Simulations are implemented for varied line spacing (VLS) spherical gratings with an F-number slower than 1.5 and groove density varying from 150 to 300 lp/mm, and the residual error less than 0.004λ RMS is obtained. The residual misalignment error after conventionally removing defocus and tilt is further analyzed and discussed. A VLS grating in which the NA is 0.13 and groove density is 200 lp/mm is chosen as an experimental sample, and the diffracted wavefront error with 0.018λ RMS is obtained.A new device architecture has been proposed in this paper implementing the all-optical cascadable logic NOR functionality. The device functions based on stimulated Raman scattering (SRS) in silicon nanocrystal embedded slotted photonic crystal waveguide (SPCW). Substantial miniaturizations both in operating power and overall footprint of the device have been achieved owing to the ultrahigh SRS gain of silicon nanocrystal and strong spatio-temporal confinement of the SPCW. Successful operation of the device has been demonstrated at a pulse rate that is as high as 125 Gbps.A concept of an easily tunable device based on hybrid Tamm modes is proposed. The device can be controlled using a high-sensitivity chiral liquid crystal serving as a mirror. The coupling of the chiral optical Tamm state with the Tamm plasmons is predicted. The Tamm plasmons are excited at different frequencies for the orthogonal linear polarizations, while the chiral Tamm state is excited at only one frequency. The properties of the proposed model are analytically and numerically calculated. The possibility of creating a two- and three-mode laser with tunable characteristics on the basis of the proposed model is discussed.We have novelly, to the best of our knowledge, developed the liquid flow microetching method that can treat a single microdisk in a microregion with precise position control for inkjet-printed microdisk lasers. The injection-drain wet etching setup consisted of two microneedles that successfully performed a formation of a fine undercut structure of an inkjet-printed microdisk on a pre-pedestal layer through the individual wet etching process. Then measurement of the undercut structure using scanning electron microscopy and lasing characteristics with whispering gallery modes were carried out to demonstrate performance of the etched microdisks. The measured lasing threshold decreased by half compared with that of the unetched microdisk directly printed on a fluorine-type film. A point to note is that this etching method exhibits an excellent undercut and lasing characteristics even when using a clad pre-pedestal layer having a refractive index higher than that of core microdisks. This technique, combined with inkjet printing, offers a powerful tool for individually designing a microdisk and can help develop novel devices that comprise several inkjet-printed microdisks being evanescently coupled.Phase-sensitive optical time-domain reflectometry (Φ-OTDR) implements distributed vibration measurements by demodulation of vibration-induced phase of Rayleigh backscattered light waves (RBLs), and suffers from measurement instability. The weak intensities of RBLs and the resulting low signal-to-noise ratios (SNRs) of intensity measurements are the dominating factors that cause the instability of vibration measurements. In this paper, dependence of the measurement stability of heterodyne Φ-OTDR on the SNR of the intensity measurement is investigated analytically and experimentally. An analytical solution of the probability density function of the demodulated phase as a function of SNR is obtained through rigorous derivation, and the dependence of the measurement stability on the SNR is investigated by analyzing the probability density function distribution of the demodulated phase. Both the theoretical predictions and experimental results reveal the impact of SNR on the measurement stability of heterodyne Φ-OTDR. This study fulfills the Φ-OTDR theory and would lead to an effective approach to stabilizing vibration quantization.This paper deals with the problem of replacing a thin lens by a thick lens with approximately the same properties as the thin lens. Equations enabling the calculation of the parameters of a thick lens that has the same focal length and the same value for one of the Seidel aberration coefficients (either the Seidel aberration coefficient of spherical aberration or the Seidel aberration coefficient of coma) as the thin lens are derived. A comparison of the proposed method for calculating the parameters of the thick lens with existing methods is given in examples. Further, the problem of replacing a thick lens made of optical glass with a given refractive index by another thick lens with a different refractive index but with the same focal length and the same Seidel aberration coefficient of spherical aberration is investigated.The ability of the human visual system (HVS) to perceive a three-dimensional (3D) image at once is finite, but the detail contrast of the light field display (LFD) is typically degraded during both acquisition and imaging stages. It is consequently difficult for viewers to rapidly find a region of interest from the displayed 3D scene. Existing image detail boosting solutions suffer from noise amplification, over-exaggeration, angular variations, or heavy computational burden.  https://www.selleckchem.com/products/sj6986.html  In this paper, we propose a selective enhancement method for the captured light field image (LFI) that empowers an attention-guiding LFD. It is based on the fact that the visually salient details within a LFI normally co-occur frequently in both spatial and angular domains. These co-occurrence statistics are effectively exploited. Experimental results show that the LFDs improved by our efficient method are free of undesirable artifacts and robust to disparity errors while retaining correct parallaxes and occlusion relationships, thus reducing HVS's efforts to cognitively process 3D images. Our work is, to the best of our knowledge, the first in-depth research on computational and content-aware LFD contrast editing, and is expected to facilitate numerous LFD-based applications.