Terahertz master-oscillator power-amplifier quantum cascade lasers

We report on the realization of a monolithically integrated master-oscillator power-amplifier architecture in a terahertzquantum cascade laser (THz-QCL) with a metal-metal waveguide. The master-oscillator section is a first-order distributed feedback(DFB) laser. Instead of using a thick anti-reflection coating, we exploit adiffraction grating together with an absorbing boundary in the power-amplifier section to efficiently extract the laser radiation and suppress the self-lasing in it. The devices demonstrate a stable generation and power amplification of single-mode emission. The amplification factor is about 5, and the output power is approximately twice that of the standard second-orderDFB lasersfabricated from the samematerial. Emission beam pattern with a divergence angle of ∼18 × 40° is achieved. Our work provides an avenue for the realization of single-mode THz-QCLs with high output power and good beam quality.

Source: Applied Physics Letters - December 7, 2016 Category: Physics Authors: Huan Zhu, Fangfang Wang, Quan Yan, Chenren Yu, Jianxin Chen, Gangyi Xu, Li He, Lianhe Li, Li Chen, A. Giles Davies, Edmund H. Linfield, Jiaming Hao, Pierre-Baptiste Vigneron and Raffaele Colombelli Source Type: research