and feasibility of the proposed method. PMID:27410897

  6. Growth and decay dynamics of a stable microbubble produced at the end of a near-field scanning optical microscopy fiber probe

    NASA Astrophysics Data System (ADS)

    Taylor, R. S.; Hnatovsky, C.

    2004-06-01

    Low power cw laser radiation coupled into a near-field scanning optical microscopy fiber probe has been used to generate a stable microbubble in water. A probe tip which was selectively chemically etched and metallized served as a microheater for the generation of the stable bubble. Bubble diameters in the range of 40-400 μm and lifetimes of over an hour have been obtained. The microbubble exhibited a linear growth phase over a period of a few seconds before reaching a maximum diameter which depended on the laser power. When the laser beam was blocked the microbubble decayed with a rate which was inversely proportional to the bubble diameter. The bubble lifetime depended on the square of the initial bubble diameter. Instabilities which transform a large stable bubble into a microjet stream of micron sized bubbles as the laser power was increased is also described.

  7. Near-Field Scanning Optical Microscopy of Soft, Biological, or Rough Objects in Aqueous Environment: Challenges and some Remedies to Circumvent

    NASA Technical Reports Server (NTRS)

    Vikram, C. S.; Witherow, W. K.

    1999-01-01

    Near-field scanning optical microscopy is an established technique for sub-wavelength spatial resolution in imaging, spectroscopy, material science, surface chemistry, polarimetry, etc. A significant amount of confidence has been established for thin hard specimens in air. However when soft, biological, rough, in aqueous environment object, or a combination is involved, the progress has been slow. The tip-sample mechanical interaction, heat effects to sample, drag effects to the probe, difficulty in controlling tip-sample separation in case of rough objects, light scattering from sample thickness, etc. create problems. Although these problems are not even fully understood, there have been attempts to study them with the aim of performing reliable operations. In this review we describe these attempts. Starting with general problems encountered, various effects like polarization, thermal, and media are covered. The roles of independent tip-sample distance control tools in the relevant situations are then described. Finally progress in fluid cell aspect has been summarized.

  8. Measuring photoluminescence spectra of self-assembly array nanowire of colloidal CdSe quantum dots using scanning near-field optics microscopy

    NASA Astrophysics Data System (ADS)

    Bai, Zhongchen; Hao, Licai; Zhang, Zhengping; Qin, Shuijie

    2016-05-01

    A novel periodic array CdSe nanowire is prepared on a substrate of the porous titanium dioxide by using a self-assembly method of the colloidal CdSe quantum dots (QDs). The experimental results show that the colloidal CdSe QDs have renewedly assembled on its space scale and direction in process of losing background solvent and form the periodic array nanowire. The main peak wavelength of Photoluminescence (PL) spectra, which is measured by using a 100-nm aperture laser beam spot on a scanning near-field optics microscopy, has shifted 60 nm with compared to the colloidal CdSe QDs. Furthermore, we have measured smaller ordered nanometer structure in thin QDs area as well, a 343-nm periodic nanowire in thick QDs area and the colloidal QDs in edge of well-ordered nanowire.

  9. Determination of critical diameters for intrinsic carrier diffusion-length of GaN nanorods with cryo-scanning near-field optical microscopy

    PubMed Central

    Chen, Y. T.; Karlsson, K. F.; Birch, J.; Holtz, P. O.

    2016-01-01

    Direct measurements of carrier diffusion in GaN nanorods with a designed InGaN/GaN layer-in-a-wire structure by scanning near-field optical microscopy (SNOM) were performed at liquid-helium temperatures of 10 K. Without an applied voltage, intrinsic diffusion lengths of photo-excited carriers were measured as the diameters of the nanorods differ from 50 to 800 nm. The critical diameter of nanorods for carrier diffusion is concluded as 170 nm with a statistical approach. Photoluminescence spectra were acquired for different positions of the SNOM tip on the nanorod, corresponding to the origins of the well-defined luminescence peaks, each being related to recombination-centers. The phenomenon originated from surface oxide by direct comparison of two nanorods with similar diameters in a single map has been observed and investigated. PMID:26876009

  10. Second harmonic generation in a KNbO3 nanorod and its detection by using a near-field scanning optical microscope

    NASA Astrophysics Data System (ADS)

    Park, D. J.; Kang, P. G.; Jung, J. H.; Lee, H. H.; Choi, S. B.

    2016-04-01

    We report on an observation of second harmonic generation in an individual KNbO3 nanorod by using a near-field scanning optical microscope. The second harmonic is successfully generated by irradiating with a femtosecond laser having center wavelengths of 1200, 1100, and 972 nm. Such a second harmonic yield shows a clear dependence on the incident laser polarization, where maximum yield is obtained when the incident laser polarization is parallel to the long axis of an individual nanorod. A spatially-resolved second harmonic image shows a bright spot at the edge of the nanorod, which is attributed to the elaborated intensity of both fundamental laser light and second harmonic light inside the nanowire owing to cavity-mode formation.

  11. Determination of critical diameters for intrinsic carrier diffusion-length of GaN nanorods with cryo-scanning near-field optical microscopy

    NASA Astrophysics Data System (ADS)

    Chen, Y. T.; Karlsson, K. F.; Birch, J.; Holtz, P. O.

    2016-02-01

    Direct measurements of carrier diffusion in GaN nanorods with a designed InGaN/GaN layer-in-a-wire structure by scanning near-field optical microscopy (SNOM) were performed at liquid-helium temperatures of 10 K. Without an applied voltage, intrinsic diffusion lengths of photo-excited carriers were measured as the diameters of the nanorods differ from 50 to 800 nm. The critical diameter of nanorods for carrier diffusion is concluded as 170 nm with a statistical approach. Photoluminescence spectra were acquired for different positions of the SNOM tip on the nanorod, corresponding to the origins of the well-defined luminescence peaks, each being related to recombination-centers. The phenomenon originated from surface oxide by direct comparison of two nanorods with similar diameters in a single map has been observed and investigated.

