Abstract: A high-strength steel laser welding filler, comprising the following components in percentages by weight: 0.05-0.5% of C, 0.1-2% of Cu, 0.2-2.5% of Cr, 0.5-3.5% of Mo, and 2-10% of Ni, with the balance being Fe and inevitable impurities. The filler is used for laser filler welding of hot-formed steel which has an aluminum-containing coating on the surface thereof, can effectively reduce the adverse effect of the aluminum-containing coating on the surface on the strength of a joint, and enables the strength and plasticity of the welded joint, after hot stamping, to reach 90% or more of those of a base material.

Abstract: An ultrastable laser system is based on a polarization-maintaining optical fiber. The ultrastable laser system comprises a laser device; acousto-optic modulators, a first beam splitter, a polarizer, an optical fiber interferometer comprising a second beam splitter, an optical fiber delay line, a third acousto-optic modulator, and a beam combiner; a beam combiner, a polarization beam splitter, photoelectric detectors, a frequency synthesizer, frequency mixers, a servo feedback circuit and a piezoelectric ceramic. The temperature interference is eliminated based on the characteristic that refractive indexes of a fast axis and a slow axis of the polarization-maintaining optical fiber differently change with a temperature, a vacuum structure can be avoided, and the ultrastable laser system has low cost, small system, simple structure and high signal stability.

Abstract: A mid-frequency error-free machining method under a magneto-rheological polishing magic angle-step includes the following steps: measuring a magneto-rheological removal function, and determining a control accuracy of a machine tool; performing two-dimensional Fourier transform on the removal function, performing compensating filtering on a frequency spectrum based on the control accuracy of the machine tool, and analyzing a corresponding step at the lowest point of an amplitude of the two-dimensional frequency spectrum that undergoes filtering in a direction of a magic angle; planning a grid path under the given step on the basis of adjusting a direction of a machining path or a posture of a magneto-rheological polishing wheel to allow an included angle between the polishing wheel and the path kept to be at the magic angle; and finally, controlling the machining of the machine tool.

Abstract: A device for realizing the splicing of an array fiber and a large-size quartz end cap comprises a carbon dioxide laser, a light splitter, a light beam shaper, a high reflectivity mirror, an image detection module, an array fiber and a carrier thereof, a large-size quartz end cap and a carrier thereof, a stepping motor, a thermodetector, and a computer; a laser beam emitted by the carbon dioxide laser is divided into two light beams through a light splitter, after the two light beams respectively pass through the beam shaper and the high reflectivity mirror, two strip-shaped light spots with uniform power density are integrally formed to heat a splicing face of the large-size quartz end cap, a uniform temperature field of a target splicing area is achieved through indirect heating and heat conduction.

Abstract: A single-beam photothermal measurement apparatus and a measurement method for absorptive defects. The apparatus comprises a common-path-type structure and a non-common-path-type structure. The present invention is simple in optical structure and convenient to align and adjustment. The measurement result is stable, and measurement signal anomalies caused by environmental vibration and sample tilt are avoided. By detecting a power change on the edge of a beam spot, the measurement sensitivity of a system is remarkably improved.

Abstract: A picometer optical comb and a device and a method for generating the same, wherein the picometer optical comb is a special grating with continuously variable widths of adjacent grating lines, wherein the width of each grating line is different from that of the adjacent grating line by a fixed difference in the magnitude of picometer to nanometer. The picometer optical comb provides a reference for picometer measurement. The picometer optical comb can generate a diffraction optical field distribution different from that of a traditional grating, which brings a new diffraction effect, achieves new diffraction optical functions, and provides tools such as picometer photolithography, picometer measurement, picometer imaging and the like. The picometer optical comb plays an important role in the fields of semiconductor photolithography, life science, interaction of light and substances in picometer scale.

Abstract: A multi-dimensional spatial positioning system and method for disturbance source. The system includes a distributed-optical fiber sensor, a sensing optical fiber, a coordinate system, a disturbance source to be monitored, a first signal group, and a second signal group. The disturbance source is positioned by combining an array signal processing method with the distributed optical fiber sensor, using different laying manners for the sensing optical fiber and a certain number of flexibly selected sensing units distributed a certain distance from each other along a line, and combining with a special signal processing method, thereby realizing a function of being capable of monitoring multi-dimensional spatial position information of the disturbance source in real time in both short and long distances.

