Abstract: Provided are a method and a system for measuring a transient time width of an ultrashort pulse in real time. The method includes: performing an interaction of a laser pulse to be measured with a linear chirped pulse in a second-order non-linear medium, to generate a sum-frequency beam, wherein an intensity sag occurs in the chirped pulse after the interaction; performing a time spreading by a time stretching system on the chirped pulse with the intensity sag; detecting the spread chirped pulse with the spread intensity sag by a photoelectric detector, and measuring and recording a time width ?? of the spread intensity sag by an oscilloscope; and obtaining the transient time width ? of the laser pulse to be measured according to a formula of ?=??/M, where M is an amplification coefficient of the time stretching system.

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: Disclosed is a method for preparing a carbon-reinforced metal-ceramic composite material, including: mixing raw materials of carbon, copper, zinc, titanium, copper oxide, calcium oxide and titanium dioxide, ball-milling the raw materials with a medium of ethanol to obtain a mixture, drying and milling the mixture to obtain a powder, sintering the powder with a laser having an irradiation power ranging from 100 to 600 W and an irradiation period of 3 min to 10 min to obtain a product, and rapidly cooling the product to allow a temperature of the product to be decreased to the room temperature within 5 min to obtain the carbon-reinforced metal-ceramic composite material.

Abstract: Disclosed are a method for preparing a ceramic material including a compound of a formula of A2BxOy and a ceramic material prepared by the method. The method includes: mixing a first oxide of AOm and a second oxide of BOn to obtain a mixture, ball-milling the mixture until a particle size of the mixture is not greater than 1 ?m with a medium selected from a group consisting of ethanol, acetone, deionized water and a combination thereof, to obtain a powder, drying the powder at a temperature in a range of 60 to 80° C., and sintering the powder with a laser irradiation having a laser wavelength of 980 nm, an irradiation power ranging from 50 to 1500 W and an irradiation period of 3 s to 8 min to obtain the ceramic material.

Abstract: Provided is a method for preparing a graphene-copper calcium titanate CCTO based ceramic composite dielectric material, which includes: dissolving metal ion sources in respective solvents to obtain respective solutions, and mixing the solutions evenly to obtain a precursor collosol of the CCTO based ceramic; allowing the precursor collosol of the CCTO based ceramic to stand for aging, followed by adding a graphene oxide dispersion to mix with the precursor collosol evenly, drying the resulting mixture to obtain dry precursor powders of the graphene-CCTO based ceramic, which are then grinded into fine powders, followed by irradiating by a low-power laser to obtain graphene-CCTO based ceramic composite powders; and compacting and molding the graphene-CCTO based ceramic composite powders, followed by catalytic synthesis with a high-power laser to obtain the graphene-CCTO based ceramic composite dielectric material.

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: The invention relates to wavelength division multiplexing (WDM) and demultiplexing of optical signals using optical filters in free space. To minimize dispersion, the present invention uses relatively small angles of incidence. To avoid the need for a large package, the present invention utilizes reflective prisms to steer the reflected beams to provide a lateral shift in the beam path that ensures that the necessary space is provided between the input/output ports. Devices including a single adjustable filter are disclosed, along with devices having a plurality of filters.

Abstract: The invention provides a simple temperature insensitive optical retarder (waveplate) having a first and a second wedge shaped birefringent crystals, and a crystal mount comprising a first material having a low thermal expansion coefficient and a second material having a high thermal expansion coefficient, wherein the first and the second wedge shaped birefrigent crystals are attached onto the first and second materials, respectively, so that the total retardance by the first and second birefringent crystals at a first temperature is substantially the same as that at a second different temperature at a given wavelength. Advantageously, the temperature insensitive optical retarder is simple, easy to construct, can be used for any birefringent crystal and does not require the use of different birefringent crystals.

Abstract: The invention relates to wavelength division multiplexing (WDM) and demultiplexing of optical signals using optical filters in free space. To minimize dispersion, the present invention uses relatively small angles of incidence. To avoid the need for a large package, the present invention utilizes reflective prisms to steer the reflected beams to provide a lateral shift in the beam path that ensures that the necessary space is provided between the input/output ports. Devices including a single adjustable filter are disclosed, along with devices having a plurality of filters.