9 research outputs found
Intensity Distribution of the 31P¬11S+ Band System of NaLi
In the framework of adiabatic approximation we perform numerical calculations of intensity distribution for the 31P¬11S+ band system of NaLi based on the Franck-Condon (FC) principle. In addition, the internuclear distances at which the most favorable transitions occurred are predicted. Comparing the calculated FC factors and the corresponding spectral lines observed recently reveals a good agreement, particularly, at node of envelop of the FC factors. Some local deviations in spectral intensity between the calculated results and experimental data indicate local perturbations in the 31P state. This result requires further investigations in details
Matching of Pumped and Laser Mode Volumes Inside a Diode Side-pumped Solid-state Laser
The condition to match the pumped-volume's width with the laser mode-volume's waist in a diode four side pumped solid-state laser is analyzed by numeric solutions of the approximation equation. As a result, the dependences of pumped volume's width on pumping diode parameter and laser mode volume's waist on cavity parameter were found. Such a matching condition was simultaneously determined by cavity, pumping beam and laser rod parameters.%Key words: Laser diode side-pumped, Coherent pump, Excitred active center distribution
Optical Bistability Effect of Two-port Nonlinear Fiber Mach-Zehnder Interferometer
In this article, the dependence of bistability characteristic of the two-port nonlinear fiber Mach-Zehnder interferometer (TPNFMZI) on initial phase shift, wavelength of input signal, nonlinear coefficient of refractive index and length of nonlinear fiber is investigated and discussed. The results of this work play an important role in designing the TPNFMZI and its application in the future
Nonlinear Coupler for Optical Fiber Mach-Zehnder Interferometer
In this article the equations for two waves propagating in two fibers of nonlinear Kerr coupler for optical Mach-Zehnder interferometer are derived. Based on the resolution of those equations, the expressions describing relation between coherent length, input intensity of the wave, nonlinear coefficient of refractive index for 3dB Kerr coupler are introduced and discussed
A Comparative Study of Optical Bistability in Three-Level EIT Configurations
We present a comparative study of optical bistability (OB) in three-level atomic configurations, including -, cascade-, and V- types under the conditions of electromagnetically induced transparency (EIT). In the steady regime, the input-output intensity relations for the OB in each configuration have been derived in analytical form. The model allows one to construct a clear picture on how the threshold intensity, and other characteristics of the OB are continuously modified with respects to controllable parameters of the laser fields, cooperation parameter, and other physical parameters of atomic system. The results showed that the threshold intensity of OB in -type system is much less than the other ones and the threshold intensity of OB in V-type system is the largest one. The analytical result is convenient to choose excitation configuration for experimental observations and related applications in photonic devices
EIT enhanced self-Kerr nonlinearity in the three-level lambda system under Doppler broadening
Using density-matrix theory, an analytical expression of the self-Kerr nonlinear coefficient of a three-level lambda EIT medium for a weak probe light is derived. Influences of the coupling light and Doppler broadening on the self-Kerr coefficient are investigated and compared to experimental observation with a good agreement. The self-Kerr nonlinearity is basically modified and greatly enhanced in the spectral region corresponding to EIT transparent window. Furthermore, sign, slope, and magnitude of the self-Kerr coefficient can be controlled with frequency and intensity of the coupling light and temperature. Such controllable Kerr nonlinearity can find interesting applications in optoelectronic devices working with low-light intensity
Financial Development and International R&D Spillovers Through Trade: Evidence From Developing Countries
This paper examines how financial development affects technological progress of 55 developing countries over the 2003 to 2016 period, with particular attention to the interaction between R&D spillovers and financial development. We find that financial development induces total factor productivity improvement in developing countries both directly and indirectly. While there has been a profound literature on the direct effect of financial development on total factor productivity improvement, the evidence of an indirect effect is relatively new. Specifically, the indirect effect takes place through international R&D spillovers from developed countries to developing countries. Between the two components of financial development, the financial institutional aspects exert a more significant effect on total factor productivity than that of their financial market counterparts. As this paper also re-examines the effectiveness of the North-South R&D spillovers, it conveys important implications for policymakers whose objectives are to promote technological development and economic performance