Optimization of Trio-Cavity Raman Laser Pumped by Pulsed Gaussian Beam

In the paper the set of dimensionless rate equations for the pump, Stokes and anti-Stokes powers in the trio-cavity Raman laser pumped by pulsed Gaussian beam is introduced. By numerical Runger-Kuta method, those equations are resolved and the optimal normalized parameters for enhance the output powers are found out

Two Spot Coupled Ring Resonators

Abstract. We consider a model of two coupled ring waveguides with constant linear gain and nonlinear absorption with space-dependent coupling. This system can be implemented in various physical situations as optical waveguides, atomic Bose-Einstein condensates, polarization condensates, etc. It is described by two coupled nonlinear Schrödinger equation. For numerical simulations, we take local two-gaussian coupling.It is found in our previous papers that, depending on the values of involved parameters, we can obtain several interesting nonlinear phenomena, which include spontaneous symmetry breaking, modulational instability leading to generation of stable circular flows with various vorticities, stable inhomogeneous states with interesting structure of currents flowing between rings, as well as dynamical regimes having signatures of chaotic behavior. This research will be associated with experimental investigation planned in Freie Universität Berlin, in the group of prof. Michael Giersig

Controllable Optical Properties of Multiple Electromagnetically Induced Transparency in Gaseous Atomic Media

The advent of electromagnetically induced transparency (EIT) offered a new coherent material with exotic and controllable optical properties. Although, studies on single-EIT are described in detail for single-EIT, however, extension from single- to multi- EIT is currently of current interest due to it gains advantages in multi-channel optical communication, waveguides for optical signal processing and multi-channel quantum information processing. In this work, we review recent research works concerning multi-EIT and some related applications, as controlling group velocity of light, giant Kerr nonlinearity, optical bistability. A special attention of the review also gives for analytical interpretations of EIT spectrum, its dispersion and related applications such as EIT enhanced Kerr nonlinearity and optical bistability to give physics insight. From experimental point of view, a latest development for measuring multi-EIT spectrum and its dispersion in hot medium is presented and compared to theoretical analytical representations

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

Polarization Labelling Spectroscopy for NaLi

We use the polarization labelling spectroscopy technique for simplification of the spectra of alkali-metal NaLi molecule. As a result, the rotational resolution observation for NaLi in the 21 electronic state is reported for the first time

Spontaneous Symmetry Breaking of Solitons Trapped in a Double-Gauss Potentials

We consider an extended model of the model considered before with double-square potential, namely one-dimensional (1D) nonlinear Schrödinger equation (NLSE) with self-focusing nonlinearity and a 1D double-gauss potential. Spontaneous symmetry breaking has been presented in terms of the control parameter which is propagation constant in the case of optics and chemical potential in the of Bose-Einstein Condensate (BEC), correspondingly. The numerical simulations predict a bifurcation breaking the symmetry of 1D trapped in the double-gauss potential of the supercritical type as in the case of double-square potential. Furthermore we have constructed bifurcation diagrams considering the stability of solitons with three methods: the method using Vakhitov–Kolokolov (V-K) Stability Criterion, Pseudospectral Method and Method for Linear-Stability Eigenvalues. It will be shown that for our model the results obtained are the same for these three methods but the third one is the fastest

OPTICAL BISTABILITY IN A DEGENERATE TWO-LEVEL EIT MEDIUM UNDER THE INFLUENCE OF AN EXTERNAL MAGNETIC FIELD: AN ANALYTICAL APPROACH