  12. Membrane specific mapping and colocalization of malarial and host skeletal proteins in the Plasmodium falciparum infected erythrocyte by dual-color near-field scanning optical microscopy.

    PubMed

    Enderle, T; Ha, T; Ogletree, D F; Chemla, D S; Magowan, C; Weiss, S

    1997-01-21

    Accurate localization of proteins within the substructure of cells and cellular organelles enables better understanding of structure-function relationships, including elucidation of protein-protein interactions. We describe the use of a near-field scanning optical microscope (NSOM) to simultaneously map and detect colocalized proteins within a cell, with superresolution. The system we elected to study was that of human red blood cells invaded by the human malaria parasite Plasmodium falciparum. During intraerythrocytic growth, the parasite expresses proteins that are transported to the erythrocyte cell membrane. Association of parasite proteins with host skeletal proteins leads to modification of the erythrocyte membrane. We report on colocalization studies of parasite proteins with an erythrocyte skeletal protein. Host and parasite proteins were selectively labeled in indirect immunofluorescence antibody assays. Simultaneous dual-color excitation and detection with NSOM provided fluorescence maps together with topography of the cell membrane with subwavelength (100 nm) resolution. Colocalization studies with laser scanning confocal microscopy provided lower resolution (310 nm) fluorescence maps of cross sections through the cell. Because the two excitation colors shared the exact same near-field aperture, the two fluorescence images were acquired in perfect, pixel-by-pixel registry, free from chromatic aberrations, which contaminate laser scanning confocal microscopy measurements. Colocalization studies of the protein pairs of mature parasite-infected erythrocyte surface antigen (MESA) (parasite)/protein4.1(host) and P. falciparum histidine rich protein (PfHRP1) (parasite)/protein4.1(host) showed good real-space correlation for the MESA/protein4.1 pair, but relatively poor correlation for the PfHRP1/protein4.1 pair. These data imply that NSOM provides high resolution information on in situ interactions between proteins in biological membranes. This method of

  13. Infrared spectroscopic near-field mapping of single nanotransistors.

    PubMed

    Huber, A J; Wittborn, J; Hillenbrand, R

    2010-06-11

    We demonstrate the application of scattering-type scanning near-field optical microscopy (s-SNOM) for infrared (IR) spectroscopic material recognition in state-of-the-art semiconductor devices. In particular, we employ s-SNOM for imaging of industrial CMOS transistors with a resolution better than 20 nm, which allows for the first time IR spectroscopic recognition of amorphous SiO(2) and Si(3)N(4) components in a single transistor device. The experimentally recorded near-field spectral signature of amorphous SiO(2) shows excellent agreement with model calculations based on literature dielectric values, verifying that the characteristic near-field contrasts of SiO(2) stem from a phonon-polariton resonant near-field interaction between the probing tip and the SiO(2) nanostructures. Local material recognition by s-SNOM in combination with its capabilities of contact-free and non-invasive conductivity- and strain-mapping makes IR near-field microscopy a versatile metrology technique for nanoscale material characterization and semiconductor device analysis with application potential in research and development, failure analysis and reverse engineering. PMID:20463381

  14. Attosecond nanoscale near-field sampling

    NASA Astrophysics Data System (ADS)

    Förg, B.; Schötz, J.; Süßmann, F.; Förster, M.; Krüger, M.; Ahn, B.; Okell, W. A.; Wintersperger, K.; Zherebtsov, S.; Guggenmos, A.; Pervak, V.; Kessel, A.; Trushin, S. A.; Azzeer, A. M.; Stockman, M. I.; Kim, D.; Krausz, F.; Hommelhoff, P.; Kling, M. F.

    2016-05-01

    The promise of ultrafast light-field-driven electronic nanocircuits has stimulated the development of the new research field of attosecond nanophysics. An essential prerequisite for advancing this new area is the ability to characterize optical near fields from light interaction with nanostructures, with sub-cycle resolution. Here we experimentally demonstrate attosecond near-field retrieval for a tapered gold nanowire. By comparison of the results to those obtained from noble gas experiments and trajectory simulations, the spectral response of the nanotaper near field arising from laser excitation can be extracted.

  15. Attosecond nanoscale near-field sampling.

    PubMed

    Förg, B; Schötz, J; Süßmann, F; Förster, M; Krüger, M; Ahn, B; Okell, W A; Wintersperger, K; Zherebtsov, S; Guggenmos, A; Pervak, V; Kessel, A; Trushin, S A; Azzeer, A M; Stockman, M I; Kim, D; Krausz, F; Hommelhoff, P; Kling, M F

    2016-01-01

    The promise of ultrafast light-field-driven electronic nanocircuits has stimulated the development of the new research field of attosecond nanophysics. An essential prerequisite for advancing this new area is the ability to characterize optical near fields from light interaction with nanostructures, with sub-cycle resolution. Here we experimentally demonstrate attosecond near-field retrieval for a tapered gold nanowire. By comparison of the results to those obtained from noble gas experiments and trajectory simulations, the spectral response of the nanotaper near field arising from laser excitation can be extracted. PMID:27241851

  16. Attosecond nanoscale near-field sampling

    PubMed Central

    Förg, B.; Schötz, J.; Süßmann, F.; Förster, M.; Krüger, M.; Ahn, B.; Okell, W. A.; Wintersperger, K.; Zherebtsov, S.; Guggenmos, A.; Pervak, V.; Kessel, A.; Trushin, S. A.; Azzeer, A. M.; Stockman, M. I.; Kim, D.; Krausz, F.; Hommelhoff, P.; Kling, M. F.

