Abstract: Disclosed are a method for determining an error component of a photoelectric theodolite and a method for compensating an error component of a photoelectric theodolite. A celestial region is divided into 60 sub-regions by star selection software, a star is selected from each sub-region to serve as a reference star, the theodolite is controlled to sequentially point at the reference stars, an azimuth deviation and an elevation deviation for each reference star are calculated, an axis systematic error pointing model, an azimuth error equation and an elevation error equation for the photoelectric theodolite are established, a least squares estimated value of an azimuth error component and a least squares estimated value of an elevation error component are calculated by a least squares method, a reference star with a large fitting residual is excluded, and an iterative calculation is performed repeatedly.

Abstract: The present disclosure relates to a coaxial four-reflection optical system with visible light long-wave infrared common-aperture imaging, and belongs to the technical field of optical systems. The technical problems that the axial length compactness and the imaging quality of the visible light/infrared composite imaging system in the existing technology need to be improved are solved. The optical system of the present disclosure includes a main reflecting mirror, a first transmitting mirror, a third reflecting mirror, a fourth reflecting mirror, a second transmitting mirror, a third transmitting mirror and a fourth transmitting mirror.

Abstract: An exemplary embodiment of the invention relates to a method of fabricating a radiation emitter (100) comprising the steps of fabricating a lower layer stack (20) on top of a substrate (10), the lower layer stack (20) comprising a lower contact layer (21) and at least one lower reflector (22), fabricating an intermediate layer stack (30) on top of the lower layer stack (20), the intermediate layer stack (30) comprising at least one active layer (31) and at least one aperture layer (32), fabricating an upper layer stack (40) on top of the intermediate layer stack (30), the upper layer stack (40) comprising at least one upper reflector (42) and an upper contact layer (41), and forming a mesa that at least comprises a mesa section of the upper layer stack (40), by locally removing at least the upper layer stack (40).

Abstract: A bidirectional Littrow two-degree-of-freedom grating interference measurement device based on double gratings includes a transmission two-dimensional grating and a reflection two-dimensional grating. A dual-frequency laser emitted by a light source passes through the transmission two-dimensional grating with a specific grating pitch to form four beams in X direction and Y direction, the four beams are incident on the reflection two-dimensional grating at a Littrow angle, and the four beams diffracted by the reflection two-dimensional grating return to the transmission two-dimensional grating in an incidence direction along the same path; different orders of transmission light of the four beams of light in different directions may form stable interference signals carrying displacement information, and the stable interference signals are received by a detector.

Abstract: Disclosed are a grating displacement measurement device and a grating displacement measurement method using a double-layer floating reading head, a medium, and an apparatus. A first measurement grating group is arranged on two first side edges of a substrate working surface, and a second measurement grating group is symmetrically arranged on both sides of a first reference line and close to a light-through member. A reading component is provided between a first measurement grating and a second measurement grating arranged on the same side, and each reading component is used to collect a first position information of the first measurement grating and a second position information of the second measurement grating. In the technical solutions, by using multi-channel position information output by two reading components in combination with a displacement solution algorithm.

Abstract: A method of fabricating at least one radiation emitter including fabricating a layer stack that includes a first reflector, an active region, an oxidizable layer, and a second reflector; and locally removing the layer stack, and thereby forming at least one mesa. The mesa includes the first reflector, the active region, the oxidizable layer and the second reflector. Before or after locally removing the layer stack and forming the mesa the following steps are carried out: vertically etching at least three blind holes inside the layer stack, wherein the blind holes vertically extend to and expose the oxidizable layer; and oxidizing the oxidizable layer via the sidewalls of the blind holes in lateral direction. An oxidation front radially moves outwards from each hole. The etching is terminated before the entire oxidizable layer is oxidized, thereby forming at least one unoxidized aperture that is limited by at least three oxidation fronts.

Abstract: An exemplary embodiment of the present invention relates to a method of fabricating at least one radiation emitter comprising the steps of depositing an etch stop layer on a top side of a substrate; depositing a layer stack on the etch stop layer, said layer stack comprising a first contact layer, a first reflector, an active region, a second reflector, and a second contact layer; locally removing the layer stack and the etch stop layer, and thereby forming at least one mesa, said at least one mesa comprising an unremoved section of the etch stop layer and a layered pillar which forms a vertical cavity laser structure based on the unremoved layer stack inside the at least one mesa; depositing a protection material on the top side of the substrate and thereby embedding the entire mesa in the protection material wherein the backside of the substrate remains unprotected; removing the substrate by applying at least one etching chemical that is capable of etching the substrate but incapable or less capable of etch

