The results showed that the threshold intensity of OB in Λ-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. | Communications in Physics, Vol. 28, No. 2 (2018), pp. 127-138 DOI: A COMPARATIVE STUDY OF OPTICAL BISTABILITY IN THREE-LEVEL EIT CONFIGURATIONS LE VAN DOAIa,† , LE THI MINH PHUONGb , NGUYEN TUAN ANHa,c , DOAN HOAI SONd , DINH XUAN KHOAa , VU NGOC SAUa AND NGUYEN HUY BANGa a Vinh University, 182 Le Duan Street, Vinh City, Vietnam b Sai Gon University, 273 An Duong Vuong street, Ho Chi Minh City, Vietnam c Ho Chi Minh City University of food industry, Ho Chi Minh City, Vietnam d Ha Tinh University, Ha Tinh Province, Vietnam † E-mail: doailv@ Received 9 May 2018 Accepted for publication 29 May 2018 Published 16 June 2018 Abstract. We present a comparative study of optical bistability (OB) in three-level atomic configurations, including Λ-, 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 Λ-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. Keywords: optical bistability, effects of atomic coherence. Classification numbers: ; . c 2018 Vietnam Academy of Science and Technology 128 A COMPARATIVE STUDY OF OPTICAL BISTABILITY IN THREE-LEVEL EIT . I. INTRODUCTION The OB is an interesting topic in nonlinear optics because of its potential applications in photonic devices, such as all-optical .