    2016-01-01

    The promise of ultrafast light-field-driven electronic nanocircuits has stimulated the development of the new research field of attosecond nanophysics. An essential prerequisite for advancing this new area is the ability to characterize optical near fields from light interaction with nanostructures, with sub-cycle resolution. Here we experimentally demonstrate attosecond near-field retrieval for a tapered gold nanowire. By comparison of the results to those obtained from noble gas experiments and trajectory simulations, the spectral response of the nanotaper near field arising from laser excitation can be extracted. PMID:27241851

  17. Attosecond nanoscale near-field sampling

    DOE PAGESBeta

    Forg, B.; Schotz, J.; SuBmann, F.; Forster, M.; Kruger, M.; Ahn, B.; Okell, W. A.; Wintersperger, K.; Zherebtsov, S.; Guggenmos, A.; et al

    2016-05-31

    The promise of ultrafast light-field-driven electronic nanocircuits has stimulated the development of the new research field of attosecond nanophysics. An essential prerequisite for advancing this new area is the ability to characterize optical near fields from light interaction with nanostructures, with sub-cycle resolution. Here we experimentally demonstrate attosecond near-field retrieval for a tapered gold nanowire. Furthermore, by comparison of the results to those obtained from noble gas experiments and trajectory simulations, the spectral response of the nanotaper near field arising from laser excitation can be extracted.

  18. Thermal infrared near-field spectroscopy.

    PubMed

    Jones, Andrew C; Raschke, Markus B

    2012-03-14

    Despite the seminal contributions of Kirchhoff and Planck describing far-field thermal emission, fundamentally distinct spectral characteristics of the electromagnetic thermal near-field have been predicted. However, due to their evanescent nature their direct experimental characterization has remained elusive. Combining scattering scanning near-field optical microscopy with Fourier-transform spectroscopy using a heated atomic force microscope tip as both a local thermal source and scattering probe, we spectroscopically characterize the thermal near-field in the mid-infrared. We observe the spectrally distinct and orders of magnitude enhanced resonant spectral near-field energy density associated with vibrational, phonon, and phonon-polariton modes. We describe this behavior and the associated distinct on- and off-resonance nanoscale field localization with model calculations of the near-field electromagnetic local density of states. Our results provide a basis for intrinsic and extrinsic resonant manipulation of optical forces, control of nanoscale radiative heat transfer with optical antennas, and use of this new technique of thermal infrared near-field spectroscopy for broadband chemical nanospectroscopy. PMID:22280474

  19. Infrared Scattering Scanning Near-Field Optical Microscopy Using An External Cavity Quantum Cascade Laser For Nanoscale Chemical Imaging And Spectroscopy of Explosive Residues

    SciTech Connect

    Craig, Ian M.; Phillips, Mark C.; Taubman, Matthew S.; Josberger, Erik E.; Raschke, Markus Bernd

    2013-02-04

    Infrared scattering scanning near-field optical microscopy (s-SNOM) is an apertureless superfocusing technique that uses the antenna properties of a conducting atomic force microscope (AFM) tip to achieve infrared spatial resolution below the diffraction limit. The instrument can be used either in imaging mode, where a fixed wavelength light source is tuned to a molecular resonance and the AFM raster scans an image, or in spectroscopy mode where the AFM is held stationary over a feature of interest and the light frequency is varied to obtain a spectrum. In either case, a strong, stable, coherent infrared source is required. Here we demonstrate the integration of a broadly tunable external cavity quantum cascade laser (ECQCL) into an s-SNOM and use it to obtain infrared spectra of microcrystals of chemicals adsorbed onto gold substrates. Residues of the explosive compound tetryl was deposited onto gold substrates. s-SNOM experiments were performed in the 1260-1400 cm-1 tuning range of the ECQCL, corresponding to the NO2 symmetric stretch vibrational fingerprint region. Vibrational infrared spectra were collected on individual chemical domains with a collection area of *500nm2 and compared to ensemble averaged far-field reflection-absorption infrared spectroscopy (RAIRS) results.

  20. Infrared scattering scanning near-field optical microscopy using an external cavity quantum cascade laser for nanoscale chemical imaging and spectroscopy of explosive residues

    NASA Astrophysics Data System (ADS)

    Craig, Ian M.; Phillips, Mark C.; Taubman, Matthew S.; Josberger, Erik E.; Raschke, Markus B.

    2013-01-01

    Infrared scattering scanning near-field optical microscopy (s-SNOM) is an apertureless superfocusing technique that uses the antenna properties of a conducting atomic force microscope (AFM) tip to achieve infrared spatial resolution below the diffraction limit. The instrument can be used either in imaging mode, where a fixed wavelength light source is tuned to a molecular resonance and the AFM raster scans an image, or in spectroscopy mode where the AFM is held stationary over a feature of interest and the light frequency is varied to obtain a spectrum. In either case, a strong, stable, coherent infrared source is required. Here we demonstrate the integration of a broadly tunable external cavity quantum cascade laser (ECQCL) into an s-SNOM and use it to obtain infrared spectra of microcrystals of chemicals adsorbed onto gold substrates. Residues of the explosive compound tetryl was deposited onto gold substrates. s-SNOM experiments were performed in the 1260-1400cm-1 tuning range of the ECQCL, corresponding to the N02 symmetric stretch vibrational fingerprint region. Vibrational infrared spectra were collected on individual chemical domains with a collection area of ~500 nm2 and compared to ensemble averaged far-field reflection-absorption infrared spectroscopy (RAIRS) results.

