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Applied Optics

APPLICATIONS-CENTERED RESEARCH IN OPTICS

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Articles 1 to 20 of 153 Next Page >>

March


Phase imaging using spiral phase diversity

  • Kedar Khare, Manoj Sharma, CHARU GAUR, and Paramasivam Senthilkumaran
  • received 01/09/2015; accepted 03/29/2015; posted 03/30/2015; Doc. ID 231494
  • [full text: PDF (3879) KB)]
  • Abstract: We demonstrate that the two-dimensional quadrature transform property of spiral phase filter may be utilized for addressing the non-interferometric iterative phase imaging problem. Two Fourier transform intensity measurements for an unknown input object are performed with and without a spiral phase mask in the aperture of a Fourier transforming lens. It is shown that the two intensity measurements along with the aperture support constraint can be used for estimating the phase of the unknown input object with an iterative algorithm. Numerical simulations are presented for comparison of the new spiral phase diversity technique and the more standard defocus diversity method. Experimental results for the spiral phase diversity are also shown to illustrate the effectiveness of this approach for imaging of amplitude/phase objects.

Keywords (OCIS):

  • (070.0070) Fourier optics and signal processing : Fourier optics and signal processing
  • (100.5070) Image processing : Phase retrieval
  • (110.1758) Imaging systems : Computational imaging

Comparative study on passive and active projector nonlinear gamma calibration

  • Song Zhang
  • received 01/14/2015; accepted 03/29/2015; posted 03/30/2015; Doc. ID 232540
  • [full text: PDF (3846) KB)]
  • Abstract: This paper presents our comparing study on active and passive projector nonlinear gamma compensation methods to reduce phase error. The {\em active method} modifies the fringe patterns before their projection to ensure sinusoidality after projection; and the {\em passive method}, in contrast, compensates for the phase error after capturing those distorted sinusoidal fringe patterns. Our study finds that the active method tends to provide more consistent high-quality fringe patterns regardless the amount of projector's defocusing; yet the effectiveness of a passive method is diminished if the measurement condition deviates from the calibration condition. Experimental results will be presented to demonstrate the differences of these two nonlinear gamma compensation methods.

Keywords (OCIS):

  • (100.2650) Image processing : Fringe analysis
  • (120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
  • (120.5050) Instrumentation, measurement, and metrology : Phase measurement

Signature simulation of infrared target by tracing multiple areal sources

  • Xin Wu and Jianqi Zhang
  • received 01/23/2015; accepted 03/29/2015; posted 03/30/2015; Doc. ID 233151
  • [full text: PDF (1110) KB)]
  • Abstract: Abstract The traditional ray tracing approach for infrared target simulation takes into account the radiance emitted from the target itself in the scene, resulting in an incomplete infrared signature of a target. We here present an practical method to enable the identification of the signature by considering radiation exchanges among all sources in the scene. Any source would contribute radiance to a target of interest. Therefore, the radiance of a target received by an infrared imager includes both self emission and reflectance, where the reflectance is contributed due to radiation exchanges from other sources. Field experiments were performed to demonstrate our proposed method by comparisons of radiance profiles between our simulated images and the real scene images. It shows that our simulated images achieve a better match with the data than the ones generated by the traditional approach.

Keywords (OCIS):

  • (110.3080) Imaging systems : Infrared imaging
  • (260.3060) Physical optics : Infrared
  • (350.4600) Other areas of optics : Optical engineering
  • (350.5610) Other areas of optics : Radiation

Zernike power spectra of clear and cloudy light-polluted urban night skies

  • Salvador Bara Vinas, Víctor Tilve, Miguel Nievas, Alejandro Sanchez de Miguel, and Jaime Zamorano
  • received 12/23/2014; accepted 03/28/2015; posted 03/30/2015; Doc. ID 231318
  • [full text: PDF (3290) KB)]
  • Abstract: The Zernike power spectra of the all-sky night brightness distributions of clear and cloudy nights are computed using a modal projection approach. The results obtained in the B, V and R Johnson-Cousins' photometric bands during a one-year campaign of observations at a light-polluted urban site show that these spectra can be described by simple power laws with exponents close to -3 for clear nights and -2 for cloudy ones. The second-moment matrices of the Zernike coefficients show relevant correlations between modes. The multiplicative role of the cloud cover, that contributes to a significant increase of the brightness of the urban night sky in comparison with the values obtained in clear nights, is described in the Zernike space.

