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Applied Optics

Qin-Zhi Fang, Jiong Qian, HyeonGyu Beom, Huimin Yu
What we believe is a novel method to measure the dimension of an object with one defocused photo of an object is presented in this paper. To do this, a photo of the object is taken by a camera. The focal plane is chosen as a reference plane. The coordinates of the object surface are obtained by using the camera's parameters and corresponding defocused distance. The depth from the reference plane is obtained by evaluating the confusion degree of the photo around an edge. The relationship between the confusion degree and the distance from the reference plane has been given theoretically and experimentally...
March 1, 2017: Applied Optics
Mathieu Coquand, François Henault, Cyril Caliot
This paper describes a backward-gazing method for measuring the optomechanical errors of solar concentrating surfaces. It makes use of four cameras placed near the solar receiver and simultaneously recording images of the sun reflected by the optical surfaces. Simple data processing then allows reconstructing the slope and shape errors of the surfaces. The originality of the method is enforced by the use of generalized quad-cell formulas and approximate mathematical relations between the slope errors of the mirrors and their reflected wavefront in the case of sun-tracking heliostats at high-incidence angles...
March 1, 2017: Applied Optics
Yan Yang, Chao Geng, Feng Li, Xinyang Li
A multiaperture receiver with a phased array is an effective approach to overcome the effect of the random optical disturbance in coherent free-space laser communications, in which one of the key technologies is how to efficiently combine the multiple laser beams received by the phased array antenna. A combining module based on coherent polarization beam combining (CPBC), which can combine multiple laser beams to one laser beam with high combining efficiency and output a linearly polarized beam, is proposed in this paper...
March 1, 2017: Applied Optics
M Stoffels, S Simon, P G Nikolic, P Stoller, J Carstensen
High-voltage gas circuit breakers, which play an important role in the operation and protection of the power grid, function by drawing an arc between two contacts and then extinguishing it by cooling it using a transonic gas flow. Improving the design of circuit breakers requires an understanding of the physical processes in the interruption of the arc, particularly during the zero crossing of the alternating current (the point in time when the arc can be interrupted). Most diagnostic techniques currently available focus on measurement of current, voltage, and gas pressure at defined locations...
March 1, 2017: Applied Optics
C Strothkämper, A Ferrero, A Koo, P Jaanson, G Ged, G Obein, S Källberg, J Audenaert, F B Leloup, F M Martínez-Verdú, E Perales, A Schirmacher, J Campos
The field of spectral radiance factor (SRF) measurements has seen growing interest in recent years. Scale conformity has so far only been established between the national metrology institutes (NMIs) of Germany and the USA. This study aims at a bigger, multilateral scale comparison. For this purpose, a total of six NMIs participated in a scale comparison of goniospectrophotometers based on neutral and colored diffusely reflecting ceramics samples. In addition, two universities, providing a home-built gonioreflectometer and two widely used commercially available color measurement instruments, respectively, were involved...
March 1, 2017: Applied Optics
Youchao Jiang, Guobin Ren, Haisu Li, Min Tang, Yu Liu, Yue Wu, Wei Jian, Shuisheng Jian
We presented a simple method for measuring the mode purity of linearly polarized orbital angular momentum (OAM) modes in optical fibers. The method is based on the analysis of OAM beam projections filtered by a polarizer. The amplitude spectrum and phase spectrum of a data ring derived from the beam pattern are obtained by Fourier transform. Then the coefficients of the mixed electric field expression can be determined and the mode purity can be obtained. The proposed method is validated and it is experimentally demonstrated in a two-mode fiber...
March 1, 2017: Applied Optics
Dennis L Waldron, Rebeckah Burke, Amanda Preske, Todd D Krauss, Joseph M Zawodny, Mool C Gupta
The optical properties of PbSe quantum dots (QDs) in AB9093 epoxy nanocomposite are examined with respect to temperature over a range of 0°C-80°C, a useful working range for many QD-based sensors and devices, and results are compared to QDs in toluene solution. A complete characterization of QD optical properties is provided as a function of temperature, including the absorption spectrum, first excitonic (1-s) absorption peak intensity and wavelength, fluorescence intensity, and peak wavelength. QD optical properties in toluene were found to be more sensitive to temperature as compared to those in AB9093...