  1. Fabrication and characterization of fluorescent rare-earth-doped glass-particle-based tips for near-field optical imaging applications.

    PubMed

    Aigouy, Lionel; De Wilde, Yannick; Mortier, Michel; Giérak, Jacques; Bourhis, Eric

    2004-07-01

    Fluorescent rare-earth-doped glass particles glued to the end of an atomic force microscope tip have been used to perform scanning near-field optical measurements on nanostructured samples. The fixation procedure of the fluorescent fragment at the end of the tip is described in detail. The procedure consists of depositing a thin adhesive layer on the tip. Then a tip approach is performed on a fragment that remains stuck near the tip extremity. To displace the particle and position it at the very end of the tip, a nanomanipulation is achieved by use of a second tip mounted on piezoelectric scanners. Afterward, the particle size is reduced by focused ion beam milling. These particles exhibit a strong green luminescence where excited in the near infrared by an upconversion mechanism. Images obtained near a metallic edge show a lateral resolution in the 180-200-nm range. Images we obtained by measuring the light scattered by 250-nm holes show a resolution well below 100 nm. This phenomenon can be explained by a local excitation of the particle and by the nonlinear nature of the excitation. PMID:15250549

  2. Volumetric Near-Field Microwave Plasma Generation

    NASA Technical Reports Server (NTRS)

    Exton, R. J.; Balla, R. Jeffrey; Herring, G. C.; Popovic, S.; Vuskovic, L.

    2003-01-01

    A periodic series of microwave-induced plasmoids is generated using the outgoing wave from a microwave horn and the reflected wave from a nearby on-axis concave reflector. The plasmoids are spaced at half-wavelength separations according to a standing-wave pattern. The plasmoids are enhanced by an effective focusing in the near field of the horn (Fresnel region) as a result of a diffractive narrowing. Optical imaging, electron density, and rotational temperature measurements characterize the near field plasma region. Volumetric microwave discharges may have application to combustion ignition in scramjet engines.

  3. A new optical recording medium

    NASA Technical Reports Server (NTRS)

    Aronson, H.; Loiacono, G. M.

    1973-01-01

    Method has been developed for doping lithium niobiate crystals with transition metal to increase rate at which crystal can record optical data. Discovery may facilitate development of system for analog storage of TV frames, printed pages, photographs, and other visual information.

  4. Parallel generation of nanochannels in fused silica with a single femtosecond laser pulse: Exploiting the optical near fields of triangular nanoparticles

    SciTech Connect

    Hubenthal, F.; Morarescu, R.; Englert, L.; Haag, L.; Baumert, T.; Traeger, F.

    2009-08-10

    We present experiments to prepare highly ordered nanochannels with subdiffraction dimensions on fused silica surfaces with femtosecond laser light. For this purpose, we exploit the strongly enhanced near field of highly ordered triangular gold nanoparticles. We demonstrate that after a single laser shot, 6 {mu}m long nanochannels with a mean depth of 4 nm and an average width of 96 nm, i.e., well below the diffraction limit, are generated. These nanochannels are prepared by ablation, caused by the localization of the near field. The crucial parameters, besides the applied fluence, are the polarization direction of the incoming laser light with respect to the triangular nanoparticles and the size of the nanoparticles.

  5. Rewriteable optical disk recorder development

    NASA Technical Reports Server (NTRS)

    Shull, Thomas A.; Rinsland, Pamela L.

    1991-01-01

    A NASA program to develop a high performance (high rate, high capability) rewriteable optical disk recorder for spaceflight applications is presented. An expandable, adaptable system concept is proposed based on disk Drive modules and a modular Controller. Drive performance goals are 10 gigabyte capacity are up to 1.8 gigabits per second rate with concurrent I/O, synchronous data transfer, and 2 to 5 years operating life in orbit. Technology developments, design concepts, current status, and future plans are presented.

  6. Optothermal property and decomposition characteristics of PtO(x) ultrathin film sandwiched between ZnS-SiO2 for super-resolution near-field recording.

    PubMed

    Her, Yung-Chiun; Liao, Bou-Yin; Hsu, Wei-Chih; Tsai, Song-Yeu

    2007-01-01

    We have investigated the optothermal property and decomposition characteristics of PtO(x) ultrathin film protected by ZnS-SiO2 layers and effects of the constituent phases of PtO(x) on super-resolution capability and read stability of the super-RENS disk. All the ZnS-SiO2/PtO(x)/ZnS-SiO2 multilayers exhibited a steep reflectivity drop at the temperature range between 265 and 350 degrees C, corresponding to the decomposition of PtO(x). The decomposition temperature of the 4-nm-thick PtO(x) ultrathin film protected by ZnS-SiO2 layers was much lower than those obtained in thick PtO(x) films without protection. The activation energy for thermal decomposition was approximately 1.3 eV. Both the decomposition temperature and activation energy for thermal decomposition were unaffected by the constituent phases of PtO(x). Carrier to noise ratios (CNR) of over 40 dB for mark size of 150 nm were achieved in all super-resolution near-field structure (super-RENS) disks, while the super-resolution readout was limited to 2.5 x 10(3) approximately 4.5 x 10(4) cycles. The effect of constituent phases of PtO(x) on the super-resolution capability of super-RENS disk with a PtO(x) mask layer was minimal. However, as the constituent phases of PtO(x) mask layer transformed from a mixture of Pt and PtO, to pure PtO, and then to a mixture of PtO and PtO2, the readout stability of super-RENS disk increased dramatically since less heat was absorbed by the PtO(x) mask layer composed of PtO and PtO2 during the readout process, prohibiting the diffusion of materials inside the bubble to the GeSbTe phase change layer. PMID:17455507

  7. Bicollimated near-field Gregorian reflector antenna

    NASA Astrophysics Data System (ADS)

    Rao, J. B. L.

