Journal of Lasers, Optics & Photonics

The transient and steady-state behavior of the absorption and the dispersion of a probe pulse laser field propagating through an InGaAs\InP double coupled quantum well are studied. The effect of terahertz radiation excitation, electron tunnelling and incoherent pumping on the optical properties of the probe field is discussed. In the terahertz (30~300 μm or 1~10 THz) intersubband transition, the incoming photon energy is (4~41 mev) and maybe in the order of electron thermal broadening (KT~6 meV-25 meV for 77 K-300 K). Therefore in the conventional structure, the incoming photon can directly excite the ground state electrons to higher energy levels and this process inhabits the correct optical switching in terahertz applications. We show that the group velocity of a light pulse can be controlled from superluminal to subluminal or vice versa by controlling the rates of incoherent pumping field and tunnelling between the quantum wells. The required switching time is calculated and we find it between 3 to 26 picoseconds.

In this paper, we study the higher-order nonlinear Schrdinger (HNLS) equations for a directional fiber optic coupler with the third-order dispersion (TOD), self-steeping (SS) and stimulated Raman scattering (SRS) effects and gain in one waveguide and loss in the other. We have reduced the system equations to an uncoupled HNLS equation which has bright and dark soliton solutions. It is shown that the Hamiltonian for this equation has a PT-symmetric form. Furthermore the equilibrium points are found and the discussion about their stability is presented.

In framework of dipole approximation it is shown, that the oscillator strengths of transitions as well as the dipole moments for transitions for one-particle electron Coulomb states emerging above the spherical surface quantum dot of metal assume giant values considerably (by two orders of magnitude) exceeding the typical values of the corresponding quantities for dielectrics. It has been established that the giant values of the light absorption cross section in the nanosystems under investigation make it possible to use such nanosystems as strongly absorbing nanomaterials in a wide range of infrared waves with a wavelength that can be varied in a wide range depending in the type of contacting materials.

Today use of lasers in Implantology has made significant progress, so that requires far less traditional methods of treatment and it has been increased speed of healing. One of the lasers applications in implantology is in the process of osseointegration which made minimum the prolonged time among of planted surgical implants, prosthesis fabrication and implant. Aim of the present survey is to examine and record the temperature changes caused by low level diode laser (Mark GIGA) around 810nm wavelength during laser interaction with tissue. Besides in a clinical study, the surface temperature changes of soft tissue recorded by IR Thermometer once before and after the diode laser radiation at 10 implants placed on 4 patients (3 women and 1 man) in 15 points (total 48 points) from different parts of tissue. Then, the temperature data analyzed by COMSOL Multiphysics 5.2 software. However, the soft tissues temperature changes under diode laser treatment of osseointegration but don’t damage tissues. Also after inserting implants, the laser irradiation cause more stability and reduce the duration of treatment.

In the laboratory of physics and general technical disciplines of the Ugra State University, an optoelectronic measuring system based on a high-speed Video Sprint video camera is used for research. The calibration of ECO has revealed a number of nonlinear effects. In the paper, a method is described that allows eliminating the afterglow of the screen of the image converter. The method is based on revealing the law of attenuation of the afterglow of a phosphor. As a result of the application, data loss is reduced, the signal-to-noise ratio is increased.

Optothermodynamic method of diagnosis of absorption coefficient of waves in inhomogeneous absorbing liquids has been developed temperature influence on wave’s absorption coefficient has been determined. Optothermodynamic method allows establishing relation between optic and thermophysical properties of liquid. Developed method is based on the application of energy conservation on the interaction of laser beams with inhomogeneous absorbing liquids.

Micro embedded ring resonator electro-optic switching in InGaAsP based quantum well structures is briefly reviewed and all optic switching is presented. A 20Gbps electro-optic modulator with >12dB extinction ratio has been proposed using quantum confined stark effect tuning, for which a novel high speed coplanar-microstrip inverted ground plane transition has also been designed. All optical tuning is used to theoretically demonstrate a 20G packets/s switching with a 5dB switching ratio. The fabricated micro embedded ring resonator ring using e-beam lithography and Al lift off mask has been demonstrated and the measured device spectrum is found to match well with the simulated results.