The present disclosure discloses a saturable absorber mirror of a composite structure, including: a substrate; a buffer layer on the substrate; a distributed Bragg reflective mirror on the buffer layer; a quantum dot or quantum well saturable absorber body on the distributed Bragg reflective mirror; a graphene saturable absorber body on the quantum dot or quantum well saturable absorber body. In the present disclosure, the graphene saturable absorber body is composited with the quantum dot saturable absorber body or the quantum well saturable absorber body to be used as the saturable absorber body in the saturable absorber mirror of the present disclosure. A thermal damage threshold and an optical property stability of the saturable absorber body are improved, and an ultrafast laser pulse with high power and short pulse mode locking, a stable output repetition cycle, a narrow pulse width, and a short response time is implemented.

An optoelectronic semiconductor chip includes a semiconductor body including a first semiconductor region and a second semiconductor region, a recess extending through the first semiconductor region, the recess having a bottom surface, where the second semiconductor region is exposed, and a blocking element arranged on the bottom surface, wherein the at least one recess has a first width and a second width parallel to the main extension plane of the semiconductor body, and the first width is smaller than the second width.

An electrochromic system and method for controlling photochromic darkening of an electrochromic device, the system including an EC device, a control unit, a voltage detector, and a power supply. The EC device includes a working electrode, a counter electrode, a solid-state polymer electrolyte disposed therebetween, and an ionically conductive and electrically insulating protective layer disposed between the electrolyte and the working electrode. The control unit is configured to control a sweep voltage applied between the working and counter electrodes, such that the sweep voltage is applied when an open circuit voltage (OCV) between the working and counter electrodes is less than a threshold voltage.

Thermally and electrically driven dynamic filters for smart windows are configured to filter electromagnetic radiation in the infrared range of wavelengths. Some thermochromic filters embodiments are configured to filter both electromagnetic radiation in the infrared range of wavelengths and electromagnetic radiation in the visible range of wavelengths.

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.

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 distributed Bragg reflectors.

Provided a light modulating device including a variable mirror including a plurality of lattice structures, the plurality of lattice structures including a material having a refractive index that changes based on a temperature of the material, a distributed Bragg mirror spaced apart from the variable mirror and provided above the variable mirror, the distributed Bragg mirror including a first material layer and a second material layer that are alternately stacked, and a refractive index of the first material layer being different from a refractive index of the second material layer, and a heating portion configured to heat the plurality of lattice structures and provided below the variable mirror opposite to the distributed Bragg mirror.

An electrochromic system and method for controlling photochromic darkening of an electrochromic device, the system including an EC device, a control unit, a voltage detector, and a power supply. The EC device includes a working electrode, a counter electrode, a solid-state polymer electrolyte disposed therebetween, and a Bragg reflector configured to selectively reflect UV radiation away from the working electrode. The control unit is configured to control a sweep voltage applied between the working and counter electrodes, such that the sweep voltage is applied when an open circuit voltage (OCV) between the working and counter electrodes is less than a threshold voltage.

An optoelectronic device includes an optical waveguide disposed on a substrate. A pair of Bragg reflectors is formed in the optical waveguide to define a resonant cavity between the Bragg reflectors. A piezoelectric material is disposed on the substrate in proximity to the optical waveguide. Electrodes are configured to apply an electric field to the piezoelectric material so as to tune a wavelength of light emitted from the resonant cavity.

A display device may have a reduced thickness while having enhanced color reproducibility by having an improved structure. The display device may include: a liquid crystal panel; a light source plate which is arranged at the rear of the liquid crystal panel to provide light to the liquid crystal panel, and which includes a printed circuit board and an LED chip mounted on the printed circuit board; and a chip cover which is provided to cover a light-emitting surface of the LED chip, and which changes the wavelength of the light emitted from the LED chip, wherein the chip cover includes: a cover layer having a first surface arranged to face the light-emitting surface of the LED chip, a second surface opposite to the first surface, and an accommodating groove provided on the second surface; a light conversion member which changes the wavelength of the light emitted from the LED chip, and which is accommodated in the accommodating groove; and a barrier layer for covering the second surface to cover the light conversion member from the outside.