The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 26, 2020
Filed:
Feb. 28, 2019
Riken, Wako-shi, Saitama, JP;
RIKEN, Saitama, JP;
Abstract
To increase the maximum operating temperature of quantum cascade lasers of a terahertz region, a quantum cascade laser elementaccording to the present invention has a semiconductor superlattice structure sandwiched between a pair of electrodes, the semiconductor superlattice structure has an active regionthat emits electromagnetic waves of a frequency in a THz region under an external voltage applied through the pair of electrodes for operation, and the active regionhas plural unit structuresU, each of which is repeatedly layered over one another. Each of the unit structuresU has a double quantum well structure formed of a first well layerWand a second well layerWseparated from each other by a barrier layer, the first well layerWand the second well layerWhave compositions different from each other, and when the external voltage is not being applied, potential energy for electrons in the second well layerWis lower than that in the first well layerW