Abstract: A glass fiber filter element for visible light photocatalysis and air purification and a method for preparing the same. The glass fiber filter element includes 4 to 7 wt % of nanoparticles including at least one selected from zinc oxide, graphene oxide, titanium oxide, and reduced graphene oxide, 2 to 7 wt % of silver nanowires, 3 to 12 wt % of an adhesive system, and 78 to 91 wt % of a glass fiber mat, based on the total weight of the glass fiber filter element. The glass fiber mat is made of at least two glass fibers with different diameters, and the diameters are in a range of 0.15 to 3.5 ?m. The nanoparticles have a particle size from 1 to 200 nm, and the silver nanowires have a diameter of 15 to 50 nm.

Abstract: The present disclosure discloses a method and apparatus for preparing a femtosecond optical filament interference direct writing volume grating/chirped volume grating. The method is characterized in that optical filaments are formed in glass by using femtosecond pulse laser, and plasma is controlled to quickly scan in the glass and etch a volume grating or chirped volume grating structure by adjusting the focal length of convex lens, laser energy and movement of motor machine. The apparatus includes a femtosecond pulse laser module, a pulse chirp management module, a pulse time domain shaping module, a laser separation and interference module, a glass volume grating processing platform module and a camera online imaging module.

Abstract: A method for film coating by pulsed laser deposition with a plasma grating includes: in step 1, providing a substrate and a target material; in step 2, generating a femtosecond pulsed laser beam which is split by a beam splitting module so as to form a plurality of femtosecond pulsed laser sub-beams; in step 3, performing a first excitation on the target material by one of the split femtosecond pulsed laser sub-beams as a pre-pulse after focus, to generate a first plasma; in step 4, synchronizing the rest of the split femtosecond pulsed laser sub-beams as post-pulses to form, after focus, filaments arriving at a surface of the target material simultaneously, to generate the plasma grating; and in step 5, performing a secondary excitation on the target material by the generated plasma grating to generate a second plasma depositing on the substrate to form the film.

Abstract: A processing method and apparatus for ultrafast laser deposition of a multilayer film including a diamond-like carbon film, an anti-reflection film and an anti-fingerprint film includes: generating primary plasma by first excitement on a target material with a femtosecond or picosecond pulsed laser beam as a pre-pulse; and generating secondary plasma by second excitement on the target material under plasma grating, formed by allowing two femtosecond pulsed laser beams to intersect at a small include angle for interaction in the primary plasma, for deposition to coat a film.

Abstract: A method for preparing a graphene based composite wave-absorbing material includes: dissolving a water soluble barium salt and a water soluble iron salt into deionized water, respectively; mixing barium salt solution and iron salt solution according to a molar ratio of Ba:Fe of 1:12 to obtain a precursor solution; dispersing a graphene material in deionized water to form a graphene dispersion; adding citric acid, nitric acid and the graphene dispersion into the precursor solution in sequence to form a mixture solution; stirring the mixture solution at a temperature of 50 to 75° C. to obtain a sol; coating and drying aged sol on a substrate to obtain a coating layer; and sintering the coating layer by a laser irradiation.

Abstract: A photocatalytic material includes activated carbon, titanium dioxide, zinc oxide, graphene, tourmaline powders, a nano-copper solution, carvacrol and deionized water. The photocatalytic material is prepared by mixing the activated carbon, the titanium dioxide, the zinc oxide, the graphene, the tourmaline powders, the nano-copper solution, the carvacrol and the deionized water for a period ranging from 1 to 12 hours. A photocatalytic air screen filter for epidemic prevention includes a substrate and the photocatalytic material. The photocatalytic material is applied on a surface of the substrate, and the photocatalytic material is dried and cured. An amount of the material loaded on the surface of the substrate is in a range of 0.1 to 100 mg/cm2.

