Device and method for measuring uniformity of refractive index of large aperture uniaxial crystal

Abstract

A large-aperture uniaxial crystal refractive index uniformity measurement device and method thereof, a collimator, a polarizer and a half-mirror are sequentially arranged on the optical path where the outgoing light of the laser is located; The light of the half-mirror is reflected and transmitted to form reflected light and transmitted light respectively; the converging mirror is arranged on the optical path where the reflected light is located and the reflected light is converged into the integrating sphere power meter; the beam reduction system objective lens, the beam reduction system eyepiece and The Shaker-Hartmann wavefront sensor is sequentially set on the optical path of the transmitted light; the large-aperture uniaxial crystal to be measured is placed between the polarizer and the half mirror; the computer communicates with the integrating sphere power meter and the Shaker-Hartmann respectively. The Hartmann wavefront sensor is connected with the large-aperture uniaxial crystal to be measured. The invention can realize the measurement of the uniformity of the refractive index of the large-diameter uniaxial crystal, is not limited by the wavelength, and is not affected by the airflow and vibration of the external environment, and can well ensure the measurement accuracy.

Description

technical field [0001] The invention belongs to the field of optics, and relates to a crystal refractive index uniformity measurement device and method, in particular to a large-aperture uniaxial crystal refractive index uniformity measurement device and method based on a Shack-Hartmann wavefront sensor. Background technique [0002] With the construction of the Shenguang III host device in my country, the large-aperture uniaxial crystal is used as a frequency conversion element in the inertial confinement fusion system, which plays a crucial role in the final output energy of the system. In particular, the large-aperture KDP crystal is the key material for frequency doubling devices and electro-optic switches in high-power lasers. The quality of its materials and component processing quality greatly affect the realization of the final indicators of the device. The photoelastic effect caused by structural defects or internal stress during the growth process of the crystal, t...

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Problems solved by technology

The disadvantages of this method are: 1) Relying on the large-caliber interferometer imported from abroad, which is expensive and the measurement cost is high; 2) The output center wavelength of the interferometer is fixed, and it is impossible to measure the uniformity of the uniaxial crystal refractive index in the actual working band; 3 ) The polarization state of the output laser of the interferometer is fixed, and the switching of the orthogonal polarization state cannot be realized; 4) The measurement needs to place a polarizer at the test port of the output laser, and the extinction ratio of the polarization state greatly affects the contrast of the interference fringes; 5) This method cannot deduct the error introduced by the tilt change introduced by the interferometer phase shifter to the measurement of the uniformity of the refractive index of the uniaxial crystal; 6) This method is susceptible to ambient air flow disturbance and vibration

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