Role of Terahertz Radiation on Optical Properties of Laser Pulse in a Double Coupled Quantum Well NanostructureShiri J1* and Malakzadeh A2
- *Corresponding Author:
- Shiri J
Young Researchers and Elite Club
North Tehran Branch, Islamic Azad University
Tel: +98 21 7731 8896
E-mail: [email protected]
Received Date: April 23, 2017; Accepted Date: May 15, 2017; Published Date: June 20, 2017
Citation: Shiri J, Malakzadeh A (2017) Role of Terahertz Radiation on Optical Properties of Laser Pulse in a Double Coupled Quantum Well Nanostructure. J Laser Opt Photonics 4: 154. doi: 10.4172/2469-410X.1000154
Copyright: © 2017 Shiri J, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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.