We investigate the behavior of optical bistability in a degenerate two-level atomic medium using an external magnetic field to separate the lower level into two distinct levels that both connect to an upper level by the probe and coupling laser fields. Based on analytical solutions, the absorption spectrum and behavior of optical bistability in an electromagnetically induced transparency regime under an external magnetic field are investigated. By controlling the external magnetic field, we find that the appearance and disappearance of the optical bistability can be easily controlled according to the strength of the magnetic field in the transparent window domain. Furthermore, the effects of the intensity of the coupling laser field and the parameters of the system on the behavior of optical bistability are also considered. The proposed model is useful for applications in all-optical switches and magneto-optic storage devices.We investigate the behavior of optical bistability in a degenerate two-level atomic medium using an external magnetic field to separate the lower level into two distinct levels that both connect to an upper level by the probe and coupling laser fields. Based on analytical solutions, the absorption spectrum and behavior of optical bistability in an electromagnetically induced transparency regime under an external magnetic field are investigated. By controlling the external magnetic field, we find that the appearance and disappearance of the optical bistability can be easily controlled according to the strength of the magnetic field in the transparent window domain. Furthermore, the effects of the intensity of the coupling laser field and the parameters of the system on the behavior of optical bistability are also considered. The proposed model is useful for applications in all-optical switches and magneto-optic storage devices

Factors Influence on Promotion Mix in E-marketing: Case of Technology Services Enterprise in Vietnam

Purpose: The objective of this study is to clarify factors affecting the promotion mix in E-Marketing, with specific target audience being enterprises operating in the technology service industry in Vietnam.   Theoretical framework: Based on the promotion theory and social exchange theory, this study focuses on the factors that influence on the promotion decision in firms.   Design/Methodology/Approach: This study applies both qualitative and quantitative methods with data collected from a questionnaire survey.   Findings: There are 4 factors respectively Sales Promotion, Advertising, Public Relations and Personal Selling that affect the mixed promotion activities in E-Marketing of technology service enterprises in Vietnam.   Research, practical & social implications: This study propose solutions to improve the promotion activities in the e – marketing of firms in Vietnam.   Originality/Value: This study is one of the early studies that have focused in this field in Vietnam.Propósito: El objetivo de este estudio es aclarar los factores que afectan la combinación de promoción en E-Marketing, con un público objetivo específico que son las empresas que operan en la industria de servicios de tecnología en Vietnam. Marco teórico: Basado en la teoría de la promoción y la teoría del intercambio social, este estudio se centra en los factores que influyen en la decisión de promoción en las empresas. Diseño/metodología/enfoque: este estudio aplica métodos cualitativos y cuantitativos con datos recopilados de una encuesta de cuestionario. Hallazgos: Existen 4 factores, respectivamente, Promoción de Ventas, Publicidad, Relaciones Públicas y Ventas Personales que afectan las actividades mixtas de promoción en E-Marketing de las empresas de servicios de tecnología en Vietnam. Implicaciones de investigación, prácticas y sociales: este estudio propone soluciones para mejorar las actividades de promoción en el marketing electrónico de las empresas en Vietnam. Originalidad/valor: Este estudio es uno de los primeros que se han centrado en este campo en Vietnam.Objetivo: O objetivo deste estudo é esclarecer os fatores que afetam o mix de promoção no E-Marketing, tendo como público-alvo específico as empresas que operam no setor de serviços de tecnologia no Vietnã.. Referencial teórico: Com base na teoria da promoção e na teoria das trocas sociais, este estudo se concentra nos fatores que influenciam a decisão de promoção nas empresas.. Desenho/metodologia/abordagem: Este estudo aplica métodos qualitativos e quantitativos com dados coletados de uma pesquisa por questionário. Resultados: Existem 4 fatores, respectivamente, Promoção de Vendas, Publicidade, Relações Públicas e Vendas Pessoais que afetam as atividades de promoção mista em E-Marketing de empresas de serviços de tecnologia no Vietnã. Pesquisa, implicações práticas e sociais: Este estudo propõe soluções para melhorar as atividades de promoção no e – marketing de empresas no Vietnã. Originalidade/valor: Este estudo é um dos primeiros estudos que se concentraram neste campo no Vietnã. Palavras-chave:  Mix de promoção; E-Marketing; Serviços de tecnologia; Vietn

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 $\Lambda$-, 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 $\Lambda$-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