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: A heterodyne one-dimensional grating measuring device and measuring method thereof, including a light source, a reading head, a photoelectric receiving module, and a signal processing system. The light source is configured to generate two linearly polarized lights having characteristics of overlapping, polarization orthogonal, and fixed frequency difference. The reading head is configured to receive two beams of polarized lights and be respectively incident on a surface of a moving measuring grating to generate a +1-order diffracted light and a ?1-order diffracted light. The photoelectric receiving module is configured to receive the +1-order diffracted light and the ?1-order diffracted light to form two paths of beat frequency signals. The signal processing system is configured to perform differential calculation on the two paths of the beat frequency signals to realize a displacement measurement of single diffraction of the measuring grating for four-fold optical subdivision.

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: Provided is an AlGaN unipolar carrier solar-blind ultraviolet detector that is based on the AlGaN polarization effect and that uses the double heterojunction of the p-AlzGa1-zN/i-AlyGa1-yN/n-AlxGa1-xN (0.45=<x,z<y) as the main structure of the detector. It makes full use of the polarization built-in electric field pointing from n-type AlGaN to p-type AlGaN to enhance the electric field strength of the i-type absorption region and enhance the efficiency of carrier absorption and separation. At the same time, the valence band step of the p-AlzGa1-zN/i-AlyGa1-yN heterojunction is used to effectively restrict holes from entering the absorption region to recombine with electrons, thereby increasing the carrier lifetime. Furthermore, during device manufacturing the structure is such designed that makes it difficult for photo-generated holes to participate in the photoconductivity so as to realize unipolar conduction of electrons, thereby obtaining a high response speed and high gain current.

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: The microobjective optical system and the optical device provided in the present disclosure use a catadioptric structure. Specifically, a catadioptric relay lens group and a complex transmissive collimating lens group are combined to effectively correct a higher-order spherical aberration, and control astigmatism, field curvature, and primary and higher-order coma related to a field of view. In a spectrum band ranging from 320 nm to 800 nm, the field of view is larger than 2 mm, a numerical aperture is 1.0, and imaging quality reaches a diffraction limit.

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 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 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 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: The present invention provides a spectral beam combined laser system comprising an optical gain element array, a transform element, a diffraction element and a reflecting element, which are sequentially positioned in an optical path, wherein said optical gain element array comprises a plurality of gain elements radiate laser beams having different wavelength; said transform element focuses and spatially overlaps the laser beams received from said optical gain element array at said diffraction element; said diffraction element diffracts the laser beams spatially overlapped by the transform element to the reflecting element; and said reflecting element feeds back a portion of the laser beams to the optical gain element array in a V-shaped off-axis external cavity with off-axis angle, wherein said V-shaped off-axis external cavity is formed between the reflecting element and the optical gain element array.

Abstract: An absolute-type linear encoder absolute signal consistency correction method, related to the field of absolute-type linear encoder measurements, for solving the problem of narrow linear range for photoelectric responses and large signal dispersion found in an existing consistency correction method for a photoelectric conversion component and a processing circuit thereof. The correction method allows for enhanced absolute signal quality and increased system measurement precision.

Abstract: A diffraction interferometer includes a reference light passage, a test light passage and a pinhole substrate. The pinhole substrate includes a test pinhole and a reference pinhole. The diffracted wavefront emitted from the test pinhole is reflected by the optical component to be tested adjacent to the pinhole substrate and a converge adjacent to the reference pinhole. The diffracted wavefront includes surface shape information of an optical component to be tested that is reflected by the pinhole substrate. Interference with the diffracted wavefront is emitted by the reference pinhole and forms interference fringes. The large numerical aperture phase-shifting dual pinhole diffraction interferometer adopts a dual pinhole substrate and a illumination manner with two converged light paths to enable the separation of the reference light and test light, to prevent disturbance between the two light paths, which would induce the change of interferogram status during phase-shifting.

Abstract: The present invention relates to a large numerical aperture phase-shifting dual pinhole diffraction interferometer and its test method, the diffraction interferometer comprises: reference light passage, test light passage and pinhole substrate; wherein, said pinhole substrate comprises test pinhole and reference pinhole; the diffracted wavefront emitted from the test pinhole would be reflected by the optical component to be tested near the pinhole substrate and converge near the reference pinhole, and said diffracted wavefront comprising surface shape information of optical component to be tested, would be reflected by the pinhole substrate and interference with the diffracted wavefront emitted by reference pinhole, forming interference fringes.

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.