Keywords (OCIS):

  • (010.1290) Atmospheric and oceanic optics : Atmospheric optics
  • (110.0110) Imaging systems : Imaging systems
  • (110.2960) Imaging systems : Image analysis

Aberration calibration in high NA spherical surfaces measurement on point diffraction interferometry

  • Yongying Yang, Xiaoyu Chen, Chen Wang, Dong Liu, Jian Bai, and Yibing Shen
  • received 01/28/2015; accepted 03/27/2015; posted 03/30/2015; Doc. ID 233276
  • [full text: PDF (2513) KB)]
  • Abstract: Systematic error in the point diffraction interferometer can significantly influence the measurement accuracy in the case that a high-numerical-aperture spherical surface is tested, in which wavefront aberrations could be observed and cannot be removed with the traditional calibration method. A calibration method, called symmetrical position aberration cancellation (SPAC) method, is proposed to remove the systematic error. With the SPAC method, the calibration needs two separate measurements with interferograms of opposite tilts and the systematic error can be reduced by averaging the test wavefronts of these two measurements. A geometrical optics model is presented for facilitating the calculation of the geometric aberrations that are introduced by the lateral deviation between the curvature center of the test surface and the center of the pinhole. Then a simulation model is built to analyze the influence of the lateral deviation and the numerical aperture of the surface under test on the systematic error. Both the computer simulation and experiments with PDI have been carried out to validate the proposed calibration method. In the final comparative experiment with ZYGO interferometer, the PDI exhibits high precision in high-numerical-aperture spherical surfaces measurement based on the proposed calibration method.

Keywords (OCIS):

  • (120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
  • (120.3180) Instrumentation, measurement, and metrology : Interferometry
  • (120.5050) Instrumentation, measurement, and metrology : Phase measurement
  • (120.6650) Instrumentation, measurement, and metrology : Surface measurements, figure

Uncertainty in the bidirectional reflectance model for oceanic waters

  • Pengwang Zhai, Yongxiang Hu, Charles Trepte, David Winker, Patricia Lucker, Zhongping Lee, and Damien Josset
  • received 02/04/2015; accepted 03/27/2015; posted 03/30/2015; Doc. ID 233902
  • [full text: PDF (522) KB)]
  • Abstract: We study the impacts of the bio-optical model variations on the angular distribution (f/Q factor) of the upwelling radiance field in ocean waters. An ocean water bio-optical model has been built and it is combined with a vector radiative transfer model to calculate the f/Q factors systematically. The f/Q factors are compared to those in [Morel, Antoine, and Gentili, Appl. Opt., 41, 6289, 2002] and the differences are found to be within ±10% for 81% of the total number of cases covering all wavelengths, Chlorophyll a concentrations, and solar and viewing geometries. The differences are attributed to the choice of ocean water scattering function and scattering coefficient biases. In addition, we study the uncertainty of f/Q factor due to three factors: I. the absorption of the colored dissolved organic matter (CDOM); II. the particle scattering coefficient; III. the ocean water depolarization. The impacts of ocean water depolarization on the f/Q variation is found to be negligible. If we perturb the CDOM absorption by a factor ranging from 0.1 to 10, the f/Q values vary within ±5% of the average behavior of ocean waters for 93% of the cases. If we perturb the scattering coefficients by a factor ranging from 0.5 to 2.0, the f/Q variation is within ±5% for 81% of the cases studied. This study contributes to understand the uncertainty of ocean color remote sensing.

Keywords (OCIS):

  • (010.4450) Atmospheric and oceanic optics : Oceanic optics
  • (290.0290) Scattering : Scattering
  • (290.4210) Scattering : Multiple scattering
  • (010.4458) Atmospheric and oceanic optics : Oceanic scattering
  • (010.5620) Atmospheric and oceanic optics : Radiative transfer

One-step fabrication of annular microstructures based on improved femtosecond laser Bessel-Gaussian beam shaping

  • Ji'an Duan, Zhi LUO, Cong Wang, Xiaoyan Sun, Youwang Hu, and Kai Yin
  • received 02/12/2015; accepted 03/27/2015; posted 03/30/2015; Doc. ID 234121
  • [full text: PDF (2735) KB)]
  • Abstract: In this study, a favorable approach is proposed for the high-efficiency fabrication of annular microstructures by shaping femtosecond Gaussian laser into Bessel-Gaussian beam. An adjustable annular beam is generated by a combination of an axicon, a lens and an objective. Uniform annular microstructures are fabricated on the surface of fused silica in a single illumination step with only one pulse and without stage translation, the parameters of which are coincident with theoretical design. By adjusting the relative distance between the lens and objective, the diameters of the annular microstructures can be flexibly controlled in a wide range.

