A compacted random laser with a triple optical cavity is designed by directly coupling the compound between three cavities: the fundamental, ring, and external cavities. The laser action in this counterintuitive cavity is enabled by feedback from strong reflections on the inner and external surfaces, as well as scattering centers silver nanowires. This unique property of the triple optical cavity results in a lower laser threshold and enhanced emission spectra. These results provide up new possibilities for designing devices integrated and miniature technology.
Optical pacing (OP) has been proved to be a feasible noninvasive alternative to electrical pacing in recent years. IR lasers can be utilized for this purpose because of the absorption rate of infrared light, particularly wavelengths of 1450 nm, in biological tissue. As a result, the goal of this research is to look at the thermal effects of infrared radiation on cardiac pacemaker cells. To begin, we investigate the heat generation and temperature increases caused by IR pulses in biological tissues as a function of pulse length and radiant exposure depth. The toad heart is then treated with a pulsed infrared laser in an experiment (wavelength of 1450 nm). By measuring the toad's heart rhythm, the temperature effect of IR radiation on its cardiac pacemaker cells is examined. The findings reveal that the thermal effect of IR pulses can alter cardiac pacemaker cells based on variations in the T wave amplitude in the toad heart rhythm. In conclusion, this work shows that non-invasive IR pulses may successfully stimulate cardiac pacemaker cells.
Considering the considerable use of sedative drugs like methadone as a frequent substitution for additive drugs, we have investigated their effect on the cell activity via highly-resolved optical sensing method. Using plasmonic ellipsometry technique, a conspicuous shift in plasmonic resonance wavelength of the cultured chips was observed due to methadone presence during the cell culture of mesenchymal stem cells. This highly-sensitive platform can open new avenues towards the detection of drug effect on human cells and in large scale, on human organs.
Plasmonics have enabled the realization of new optical components in nanostructures such as polarizers. We construct nanostructures by polycarbonate grating comprising silver nanospikes prepared by an oblique angle deposition technique. Surface, wavelength, and polarization properties of these devices have been investigated by atomic force microscopy, fiber-coupled spectrometer, and rotating analyzer, respectively. Our results show that we can reach 31% polarization ratio with the aid of two pieces of metalized gratings placed back to back by index-matching gel. Also, we can reach the broadband optical polarizer in the visible region according to the concentration and direction of nanospike in each of metalized nanogratings, which can open up directions toward cheap and one-dimensional optical polarizers.
Ring resonators based on photonic crystals have attracted worldwide attention due to their wide applications attributed to their significant properties. By comparing different inner rod configurations reported for photonic crystal ring resonators (PCRRs), we propose a configuration for inner rods similar to diamond, which is called the “diamond inner rod configuration.” In comparison with previous proposed configurations for inner rods, the diamond inner rod configuration increases the vertical waveguide output with respect to the horizontal waveguide. With this configuration a 50-50 output can be gained for two outputs, horizontal and vertical waveguides, at 1.829 and 1.6777 μm. Additionally, at 1.8438 μm there is a considerable drop toward a vertical waveguide. In order to have a comparison among the PCRRs with various inner rod configurations, the maximum power of outputs and also the quality factors have been shown schematically. To generalize our proposed configuration, in addition to a channel drop filter (CDF) based on a single-ring resonator, we designed a double-ring resonator in which the same powers can also be successively gained from three outputs at 1.876 μm by engineering the parameters of the structure.
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