    1983-02-01

    A bicollimated near-field Gregorian reflector is structurally similar to a classical confocal parabolic reflector, but its surfaces are shaped to have better scan capability. A geometrical optics procedure is used in designing the reflector surfaces. A three dimensional ray tracing procedure is used in analyzing the aperture phase errors as the beam is scanned to different angles. The results show that the bicollimated configuration has about 45% greater angular scanning range than the corresponding confocal parabolic dual-reflector system.

  8. Spaceflight optical disk recorder development

    NASA Technical Reports Server (NTRS)

    Jurczyk, Stephen G.; Hines, Glenn D.; Shull, Thomas A.

    1992-01-01

    Mass memory systems based on rewriteable optical disk media are expected to play an important role in meeting the data system requirements for future NASA spaceflight missions. NASA has established a program to develop a high performance (high rate, large capacity) optical disk recorder focused on use aboard unmanned Earth orbiting platforms. An expandable, adaptable system concept is proposed based on disk drive modules and a modular controller. Drive performance goals are 10 gigabyte capacity, 300 megabit/s transfer rate, 10 exp -12 corrected bit error rate, and 150 millisec access time. This performance is achieved by writing eight data tracks in parallel on both sides of a 14 in. optical disk using two independent heads. System goals are 160 gigabyte capacity, 1.2 gigabits/s data rate with concurrent I/O, 250 millisec access time, and two to five year operating life on orbit. The system can be configured to meet various applications. This versatility is provided by the controller. The controller provides command processing, multiple drive synchronization, data buffering, basic file management, error processing, and status reporting. Technology developments, design concepts, current status including a computer model of the system and a Controller breadboard, and future plans for the Drive and Controller are presented.

  9. Morphological and biochemical analysis by atomic force microscopy and scanning near-field optical microscopy techniques of human keratinocytes (HaCaT) exposed to extremely low frequency 50 Hz magnetic field

    NASA Astrophysics Data System (ADS)

    Rieti, Sabrina; Manni, Vanessa; Lisi, Antonella; Grimaldi, Settimio; Generosi, Renato; Luce, Marco; Perfetti, Paolo; Cricenti, Antonio; Pozzi, Deleana; Giuliani, Livio

    2002-10-01

    We studied the effect of the interaction of electromagnetic radiation with human keratinocytes (HaCaT), at low (50 Hz, 1 mT) frequency using both atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM) techniques. AFM analysis showed modifications in shape and morphology in exposed cells, while SNOM indirect immunofluorescence analysis revealed an increase of segregation of β4 integrin (an adhesion marker) in the cell membrane of the same cells, suggesting that a higher percentage of the exposed cells shows a modified pattern of this adhesion marker.

  10. Nonoptically probing near-field microscopy for the observation of biological living specimens

    NASA Astrophysics Data System (ADS)

    Kawata, Yoshimasa; Murakami, Manabu; Egami, Chikara; Sugihara, Okihiro; Okamoto, Naomichi; Tsuchimori, Masaaki; Watanabe, Osamu; Nakamura, Osamu

    2001-04-01

    We present the observation of living specimens with subwavelength resolution by using the nonoptically probing near-field microscopy we have developed recently. In the near-field microscope, the optical field distributions near the specimens are recorded as the surface topography of a photosensitive film, and the topographical distributions are readout with an atomic-force microscopy. Since the near-field microscope does not require the scanning of a probe tip for illumination or detection or scattering of light, it is possible to observe moving biological specimens and fast phenomena. We demonstrate the observation of a moving paramecium and euglena gracilis with subwavelength resolution. The observation of the nucleus inside a euglena cell was also demonstrated.

  11. Far-Field Spectroscopy and Near-Field Optical Imaging of Coupled Plasmon-Phonon Polaritons in 2D van der Waals Heterostructures.

    PubMed

    Yang, Xiaoxia; Zhai, Feng; Hu, Hai; Hu, Debo; Liu, Ruina; Zhang, Shunping; Sun, Mengtao; Sun, Zhipei; Chen, Jianing; Dai, Qing

    2016-04-01

    A new hybridized plasmon-phonon polariton mode in graphene/h-BN van der Waals heterostructures is presented, featuring the ultrahigh field confinement characteristic of the graphene plasmon and the long lifetime property of the h-BN transverse optical phonon. This enables an ultralong hybrid plasmon lifetime of up to 1.6 ps (with ultrahigh mode confinement up to >l0 (2) /7000 and ultrasmall group velocity down to 0.001c, where c is the speed of light in vacuum), superior to any localized plasmon ever demonstrated. PMID:26889663

  12. Curved laser microjet in near field.

    PubMed

    Kotlyar, Victor V; Stafeev, Sergey S; Kovalev, Alexey A

    2013-06-20

    With the use of the finite-difference time-domain-based simulation and a scanning near-field optical microscope that has a metal cantilever tip, the diffraction of a linearly polarized plane wave of wavelength λ by a glass corner step of height 2λ is shown to generate a low divergence laser jet of a root-parabolic form: over a distance of 4.7λ on the optical axis, the beam path is shifted by 2.1λ. The curved laser jet of the FWHM length depth of focus=9.5λ has the diameter FWHM=1.94λ over the distance 5.5λ, and the intensity maximum is 5 times higher than the incident wave intensity. The discrepancy between the analytical and the experimental results amounts to 11%. PMID:23842153

