8results about How to "High damage threshold" patented technology

The utility model discloses a metasurface unit structure and a metasurface formed by the metasurface unit structure, and belongs to the technical field of nonlinear optics. The metasurface unit structure comprises a substrate layer and a dielectric layer which are arranged from bottom to top, wherein a convex groove or a concave groove is formed in the dielectric layer. The sections of the substrate layer and the dielectric layer are square, and the sizes are nanoscale; the substrate layer is made of SiO2, and the dielectric layer is made of DAST crystals. The metasurface is formed by periodically arranging a plurality of metasurface unit structures. According to the utility model, the convex or concave grooved structure, the substrate layer with low refractive index, the DAST dielectric layer which has a higher damage threshold and is easy to process and the like are introduced, so that the loss can be reduced, the asymmetry degree can be conveniently adjusted by changing the grooved structure, the quality factor Q can be changed, the local electric field distribution can be optimized, and different application requirements can be met.

The invention relates to the field of semiconductor technology, and proposes a method for passivating the cavity surface of a GaN-based EEL laser chip, comprising the following steps: S1, cavity surface dehumidification: heating the cavity surface of a bar strip to remove the moisture; S2, cavity surface cleaning: continuing to increase the temperature, and introducing gas to bombard the cavity surface; S3, cavity surface annealing: continuing to increase the temperature, and introducing gas to bombard the cavity surface, and then annealing to form a transition layer; the gas in steps S2 and S3 is one or more of O2, N2 and H2; S4, cavity surface passivation: transferring the bar strip into a passivation chamber, maintaining the annealing temperature, introducing one or more of O2, O3 or N2 to bombard the cavity surface, and forming an Al2O3, AlON or AlN single crystal film on the surface of the transition layer. The invention adopts high-temperature annealing to form a transition layer on the cavity surface. Compared with CaN, the mismatch rate between the transition layer and Al2O3, AlON and AlN is lower, it is easier to grow a single crystal film, and it will not cause light absorption of the cavity surface, thereby achieving the technical effect of increasing the cavity surface damage threshold and extending the service life of the laser.

The invention provides a JGS1 substrate antireflection film and a preparation method and application thereof. According to the JGS1 substrate antireflection film provided by the invention, the JGS1 quartz glass substrate with relatively high transmittance in a deep ultraviolet band is adopted to replace a calcium fluoride substrate, so that the cost is greatly reduced; meanwhile, a new film system design is adopted on the JGS1 quartz glass substrate: an F-SiO2 thin film layer is arranged on the JGS1 quartz glass substrate, and then an antireflection film layer is arranged; adding a protective layer on the antireflection film layer; according to the film system design, the adsorption force between the antireflection film layer and the JGS1 quartz glass substrate can be increased, and the mechanical strength of the film layer is improved; the deposition of organic matters is effectively prevented, and the JGS1 substrate antireflection film has a higher heat damage threshold value while the ultrahigh transmittance (greater than 99.5%) in a deep ultraviolet band (193nm) is realized.

This application relates to a special optical fiber, comprising a core layer and an outer cladding layer arranged sequentially from the inside to the outside along the radial direction of the special optical fiber, wherein the core layer includes a silicon nitride layer. The special optical fiber provided by this application incorporates a silicon nitride layer, disposed within the outer cladding layer. Silicon nitride has excellent thermal conductivity, enabling rapid dissipation of heat accumulated within the core / cladding layer, preventing localized hotspots that could degrade fiber quality and increasing the damage threshold. Silicon nitride remains stable at temperatures above 1200°C in an inert atmosphere and is unlikely to react with other substances, completely solving the problem of polymer carbonization. In terms of mechanical and chemical protection, silicon nitride acts as a chemical barrier. The dense, non-porous structure of the silicon nitride film gives this special optical fiber resistance to salt spray and hydrogen sulfide corrosion. Silicon nitride is a more effective Compton scatterer than silicon dioxide, reducing gamma photons incident deep within the optical fiber and improving its irradiation performance.

