4results 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.

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%.

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.