Abstract: A method of fabricating a radiation emitter including fabricating a layer stack that includes a first reflector, at least one intermediate layer, an active region and a second reflector; locally oxidizing the intermediate layer and thereby forming at least one unoxidized aperture; and locally removing the layer stack, and thereby forming a mesa that includes the first reflector, the unoxidized aperture, the active region, and the second reflector. Before or after locally removing the layer stack and forming the mesa: forming at least a first unoxidized aperture and at least a second unoxidized aperture inside the intermediate layer; etching a trench inside the layer stack, the trench defining a first portion and a second portion of the mesa, wherein the trench severs the intermediate layer(s) so that the first aperture is located in the first portion and the second aperture is located in the second portion of the mesa.

Abstract: Disclosed are a thin-disk regenerative amplifier and an amplification method. The thin-disk regenerative amplifier includes an input and output light path and an amplification light path. A seed laser is input into the thin-disk regenerative amplifier through the input and output light path, and reflected and amplified by the amplification optical path to obtain an amplified laser. After reaching a predetermined threshold, the amplified laser is output through the input and output light path. The input and output optical path includes an optical isolator, a first polarization beam splitter, an optical rotator, a second polarization beam splitter, a first reflective mirror, and a second reflective mirror. The amplification light path includes an input mirror, a thin-disk crystal, a pumping device, a first concave reflective mirror, and a second concave reflective mirror.

Abstract: A laser device includes a gain medium, a zero-degree reflective mirror, a first retro-reflective mirror, a second retro-reflective mirror, and an output coupling mirror. The gain medium is used to generate radiation light; the zero-degree reflective mirror has a common optical axis with the gain medium, and the zero-degree reflective mirror is used to totally reflect second-direction radiation light that is incident on the zero-degree reflective mirror in an optical-axis direction; the first-direction radiation light and the first emitted light are spaced from and parallel to each other in opposite directions; the first emitted light and the second emitted light are spaced from and parallel to each other in opposite directions; a resonant cavity is formed between the zero-degree reflective mirror and the output coupling mirror; the output coupling mirror is used to transmit and output first partial radiation light, and reflect second partial radiation light.

Abstract: The present disclosure relates to a coaxial four-reflection optical system with visible light long-wave infrared common-aperture imaging, and belongs to the technical field of optical systems. The technical problems that the axial length compactness and the imaging quality of the visible light/infrared composite imaging system in the existing technology need to be improved are solved. The optical system of the present disclosure includes a main reflecting mirror, a first transmitting mirror, a third reflecting mirror, a fourth reflecting mirror, a second transmitting mirror, a third transmitting mirror and a fourth transmitting mirror.

Abstract: An exemplary embodiment of the present invention relates to a method of fabricating at least one radiation emitter comprising the steps of depositing an etch stop layer on a top side of a substrate; depositing a layer stack on the etch stop layer, said layer stack comprising a first contact layer, a first reflector, an active region, a second reflector, and a second contact layer; locally removing the layer stack and the etch stop layer, and thereby forming at least one mesa, said at least one mesa comprising an unremoved section of the etch stop layer and a layered pillar which forms a vertical cavity laser structure based on the unremoved layer stack inside the at least one mesa; depositing a protection material on the top side of the substrate and thereby embedding the entire mesa in the protection material wherein the backside of the substrate remains unprotected; removing the substrate by applying at least one etching chemical that is capable of etching the substrate but incapable or less capable of etch

Abstract: An exemplary embodiment of the invention relates to a method of fabricating a radiation emitter (100) comprising the steps of fabricating a layer stack (10) that comprises a first reflector (12), an active region (13), an oxidizable layer (21-24), and a second reflector (14); and locally removing the layer stack (10), and thereby forming a mesa (M) of the radiation emitter (100), wherein said mesa (M) comprises the first reflector (12), the active region (13), the oxidizable layer (21-24) and the second reflector (14), wherein before or after locally removing the layer stack (10) and forming said mesa (M) the following steps are carried out: vertically etching blind holes (30) inside the layer stack (10), wherein the blind holes (30) vertically extend at least to the oxidizable layer (21-24) and expose the oxidizable layer (21-24); and oxidizing the oxidizable layer (21-24) via the sidewalls (31) of the blind holes (30) in lateral direction, wherein from each hole an oxidation front (32) radially moves outwar

Abstract: A method of fabricating a radiation emitter including fabricating a layer stack that includes a first reflector, at least one intermediate layer, an active region and a second reflector; locally oxidizing the intermediate layer and thereby forming at least one unoxidized aperture; and locally removing the layer stack, and thereby forming a mesa that includes the first reflector, the unoxidized aperture, the active region, and the second reflector. Before or after locally removing the layer stack and forming the mesa: forming at least a first unoxidized aperture and at least a second unoxidized aperture inside the intermediate layer; etching a trench inside the layer stack, the trench defining a first portion and a second portion of the mesa, wherein the trench severs the intermediate layer(s) so that the first aperture is located in the first portion and the second aperture is located in the second portion of the mesa.