Abstract: A radiation-resistant laser optical fiber preform core rod at least includes one type of activated ion (Yb3+, Er3+) and one or more types of co-doped ion (Al3+, P5+, Ge4+, Ce3+, F?), and —OD group of 16-118 ppm. Irradiation resistance of core rod glass can be effectively improved by sequentially performing pre-treatments, i.e. deuterium loading, pre-irradiation and thermal annealing on a preform core rod. Electron paramagnetic resonance test shows that, under the same radiation condition, the radiation induced color center concentration in a preform core rod treated by the method above is lower than in an untreated core rod by one or more orders of magnitude. The obtained core rod can be used for preparing a radiation-resistant rare earth-doped silica fiber, and has the advantages of high laser slope efficiency, low background loss, being able to be used stably in a vacuum environment for a long time, for example.

Abstract: A distributed fiber-optic acoustic sensing system and a signal processing method. The distributed fiber-optic acoustic sensing system is based on a high spatial resolution distributed fiber-optic acoustic sensor. The interval between adjacent sensing units is centimeter or millimeter level. Through specific digital signal processing, signal enhancement can be realized, noise in the system and environment are suppressed, at the same time, problems such as interference fading is solved, and the sensor signal-to-noise ratio of subunits can be increased by two to three orders of magnitude. Each subunit can serve as an independent high-sensitivity sensor for sensing. The multiple subunits can form one or more new sensor arrays. The azimuth estimation and spatial orientation of signal sources can be realized by the array signal processing method.

Abstract: A resistance spot welding electrode cap contains a groove at the center of the welding contact interface. During welding, because of the groove, the area of contact between the electrode cap and a metal workpiece to be soldered is reduced. In the initial stage, the overall heat generation is concentrated on the outer ring of the weld point and heat dissipation becomes slower, helping a weld nugget to form from the outside to the inside. Due to the presence of the groove, the metal workpiece expands toward the groove at the center of the electrode, thereby increasing the size of the weld nugget and reducing splash and deformation. In comparison with conventional electrode caps, the welding current required to form weld points of the same size is lower, saving on electricity costs, and weld points obtained using the same current have higher strength and stability with fewer welding defects.

Abstract: A laser driving device and a method for enabling a uniform light field, wherein the laser driving device is a high-power laser driving device that enables a uniform light field on the basis of a narrow-band low-spatial-coherence light and is provided for laser fusion. The narrow-band low-spatial-coherence light is configured as a seed of the laser driving device, an amplification and transmission unit amplifies the seed, a frequency conversion unit converts a frequency of the laser, and a focusing component is configured for laser focusing and uniform illumination.

Abstract: A simultaneous phase-shift point diffraction interferometer and method for detecting wave aberration. The interferometer comprises an ideal spherical wave generation module, an optical system to be measured, an image plane mask, a polarization phase shift module, a two-dimensional polarization imaging photodetector and a data processing unit. Single photodetector is adopted to realize simultaneous detection of more than three phase shift interference patterns, and has the advantages that environmental interference suppression, a flexible optical path, high measurement accuracy, and calibration of system errors of the interferometer may be realized.

Abstract: A photodarkening-resistant ytterbium-doped quartz optical fiber and a method for prpearing such a fiber are provided. Glass of a photodarkening-resistant ytterbium-doped quartz optical fiber core rod includes at least Yb2O3, Al2O3, P2O5, SiO2. The proportions of Yb2O3, Al2O3, and P2O5 in the entire substance are Yb2O3: 0.05-0.3 mol %, Al2O3: 1-3 mol %, and P2O5: 1-5 mol %, respectively. In the preparation method for the photodarkening-resistant ytterbium-doped quartz optical fiber, a sol-gel method and an improved chemical vapor deposition method are combined. By using the molecular-level doping uniformity and the low preparation loss thereof respectively, ytterbium ions, aluminum ions and phosphorus ions are effectively doped in a quartz matrix, thereby effectively solving the problems in the optical fiber of high loss, photodarkening caused by cluster or the like, and a central refractive index dip.