Keywords (OCIS):

  • (220.4000) Optical design and fabrication : Microstructure fabrication
  • (320.2250) Ultrafast optics : Femtosecond phenomena
  • (320.5540) Ultrafast optics : Pulse shaping

Flicker-glare and visual-comfort assessments of light emitting diode billboards II: color display

  • Yi-Chun Chen, Meng-Wei Lin, Ming-Wei Lee, and Erik Chang
  • received 11/07/2014; accepted 03/26/2015; posted 03/26/2015; Doc. ID 226509
  • [full text: PDF (1132) KB)]
  • Abstract: The flicker glare and visual comfort of multicolor LED billboards are investigated in this study. The influences of two factors, flicker frequency and panel luminance, on visual discomfort and tiredness are examined. The results of ergonomic assessments show that visual comfort is affected by both the flicker frequency and luminance, but visual tiredness is not influenced by either factor. By curve fitting the experimental data, comfort rating models as functions of the flicker frequency and luminance are proposed. Furthermore, the ranges of proper operating conditions are suggested based on the predictions of the proposed models.

Keywords (OCIS):

  • (330.0330) Vision, color, and visual optics : Vision, color, and visual optics
  • (330.5020) Vision, color, and visual optics : Perception psychology
  • (330.5510) Vision, color, and visual optics : Psychophysics

Optical properties of edible oils within spectral range from 300 to 2500 nm determined by double optical pathlength transmission method

  • Lin Hua Liu, Xingcan Li, Junming Zhao, and Jianyu Tan
  • received 12/12/2014; accepted 03/26/2015; posted 03/26/2015; Doc. ID 230596
  • [full text: PDF (7691) KB)]
  • Abstract: The optical properties of nine different samples of edible oils were experimentally determined by double optical pathlength transmission method (DOPTM) in the spectral range from 300 to 2500 nm between 20 and 80 °C. The index of refraction exhibits little difference from the different types of edible oils. The index of absorption of all brands of studied edible oils decreased with the increasing temperature in the spectral range from 500 to 1100 nm. The variation of index of absorption was found to be insensitive to the increasing of temperature in the spectral range from 300 to 500 nm and from 1100 to 2500 nm. The absorption peaks locating at 900, 1210, 1400, 1750, 2150 and 2300 nm of the measured edible oils were corresponding to the result of overtones and combinations of C–H stretching vibration of various chemical groups. A difference of index of absorption was observed among the peanut oil, soybean oil and sunflower oil in the spectral range from 300 to 500 nm.

Keywords (OCIS):

  • (120.4530) Instrumentation, measurement, and metrology : Optical constants
  • (300.1030) Spectroscopy : Absorption
  • (300.6340) Spectroscopy : Spectroscopy, infrared
  • (300.6540) Spectroscopy : Spectroscopy, ultraviolet
  • (300.6550) Spectroscopy : Spectroscopy, visible

A study on the feasibility of LED in the wound healing application

  • Xin Gu, Xiaoli Zhou, Xihong Bao, Shenglong Fan, Muqing Liu, and Lixin Wang
  • received 12/29/2014; accepted 03/26/2015; posted 03/27/2015; Doc. ID 231133
  • [full text: PDF (1130) KB)]
  • Abstract: Poor wound healing is a common secondary complication for many diseases. Light therapy is a new way to improve wound healing. In this paper, a 630 nm and 830 nm LED was used to research the influence of low level light therapy on wound healing through cytological and animal experiments. In the cytological experiment, the cell viability and synthesis of hydroxyproline was measured. In the animal experiment, rats were given an artificial wound. Then, the effects of LED irradiation on wound healing were compared with control rats that did not receive the light therapy. The wound healing rate and collagen fiber formation was researched. The optimal parameter combination of wavelength, power and irradiation time was found. The effect of LED application on the wound healing was explored.