March 1, 2017: Applied Optics
Eyal Schwartz, Erez N Ribak
We propose a simple analysis to improve the resolution of interference patterns which consist of straight fringes. As the pattern is rotated with respect to the detector, each row or column in the camera perceives it in a slightly shifted manner. We support this proposed method by analyzing both simulated and experimental interference patterns, and verify it using an interferogram obtained from a spectrally complex light source. The results imply that this technique could be implemented in different aspects of image analysis common in many fields in physics...
March 1, 2017: Applied Optics
Min-Cheng Zhong, Zi-Qiang Wang, Yin-Mei Li
Optical tweezers have been used to trap and manipulate microparticles within living animals. When the optical trap is constructed with an oil-immersion objective, it suffers from spherical aberration. There have been many investigations on the influence of spherical aberration when the particles are trapped in a water medium. However, the dependence of optical force on trapping depth is still ambiguous when the trapped particles are immersed in a high refractive index medium (such as biological tissue, refractive index solution) in experiments...
March 1, 2017: Applied Optics
Fuzheng Zhang, Haisong Xu, Zhehong Wang
The trade-off between the color fidelity index (R<sub>f</sub>) released recently by the Illuminating Engineering Society of North America (IES) and luminous efficacy of radiation (LER) was investigated by adjusting the peak wavelengths, spectral widths, and intensities of four-channel LEDs utilizing a multiobjective optimization algorithm based on differential evolution in the correlated color temperature (CCT) ranging from 2800 to 6500 K for general lighting. The results indicate that R<sub>f</sub> at a specific LER value decreases with the increasing CCT, and vice versa, and that R<sub>f</sub> has significant improvements over the Commission Internationale de l'Eclairage (CIE) color rendering index (CRI) in avoiding spectral gaming and evaluating the light sources even with negative CIE general CRI (R<sub>a</sub>)...
March 1, 2017: Applied Optics
Mohammad Rashidi, Ali Rostami, Mahboubeh Dolatyari, Ghassem Rostami
This paper presents a computational and semi-analytical approach for theoretical evaluation of solution-process-based optoelectronic devices, such as quantum dot (QD) infrared photodetectors. The dark current and photocurrent for infrared photodetectors are extracted on the basis of the model presented here. In this model, two main mechanisms have been assumed to contribute to the current of the device: the electron tunneling in the confined states and the drift of electrons in the continuum states. For the former, the Landauer-Büttiker formalism, in which the transmission function was obtained through the Green's function method was used...
March 1, 2017: Applied Optics
Jinbang Wang, Hanxue Mei, Kui Yang, Lu Zhao, Zhiguo Liu, Tao Zhang
Material made of artificial molecules fabricated from cage-shaped granules of conductor (CGC) is introduced and its electrical and magnetic characteristics are presented. Its refractive index, calculated using complex relative permittivity and complex relative permeability, is 1.504 at 35 GHz. A two-element lens, consisting of a pair of spherical plano-convex lenses, was designed and fabricated by embedding CGC in poly(methyl methacrylate). The active millimeter-wave imaging system was constructed with the two-element lens by having the curved surfaces face each other...
March 1, 2017: Applied Optics
Weichao Yan, Zhongquan Nie, Xueru Zhang, Yuxiao Wang, Yinglin Song
Combining the vector diffraction theory with the inverse Faraday effect, we have theoretically studied magnetization shaping generated by tight focusing of an azimuthally polarized multi-Gaussian beam superimposed with a helical phase. By selecting optimized parameters of a multi-Gaussian beam and topological charge of a spiral phase plate, not only a super-long and sub-wavelength longitudinal magnetization needle with single/dual channels for a single-lens high numerical aperture focusing system, but also an extra-long and three-dimensional super-resolution longitudinal magnetization chain with single/dual channels for a 4π high numerical aperture focusing system is achieved in the focal region...
March 1, 2017: Applied Optics
Ping Yan, Junyi Sun, Yusheng Huang, Dan Li, Xuejiao Wang, Qirong Xiao, Mali Gong
We designed and fabricated a high-power cladding light stripper (CLS) by combining a fiber-etched CLS with a cascaded polymer-recoated CLS. The etched fiber reorganizes the numerical aperture (NA) distribution of the cladding light, leading to an increase in the leakage power and a flatter distribution of the leakage proportion in the cascaded polymer-recoated fiber. The index distribution of the cascaded polymer-recoated fiber is carefully designed to ensure an even leakage of cladding light. More stages near the index of 1...
