有限尺寸光栅压缩器的优化设计

Optimal Design of Grating-Size-Limited Compressor

分析了超短超强激光系统中有限尺寸光栅压缩器设计的关键物理参数及约束条件,得到了压缩器优化的三项基本变量。给出了一种输出能量最大化的压缩器优化方法,进而确定了有限尺寸光栅压缩器的最大工作能力。针对传统的圆光束方案提出了改进的椭圆光束方案,增大了聚焦能量,减小了焦斑尺寸,提高了峰值聚焦功率密度。通过数值模拟对500 mm曝光口径介质膜光栅在圆光束和椭圆光束两种方案下的最大输出能力进行分析比较,指出单块光栅在椭圆光束方案下可以实现500 fs,500 J,1 PW的脉冲输出。

Pivotal parameters and restricted condition of the grating-size-limited compressor in an ultra-short, ultraintense laser system are analyzed, and three basic parameters are obtained. An optimal method for compressor to output a maximal pulse energy is developed, and the maximal output pulse energy of the grating-size-limited compressor is given. Compared with the traditional circular beam method, an advanced elliptical beam method is presented, which could be used to output much higher pulse energy, a smaller spot size and a larger focal intensity. Using numerical simulation, the maximal output pulse energy of the 500 mm grating compressor based on the circular beam and the elliptical beam are calculated separately. The results show that the 500 fs, 500 J, 1 PW pulse can be obtained without using tiled grating technology if elliptical beam method is used.