Abstract: A transmissive optical element may include a substrate. The transmissive optical element may include a first anti-reflectance structure for a particular wavelength range formed on the substrate. The transmissive optical element may include a second anti-reflectance structure for the particular wavelength range formed on the first anti-reflectance structure. The transmissive optical element may include a third anti-reflectance structure for the particular wavelength range formed on the second anti-reflectance structure. The transmissive optical element may include at least one layer disposed between the first anti-reflectance structure and the second anti-reflectance structure or between the second anti-reflectance structure and the third anti-reflectance structure.

Abstract: A zoned waveplate has a series of transversely stacked birefringent zones alternating with non-birefringent zones. The birefringent and non-birefringent zones are integrally formed upon an AR-coated face of a single substrate by patterning the AR coated face of the substrate with zero-order sub-wavelength form-birefringent gratings configured to have a target retardance. The layer structure of the AR coating is designed to provide the target birefringence in the patterned zones and the reflection suppression.

Abstract: A sub-wavelength grating is placed inside a liquid crystal variable optical retarder to reduce polarization dependence of the optical retardation generated by the variable optical retarder. A small thickness of the sub-wavelength grating, as compared to a conventional waveplate, reduces the driving voltage penalty due to the in-cell placement of the sub-wavelength grating.

Abstract: A zoned waveplate has a series of transversely stacked birefringent zones alternating with non-birefringent zones. The birefringent and non-birefringent zones are integrally formed upon an AR-coated face of a single substrate by patterning the AR coated face of the substrate with zero-order sub-wavelength form-birefringent gratings configured to have a target retardance. The layer structure of the AR coating is designed to provide the target birefringence in the patterned zones and the reflection suppression.

Abstract: A sub-wavelength grating is placed inside a liquid crystal variable optical retarder to reduce polarization dependence of the optical retardation generated by the variable optical retarder. A small thickness of the sub-wavelength grating, as compared to a conventional waveplate, reduces the driving voltage penalty due to the in-cell placement of the sub-wavelength grating.

Abstract: A diffraction grating may include a substrate. The diffraction grating may include an etch stop layer to prevent etching of the substrate. The etch stop layer may be deposited on the substrate. The diffraction grating may include a marker layer to indicate an etch end-point associated with etching of a dielectric layer. The marker layer may be deposited on a portion of the etch stop layer. The diffraction grating may include the dielectric layer to form a grating layer after being etched. The dielectric layer may be deposited on at least the marker layer.

Abstract: A method may include receiving, by a switching engine, an optical signal. The optical signal may carry a super-channel that includes a plurality of sub-carriers to be directed toward respective output ports. The switching engine may have a plurality of regions of pixels on which respective sub-carriers, of the plurality of sub-carriers, are incident. The method may include applying, by the switching engine, respective single beam steering gratings to first, overlapping, areas of the plurality of regions of pixels. The method may include applying, by the switching engine, one or more respective pluralities of beam steering gratings to second, overlapping areas of the plurality of regions of pixels. The method may include directing, based on the single beam steering gratings and the one or more pluralities of beam steering gratings, parts of the optical signal toward the respective output ports.

Abstract: A zoned waveplate has a series of transversely stacked birefringent zones alternating with non-birefringent zones. The birefringent and non-birefringent zones are integrally formed upon an AR-coated face of a single substrate by patterning the AR coated face of the substrate with zero-order sub-wavelength form-birefringent gratings configured to have a target retardance. The layer structure of the AR coating is designed to provide the target birefringence in the patterned zones and the reflection suppression.

Abstract: A reflective diffraction grating and a fabrication method are provided. The reflective diffraction grating includes a substrate, a UV-absorbing layer, a grating layer having a binary surface-relief pattern formed therein, and a conforming reflective layer. Advantageously, the UV-absorbing layer absorbs light at a UV recording wavelength to minimize reflection thereof by the substrate during holographic patterning at the UV recording wavelength.

Abstract: A reflective diffraction grating and a fabrication method are provided. The reflective diffraction grating includes a substrate, a UV-absorbing layer, a grating layer having a binary surface-relief pattern formed therein, and a conforming reflective layer. Advantageously, the UV-absorbing layer absorbs light at a UV recording wavelength to minimize reflection thereof by the substrate during holographic patterning at the UV recording wavelength.