March 1, 2017: Applied Optics
Qiu-Shun Li, Dong Xiang, Zhi-Min Chang, Jian-Guo Shi, Yao-Hong Ma, Lei Cai, Dong Feng, Wen-Fei Dong
We propose a novel, highly sensitive refractive index (RI) sensor by means of combining the Kretschmann prism with a TiO<sub>2</sub> nanowire array and do not use a metallic layer in the Kretschmann configuration. Its RI sensing performance was investigated through measuring different concentrations of sodium chloride solution. Experimental results showed that, with increasing RI of liquid, the resonant wavelength in the reflectance spectrum redshifted gradually in the visible light range. There was a very good linear relationship between resonant wavelength and RI in the range of 1...
March 1, 2017: Applied Optics
Jiuning Lin, Qing Tong, Yu Lei, Zhaowei Xin, Dong Wei, Xinyu Zhang, Jing Liao, Haiwei Wang, Changsheng Xie
An electrically tunable infrared (IR) filter based on a key cascaded liquid-crystal Fabry-Perot (C-LC-FP) working in the wavelength range of 3-5 μm is presented. The C-LC-FP is constructed by closely stacking two FP microcavities with different depths of 12 and 15 μm and fully filled by nematic LC materials. Through continuous wavelength selection of both microcavities, radiation with a high transmittance and narrow bandwidth can pass through the filter. According to the electrically controlled birefringence characteristics of nematic LC molecules, the transmission spectrum can be shifted through applying a dual voltage signal over the C-LC-FP...
March 1, 2017: Applied Optics
Mehdi Heydari, Mohammad Sabaeian
In this work, Ag nanogratings comprised of arrays of nanostrips with three different cross sections of triangular, rectangular, and trapezoidal shape were considered and put at the top of the thin-film metal-insulator-metal (MIM) and semiconductor-on-insulator (SOI) solar cells. Then, the optical absorption and the short-circuit current density (J<sub>SC</sub>) enhancement (relative to a bare cell) were calculated and compared. In addition, the best strip cross section among three types of cross sections and the optimum grating period were found...
March 1, 2017: Applied Optics
Carol E Tanner, Nan Sun, Alison Deatsch, Frank Li, Steven T Ruggiero
This paper describes light transmission spectroscopy (LTS), a technique for eliminating spectral noise and systematic effects in real-time spectroscopic measurements. In our work, we combine LTS with spectral inversion for the purpose of nanoparticle analysis. This work employs a wideband multi-wavelength light source and grating spectrometers coupled to CCD detectors. The light source ranges from 210 to 2000 nm, the wavelength-dependent light detection system ranges from 200 to 1100 nm with ≤1  nm resolution, and the nanoparticle diameters range from 1 to 3000 nm...
March 1, 2017: Applied Optics
Francisco Javier Gantes-Nuñez, Zacarías Malacara-Hernández, Daniel Malacara-Doblado, Daniel Malacara-Hernández
Instead of measuring the wavefront deformations, Hartmann and Shack-Hartmann tests, we measure the wavefront slopes, which are equivalent to the ray transverse aberrations. Numerous different integration methods have been described in the literature to obtain the wavefront deformations from these measurements. Basically, they can be classified in two different categories, i.e., modal and zonal. In this paper, we describe a proposed new zonal procedure. This method finds a different analytical expression for each square cell formed by four sampling points in the pupil of the system...
March 1, 2017: Applied Optics
Jin Seog Gwag
Optical fine-tuning was performed to reduce blue light leakage in a conventional reflective LCD and to obtain a reflective LCD with a better contrast ratio. Total light leakage in the dark state was examined by simulation, according to the optical axes of the half-wave plate and LC layer and the central wavelength used in the optical design of the LCD. The contrast ratio of the reflective LCD could be improved by more than fivefold, compared to that of a conventional LCD with a wide-band optical design, when the optical axis angles of the half-wave plate and the LC layer were 75° and 15...
March 1, 2017: Applied Optics
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