Abstract: Provided are a nonlinear polarization filtering method, device, and apparatus. The device comprises a pump source, a coupler, a birefringent medium, and several polarizers; wherein the pump source is applied to output a pump laser, so as to make a photo-induced birefringence effect occur at the birefringent medium; the polarizer is applied to polarize a signal light according to a preset polarizing angle; and the coupler is applied to couple the pump laser and the signal light into the birefringent medium, wherein an angle except 0° exists between the birefringent medium and the preset polarizing angle of the polarizer.

Abstract: Provided is a method for preparing a graphene material from an industrial hemp material by laser induction, which uses a skin, a stem and/or a root of industrial hemp as a carbon precursor-containing material and reduce the carbon precursor-containing material into graphene by laser induction, so as to prepare graphene, graphene quantum dots, a graphene mesoporous material and a graphene composite material.

Abstract: A frequency stabilizing system for high precision single-cavity multi-frequency comb includes a single-cavity multi-comb pulse oscillator, a frequency detection system, and a frequency feedback control system. The single-cavity multi-comb pulse oscillator is configured to output mode-locked pulse trains with a certain repetition rate difference at two or more central wavelengths. The frequency detection system is configured to detect the frequency signal, and output the corresponding electrical signal. The frequency feedback control system is configured to process the electrical signal from the frequency detection system, and transmit it to the frequency response component in the single-cavity multi-comb pulse oscillator to control a strain of the frequency response component, so as to realize feedback control on the frequency (repetition rate, repetition rate difference, and carrier envelope offset frequency) of the mode-locked pulse trains.

Abstract: Provided are a time and frequency control method and system for optical comb. The method includes: controlling an optical comb measuring system to start and to generate an optical comb; obtaining monitoring data, wherein the monitoring data comprises a working temperature, a mode-locked frequency and a light pump power, wherein the mode-locked frequency comprises a repetition frequency and a carrier envelope phase locked at the end of starting the optical comb measuring system; determining whether an offset of the mode-locked frequency exceeds a self-feedback adjustment range of a hardware adjustment circuit; and in response to any of the repetition frequency and the carrier envelope phase exceeds the self-feedback adjustment range, adjusting the working temperature and the light pump power until the mode-locked frequency returns back into the self-feedback adjustment range.

Abstract: Provided is a system for measuring gas temperature and component concentrations in a combustion field based on optical comb. The system includes two pulse laser devices, two continuous laser devices, a beam splitting device, a measurement path, an interference signal detecting device, an optical processing and electrical processing device and a signal acquisition and analysis device. The measurement path refers to the combustion field to be measured. The interference signal detecting device outputs an interference signal. The optical processing and electrical processing device includes several optic elements and electrical elements, and outputs an adaptive compensation signal and an asynchronous sampling clock signal after a series of processing on output of the two pulse laser devices and two continuous laser devices. The signal acquisition and analysis device outputs the measurement result based on the adaptive compensation signal, the asynchronous sampling clock signal and a stable interference signal.

Abstract: The present disclosure provides a stealth dicing method and apparatus. With the method, the focusing element focuses the laser beam on the surface of material to be diced, and the dynamic-equilibrium plasma channel is formed in the material to be diced by means of self-focusing and defocusing effect of plasma generated by ionizing the material to be diced. The modified layer may be formed in the material to be diced throughout the plasma channel, so as to realize stealth dicing.

Abstract: A method for preparing a core-shell structure photocatalytic material includes: obtaining a titanyl sulfate solution by mixing and reacting sulfuric acid and metatitanic acid; obtaining a mixed solution by adding a porous material having a hydrophilic surface into the titanyl sulfate solution; adding an alkali into the mixed solution to obtain a precipitation product by reacting the alkali with the titanyl sulfate coated on the surface of the porous material; and filtering, washing, drying and calcining the precipitation product to obtaining a core-shell structure photocatalytic material with the porous material as a core and a mesoporous quantum titanium oxide as a shell.

