啁啾脉冲参数对合成光束的远场光强的影响

Influence of chirp pulse parameters on far-field intensity distribution of combined beams

光束合成是提高激光功率及光束质量的一种有效方法,啁啾脉冲高斯光束的各参数都会影响合成的效果。利用夫琅禾费衍射积分公式导出了两束啁啾脉冲高斯光束合成的远场光强的解析式,得知远场光强与啁啾参数、脉宽及谱宽等参数有关。对远场光强进行了数值模拟,结果表明:对甚多束光束合成而言,单元激光间的啁啾参数增大、脉宽差值减小或者谱宽差值增大,均有利于轴上光强的增大及远场光强分布集中于传输轴附近。

The beam combination is an effective method to improve laser power and beam quality,the parameters of chirped pulsed Gaussian beam will affect the result.Based on the Fraunhofer diffraction integral formula,the formulas for the far-field relative intensity of two chirped pulsed Gaussian beams combination are derived.It is shown that the far-field relative intensity distribution of the combined beams depends on the chirp parameter,pulse duration,and spectral bandwidth.The numerical simulation result of the intensity indicates that,the far-field relative intensity distribution of combined beams increases and is more concentrated in the vicinity of transmission shaft with the increment of chirp parameter or with the decrement of pulse duration difference or the increment of spectral bandwidth difference.