A display device includes: a color filter including a first transmissive filter, a second transmissive filter, and a third transmissive filter, the first, second and third transmissive filters being configured to transmit respective light beams having peak wavelengths different from each other; a first selective-wavelength-reflection layer adjacent to an optical-input surface of the first transmissive filter, the first selective-wavelength-reflection layer being configured to reflect light of a wavelength band that passes through the third transmissive filter; a second selective-wavelength-reflection layer adjacent to an optical-input surface of the second transmissive filter, the second selective-wavelength-reflection layer being configured to reflect light of a wavelength band that passes through the third transmissive filter, the second selective-wavelength-reflection layer being identical in composition to the first selective-wavelength-reflection layer; and a light emitter configured to emit light that travels toward the color filter.

The present invention discloses a TMOS based on slab PhCs with a high DOP and a large EXR, which comprises an upper slab PhC and a lower slab PhC; the upper slab PhC is called as a first square-lattice slab PhC with a TE bandgap, the unit cell of the first square-lattice slab PhC includes a high-refractive-index rotating-square pillar, a single first flat dielectric pillar and a background dielectric, the first flat dielectric pillar includes a high-refractive-index dielectric pipe and a low-refractive-index dielectric, or a high-refractive-index flat film, or a low-refractive-index dielectric; the lower slab PhC is a second square-lattice slab PhC with a complete bandgap, wherein the unit cell of the second square-lattice slab PhC includes a high-refractive-index rotating-square pillar, a single second flat dielectric pillar and a background dielectric, and a normalized operating frequency of the TMOS with high DOP and large extinction ratio is 0.252 to 0.267.

The present invention discloses a TEOS with a high extinction ratio based on slab PhCs which comprises an upper slab PhC and a lower slab PhC connected as a whole; the upper slab PhC is a first square-lattice slab PhC, the unit cell of the first square-lattice slab PhC includes a high-refractive-index rotating-square pillar, three first flat dielectric pillars and a background dielectric, the first flat dielectric pillars include a high-refractive-index dielectric pipe and a low-refractive-index dielectric, or 1 to 3 high-refractive-index flat films, or a low-refractive-index dielectric; the lower slab PhC is a second square-lattice slab PhC with a complete bandgap, the unit cell of the second square-lattice slab PhC includes a high-refractive-index rotating-square pillar, three second flat dielectric pillars and a background dielectric is a low-refractive-index dielectric; and an normalized operating frequency of the TEOS is 0.4057 to 0.406.

A backlight unit includes a light guide plate; a light source provided on a side surface of the light guide plate, and configured to inject light into the light guide plate; a circular polarizing reflective layer provided on a front surface of the light guide plate, and configured to reflect a first polarizing component and transmit a second polarizing component among components of light emitted from the light guide plate; and a cholesteric liquid crystal layer provided on the front surface of the circular polarizing reflective layer and including a plurality of regions, and configured to reflect or transmit the second polarizing component that has passed through the circular polarizing reflective layer according to a voltage applied to each of the plurality of regions.

The present invention discloses a TMOS with a high extinction ratio based on slab PhCs which comprises an upper slab PhC and a lower slab PhC connected as a whole; the upper slab PhC is called as a first square-lattice slab PhC, wherein the unit cell of the first square-lattice slab PhC includes a high-refractive-index rotating-square pillar, three first flat dielectric pillars and a background dielectric, and the first flat dielectric pillars includes a high-refractive-index dielectric pipe and a low-refractive-index dielectric, or of 1 to 3 high-refractive-index flat films, or of a low-refractive-index dielectric; the lower slab PhC is a second square-lattice slab PhC with a complete bandgap, the unit cell of the second square-lattice slab PhC includes a high-refractive-index rotating-square pillar, three second flat dielectric pillars and a background dielectric is a low-refractive-index dielectric and an normalized operating frequency of the TMOS is 0.4057 to 0.406.

The present invention discloses a TEOS based on slab PhCs with a high DOP and large EXR, which comprises an upper slab PhC and a lower slab PhC; the upper slab PhC is a first square-lattice slab PhC with a TM bandgap and a complete bandgap, wherein the unit cell of the first square-lattice slab PhC includes a high-refractive-index rotating-square pillar, a single first flat dielectric pillar and a background dielectric, the first flat dielectric pillar includes a high-refractive-index dielectric pipe and a low-refractive-index dielectric, or a high-refractive-index flat film, or a low-refractive-index dielectric; the lower slab PhC is a second square lattice slab PhC with a TM bandgap and complete bandgap, wherein the unit cell of the second square-lattice slab PhC includes a high-refractive-index rotating-square pillar, a single second flat dielectric pillar and a background dielectric, and an normalized operating frequency of the TEOS is 0.453 to 0.458.

Provided is an electro-optical phase modulation system, including: an electro-optical crystal, a radio frequency circuit and a light source, light incident surface of the electro-optical crystal is in parallel with light exit surface, upper electrode surface thereof is in parallel with lower electrode surface, and an angle between light incident surface and upper electrode surface is Brewster angle; two electrodes of radio frequency circuit are connected to upper and lower electrode surfaces respectively, for transmitting radio frequency signals to upper and lower electrode surfaces, so that an electric filed, direction of which is perpendicular to upper electrode surface, is formed between upper and lower electrode surfaces; light source is located at a side of light incident surface, and incidence angle of beams from light source with respect to light incident surface is Brewster angle. The system is used to reduce residual amplitude modulation, and increase accuracy of phase modulation.

An optical logic gate includes: a DNA based nanostructure including DNA and metal nanoparticles coupled to the DNA, the DNA based nanostructure being configured to rotate a polarization plane of an incident light; a polarizer to which light passing through the DNA based nanostructure is incident, the polarizer being configured to extract a component in a direction of a predetermined reference axis from light whose polarization plane is rotated by the DNA based nanostructure; and a detection unit to which light passing through the polarizer is incident, the detection unit being configured to generate a logic signal based on a result obtained by comparing the intensity of the component in the reference axis direction extracted by the polarizer with a predetermined threshold value.

An optical transmitter includes: a splitter; a first optical modulator and a second optical modulator that modulate each of light beams split by the splitter; a first semiconductor optical amplifier (SOA) and a second SOA that are connected to a subsequent stage of the first optical modulator and a subsequent stage of the second optical modulator, respectively; a first detector and a second detector that detect light output intensity of the first SOA and light output intensity of the second SOA, respectively; a controller that sets gains of the first and second SOAs such that the first and second SOAs are equal in the light output intensity based on detection values of the first and second detectors; and a combiner that combines an output light beam of the first SOA and an output light beam of the second SOA.

An optical modulator element includes first and second optical modulators, an optical input terminal, and a branch coupler. Each of the first and second optical modulators includes a pair of Mach-Zehnder waveguides, a first optical coupler to split rays from the branch coupler into the pair of Mach-Zehnder waveguides, and a second optical coupler to combine rays transmitted through the pair of Mach-Zehnder waveguides. The first and second optical modulators are disposed in such a manner that a traveling direction of rays propagating through the pair of Mach-Zehnder waveguides of the first optical modulator and a traveling direction of rays propagating through the pair of Mach-Zehnder waveguides of the second optical modulator are angled toward each other.