In addition, physical experiments have strict requirements on the spot size and contour focused on the target. In many cases, laser pointer shooting requires a uniform spot with a certain size (such as a size of about 0.5mm), and the focal spot focused by the lens is generally less than 0.05mm, so beam control technology (usually inserted into a type of optical element, commonly known as beam Smooth element) to adjust the focus spot to the required size. In the early 1990s, the “fly-eye array lens technology” proposed by Academician Deng Ximing of the United Room successfully solved this problem. It was made of a series of small lenses cemented, commonly known as the “Shanghai method”, and was used by domestic and foreign academic circles. Respect.
In order to solve the problem of line focusing in the X laser experiment (need to transform the light spot into a thin and long thin line), Huang Hongyi, Chen Wannian, Wang Shusen, etc., the team leaders of the older generation range group, developed the idea similar to fly eye array lens and developed Cylindrical mirrors formed by the cementing of some cylindrical lenses form a new direction for X laser physics experiments. Until now, although more advanced continuous phase plates have been able to achieve more convenient spot control, in some experimental areas, the two still have good use value.
In order to integrate multiple functions such as spot control, harmonic conversion, lens focusing, etc., we used the range terminal optical components. Similar to the lens group of SLR cameras, the related 7-8 transmissive optical elements are “stringed” together and enclosed in a complete mechanical structure. The following figure is a macro picture of multiple FOAs. They are combined with the target ball and can be regarded as a fully equipped giant robot: the heart is at the target point, the torso is the target ball, and the limb is the FOA system. The advantage of FOA is that it is easy to assemble and debug after integrated modularization, and the overall environment can be controlled. However, under the irradiation of high-power green laser pointer, the residual reflected light on multiple surfaces gradually destroys the mechanical and optical components, which has become an unavoidable technical problem for the FOA system.
The laser focused shooting has condensed the efforts and efforts of many generations of scientists. At present, the target ball of the Shenguang device is at most 9 beams of laser shooting. In order to maximize the focus shooting energy in order to approach the theoretical fusion ignition conditions, one is to increase the number of laser paths, and the other is to further increase the energy of the single beam laser, so a new set 192 or more beams of ultra-large laser devices are on the agenda. For the shooting range, this will place higher requirements on the target ball, mirror and FOA system. How to optimize the configuration of the FOA optical path, improve the performance of optical components, and control the best working environment have become a major technical difficulty that the shooting range needs to overcome in the future.