Abstract: A method of fabricating at least one radiation emitter including fabricating a layer stack that includes a first reflector, an active region, an oxidizable layer, and a second reflector; and locally removing the layer stack, and thereby forming at least one mesa. The mesa includes the first reflector, the active region, the oxidizable layer and the second reflector. Before or after locally removing the layer stack and forming the mesa the following steps are carried out: vertically etching at least three blind holes inside the layer stack, wherein the blind holes vertically extend to and expose the oxidizable layer; and oxidizing the oxidizable layer via the sidewalls of the blind holes in lateral direction. An oxidation front radially moves outwards from each hole. The etching is terminated before the entire oxidizable layer is oxidized, thereby forming at least one unoxidized aperture that is limited by at least three oxidation fronts.

Abstract: A semiconductor laser is disclosed. Trim loss region is provided in inner ridge region of surface of transmission layer facing away from substrate, blind hole is provided in trim loss region, and distance from bottom surface of blind hole to surface of second cladding layer facing to substrate is smaller than evanescent wave length in transmission layer. Blind hole can affect optical field characteristics of light transmission in semiconductor laser by affecting evanescent wave. A method for fabricating a semiconductor laser is also provided.

Abstract: A laser beam combining system, including at least one beam combining unit. The beam combining unit includes reflective device, polarization conversion element and beam combining device. The reflective device includes two reflective surfaces configured to divide a high-polarization laser into a first beam and a second beam. The first beam is incident on the beam combining device. The polarization conversion element is provided on a propagation path of the second beam to convert the second beam into a light having a polarization direction perpendicular to an original polarization direction of the second beam. The converted light is guided to the beam combining device which is configured to combine the first beam and the converted light into one beam for outputting.

Abstract: Apparatus and methods for detecting wave front aberration of a projection objective lens in a photolithography machine are disclosed. The apparatus comprises: a light source system configured to generate an illuminating beam; a spatial filter configured to receive the illuminating beam and generate ideal spherical wave; a splitter plate arranged downstream to the spatial filter at a predetermined angle with respect to an optical axis of the spherical wave and having a transflective film being applied on a surface thereof; the projection objective lens configured to receive a beam from the splitter plate and generate an output beam; a spherical mirror configured to reflect the output beam from the projection objective lens to the projection objective lens, light passing through the projection objective lens being reflected by the splitter plate; and an interferometer configured to receive light reflected by the splitter plate and measure the wave front aberration of the projection objective lens.

Abstract: A display driver circuitry with permutation and superposition gray-level control comprises a gray-level controller. The controller may comprise a permutation and superposition adder configured to divide N-bit gray-level data G into M most significant bits, serving as a superposition reference GH, and (N?M) least significant bits, serving as a superposition increment GL, and to superpose superposition values Xi onto GH to derive pieces of scan data Gi for S scan operations; an overflow bit setting unit configured to set an overflow bit F; and an output unit configured to output the scan data Gi. A display driven this way has an improved refreshing frequency with the same gray-level reproduction ability as PWM-based schemes. Further, the duration of each scan operation, or scan period, is constant, resulting in convenience in software implementations. Furthermore, the pulse width representative of the gray-level value is determined by superposition of the scan operations.

Abstract: A display driver circuitry with permutation and superposition gray-level control comprises a gray-level controller. The controller may comprise a permutation and superposition adder configured to divide N-bit gray-level data G into M most significant bits, serving as a superposition reference GH, and (N-M) least significant bits, serving as a superposition increment GL, and to superpose superposition values Xi onto GH to derive pieces of scan data Gi for S scan operations; an overflow bit setting unit configured to set an overflow bit F; and an output unit configured to output the scan data Gi. A display driven this way has an improved refreshing frequency with the same gray-level reproduction ability as PWM-based schemes. Further, the duration of each scan operation, or scan period, is constant, resulting in convenience in software implementations. Furthermore, the pulse width representative of the gray-level value is determined by superposition of the scan operations.