  13. Digital optical recorder-reproducer system

    NASA Technical Reports Server (NTRS)

    Reddersen, Brad R. (Inventor); Zech, Richard G. (Inventor); Roberts, Howard N. (Inventor)

    1980-01-01

    A mass archival optical recording and reproduction system includes a recording light source such as a laser beam focussed and directed upon an acousto-optic linear modulator array (or page composer) that receives parallel blocks of data converted from a serial stream of digital data to be stored. The page composer imparts to the laser beam modulation representative of a plurality of parallel channels of data and through focussing optics downstream of the page composer parallel arrays of optical spots are recorded upon a suitable recording medium such as a photographic film floppy disc. The recording medium may be substantially frictionlessly and stably positioned for recording at a record/read station by an air-bearing platen arrangement which is preferably thermodynamically non-throttling so that the recording film may be positioned in the path of the information-carrying light beam in a static or dynamic mode. During readout, the page composer is bypassed and a readout light beam is focussed directly upon the recording medium containing an array of previously recorded digital spots, a sync bit, data positioning bits, and a tracking band. The readout beam which has been directed through the recording medium is then imaged upon a photodetector array, the output of which may be coupled to suitable electronic processing circuitry, such as a digital multiplexer, whereby the parallel spot array is converted back into the original serial data stream.

  14. Shape effects of GeSbTe nanodots on the near-field interaction with a silver triangle antenna

    NASA Astrophysics Data System (ADS)

    Kojima, Naoto; Ota, Norio; Asakawa, Kiyoshi; Shiraishi, Kenji; Yamada, Keisaku

    2015-04-01

    We investigated the shape effects of GeSbTe nanodots on the near-field interaction with a silver triangle antenna using the three-dimensional finite-difference time-domain method, avoiding the difficulty of detecting near-field signals from a single dot that occurs in current measurements. The surface plasmon resonance of silver strengthens the near-field around nanodots made of GeSbTe, commonly used in phase-change recording. Using GeSbTe spheres and pillar dots with various top plane shapes, we investigated the relationship between the inner electric field concentration of GeSbTe nanodots and the radius of curvature of the corners facing the antenna tip. Reducing the radius of curvature strengthens the inner electric field of the dots, enhancing the near-field difference in intensity for the GeSbTe phase change. GeSbTe diamond pillars with a radius of curvature of 1 nm exhibit a near-field difference in intensity of 28% for the phase change. Using the antenna and the GeSbTe nanodot array, optical write-once recording is realized. The preliminary research in this study is expected to realize future optical disk storage using GeSbTe nanodots with diameters below 10 nm.

  15. Characterization of semiconductor materials using synchrotron radiation-based near-field infrared microscopy and nano-FTIR spectroscopy.

    PubMed

    Hermann, Peter; Hoehl, Arne; Ulrich, Georg; Fleischmann, Claudia; Hermelink, Antje; Kästner, Bernd; Patoka, Piotr; Hornemann, Andrea; Beckhoff, Burkhard; Rühl, Eckart; Ulm, Gerhard

    2014-07-28

    We describe the application of scattering-type near-field optical microscopy to characterize various semiconducting materials using the electron storage ring Metrology Light Source (MLS) as a broadband synchrotron radiation source. For verifying high-resolution imaging and nano-FTIR spectroscopy we performed scans across nanoscale Si-based surface structures. The obtained results demonstrate that a spatial resolution below 40 nm can be achieved, despite the use of a radiation source with an extremely broad emission spectrum. This approach allows not only for the collection of optical information but also enables the acquisition of near-field spectral data in the mid-infrared range. The high sensitivity for spectroscopic material discrimination using synchrotron radiation is presented by recording near-field spectra from thin films composed of different materials used in semiconductor technology, such as SiO2, SiC, SixNy, and TiO2. PMID:25089414

  16. Near field zones of quiet

    NASA Astrophysics Data System (ADS)

    Joseph, P.; Elliott, S. J.; Nelson, P. A.

    1994-05-01

    This paper examines the consequences of driving a single secondary loudspeaker to cancel the pressure due to some primary source at a point in its near field. This simple technique has been applied to the sound field in a highly reverberant room to produce zones of quiet in the vicinity of the loudspeaker, which have diameters that are typically equal to one-tenth of the acoustic wavelength, within which the sound pressure level is attenuated by at least 10 dB. The principal advantage gained with this strategy over other active techniques for controlling the sound field in rooms is that the sound pressure level well away from the control point is largely unaffected, an increase of only a small fraction of one dB being typical. Such a loudspeaker-microphone configuration could be located, for example, in the head rests of cars or aeroplanes, or indeed anywhere where the listener is seated for significant lengths of time and subjected to high ambient noise levels such that auditory comfort may be disturbed.

  17. Report of near field group

    SciTech Connect

    Palmer, R.B.; Baggett, N.; Claus, J.; Fernow, R.; Stumer, I.; Figueroa, H.; Kroll, N.; Funk, W.; Lee-Whiting, G.; Pickup, M.

    1985-04-01

    Substantial progress since the Los Alamos Workshop two years ago is reported. A radio-frequency model of a grating accelerator has been tested at Cornell, and extensive calculations compared with observations. Alternative structures consisting of either hemispherical bumps on a plane, or conducting spheres in space, have also been rf modeled. The use of liquid droplets to form such structures has been proposed and a conceptual design studied. Calculations and experiments have examined the effects of surface plasmas, and shown that in this case the reflectivity is low. However, calculations and observations suggest that gradients in excess of 1 GeV/meter should be obtainable without forming such plasma. An examination of wake fields shows that, with Landau damping, these are independent of wavelength. The use of near field structures to act as high gradient focusing elements has been studied and shows promise, independent of the acceleration mechanism. A proposal has been made to establish a facility that would enable ''proof of principle experiments'' to be performed on these and other laser driven accelerator mechanisms. 11 refs., 10 figs.

