Bipolar THz-Lasing Structures Based on InAs-GaSb Coupled Quantum Wells and Their Potential for Security Checks

Abstract

Development of compact low-cost sources of a coherent radiation with a high efficiency in the range of several THz remains one of the key challenges of the modern security technologies. In spite of rather impressive achievements in intersubband quantum cascade lasers their current parameters are still far from the needs of practical implementation. We present here a bird-eye view on the current state of the field. We compare theoretical prospects of the optimal gain of lasers in the range of few THz for two cases: intersubband GaAs-based quantum cascade lasers and interband laser based on coupled quantum wells InAs-GaSb. We show that the last case promises the gain that could be three orders of magnitude higher.