Abstract: Provided are an integrated super-resolution laser direct-writing device and a direct-writing method. The integrated super-resolution laser direct-writing device includes a first continuous laser, a first optical fiber coupler, a mono-mode optical fiber, a second continuous laser, a second optical fiber coupler, a first annular photonic crystal fiber, a bifurcated optical fiber, a lens group, a first dichroic mirror, an LED light source, a lens, a second dichroic mirror, an auto-focusing module, a third dichroic mirror, a third optical fiber coupler, a square-law graded index fiber, a nanometer displacement table, a second lens, a CMOS camera and a control system. According to the present invention, an original large direct-writing device based on a free optical path can achieve optical fibers of key devices and integration of systems and can be better applied to the field of laser direct-writing.

Abstract: A single-shot Fresnel non-coherent correlation digital holographic device based on a polarization-oriented planar lens, comprising: A polarization-oriented planar lens (1) for wavefront modulation and beam splitting, a focusing element (2), a half-wave plate (3) with a small hole and a polarization imaging camera (4). Incident light passes through the polarization-oriented planar lens (1) and the focusing element (2) and is divided into two beams with different polarizations, that is, focused and parallel or focused and divergent beams, wherein the focused beam passes through the small hole of the half-wave plate (3), the parallel or divergent beam passes through the half-wave plate (3), so as to make the polarization of the two beams consistent behind pass through the half-wave plate (3).

Abstract: Apparatus and method for detecting wavefront aberration of an objective lens, comprising a wavefront detection system, a planar mirror, and a planar mirror adjusting mechanism; the objective lens is placed between planar mirror and wavefront detection system; planar mirror is positioned at focal point of the objective lens. A test wavefront emitted by wavefront detection system passes through the objective lens, gets reflected by the planar mirror, and t passes through the objective lens again; the wavefront detection system receives and detects the test wavefront to derive a phase distribution thereof; an angle of the planar mirror tilts at is adjusted to obtain different return wavefronts; a polynomial for expressing wavefront aberration is selected, and expressions corresponding to all the return wavefronts are calculated; result of fitting the wavefront aberration of the objective lens when expressed by the selected polynomial is derived through fitting with the polynomial.

Abstract: A multi-channel device and method for measuring the distortion and magnification of objective lens. The multi-channel device for measuring the distortion and magnification of objective lens comprises an illumination system, a reticle stage, a test reticle, a projection objective lens, a wafer stage and a multi-channel image plane sensor, wherein the multi-channel image plane sensor simultaneously measures the image placement shifts between actual image points and nominal image points after a plurality of object plane test marks are imaged by the projection objective lens, and calculates the distortion and magnification errors of the objective lens by fitting, which shortens the measurement time, eliminates the influence of wafer stage errors on the measurement accuracy and improves the measurement accuracy.

Abstract: Laser ablation processing method for debris-free and efficient removal of materials comprises the step of using a refrigeration device to condense the water vapor and form a thin frost layer on the materials at temperatures below the freezing point. The residual debris produced during the ablation process deposits on the frost layer that covers the material, which is easily removed when the frost layer melts. At the same time, the frost layer in the laser irradiation area melts to a liquid layer, which can effectively reduce the deposition of debris on the inner wall of the groove and thus improve the efficiency and quality of laser ablation. The method is applicable to debris-free laser processing on an arbitrary curved surface.

Abstract: Method for simultaneously compensating pupil coordinate distortion and shear amount change in a process of wavefront reconstruction in grating transverse shear interference. Where a wavefront is diffracted by a grating, the shapes and light paths of the diffracted wavefronts of all the orders are different, so that on one hand, a coordinate system detected by a detector plane is distorted relative to a pupil coordinate system, and on the other hand, a shear amount changes along with a coordinate position.

Abstract: An apparatus and method herein efficiently couple spatial light to optical fiber light for achieving stability of an optical axis without a position sensor. The basic concept of the method includes: first, obtaining, according to a theoretical coupling efficiency model, a model parameter by means of fitting calculation; second, using a four-point tracking algorithm to calculate an optical fiber nutation trajectory according to the optical fiber nutation principle; and finally, using the nutation trajectory to calculate the position deviation of a central point. The optical axis is ensured to be stable by correcting the position deviation, and the high coupling efficiency remains. The method is used for the stability of the optical axis in a space coherent laser communication DPSK link. The high efficiency coupling is a key technology of long-distance, high bit rate transmission in space laser communication, and is significant in the development of inter-satellite optical communications.