强非局域介质中1+1维Sech损耗光孤子

1+1 D Sech Lossy Soliton in Strongly Nonlocal Media

运用变分法研究1+1维sech光束在存在小损耗强非局域非线性介质中的传输特性,得到了光束各参量的近似演化方程和束宽的近似演化规律以及一个临界功率。当初始功率大于临界功率时,束宽按准正弦和准余弦函数规律作准周期的压缩变化;当初始功率小于临界功率时,束宽按准正弦和准余弦函数规律作准周期的展宽变化;当初始功率等于临界功率时,可以得到束宽随传输距离缓慢展宽的准sech空间孤子。

The variational approach is used in discussing the propagation properties of thel ＋ 1 D sech optical beam in small loss strongly nonlocal nonlinear media, a set of optical beam approximate evolution equations,the beam width approximate evolution law and a critical power are obtained. The initial power is bigger than the critical power, the beam width compresses periodically and obeys the quasi -sine function law and the quasi -cosine function law, with sech optical beam propagating in small loss strongly nonlocal nonlinear media; otherwise, the initial power is smaller than the critical power,the beam width broadens periodically and obeys the above function laws;when the loss is small,a quasi -sech spatial soliton of the beam width slow broaden is obtained.