https://www.selleckchem.com/products/Perifosine.html The referenced article [Appl. Opt.59, 11112 (2020)APOPAI0003-693510.1364/AO.412267] has been retracted by the author.A comparator is one of the important combinational logic circuits. An optical comparator was designed and simulated based on photonic crystals. Point and linear defects were also used in the proposed optical comparator. The use of simple defect paths and the absence of ring resonators reduced the complexity of the structure. One of the characteristics of the proposed structure is that it has a very small size, which leads to the suitability of this comparator for optical integrated circuits. Another characteristic of this comparator is an increase in the optical power difference for the logical values "0" and "1," which reduces the bit detection error in the output. This comparator is also designed to operate on the 1.55 µm wavelength, and it can be used in today's optical telecommunication circuits.A Laguerre-Gaussian (LG) vortex beam is employed as an illumination source for a dark-field microscopy imaging system. To discover the influences of beam characteristics on the imaging quality, an analysis model has been established to show the light-field change rule on both object and image planes. The analytic expressions of the light field on the two planes are deduced. When a rectangular defect is simulated, the light distributions on the object and image planes with different parameters are calculated. The results show that the size of the beam spot on the object plane can be changed by adjusting the topological charge of the vortex beam to obtain the best imaging effect for defects of different scales.We report a study of the response function parameters (amplitude and rise/fall time) of a high-speed GaSb/GaInAsSb/GaAlAsSb photodiode operating at 1.9 µm as a function of optical input power and reverse bias voltage. The experimental measurement results yield the optimal pulse energy and optimal rev