Keywords (OCIS):

  • (170.0170) Medical optics and biotechnology : Medical optics and biotechnology
  • (170.3890) Medical optics and biotechnology : Medical optics instrumentation
  • (230.3670) Optical devices : Light-emitting diodes
  • (350.4600) Other areas of optics : Optical engineering

High-Speed Dual-Beam, Crossed Line-Scanning Fluorescence Microscope with a Point Confocal Resolution

  • HyunWoo Jeong, Hyung-Jin Kim, Jung Eun, Seungjin Heo, Mikyoung Lim, Yong-Hoon Cho, and Beop-Min Kim
  • received 01/08/2015; accepted 03/26/2015; posted 03/27/2015; Doc. ID 231800
  • [full text: PDF (567) KB)]
  • Abstract: Line-scanning microscopes are often used to overcome the limited scanning speed of conventional point-scanning confocal microscopes, at the cost, however, of spatial resolution. In this paper, present a dual-beam fluorescence line-scanning microscope that can restore the original confocal resolution. This microscope forms two orthogonal line foci in the object plane with perpendicular scanning directions, which create two line-scan images of the same area. From these images, the real noise and confocal characteristics are analyzed. Based on this information, we developed an image restoration algorithm to produce a final image with spatial resolution comparable to that of a conventional point-scanning confocal microscope. This algorithm was derived with the total variation regularization, and the critical image restoration factor for the algorithm was determined via an iterative process. Our results indicate that the intrinsic resolution limit of line-scanning microscopes can be overcome without subsequent deterioration in spatial resolution.

Keywords (OCIS):

  • (110.0110) Imaging systems : Imaging systems
  • (110.0180) Imaging systems : Microscopy
  • (180.1790) Microscopy : Confocal microscopy
  • (180.2520) Microscopy : Fluorescence microscopy

Double-layered light shutter using long-pitch cholesteric liquid crystal cells

  • Tae-Hoon Yoon, Jae-Won Huh, Byeong-Hun Yu, and Joon Heo
  • received 01/14/2015; accepted 03/26/2015; posted 03/27/2015; Doc. ID 232581
  • [full text: PDF (752) KB)]
  • Abstract: We propose a double-layered light shutter device using two cholesteric liquid crystal (ChLC) cells. The proposed light shutter consists of a light-scattering layer using long-pitch cholesteric LCs and a light-absorption layer using dye-doped ChLCs. The light shutter has four switchable states: light scattering, light absorption, absorption & scattering, and transparent. The light shutter in the absorption & scattering state can block the background image and provide a black color. By switching of the proposed light shutter positioned at the rear side of a transparent display, we can operate a transparent display in various modes, not just showing the images produced by a transparent display along with the background.

Keywords (OCIS):

  • (230.0230) Optical devices : Optical devices
  • (230.3720) Optical devices : Liquid-crystal devices

Packaged and robust microcavity device based on a microcylinder-taper coupling system

  • Yongchao Dong, Wang Wang, and Xueying Jin
  • received 02/04/2015; accepted 03/25/2015; posted 03/26/2015; Doc. ID 234004
  • [full text: PDF (4888) KB)]
  • Abstract: We propose and realize a packaged structure for the microcylinder-taper coupling system by only gluing a glass tube and two glass plates together. Our package method avoids embedding the coupling system into the polymer, thus leaving the whispering gallery mode (WGM) evanescent fields available for environmental sensing. The excitation of localized high-order axial modes in the cylinder resonator fabricated by using a fusion splicer is demonstrated and a quality factor (Q) up to 1.4 × 107 is obtained. The Q maintenance and stable spectrum are realized by sealing the packaged device in a clean box. Moreover, the robustness of the packaged structure is also tested, demonstrating its remarkable anti-vibration ability. The portability and robustness of the device make it attractive in practical applications such as sensors, lasers, and especially some applied areas in strong vibration environments.

Keywords (OCIS):

  • (140.4780) Lasers and laser optics : Optical resonators
  • (140.3948) Lasers and laser optics : Microcavity devices
  • (280.4788) Remote sensing and sensors : Optical sensing and sensors

Polarization circulation effect in microbend-induced long-period fiber gratings for polarization-insensitive filter response

  • Hajime Sakata and Tomohiro Harada
  • received 01/21/2015; accepted 03/25/2015; posted 03/26/2015; Doc. ID 233017
  • [full text: PDF (547) KB)]
  • Abstract: We analyze the reduction mechanism of polarization dependence in loss-peak wavelength for microbend-induced long-period fiber gratings (M-LPFGs) formed in twisted fibers. The analysis model consists of the stress-induced birefringence associated with the microbend as well as the optical activity induced by the twisted fiber. We verify the analysis model by measuring the change in the state of polarization (SOP) through the torsion M-LPFG. We reveal that the efficient circulation of the polarization components occurs in the torsion M-LPFG so that the polarization dependence of the loss-peak wavelengths is reduced. In the experiments, the M-LPFG is controlled by an electromagnet in the combination of a coil spring. The experimental results demonstrate a good agreement with the calculated expectation for the polarization-insensitive M-LPFGs.