Abstract: A high-precision repetition rate locking apparatus for an ultra-fast laser pulse includes: an electronic controlling component comprising: a standard clock, configured to provide a high-precision frequency standard; a pulse generator (PG), configured to provide an electrical pulse signal with adjustable repetition rate, pulse width and voltage magnitude; and a signal generator (SG), connected to the standard clock and the PG, and configured to provide a stable frequency signal for the PG, a phase-shift adjusting component, connected to the electronic controlling component and configured to implement phase modulation through electrically induced refractive index change; a resonant cavity component, comprising a phase shifter, a doped fiber, a laser diode, a wavelength division multiplexer and a reflector, and configured to generate a mode-locked pulse; and a detection system, configured to measure a repetition rate of an output pulse.

Abstract: The present disclosure relates to a gain optical fiber heat-dissipating device for high power ultra-fast laser, including a gain optical fiber and a heat-dissipating structure. The heat-dissipating structure includes a metal tube, a flexible heat-conducting layer and a water-cooling structure. The gain optical fiber is passed through the metal tube, and the flexible heat-conducting layer is provided between the metal tube and the gain optical fiber. The water-cooling structure is provided on the metal tube to reduce temperature of the gain optical fiber. The gain optical fiber heat-dissipating device according to the present disclosure can dissipate the heat through a water-cooling mode, and realize rapid heat dissipation, thus improving heat-dissipating efficiency.

Abstract: A process for preparing a graphene quantum material includes: providing a carbon-containing precursor; decomposing the carbon-containing precursor with ultra-fast laser to obtain the graphene quantum material; optionally reducing graphene oxide into graphene with laser; and optionally subjecting the graphene quantum material to microwave heating.

Abstract: A hyperspectral imaging method includes: providing time-domain synchronous mid-infrared ultrashort pulse and near-infrared ultrashort pulse as pump light and signal light, respectively; subjecting the signal light to optical time-stretching to broaden a pulse width of the signal light; directing the time-stretched signal light to a target sample to be detected; directing the pump light to a time delayer to adjust the time when the pump light reaches a silicon-based camera; spatially combining the time-stretched signal light from the target sample with the pump light from the time delayer; directing combined light to a silicon-based camera where the signal light is detected through non-degenerate two-photon absorption of the signal light under the action of the pump light to acquire hyperspectral imaging data; and obtaining an image of the target sample based on the hyperspectral imaging data.

Abstract: A mid-infrared upconversion imaging method and a mid-infrared upconversion imaging device are provided, which are used for imaging detection in a mid-infrared wavelength band, and related to a technical field of infrared imaging. The method includes directing pump laser and mid-infrared light into a chirped crystal component located in an optical cavity to obtain visible light; and imaging an object with the visible light.

Abstract: An electrically tunable non-reciprocal phase shifter, an electrically tunable polarization filter, a NALM mode-locked laser and a Sagnac loop are provided. The electrically tunable non-reciprocal phase shifter includes a modulation crystal device, a birefringent crystal device, a Faraday rotator, and a fiber coupler. The phase shifter is configured to couple two beams of light to a fast axis and a slow axis of the modulation crystal device, respectively; and change a refractive index difference between the fast axis and the slow axis to introduce different phase delays for the two beams of the light, so as to control a non-reciprocal linear phase shift amount between the two beams of the light.

Abstract: A detection method based on laser-induced breakdown spectroscopy enhanced by a two-dimensional plasma grating includes: generating a femtosecond laser pulse by a femtosecond laser, and splitting the femtosecond laser pulse into three sub-pulses by a beam splitting unit; focusing the three sub-pulses separately by a focusing unit to allow focused sub-pulses to be overlapped at an intersection in space, wherein before reaching the intersection, the three sub-pulses form two planes; synchronizing the three sub-pulses in a time domain by adjusting optical paths of the three sub-pulses in such a way that they have the same optical length and the three sub-pulses arrive at the intersection in space simultaneously and form the two-dimensional plasma grating; and exciting a sample on a stage based on the two-dimensional plasma grating to generate a plasma cluster, and acquiring a spectrum of the sample.