The present invention discloses a KDP frequency doubling
crystal structure, which includes a
crystal fixing structure, a KDP
crystal, a π polarization tube, and a σ polarization tube; the π polarized light with a central
wavelength of 800 nm passes through the π polarization tube, enters the KDP crystal, and the KDP crystal doubles the π polarized light with a central
wavelength of 800 nm into σ polarized light with a central
wavelength of 400 nm, and finally outputs from the σ polarization tube. The inclined surfaces of the closed ends of the π polarization tube and the σ polarization tube are both designed with Brewster angles. The KDP crystal is placed in a vacuum
closed cavity formed by the π polarization tube, the σ polarization tube, and the crystal fixing structure, eliminating the cumbersome process of crystal
coating, avoiding the deliquescence of the KDP crystal in the air, and overcoming the problems that the
coating layer of the existing KDP crystal is easily damaged by high-intensity
fundamental frequency light, resulting in a short service life of the crystal, an increase in
coating difficulty, and an improvement in coating technical requirements. The structure of the present invention is simple, can be obtained through simple mechanical
processing, and has a low manufacturing cost.