Patent ID: 9240674
Filing Date: 2016-01-19
CPC Classification: B82Y,H01S

Claim Text:
1. A quantum cascade laser comprising: a semiconductor substrate; and an active layer that is provided on the semiconductor substrate, and has a cascade structure in which quantum well emission layers and injection layers are alternately laminated by multistage-laminating unit laminate structures each consisting of the quantum well emission layer and the injection layer, the active layer generates light by intersubband transition in a quantum well structure, wherein in a laser cavity structure in a device main body including the semiconductor substrate and the active layer, for light with a predetermined wavelength within a wavelength region of 7 to 15 μm to be generated in the active layer, a CeO the reflection control film is a multilayer film in which a low refraction index film and a high refraction index film respectively made of predetermined materials are laminated, and the high refraction index film in the multilayer film is a Ge film.