Beam combining of high energy fibre lasers is the research hotspot especially for the directed energy application in recent years, which can overcome the output power lever limits of one single-mode fibre laser, and establish the theoretical foundation for the application of laser weapons with high power and perfect beam quality. Research status of fibre laser incoherent combining and coherent combining were presented. In the section of incoherent combining, the combining principle and combining level of beam overlap and spectral beam combining were introduced. In the section of coherent combining, the key combining apparatus of transmission-type and reflection-type equivalent large aperture laser array output and optical element of single aperture output were analyzed in detail. The advantages and disadvantages and range of application of high power fibre laser beam coherent combining and incoherent combining were compared briefly.

Due to the nonlinear effect and the thermal effect, a single optical fiber has limitations in the output power. A beam combination of laser arrays based on adaptive optics can both improve the output...

A prime-focus optical system is a common type of large aperture survey telescope with a small obscuration ratio, high transmittance, and simple structure. As the detection capabilities and search efficiency of the telescope are improved, the aperture of the primary mirror becomes larger. The primary mirror aperture of a high-performance survey telescope has a four-meter scale, and the aperture of the corrector lenses of a corresponding prime-focus optical system can reach a one-meter scale. In this study, optical surface shape changes due to gravity were studied via an integrated optomechanical analysis. The Zernike polynomial was used to characterize the changed optical surface. The influence of optical surface variations on the wavefront and imaging quality of the optical system was analyzed by calculating the optical path differences. From the perspective of optical aberration, the optical properties of meter-level corrector lenses were quantitatively analyzed. The effect of the meter-level corrector lenses on imaging was explained in principle, and the feasibility of this optical scheme was verified.

The wide-field telescope will be an important tool in the discovery and birth of new theories of astronomy in future. The detectors in this kind of telesco