Abstract: A diffractive MEMS device has an in-plane binary reflective diffraction pattern formed in an outer surface of a tillable platform. The binary reflective diffraction pattern includes rectangular or trapezoidal ridges and valleys, or grooves, of a same depth. The binary reflective diffractive pattern has a high diffraction efficiency even though the surfaces of the “grooves” or “ridges” are not perpendicular to the incoming optical beam. The diffractive pattern is supported by a pair of torsional hinges and is tiltable by an electrostatic actuator. The electrostatic actuator can include at least one side electrode for linearization of dependence of tilt angle on the voltage applied to the actuator.

Abstract: A sub-wavelength thin-film metal grating is placed inside a liquid crystal variable optical retarder at a selected distance from a reflective electrode to form a reflective half wave plate, thereby reducing polarization dependence of the optical retardation generated by the variable optical retarder. The approach enables to form within the device the reflective half wave plate that is suitably thin without modifying the reflective electrode of the device.

Abstract: A zoned waveplate has a series of transversely stacked birefringent zones alternating with non-birefringent zones. The birefringent and non-birefringent zones are integrally formed upon an AR-coated face of a single substrate by patterning the AR coated face of the substrate with zero-order sub-wavelength form-birefringent gratings configured to have a target retardance. The layer structure of the AR coating is designed to provide the target birefringence in the patterned zones and the reflection suppression.

Abstract: A diffractive MEMS device has an in-plane binary reflective diffraction pattern formed in an outer surface of a tiltable platform. The binary reflective diffraction pattern includes rectangular or trapezoidal ridges and valleys, or grooves, of a same depth. The binary reflective diffractive pattern has a high diffraction efficiency even though the surfaces of the “grooves” or “ridges” are not perpendicular to the incoming optical beam. The diffractive pattern is supported by a pair of torsional hinges and is tiltable by an electrostatic actuator. The electrostatic actuator can include at least one side electrode for linearization of dependence of tilt angle on the voltage applied to the actuator.

Abstract: A sub-wavelength thin-film metal grating is placed inside a liquid crystal variable optical retarder at a selected distance from a reflective electrode to form a reflective half wave plate, thereby reducing polarization dependence of the optical retardation generated by the variable optical retarder. The approach enables to form within the device the reflective half wave plate that is suitably thin without modifying the reflective electrode of the device.

Abstract: A zoned waveplate has a series of transversely stacked birefringent zones alternating with non-birefringent zones. The birefringent and non-birefringent zones are integrally formed upon an AR-coated face of a single substrate by patterning the AR coated face of the substrate with zero-order sub-wavelength form-birefringent gratings configured to have a target retardance. The layer structure of the AR coating is designed to provide the target birefringence in the patterned zones and the reflection suppression.

Abstract: A method may include receiving, by a switching engine, an optical signal. The optical signal may carry a super-channel that includes a plurality of sub-carriers to be directed toward respective output ports. The switching engine may have a plurality of regions of pixels on which respective sub-carriers, of the plurality of sub-carriers, are incident. The method may include applying, by the switching engine, respective single beam steering gratings to first, overlapping, areas of the plurality of regions of pixels. The method may include applying, by the switching engine, one or more respective pluralities of beam steering gratings to second, overlapping areas of the plurality of regions of pixels. The method may include directing, based on the single beam steering gratings and the one or more pluralities of beam steering gratings, parts of the optical signal toward the respective output ports.

Abstract: This disclosure provides systems, methods and apparatus for managing a capacitor system. In one aspect, an energy storage system includes a capacitor system, a charging circuit, and a controller. The capacitor system includes one or more capacitors. The charging circuit is configured to charge the capacitor system to a first target voltage. The controller is configured to detect a first condition and is programmed, in response to the first condition, to instruct the charging circuit to charge the capacitor system to a second target voltage that is less than the first target voltage. The controller is programmed to provide a notification that the capacitor system is operating in a degraded state.

Abstract: A reflective diffraction grating and a fabrication method are provided. The reflective diffraction grating includes a substrate, a UV-absorbing layer, a grating layer having a binary surface-relief pattern formed therein, and a conforming reflective layer. Advantageously, the UV-absorbing layer absorbs light at a UV recording wavelength to minimize reflection thereof by the substrate during holographic patterning at the UV recording wavelength.

Abstract: A sub-wavelength thin-film metal grating is placed inside a liquid crystal variable optical retarder at a selected distance from a reflective electrode to form a reflective half wave plate, thereby reducing polarization dependence of the optical retardation generated by the variable optical retarder. The approach enables to form within the device the reflective half wave plate that is suitably thin without modifying the reflective electrode of the device.