  18. Optical recording in copper-silica nanocomposite

    NASA Astrophysics Data System (ADS)

    Dmitruk, Igor; Blonskiy, Ivan; Korenyuk, Petro; Kadan, Viktor; Zubrilin, Mykola; Dmytruk, Andriy; Yeshchenko, Oleg; Alexeenko, Alexandr; Kotko, Andriy

    2014-05-01

    The application of field enhancement effect, which takes place when light, interacts with surface plasmon, for optical recording has been suggested. Copper-silica nanocomposite demonstrates possibility of optical writing and erasing under irradiation by second harmonic (400 nm) and fundamental wavelength (800 nm) of femtosecond titanium-sapphire laser, respectively.

  19. Photonic near-field imaging in multiphoton photoemission electron microscopy

    NASA Astrophysics Data System (ADS)

    Fitzgerald, J. P. S.; Word, R. C.; Saliba, S. D.; Könenkamp, R.

    2013-05-01

    We report the observation of optical near fields in a photonic waveguide of conductive indium tin oxide (ITO) using multiphoton photoemission electron microscopy (PEEM). Nonlinear two-photon photoelectron emission is enhanced at field maxima created by interference between incident 410-nm and coherently excited guided photonic waves, providing strong phase contrast. Guided modes are observed under both transverse magnetic field (TM) and transverse electric field (TE) polarized illuminations and are consistent with classical electromagnetic theory. Implications on the role of multiphoton PEEM in optical near-field imaging are discussed.

  20. Shaping the nonlinear near field.

    PubMed

    Wolf, Daniela; Schumacher, Thorsten; Lippitz, Markus

    2016-01-01

    Light scattering at plasmonic nanoparticles and their assemblies has led to a wealth of applications in metamaterials and nano-optics. Although shaping of fields around nanostructures is widely studied, the influence of the field inside the nanostructures is often overlooked. The linear field distribution inside the structure taken to the third power causes third-harmonic generation, a nonlinear optical response of matter. Here we demonstrate by a far field Fourier imaging method how this simple fact can be used to shape complex fields around a single particle alone. We employ this scheme to switch the third-harmonic emission from a single point source to two spatially separated but coherent sources, as in Young's double-slit assembly. We envision applications as diverse as coherently feeding antenna arrays and optical spectroscopy of spatially extended electronic states. PMID:26762487

  1. Shaping the nonlinear near field

    PubMed Central

    Wolf, Daniela; Schumacher, Thorsten; Lippitz, Markus

    2016-01-01

    Light scattering at plasmonic nanoparticles and their assemblies has led to a wealth of applications in metamaterials and nano-optics. Although shaping of fields around nanostructures is widely studied, the influence of the field inside the nanostructures is often overlooked. The linear field distribution inside the structure taken to the third power causes third-harmonic generation, a nonlinear optical response of matter. Here we demonstrate by a far field Fourier imaging method how this simple fact can be used to shape complex fields around a single particle alone. We employ this scheme to switch the third-harmonic emission from a single point source to two spatially separated but coherent sources, as in Young's double-slit assembly. We envision applications as diverse as coherently feeding antenna arrays and optical spectroscopy of spatially extended electronic states. PMID:26762487

  2. A sensitive near-field microscope for thermal radiation.

    PubMed

    Kajihara, Yusuke; Kosaka, Keishi; Komiyama, Susumu

    2010-03-01

    A scattering-type scanning near-field optical microscope in long-wavelength infrared (LWIR) region is developed by using an extremely sensitive detector, called the charge-sensitive infrared phototransistor. A tungsten probe attached to a quartz tuning fork is controlled in shear-force mode. Evanescent wave at a sample surface is periodically scattered by slowly (2 Hz) modulating the probe in the direction normal to the sample surface. Near-field microscopy of thermal LWIR radiation from room-temperature Au/GaAs gratings is demonstrated without using any external illumination or excitation. Achieved spatial resolution is better than 300 nm. PMID:20370184

  3. Near Field Communication: Introduction and Implications

    ERIC Educational Resources Information Center

    McHugh, Sheli; Yarmey, Kristen

    2012-01-01

    Near field communication is an emerging technology that allows objects, such as mobile phones, computers, tags, or posters, to exchange information wirelessly across a small distance. Though primarily associated with mobile payment, near field communication has many different potential commercial applications, ranging from marketing to nutrition,…

  4. Near-Field Spectroscopy with Nanoparticles Deposited by AFM

    NASA Technical Reports Server (NTRS)

    Anderson, Mark S.

    2008-01-01

    An alternative approach to apertureless near-field optical spectroscopy involving an atomic-force microscope (AFM) entails less complexity of equipment than does a prior approach. The alternative approach has been demonstrated to be applicable to apertureless near-field optical spectroscopy of the type using an AFM and surface enhanced Raman scattering (SERS), and is expected to be equally applicable in cases in which infrared or fluorescence spectroscopy is used. Apertureless near-field optical spectroscopy is a means of performing spatially resolved analyses of chemical compositions of surface regions of nanostructured materials. In apertureless near-field spectroscopy, it is common practice to utilize nanostructured probe tips or nanoparticles (usually of gold) having shapes and dimensions chosen to exploit plasmon resonances so as to increase spectroscopic-signal strengths. To implement the particular prior approach to which the present approach is an alternative, it is necessary to integrate a Raman spectrometer with an AFM and to utilize a special SERS-active probe tip. The resulting instrumentation system is complex, and the tasks of designing and constructing the system and using the system to acquire spectro-chemical information from nanometer-scale regions on a surface are correspondingly demanding.