The application discloses a quartz crystal-based adjustable strong-field terahertz light source and an adjusting method thereof, and belongs to the optical field. The terahertz light source is designed by using the high damage threshold and low absorption characteristics of the quartz crystal in the terahertz wave band. In addition to the femtosecond laser, the beam-reducing system, the grating, a pair of X-direction achromatic column lenses, the 1 / 2 wave plate and the quartz crystal required by the general inclined wave front, the terahertz light source further comprises a pair of Y-direction column lenses. One of the X-direction achromatic column lenses is replaced by a double-lens combined lens. The focal length of the combined lens is finely adjusted by adjusting the lens spacing of the combined lens. The grating front mirror is placed on a translation stage to adjust the grating incidence angle. The inclination angle of the quartz crystal is 43 degrees, and the terahertz light is emitted along the inclined surface of the quartz crystal. The application adjusts the THz center frequency from 2 to 4 THz and the terahertz spectrum width from 0 to 6 THz by simultaneously adjusting the focal length of the combined lens, the grating incidence angle and the emission angle, and realizes the terahertz generation efficiency of nearly 0.04%.

The invention discloses a congruent molten halogen vanadate compound, a vanadium zinc rubidium bromide nonlinear optical crystal as well as a preparation method and application of the vanadium zinc rubidium bromide nonlinear optical crystal. The chemical formula of the vanadate compound is Rb3ZnV4O12Br, the vanadium zinc rubidium bromide nonlinear optical crystal Rb3ZnV4O12Br can be prepared through the vanadate compound, the obtained nonlinear optical crystal is of a non-centrosymmetric structure and belongs to an orthorhombic system, the space group is C mm < 2 >, unit cell parameters are # imgabs0 # imgabs1 #, alpha is equal to 90 degrees, beta is equal to 90 degrees, gamma is equal to 90 degrees, and Z is equal to 2. The nonlinear optical crystal provided by the invention has the characteristics of high damage threshold, large nonlinear optical effect, high electro-optic coefficient, wide transmission range, easiness in crystal growth and the like, and the frequency doubling effect of the nonlinear optical crystal is 0.7-1.4 times that of an AGS crystal. The invention also discloses application of the nonlinear optical crystal in preparation of laser nonlinear optical composite functional devices, electro-optical crystal devices, lasers and other devices.

The invention provides a method for inhibiting end face failure of a laser, belongs to the technical field of semiconductor lasers, and is used for solving the technical problem that the electric field intensity at the junction of an epitaxial material and an optical coating material of the laser is too large. The method comprises the following steps: (1) cleaving a semiconductor laser wafer into bars, and evaporating first film layers on front cavity surfaces and rear cavity surfaces of the bars respectively; (2) evaporating an antireflection film on the front cavity surface of the bar, and evaporating a high-reflection film on the rear cavity surface of the bar; and the thickness of the first film layer is the thickness when the electric field intensity at the junction of the laser epitaxial material and the optical coating material is reduced to zero. According to the invention, the electric field intensity at the junction of the laser epitaxial material and the optical coating material is reduced to zero, the design of zero electric field intensity reduces non-radiative recombination excited by the electric field, and the purposes of improving the end surface damage threshold and improving the reliability are achieved.

This application belongs to the field of laser regenerative amplification, specifically disclosing a high-energy pulse train regenerative amplifier based on electro-optic modulation programmable. This application applies phase disturbance and amplitude modulation to the pulses using an electro-optic modulator (EOM), coupled with an active feedback system based on a spectrometer and piezoelectric ceramic (PZT). The electro-optic modulator and PZT are matched in response speed; the bandwidth of the EOM must be sufficiently high to handle the independent modulation of each pulse, while the bandwidth of the PZT needs to be able to track cavity length changes caused by environmental disturbances. Because the electro-optic modulator can precisely and rapidly control the phase and amplitude of each pulse, disrupting the fixed phase relationship between pulses, it avoids spectral modulation effects caused by coherent superposition, improves spectral uniformity, and achieves uniform and efficient amplification of multiple pulse trains, significantly improving energy extraction efficiency and system output stability.