Abstract: A QWIP structure is disclosed that includes a graded emitter barrier and can further be configured with a blocked superlattice miniband. The graded emitter barrier effectively operates to launch dark electrons into the active quantum well region, thereby improving responsivity. A graded collector barrier may also be included for reverse bias applications. The configuration operates to eliminate or otherwise reduce image artifacts or persistence associated with dielectric relaxation effect in low-background applications.

Abstract: A tunable QWIP FPA device that is configured for spectral tunability for performing the likes of imaging and spectroscopy is disclosed. A selected bias voltage is applied across the contacts associated with a particular detector layer/channel of the device, where each applied bias corresponds to a particular target spectrum/color for detection. Each detector layer/channel can be coarse tuned for a bimodal or dual-band operation (e.g., MWIR/LWIR). Also, each detector layer/channel is configured for continuous or fine tuning within a particular mode (e.g., MWIR/MWIR). Thus, dynamic bias-controlled tuning is enabled. Asymmetric quantum well configurations enable this tunability.

Abstract: A QWIP structure is disclosed that is configured with enhanced optical coupling to improve absorption capability and efficiency. A waffle-type light-coupling grating having a pattern of etched wells operates to improve absorption by preventing photons from bouncing out of the detector sensing areas. A post-type light coupling grating can also be used. Parameters of the grating, including its orientation, pitch, and etch depth, can be adjusted to optimize specific color detection. The grating can include a hybrid metal layer including both ohmic and reflective qualities to further improve quantum and conversion efficiency. A “photon-in-a-box” configuration is also disclosed, where sides of the QWIP sensing areas are coated with reflective metal to further inhibit the escaping of photons. The material design and number of quantum wells per QWIP can be selected so as to exploit the avalanche effect, thereby increasing device responsivity.

Abstract: A QWIP structure is disclosed that includes a graded emitter barrier and can further be configured with a blocked superlattice miniband. The graded emitter barrier effectively operates to launch dark electrons into the active quantum well region, thereby improving responsivity. A graded collector barrier may also be included for reverse bias applications. The configuration operates to eliminate or otherwise reduce image artifacts or persistence associated with dielectric relaxation effect in low-background applications.

Abstract: A tunable QWIP FPA device that is configured for spectral tunability for performing the likes of imaging and spectroscopy is disclosed. A selected bias voltage is applied across the contacts associated with a particular detector layer/channel of the device, where each applied bias corresponds to a particular target spectrum/color for detection. Each detector layer/channel can be coarse tuned for a bimodal or dual-band operation (e.g., MWIR/LWIR). Also, each detector layer/channel is configured for continuous or fine tuning within a particular mode (e.g., MWIR/MWIR). Thus, dynamic bias-controlled tuning is enabled. Asymmetric quantum well configurations enable this tunability.

Abstract: A QWIP structure is disclosed that is configured with enhanced optical coupling to improve absorption capability and efficiency. A waffle-type light-coupling grating having a pattern of etched holes operates to improve absorption by preventing photons from bouncing out of the detector sensing areas. A post-type light coupling grating can also be used. Parameters of the grating, including its orientation, pitch, and etch depth, can be adjusted to optimize specific color detection. The grating can include a hybrid metal layer including both ohmic and reflective qualities to further improve quantum and conversion efficiency. A “photon-in-a-box” configuration is also disclosed, where sides of the QWIP sensing areas are coated with reflective metal to further inhibit the escaping of photons. The material design and number of quantum wells per QWIP can be selected so as to exploit the avalanche effect, thereby increasing device responsivity.

Abstract: A switching device for switching an optical beam between first and second outputs each associated with first and second paths in a thin-film optical wave guide supported on a substrate. Switching occurs by reason of mode conversion in a first or second path as determined by the direction of a variable magnetic field. A common optical path is defined, in said wave guide, by a first optical coupler, for coupling an optical beam into or out of said wave guide, and a beam splitter. First and second optical paths are defined, in the same wave guide, between the beam splitter and second and third couplers each co-linear with said beam splitter. At least a portion of each of said first and second optical paths include means for periodically varying the magnetization in said path. The wave guide is subjected to a d.c. magnetic field in the plane of the wave guide and at an angle with respect to both said first and second paths. Preferably the first and second paths are perpendicular and the d.c. field makes a 45.