Keywords (OCIS):

  • (050.2770) Diffraction and gratings : Gratings
  • (060.2340) Fiber optics and optical communications : Fiber optics components
  • (260.5430) Physical optics : Polarization
  • (050.2555) Diffraction and gratings : Form birefringence
  • (230.7408) Optical devices : Wavelength filtering devices

Modal wavefront reconstruction from its gradient

  • Iacopo Mochi and Kenneth Goldberg
  • received 02/04/2015; accepted 03/24/2015; posted 03/25/2015; Doc. ID 233363
  • [full text: PDF (1095) KB)]
  • Abstract: Several wavefront sensing techniques provide direct or indirect measurements of the wavefront error gradient, for example the Shack Hartmann sensor, the Foucault knife-edge test, shearing interferometry and many others. We developed and tested a non-iterative method to reconstruct the wavefront error from its gradient. The method is based on the projection of the measured gradients onto a basis derived from multiple directional derivatives that have been combined into an intermediate set of orthogonal functions. To reduce errors that arise from linear approximations, the intermediate functions can be calculated with parameters that match the known experimental conditions. This method can be implemented using any convenient set of smooth polynomials defined on a two-dimensional domain and it is not computationally intensive. In this paper we describe the method in detail, provide an example of a possible implementation, and discuss the effect that random noise in the measured gradient has on the reconstruction.

Keywords (OCIS):

  • (110.0110) Imaging systems : Imaging systems
  • (120.3180) Instrumentation, measurement, and metrology : Interferometry
  • (110.7348) Imaging systems : Wavefront encoding

Nonlinear Pulse Propagation in Wavelength Dependence of Birefringence Fiber Optics

  • Rodrigo Acuna Herrera
  • received 02/05/2015; accepted 03/24/2015; posted 03/25/2015; Doc. ID 233889
  • [full text: PDF (352) KB)]
  • Abstract: We performance analytical and numerical analysis of the influence of wavelength dependence of birefringence (WDB) in nonlinear pulse propagation trough fiber optics. We find a set of coupled nonlinear equations which allow to study WDB in fibers. By first time, the concept of cross-dispersion birefringence (CDB) is introduced what makes spectral pulse evolution broadens faster than usual. Some linear and nonlinear phenomenon are analyzed such as polarization trajectories, four wave mixing (FWM), and supercontinuum (SC) generation. We show that WDB changes dramatically the polarization states, and Stoke and anti-Stoke waves linearly move toward longer and shorter wavelengths, respectively. Finally, we see that CDB has the capability to generate SC with immunity to initial polarization angle.

Keywords (OCIS):

  • (060.2310) Fiber optics and optical communications : Fiber optics
  • (060.2420) Fiber optics and optical communications : Fibers, polarization-maintaining
  • (190.4370) Nonlinear optics : Nonlinear optics, fibers
  • (260.1440) Physical optics : Birefringence

Characterization of the photonic generation of phase-coded RF signals based on pulse shaping and frequency-to-time mapping

  • Hao Chi, Yuan Mei, Tao Jin, Shilie Zheng, Xiaofeng Jin, and Xianmin Zhang
  • received 02/05/2015; accepted 03/24/2015; posted 03/25/2015; Doc. ID 234027
  • [full text: PDF (596) KB)]
  • Abstract: Photonic generation of arbitrary waveforms based on pulse shaping and frequency-to-time mapping is of great interest since it offers an effective way to generate complex signals with large bandwidth. In this paper, we mathematically study the photonic generation of phase-coded radiofrequency (RF) signals based on pulse shaping and frequency-to-time mapping in detail. By mathematically analyzing the process of signals generation and utilizing a less restrictive dispersion requirement, a design criterion for the generation of well-shaped phase-coded RF waveforms is presented, by which we can properly set the spatial light modulator (SLM) in the pulse shaper and dispersion in the system according to the carrier frequency and modulating frequency of the desired waveform. In addition, the maximum achievable time-bandwidth product of phase-coded RF signals that can be generated is estimated. The theory is verified by numerical and experimental results. The presented results can be used to guide the design of a photonic system for the generation of high-quality phase-coded RF signals.

