Abstract: Quantum dots are modified with varying amounts of (a) a redox-active moiety effective to perform charge transfer quenching, and (b) a fluorescent dye effective to perform fluorescence resonance energy transfer (FRET), so that the modified quantum dots have a plurality of photophysical properties. The FRET and charge transfer pathways operate independently, providing for two channels of control for varying luminescence of quantum dots having the same innate properties.

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 high purity nano-sized Yb3+ doped Y2O3 (Yb:Y2O3) ceramic powder with a narrow size distribution and without hard agglomerates is provided. Also provided is a process for manufacturing the same wherein water in the reaction bath is replaced by a non-water washing agent having little or no hydrogen bonding capability to inhibit the formation of hard agglomerates in the ceramic powder.