Patent ID: 8098702
Filing Date: 2012-01-17
Classification: B82Y,H01S

Abstract:
1. A quantum cascade structure comprising: a semiconductor heterostructure having a plurality of lasing sections functionally associated in series, each of said plurality of lasing sections having at least one quantum well; at least one of said at least one quantum well of at least one of said plurality of lasing sections being a step well formed of lattice matched materials; and said step well having, in the presence of an applied electric field, an upper lasing state, a lower lasing state, and a lower state, wherein said upper lasing state and said lower lasing state are separated by an energy corresponding to an optical frequency in a range from about 1 terahertz to about 5 terahertz, such that a radiative lasing transition between said upper lasing state and said lower lasing state is spatially vertical and occurs within said step well, wherein electrons populating said lower lasing state undergo non-radiative transition via resonant emission of a LO-phonon into said lower state of said step quantum well, and said resonant LO-phonon emission selectively depopulates the lower lasing state such that the lifetime of said upper lasing state is greater than the lifetime of said lower lasing state.