An optical modulator is provided, including a lower reflection layer, an active layer formed on the lower reflection layer, and an upper reflection layer formed on the active layer. The active layer includes a multiple quantum well structure including a quantum well layer and a quantum barrier layer. The upper reflection layer includes a dielectric material. A plurality of micro cavity layers are included in the upper reflection layer.

A display apparatus, includes: a liquid crystal panel; and a backlight configured to provide light to the liquid crystal panel, the backlight including a substrate and a light-emitting diode (LED) that is mounted on the substrate. The LED includes a plurality of light-emitting layers configured to emit light of different wavelengths. A wavelength of light emitted from each of the plurality of light-emitting layers is greater than or equal to 430 nm and less than or equal to 480 nm.

Various of the disclosed embodiments incorporate wavelength-shifting (WLS) materials to facilitate high data rate communication. Some embodiments employ a waveguide incorporating such WLS materials to receive a wireless signal from a source. The signal may be, e.g., in the optical or ultraviolet ranges, facilitating a 10 Gbps data rate. Because the WLS material is sensitive in all directions, the source may be isotropic or wide-angled. The WLS material may be shaped into one or more bands that may cover an object, e.g., a head-mounted display. A detector may be coupled with the bands to receive the wavelength-shifted signal and to recover the original signal from the source. The WLS material may be modified to improve the waveguide retention, e.g., by incorporating layers of material having a different reflection coefficient or a Bragg reflector.

A display apparatus includes a liquid crystal panel; and a backlight unit configured to provide light to the liquid crystal panel, wherein the backlight unit includes: a substrate; and a plurality of light emitting diode groups provided on an upper surface of the substrate, wherein each of the plurality of light emitting diode groups includes a red light emitting diode, a green light emitting diode, and a blue light emitting diode, wherein each of the red light emitting diode, the green light emitting diode, and the blue light emitting diode includes: a light emitting layer; and a distributed Bragg reflector (DBR) provided on the light emitting layer, and wherein reflectivities of the distributed Bragg reflectors of the red light emitting diode, the green light emitting diode, and the blue light emitting diode are within a same range of reflectivity according to an incident angle of light incident on the DBRs.

A spatial light modulator includes an upper reflective layer on which light is incident, a lower reflective layer below the upper reflective layer, and a cavity layer between the upper reflective layer and the lower reflective layer, the cavity layer having a refractive index configured to change based on an electrical signal, where the cavity layer includes a first material layer having a first refractive index, and at least one second material layer having a second refractive index that is less than the first refractive index.

Tunable optical structures operating based on slot resonances can be produced with periodic structures where each period includes at least two parallel nanobars with a slot therebetween. The slots include periodic notches served to generate resonances, the wavelength and the quality-factor of which can be controlled by applying bias voltages to nanobars thus generating mechanical movement of such nanobars. Phase modulators with close to unity reflection and beam steering devices can also be made based on these concepts.

A display apparatus includes a liquid crystal panel; and a backlight unit configured to provide light to the liquid crystal panel, wherein the backlight unit includes: a substrate; and a plurality of light emitting diode groups provided on an upper surface of the substrate, wherein each of the plurality of light emitting diode groups includes a red light emitting diode, a green light emitting diode, and a blue light emitting diode, wherein each of the red light emitting diode, the green light emitting diode, and the blue light emitting diode includes: a light emitting layer; and a distributed Bragg reflector (DBR) provided on the light emitting layer, and wherein reflectivities of the distributed Bragg reflectors of the red light emitting diode, the green light emitting diode, and the blue light emitting diode are within a same range of reflectivity according to an incident angle of light incident on the DBRs.

The present disclosure relates to an electrically controllable optical modulation device and, in more detail, an optical modulation device that can be electrically controlled because it has a Tamm plasmon structure.

Systems, devices, and techniques are described herein solidly mounted acousto-optical devices. One aspect includes a piezoelectric layer comprising a top surface and a bottom surface, waveguide on the top surface of the piezoelectric layer, a first interdigital transducer disposed on the top surface of the piezoelectric layer, wherein the first interdigital transducer is positioned on a first side of the waveguide, and a second interdigital transducer disposed on the top surface of the piezoelectric layer, wherein the second interdigital transducer is positioned on a second side of the waveguide opposite the first side.

Electrochromic devices with reflective structure and related manufacturing methods are provided. One of the electrochromic devices includes a bottom electrode layer, an electrochromic layer on the bottom electrode layer, an electrolyte layer on the electrochromic layer, a charge storage layer on the electrolyte layer, and a top electrode on the charge storage layer. The transmittance of the electrochromic device changes in response to a voltage applied between the bottom electrode layer and the top electrode layer. One of the bottom and the top electrode layers is a reflective conductive layer, while the other being a transparent conductive layer. This electrochromic device has a simplified structure due to the removal of a separated reflective film, which also results in simplified manufacturing process.