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Applied Optics

Detlev Ristau, Li Li, Robert Sargent, Anna Sytchkova
This feature issue of Applied Optics is dedicated to the 13th Topical Meeting on Optical Interference Coatings, which was held June 19-24, 2016, in Tucson, Arizona, USA. The conference, taking place every three years, is a focal point for global technical interchange in the field of optical interference coatings and provides premier opportunities for people working in the field to present their new advances in research and development. Papers presented at the meeting covered a broad range of topics, including fundamental research on coating design theory, new materials, and deposition and characterization technologies, as well as the vast and growing number of applications in electronic displays, communication, optical instruments, high power and ultra-fast lasers, solar cells, space missions, gravitational wave detection, and many others...
February 1, 2017: Applied Optics
Shigeng Song, Cheng Li, Hin On Chu, Des Gibson
Drum-based metal-like film deposition for oxide was investigated using single wavelength in situ monitoring. The data were used to investigate the oxidation mechanism using combined second-order kinetic and parabolic models. A critical Nb<sub>2</sub>O<sub>5</sub> deposition rate of 0.507 nm/s was found at drum rotation of 1 rev/s. However, Nb<sub>2</sub>O<sub>5</sub> samples prepared at varying deposition rates showed that the deposition rate must be much lower than the critical deposition rate to achieve reasonable absorption...
February 1, 2017: Applied Optics
Junliang Liu, Shangfeng Chen, Huanzhang Lu, Bendong Zhao
Micro-motion dynamics and geometrical shape are considered to be essential evidence for infrared (IR) ballistic target recognition. However, it is usually hard or even impossible to describe the geometrical shape of an unknown target with a finite number of parameters, which results in a very difficult task to estimate target micro-motion parameters from the IR signals. Considering the shapes of ballistic targets are relatively simple, this paper explores a joint optimization technique to estimate micro-motion and dominant geometrical shape parameters from sparse decomposition representation of IR irradiance intensity signatures...
February 1, 2017: Applied Optics
William E Vargas
An accepted-probability-controlled simulated annealing (APCSA) method has shown to be a valuable tool to describe, in parametric form, by means of an extended Drude-Lorentz model, the dielectric function of several metals through infrared, visible, and ultraviolet photon energies [Appl. Opt.37, 5271 (1998)APOPAI0003-693510.1364/AO.37.005271]. In this work, an improved APCSA approach is used to estimate the parameters involved in an extended Drude-Lorentz type model which incorporates the dielectric constant due to a background electronic polarization in the Drude term and the normalization of the individual oscillation strengths involved in the Lorentz contributions to the dielectric function...
February 1, 2017: Applied Optics
Norbert Lauinger
Diffraction of light at the spatial cellular phase grating outer nuclear layer of the retina could produce Fresnel near-field interferences in three RGB diffraction orders accessible to photoreceptors (cones/rods). At perpendicular light incidence the wavelengths of the RGB diffraction orders in photopic vision-a fundamental R-wave with two G+B-harmonics-correspond to the peak wavelengths of the spectral brightness sensitivity curves of the cones at 559 nmR, 537 nmG, and 447 nmB. In scotopic vision the R+G diffraction orders optically fuse at 512 nm, the peak value of the rod's spectral brightness sensitivity curve...
February 1, 2017: Applied Optics
QuanXin Na, Chunqing Gao, Qing Wang, Yixuan Zhang, Mingwei Gao, Qing Ye, Meng Zhang, YuJia Wang
A single-frequency two-stage amplifier delivering up to 44 mJ at 2.1 μm is demonstrated. The first-stage amplifier is double-end-pumped by a 1.9 μm Tm:YLF laser, and is seeded with a 15 mJ single-frequency Ho:YAG laser operating at 200 Hz. The second-stage amplifier is end-pumped by another 1.9 μm Tm:YLF laser. The output pulse width from the second-stage amplifier is 113 ns, with a beam quality of M<sup>2</sup>∼1.32.
