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Zhejiang Normal University. Dynamics of Coupled Ultraslow Optical Solitons in a Coherent Four State Double Lambda System. Hui-jun Li. Collaborator: Prof. Guoxiang Huang. Field of Study: Nonlinear Physics and Nonlinear Optics. Outline. 1. Introduction
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Zhejiang Normal University Dynamics of Coupled Ultraslow Optical Solitons in a Coherent Four State Double Lambda System Hui-jun Li Collaborator: Prof. Guoxiang Huang Field of Study: Nonlinear Physics and Nonlinear Optics
Outline • 1. Introduction • 2. Model and solution in linear regime • 3. Asymptotic expansion and nonlinear envelope equation • 4. Coupled optical solitons • 5. Summary
1. Introduction EIT Why do the EIT being important? Changing the dispersion relationship, the absorption and group velocity Enhanced the Kerr nonlinearity
Why do we study the two-component optical solitons in EIT system? • 1. low light intensity • 2. two-component • 3. stable propagation of solitons
Linear solution If the probe fields are so weak that the ground state is not depleted, and we can take Under this approximation, we can get
Linear propagation property If the incident probe fields are Guass function, we can get the probe fields
3. Asymptotic expansion and nonlinear envelope equation
Asymptotic expansion Stable state: Asymptotic expansion:
Asymptotic expansion In first order, we can get the linear dispersion relation and In second order, we can get
Asymptotic expansion In third order, we can get
Asymptotic expansion Combining every order, and returning to original variables, we obtain
Single-mode optical soliton Evolution of probe field with input condition verse the delay time for different propagating distances
Two-component solitons Bright-bright solitons:
Two-component solitons Evolution of probe field with input condition verse the delay time
Summary • 1. obtain the coupled NLSE from original model • 2. the single-mode solitons • 3. the two-component solitons • 4. prove the stability of solitons by simulation