公开(公告)号：US09912119B2

公开(公告)日：2018-03-06

申请号：US15253382

申请日：2016-08-31

Applicant: HAMAMATSU PHOTONICS K.K.

Inventor： Akio Ito ,  Tatsuo Dougakiuchi ,  Kazuue Fujita ,  Tadataka Edamura

IPC: H01S5/24 ,  H01S5/14 ,  H01S5/34 ,  H01S5/06 ,  H01S5/10 ,  H01S5/12 ,  H01S5/02

CPC classification number: H01S5/142 ,  H01S5/0207 ,  H01S5/0604 ,  H01S5/1092 ,  H01S5/12 ,  H01S5/24 ,  H01S5/3402 ,  H01S2302/02

Abstract: A quantum cascade laser is configured with a semiconductor substrate, and an active layer having a multistage lamination of emission layers and injection layers. The active layer is configured to be capable of generating first pump light of a frequency ω1 and second pump light of a frequency ω2, and to generate output light of a difference frequency ω by difference frequency generation. An external diffraction grating is provided for generating the first pump light, outside an element structure portion including the active layer, and an internal diffraction grating is provided for generating the second pump light, inside the element structure portion. The frequency ω2 is set to be fixed to a frequency not coincident with a gain peak, and the frequency ω1 is set to be variable to a frequency different from the frequency ω2.