February 1, 2017: Applied Optics
Limeng Zhang, Biwei Pan, Guangcan Chen, Dan Lu, Lingjuan Zhao
We experimentally demonstrate a compact, long-range, high-resolution chaotic correlation optical time-domain reflectometry based on a monolithic integrated chaotic laser (MICL). The MICL can directly generate a broadband chaotic signal covering a RF frequency range of over 40 GHz. Multi-reflection events can be precisely located in a detection range of ∼47  km with a range-independent resolution of 2.6 mm.
February 1, 2017: Applied Optics
Bassem Arar, Max Schiemangk, Hans Wenzel, Olaf Brox, Andreas Wicht, Achim Peters, Günther Tränkle
A flexible method to measure the modulation efficiency and residual amplitude modulation, including non-linearities, of phase modulators is presented. The method is based on demodulation of the modulated optical field in the optical domain by means of a heterodyne interferometer and subsequent analysis of the I&Q quadrature components of the corresponding RF beat note signal. As an example, we determine the phase modulation efficiency and residual amplitude modulation for both the TE and TM modes of a GaAs chip-based phase modulator at the wavelength of 1064 nm...
February 1, 2017: Applied Optics
Hanxue Zhao, Zhenggan Zhou, Jin Fan, Gen Li, Guangkai Sun
This paper reports the application of the least-squares regression method in the step-heating thermographic inspection of steel structures. The surface temperature variation of a slab with finite thickness during both the step-heating phase and the cooling-down phase is presented. A mild steel slab with holes of various depths and diameters is chosen as the specimen. The step-heating thermographic inspection experiments are carried out on the specimen with different heating times. The heating as well as the cooling-down phases are recorded with an infrared camera and are analyzed separately by linear regression of the double logarithmic temperature increase versus time plots...
February 1, 2017: Applied Optics
Ron Driggers
Editor-in-Chief Ron Driggers shares his thoughts on gender balance in engineering and physics.
February 1, 2017: Applied Optics
Md Saiful Islam, Jakeya Sultana, Javid Atai, Derek Abbott, Sohel Rana, Mohammad Rakibul Islam
In this paper, we present the design and analysis of a novel hybrid porous core octagonal lattice photonic crystal fiber for terahertz (THz) wave guidance. The numerical analysis is performed using a full-vector finite element method (FEM) that shows that 80% of bulk absorption material loss of cyclic olefin copolymer (COC), commercially known as TOPAS can be reduced at a core diameter of 350 μm. The obtained effective material loss (EML) is as low as 0.04  cm<sup>-1</sup> at an operating frequency of 1 THz with a core porosity of 81%...
February 1, 2017: Applied Optics
Cheng-Shane Chu, Jhih-Jheng Syu
An optical sensor for the dual sensing of oxygen (O<sub>2</sub>) and carbon dioxide (CO<sub>2</sub>) based on sensing films coated on filter paper is proposed. Ethyl cellulose (EC) doped with platinum(II) meso-tetrakis(pentafluorophenyl)porphyrin (PtTFPP) and 7-amino-4-trifluoromethyl coumarin serve as the oxygen sensing material and reference blue emission dye for the pH indicator, respectively. The CO<sub>2</sub> sensing layer includes the pH-sensitive fluorescent indicator 1-hydroxy-3,6,8-pyrenetrisulfonic acid trisodium salt immobilized within the EC...
February 1, 2017: Applied Optics
Alejandro Téllez-Quiñones, Daniel Malacara-Doblado, Zacarias Malacara-Hernández, David A Gutiérrez-Hernández, Daniel Malacara-Hernández
In a previous work, we introduced the concept of transversal aberrations {U,V} calculated at arbitrary Hartmann-plane distances z=r [Appl. Opt.55, 2160 (2016)APOPAI1559-128X10.1364/AO.55.002160]. These transversal aberrations can be used to estimate the wave aberration function W, as well as the classical transversal aberrations {X,Y} calculated at a theoretical plane z=f, where f is the radius of a reference semisphere. However, when the ray identification is difficult to achieve at z=f, the use of {U,V} can be of great help...