Keywords (OCIS):

  • (320.5540) Ultrafast optics : Pulse shaping
  • (060.5625) Fiber optics and optical communications : Radio frequency photonics
  • (070.6120) Fourier optics and signal processing : Spatial light modulators

Optimization of plasmonic high harmonic generation in a 3D pyramidal nano-waveguide by tuning aspect ratio of its rectangle cross section and chirp and polarization of femtosecond incident pulses

  • Reza Massudi and Hanieh Alinejad
  • received 02/09/2015; accepted 03/24/2015; posted 03/25/2015; Doc. ID 234365
  • [full text: PDF (544) KB)]
  • Abstract: Surface Plasmon Polariton propagation in a pyramidal 3D nano-structural waveguide with rectangular cross section carved in silver is studied using FDTD. Effect of the amount of aspect ratio of rectangle sides on enhancement factor is studied and for r=0.4 maximum field enhancement of 96 dB is obtained. Furthermore, it is observed that by adjusting amount of the incident chirp this factor can increases to 100 dB. It was also found that polarization of the incident beam doesn’t change optimum value of aspect ratio, but the maximum enhancement factor for linearly polarized and elliptically polarized beam along y axis is larger.

Keywords (OCIS):

  • (190.2620) Nonlinear optics : Harmonic generation and mixing
  • (190.7110) Nonlinear optics : Ultrafast nonlinear optics
  • (240.6680) Optics at surfaces : Surface plasmons
  • (310.6628) Thin films : Subwavelength structures, nanostructures

A Novel Slant Edge Method for Point Spread Function Estimation

  • Grand Li, Chong Fan, and Chao Tao
  • received 01/07/2015; accepted 03/24/2015; posted 03/27/2015; Doc. ID 229221
  • [full text: PDF (1462) KB)]
  • Abstract: The traditional edge method (TEM) is applicable only in areas whose knife-edges are horizontal or vertical. The slant edge method (SEM) requires using the approximate function in the edge spread function (ESF) fitting. The ESF sample is uneven and therefore affects the accuracy of the estimated point spread function (PSF). This study proposes a novel slant edge method (NSEM), including a knife-edge area extraction algorithm which ensures the evenness of the ESF sample and a PSF estimation algorithm which directly fits the line spread function to improve the accuracy of the estimated PSF. The validity of the NSEM has been proven in theory, and its practicability in practice. Compared with the TEM and SEM, the NSEM exhibits a clear improvement in accuracy and stability across the three experiments conducted in this study.

Keywords (OCIS):

  • (100.3020) Image processing : Image reconstruction-restoration
  • (280.0280) Remote sensing and sensors : Remote sensing and sensors

Passive imaging of concealed subjects in terahertz and long wavelength infrared

  • Marcin Kowalski, Mariusz Kastek, Norbert Palka, Michal Walczakowski, and Mieczyslaw Szustakowski
  • received 01/05/2015; accepted 03/24/2015; posted 03/25/2015; Doc. ID 231808
  • [full text: PDF (1361) KB)]
  • Abstract: Terahertz and infrared radiation have unique properties applicable to the field of surveillance and security systems. We investigated the possibility of detecting potentially dangerous objects covered by various types of clothing using passive imagers operating at 1.2 mm (250 GHz) and long-wavelength infrared (LWIR) at 6–15 μm (20–50 THz). We developed a measurement methodology that assumes to investigate theoretical limitations, performance of imagers and physical properties of fabrics. To evaluate stability of the detection capabilities of imagers, we performed measurement sessions each lasting 30 minutes. We present a theoretical comparison of the two spectra and results of experiments using state of the art equipment.

Keywords (OCIS):

  • (110.3080) Imaging systems : Infrared imaging
  • (110.6820) Imaging systems : Thermal imaging
  • (330.1880) Vision, color, and visual optics : Detection
  • (330.5000) Vision, color, and visual optics : Vision - patterns and recognition
  • (040.2235) Detectors : Far infrared or terahertz
  • (110.6795) Imaging systems : Terahertz imaging

Articles 1 to 20 of 153 Next Page >>





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