Chinese Academy of Sciences

Chongqing University

Shanghai Hengyi Optics and Fine Mechanics Co., Ltd

Jianda Shao

Bin Wang

Shijie Liu

Hongji Qi

Duanyang Chen

Qi Lu

Weiwei Wang

Tianzhu Xu

Shenghao Wang

Kaizao Ni

Hu Wang

Chuan Zhou

Chaoyang Wei

Songlin Wan

Haojin Gu

Yingjia Li

Mingwei Li

You Zhou

Xiaoyi Xie

Hang Liu

Huawei Yin

A method for growing long-seed DKDP crystal by two-dimensional motion grows the crystal along the cylindrical surface, and there is no cylinder-cone interface with low optical quality, while avoiding three flow regions which are inevitable in the crystal growth process by rotating crystal method, including incident flow, side flow and wake flow, and easily cause inclusion formation. The long seed crystal moves periodically in the fresh solution, four cylindrical surfaces can achieve reversible shear flow in one cycle, and any point on the cylindrical surface experiences the same hydrodynamic conditions in one movement cycle, so that the solute supply is sufficient and uniform, the growth velocity is improved, and the stability of morphology is ensured. The method facilitates rapid growth of high quality DKDP crystals and provides a better solution for the large-size, high-quality DKDP crystal growth required by the ICF laser device.

Method for growing long-seed DKDP crystal by two-dimensional motion

A mid-frequency error-free machining method under a magneto-rheological polishing magic angle-step includes the following steps: measuring a magneto-rheological removal function, and determining a control accuracy of a machine tool; performing two-dimensional Fourier transform on the removal function, performing compensating filtering on a frequency spectrum based on the control accuracy of the machine tool, and analyzing a corresponding step at the lowest point of an amplitude of the two-dimensional frequency spectrum that undergoes filtering in a direction of a magic angle; planning a grid path under the given step on the basis of adjusting a direction of a machining path or a posture of a magneto-rheological polishing wheel to allow an included angle between the polishing wheel and the path kept to be at the magic angle; and finally, controlling the machining of the machine tool.

Mid-frequency error-free machining method under magneto-rheological polishing magic angle-step

A single-beam photothermal measurement apparatus and a measurement method for absorptive defects. The apparatus comprises a common-path-type structure and a non-common-path-type structure. The present invention is simple in optical structure and convenient to align and adjustment. The measurement result is stable, and measurement signal anomalies caused by environmental vibration and sample tilt are avoided. By detecting a power change on the edge of a beam spot, the measurement sensitivity of a system is remarkably improved.

Single-beam photothermal measurement apparatus and measurement method for absorptive defects

A pyramidal growth method for long-seed KDP-type crystal. In the growth method provided by the present invention, the lower end of the long-seed crystal is restricted by a lower tray, and the upper end is free to grow into a pyramidal. At the same time, the four prismatic faces at two directions of [100] and [010] can grow, avoiding growth stress problem during crystal growth, and all cut optical elements have high optical quality. Because the growth process is that four prismatic faces with highly similar growth environments grow at the same time and stirring is applied by blade-like stirring paddles during the crystal growth process, the cut optical elements have high optical uniformity.

Method for rapid growth of long seed KDP-type crystals

A surface defect measuring apparatus and method by microscopic scattering polarization imaging is provided. The apparatus mainly comprises a laser, a first converging lens, a rotary diffuser, a second converging lens, a diaphragm, a third converging lens, a pinhole, a fourth converging lens, a polarizer, a half-wave plate, a polarizing beam splitter, an X-Y translation stage, a sample, a microscope lens, a quarter-wave plate, a micro-polarizer array, a camera and a computer. The micro-polarizer array is adopted to realize real-time microscopic scattering polarization imaging of the surface defects; a polarization-degree image is calculated to improve the sensitivity for detecting the surface defects of the ultra-smooth element, and the effective detection of the surface defects of a high-reflective coating element is also realized, and the requirement for rapid detection of the surface defects of a meter-scale large-aperture ultra-smooth element can be met.

Surface defect measuring apparatus and method by microscopic scattering polarization imaging

Device and method for measuring in-situ time-resolved X-ray absorption spectrum. The device comprises an X-ray source, a first slit, an acousto-optic tunable X-ray filter, a radio frequency transmitter, a second slit, a front ionization chamber, a front ionization chamber signal amplifier, a sample to be tested, a rear ionization chamber, a rear ionization chamber signal amplifier, a data collector, and a computer. The X-ray source, the acousto-optic tunable X-ray filter, and the radio frequency transmitter are used to generate a monochromatic X-ray beam; the front ionization chamber is used to measure the intensity of the X-ray beam before passing through the sample; the rear ionization chamber is used to measure the intensity of the X-ray beam after passing through the sample; the front ionization chamber signal amplifier, the rear ionization chamber signal amplifier, the data collector, and the computer are used for data acquisition and data processing.

Device and method for measuring in-situ time-resolved X-ray absorption spectrum

Method for limiting growth of KDP-type crystals with a long seed where an upper and a lower ends of the long seed crystal are respectively limited by an upper baffle plate and a lower tray to restrain growth of a pyramidal surface and allow only four prismatic surfaces in [100] and [010] directions to grow. Finally grown crystal contains no pyramid-prism interface that severely restricts quality of optical element, and all cut optical elements have high optical quality. As four prismatic surfaces are subjected to highly similar growing environment and grow simultaneously, all optical elements cut therefrom have high optical uniformity. Due to uniqueness of a cutting angle of a KDP crystal frequency-tripled element, high cutting efficiency is achieved in the element, and an area of a maximum frequency-tripled element that may be cut is known in advance according to a horizontal size of the grown crystal.

Method for limiting growth of KDP-type crystals with a long seed

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Shanghai, China

Jianda Shao