SURFACE-EMISSION QUANTUM CASCADE LASER

• Main Authors: SUMINO TSUTOMU, HASHIMOTO REI, SAITO SHINJI, TAKASE TOMOHIRO
• Format: Patent
• Language: English; Japanese
• Published: 13.06.2019
• Subjects: BASIC ELECTRIC ELEMENTS; DEVICES USING STIMULATED EMISSION; ELECTRICITY

To provide a surface-emission quantum cascade laser which enables the improvement in optical characteristic in high output.SOLUTION: A surface-emission quantum cascade laser comprises: a semiconductor laminate 10; an upper electrode 50; and a lower electrode 52. The semiconductor laminate has: an active layer 20 having a quantum well layer which causes an inter-subband transition, and emitting IR (infrared) laser light; a first semiconductor layer 30 provided on the active layer, and having a photonic crystal layer in which a pit part forms a rectangular grating; and a second semiconductor layer 39 provided under the active layer. The lower electrode is provided in a region of a lower face of the second semiconductor layer, which overlaps with the upper electrode. In plan view, the semiconductor laminate has a surface-emission region 70 including the photonic crystal layer, and a current-injection region 72 having the upper electrode provided therein and surrounding the surface-emission region. The active layer causes an inter-subband transition, which can emit IR laser light toward a direction perpendicular to the surface-emission region while causing an optical resonance by a 2D diffraction grating.SELECTED DRAWING: Figure 1 【課題】高出力時に光学特性が改善可能な面発光量子カスケードレーザを提供する。【解決手段】面発光量子カスケードレーザは、半導体積層体１０と、上部電極５０と、下部電極５２と、を有する。半導体積層体は、サブバンド間遷移を生じる量子井戸層を有しかつ赤外レーザ光を放出する活性層２０と、活性層の上に設けられかつピット部が直方格子を構成するフォトニック結晶層を有する第１半導体層３０と、活性層の下方に設けられた第２半導体層３９と、を有する。下部電極は、第２半導体層の下面のうち、上部電極と重なる領域に設けられる。平面視にて、半導体積層体は、フォトニック結晶層を含む面発光領域７０と、上部電極が設けられかつ面発光領域を取り囲む電流注入領域７２と、を有する。活性層は、サブバンド間遷移を生じ、二次元回折格子により光共振を生じつつ面発光領域の垂直方向へ赤外レーザ光を放出可能とする。【選択図】図１