February 1, 2017: Applied Optics
Cheng-Yu Chi, Guan-Jhong Lin, Shui-Shang Hu, Sin-Yan Tsai, Tien-Jung Chen, Ja-Hon Lin, Yin-Jay Yang, Jin-Jei Wu
In this study, the Kerr constant of pure blue-phase liquid crystal (BPLC) without polymer doping at room temperature and the optoelectronic properties dependent on the cell thickness are explored. The relation between the phase and the voltage in oblique incident light was measured via a reasonable vertical electric field for different thicknesses of BPLC cells. It was found that the Kerr constant formula can be amended with the functions related to the cell gap. This study demonstrates a method to estimate the Kerr constant, especially for cells within a small electrical field, which will benefit optoelectronic applications...
February 1, 2017: Applied Optics
Mutasem Odeh, Bob Voort, Arslan Anjum, Bruna Paredes, Clara Dimas, Marcus S Dahlem
We demonstrate a gradient-index (GRIN) optofluidic waveguide using polydimethylsiloxane cured with a radial variation of temperature. The waveguide wraps the microfluidic channel and the GRIN profile localizes the light around it, making the device suitable for evanescent sensing applications. The fabricated waveguide shows good light confinement, with a propagation loss of 1.47 dB/cm at a wavelength of 632.8 nm.
February 1, 2017: Applied Optics
Yasukuni Shibata, Chikao Nagasawa, Makoto Abo
An experiment for the measurement of atmospheric CO<sub>2</sub> vertical profiles up to a 7 km altitude was successfully conducted using a 1.6 μm ground-based differential absorption Lidar developed by Tokyo Metropolitan University. To achieve a high pulse repetition rate, large power output, and high frequency stabilization, we developed a new 1.6 μm Lidar system using an optical parametric generator (OPG) transmitter. Unlike the previous system's transmitter, OPG does not need a resonator. We amplified its output with two optical parametric amplifiers...
February 1, 2017: Applied Optics
Jan Hosek, Vlastimil Havran, Sarka Nemcova, Jiri Bittner, Jiri Cap
Recent developments in optoelectronics and material processing techniques make it possible to design and produce a portable and compact measurement instrument for bidirectional texture function (BTF). Parallelized optics, on-board data processing, rapid prototyping, and other nonconventional production techniques and materials were the key to building an instrument capable of in situ measurements with fast data acquisition. We designed, built, and tested a prototype of a unique portable and compact multi-camera system for BTF measurement which is capable of in situ measurement of temporally unstable samples...
February 1, 2017: Applied Optics
Mickaël Gilliot
Ellipsometry is a highly sensitive and powerful optical technique of thin film characterization. However, the indirect and nonlinear character of the ellipsometric equations requires numerical extraction of interesting information, such as thicknesses and optical constants of unknown layers. A method is described to perform the inversion of ellipsometric spectra for the simultaneous determination of thickness and optical constants without requiring particular assumptions about the shape of a model dielectric function like in the traditional method of data fitting...
February 1, 2017: Applied Optics
Zhijun Wang, Shuqin Lou, Panlai Li, Zhenggang Lian
A novel, near-ultraviolet-excited white-light-emitting phosphor Sr<sub>3</sub>La(PO<sub>4</sub>)<sub>3</sub>:Eu<sup>2+</sup>, Mn<sup>2+</sup> was synthesized by the solid-state method. Luminescence properties and the energy transfer mechanism were investigated in detail by photoluminescence spectra and decay curves. With the energy transfer between Eu<sup>2+</sup> and Mn<sup>2+</sup>, a cold white light with chromaticity coordinates of (0...
February 1, 2017: Applied Optics
Michael Raju, Sujatha Narayanan Unni
Dilutions of Intralipid 20% are widely used as optical phantoms for mimicking scattering properties of turbid media such as tissues. One of the frequently used methodologies for quantifying the scattering coefficient and anisotropy of Intralipid 20% is the use of single-particle Mie scattering theory, which in fact is not valid for nontenuous media. Hence, two methodologies consisting of analytical wave theory and effective medium theory, incorporating particle size distribution and concentration-dependent correlated scattering phenomena, are used to estimate the effective scattering coefficient and anisotropy of Intralipid 20% dilutions (1%-100% v/v) from 380 to 1000 nm...
February 1, 2017: Applied Optics
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