Abstract: An interband cascade gain medium is provided. The gain medium can include at least one thick separate confinement layer comprising Ga(InAlAs)Sb between the active gain region and the cladding and can further include an electron injector region having a reduced thickness, a hole injector region comprising two hole quantum wells having a total thickness greater than about 100 ?, an active gain quantum well region separated from the adjacent hole injector region by an electron barrier having a thickness sufficient to lower a square of a wavefunction overlap between a zone-center active electron quantum well and injector hole states, and a thick AlSb barrier separating the electron and hole injectors of at least one stage of the active region.

Abstract: A gain medium and an interband cascade laser, having the gain medium are presented. The gain medium can have one or both of the following features: (1) the thicknesses of the one or more hole quantum wells in the hole injector region are reduced commensurate with the thickness of the active hole quantum well in the active quantum well region, so as to place the valence band maximum in the hole injector region at least about 100 meV lower than the valence band maximum in the active hole quantum well; and (2) the thickness of the last well of the electron injector region is between 85 and 110% of the thickness of the first active electron quantum well in the active gain region of the next stage of the medium. A laser incorporating a gain medium in accordance with the present invention can emit in the mid-IR range from about 2.5 to 8 ?m at high temperatures with room-temperature continuous wave operation to wavelengths of at least 4.

Abstract: A gain medium and an interband cascade laser, having the gain medium are presented. The gain medium can have one or both of the following features: (1) the thicknesses of the one or more hole quantum wells in the hole injector region are reduced commensurate with the thickness of the active hole quantum well in the active quantum well region, so as to place the valence band maximum in the hole injector region at least about 100 meV lower than the valence band maximum in the active hole quantum well; and (2) the thickness of the last well of the electron injector region is between 85 and 110% of the thickness of the first active electron quantum well in the active gain region of the next stage of the medium. A laser incorporating a gain medium in accordance with the present invention can emit in the mid-IR range from about 2.5 to 8 ?m at high temperatures with room-temperature continuous wave operation to wavelengths of at least 4.

Abstract: A gain medium and an interband cascade laser, having the gain medium are presented. The gain medium can have one or both of the following features: (1) the thicknesses of the one or more hole quantum wells in the hole injector region are reduced commensurate with the thickness of the active hole quantum well in the active quantum well region, so as to place the valence band maximum in the hole injector region at least about 100 meV lower than the valence band maximum in the active hole quantum well; and (2) the thickness of the last well of the electron injector region is between 85 and 110% of the thickness of the first active electron quantum well in the active gain region of the next stage of the medium. A laser incorporating a gain medium in accordance with the present invention can emit in the mid-IR range from about 2.5 to 8 ?m at high temperatures with room-temperature continuous wave operation to wavelengths of at least 4.

Abstract: A gain medium and an interband cascade laser, having the gain medium are presented. The gain medium can have one or both of the following features: (1) the thicknesses of the one or more hole quantum wells in the hole injector region are reduced commensurate with the thickness of the active hole quantum well in the active quantum well region, so as to place the valence band maximum in the hole injector region at least about 100 meV lower than the valence band maximum in the active hole quantum well; and (2) the thickness of the last well of the electron injector region is between 85 and 110% of the thickness of the first active electron quantum well in the active gain region of the next stage of the medium. A laser incorporating a gain medium in accordance with the present invention can emit in the mid-IR range from about 2.5 to 8 ?m at high temperatures with room-temperature continuous wave operation to wavelengths of at least 4.

Abstract: An interband cascade gain medium is provided. The gain medium can include at least one thick separate confinement layer comprising Ga(InAlAs)Sb between the active gain region and the cladding and can further include an electron injector region having a reduced thickness, a hole injector region comprising two hole quantum wells having a total thickness greater than about 100 ?, an active gain quantum well region separated from the adjacent hole injector region by an electron barrier having a thickness sufficient to lower a square of a wavefunction overlap between a zone-center active electron quantum well and injector hole states, and a thick AlSb barrier separating the electron and hole injectors of at least one stage of the active region.

Abstract: A gain medium and an interband cascade laser, an interband cascade amplifier, and an external cavity laser having the gain medium are presented.

Abstract: A surface plasmon polariton device that may be integrated onto a single microchip is disclosed. The device employs a laser that emits polarized light across a gap into a plasmonic waveguide. Surface plasmon polaritons are thereby created in an efficient matter. The device provides a source of surface plasmon polaritons at near infrared wavelengths in an integrated package.

Abstract: An optical limiter structure which includes a limiter material preferably dissolved in a host. The limiter material is selected from substituted and unsubstituted phthalocyanines, naphthalocyanines, porphyrins, salts of these materials and mixtures thereof, whereas the host is selected from any material which can dissolve the limiter material to at least the extent of 0.1% by weight.

Abstract: A protective layer laser hardens an optical detector. The material for the rotective layer is Hg.sub.1-Y Cd.sub.Y Te, where Y is selected so that the band gap of the protective layer is higher than the expected energy level for photons impinging on the protective layer. Photons with energy levels lower than the band gap are transmitted by the protective layer while photons exceeding the band gap energy level are absorbed or reflected by the protective layer. A semiconductor junction can be formed on the opposite side of the substrate from a Hg.sub.X Cd.sub.X Te layer with a band gap lower than the expected energy level, so that photons transmitted through the substrate are absorbed in the Hg.sub.X Cd.sub.X Te layer and, therefore, detected at the junction. At sufficiently high intensities where detector damage could result, the protective layer switches so that the incident photons are either absorbed or reflected, thus protecting the detector from damage.