  5. Using optical metrology to reconstruct sound recordings

    NASA Astrophysics Data System (ADS)

    Cornell, E. W.; Fadeyev, V.; Haber, C.; Jin, J.; Nordmeyer, R.; Golden, M.

    2007-09-01

    Prior to 1950 nearly all sound recordings were made on mechanical media such as wax, foil, shellac, lacquer, and plastic. Some of these older recordings contain material of great historical value or interest but are damaged, decaying, or now considered too delicate to play. Archives seek to preserve and also create broad access to their collections. An ongoing effort at Berkeley Lab has applied methods of optical metrology and image processing to reconstruct sound stored on these mechanical carriers. This approach was inspired by the use of precision optical metrology to align and fabricate silicon tracking arrays for high-energy physics experiments and by track finding and fitting data analysis methods. The technology has matured to the point that an optical metrology system for sound restoration has been designed and built for the Library of Congress.

  6. Near-field energy extraction with hyperbolic metamaterials.

    PubMed

    Shi, Jiawei; Liu, Baoan; Li, Pengfei; Ng, Li Yen; Shen, Sheng

    2015-02-11

    Although blackbody radiation described by Planck's law is commonly regarded as the maximum of thermal radiation, thermal energy transfer in the near-field can exceed the blackbody limit due to the contribution from evanescent waves. Here, we demonstrate experimentally a broadband thermal energy extraction device based on hyperbolic metamaterials that can significantly enhance near-field thermal energy transfer. The thermal extractor made from hyperbolic metamaterials does not absorb or emit any radiation but serves as a transparent pipe guiding the radiative energy from the emitter. At the same gap between an emitter and an absorber, we observe that near-field thermal energy transfer with thermal extraction can be enhanced by around 1 order of magnitude, compared to the case without thermal extraction. The novel thermal extraction scheme has important practical implications in a variety of technologies, e.g., thermophotovoltaic energy conversion, radiative cooling, thermal infrared imaging, and heat assisted magnetic recording. PMID:25622221

  7. Photon-induced near-field electron microscopy.

    PubMed

    Barwick, Brett; Flannigan, David J; Zewail, Ahmed H

    2009-12-17

    In materials science and biology, optical near-field microscopies enable spatial resolutions beyond the diffraction limit, but they cannot provide the atomic-scale imaging capabilities of electron microscopy. Given the nature of interactions between electrons and photons, and considering their connections through nanostructures, it should be possible to achieve imaging of evanescent electromagnetic fields with electron pulses when such fields are resolved in both space (nanometre and below) and time (femtosecond). Here we report the development of photon-induced near-field electron microscopy (PINEM), and the associated phenomena. We show that the precise spatiotemporal overlap of femtosecond single-electron packets with intense optical pulses at a nanostructure (individual carbon nanotube or silver nanowire in this instance) results in the direct absorption of integer multiples of photon quanta (nhomega) by the relativistic electrons accelerated to 200 keV. By energy-filtering only those electrons resulting from this absorption, it is possible to image directly in space the near-field electric field distribution, obtain the temporal behaviour of the field on the femtosecond timescale, and map its spatial polarization dependence. We believe that the observation of the photon-induced near-field effect in ultrafast electron microscopy demonstrates the potential for many applications, including those of direct space-time imaging of localized fields at interfaces and visualization of phenomena related to photonics, plasmonics and nanostructures. PMID:20016598

  8. Electron beam recording of optical disc

    NASA Astrophysics Data System (ADS)

    Cartwright, Giles; Reynolds, Gerald; Baylis, Chris; Pearce, Adrian; Dix, Colin; Ogilvie, Nick

    2002-09-01

    The Nimbus Technology & Engineering e -Beam Mastering System was developed to gain a large improvement in optical disc and structured hard disc recording capacity, significantly more than is possible from deep UV and SIL mastering. The current electron beam recorder is essentially a production machine capable of making full-length exposures at capacities of up to 50 GB with a simple low-cost upgrade path to disc capacities of several hundred gigabytes and beyond and hard disk drives (HDD) with capacities of up to 1 tera bit per square inch.

  9. Near field heat transfer in superlattices

    NASA Astrophysics Data System (ADS)

    Esquivel-Sirvent, Raul

    2015-03-01

    I present a theoretical calculation of the near field heat transfer between super lattices made of alternative layers of both metallic and semiconducting materials. The calculation of the near field transfer requires the knowledge of the reflectivities, that are obtained by calculating the surface impedance of the super lattice. Depending on the periodicity of the lattice and the dielectric function of the materials the near field heat transfer can be modulated or engineered. Additional control on the heat transfer is achieved by introducing defects in the superlattice. The results are extended to include photonic hypercrystals that effectively behave like a hyperbolic metamaterial even in the near field (1), where the tuning of the heat transfer is modified by Partial Support from DGAPA-UNAM project IN 111214.

  10. Millimeter wave near-field study

    NASA Technical Reports Server (NTRS)

    Kefauver, Neill

    1990-01-01

    The possibility is evaluated of current technology measuring large aperture millimeter wave antennas. Included are a mathematical modeling of system errors, experimental data supporting error model, predictions of system accuracy at millimeter wavelengths, advantage of near-field measurements, and a cost estimate for a facility upgrade. The use is emphasized of software compensation and other inexpensive alternatives to develop a near optimum solution to near-field measurement problems at millimeter wavelengths.