半導体結合共振器による面発光テラへルツ素子

摘要

We have developed a novel kind of surface emitting terahertz device based on a semiconductor coupled multilayer cavity that consists of two identical cavity layers and three distributed Bragg reflector (DBR) multilayers. Two cavity modes are realized since two cavities are coupled by the intermediate DBR and the optical frequency difference between two modes can be tuned in the terahertz region by the periods of the intermediate DBR. The current injection into the device enables two-color lasing in the nearinfrared region and its difference-frequency generation (DFG) owing to the second-order nonlinear process inside the coupled cavity brings a terahertz emission in one elemental device. In this article, we briefly describe the design and fabrication methods of the GaAs-based coupled multilayer cavity for efficient terahertz DFG of two modes. We also show recent results on two-color lasing of the prototype devices by pulsed current injection at room temperature.