摘要
采用数值模拟方法研究了受到高斯光阑限制的啁啾高斯脉冲在色散介质中的光谱特性。建立了色散介质中受高斯光阑限制的啁啾高斯脉冲模型,推导出了脉冲功率谱表达式。以功率谱表达式为基础,仿真分析了高斯光阑半径、啁啾参数、传输距离和离轴半径等因素对光谱特性的影响。结果表明啁啾参数对光谱的影响只取决于其绝对值,啁啾参数使近场光谱偏离高斯分布,高斯光阑的限制可有效抑制这种偏离。啁啾参数绝对值越大,远场光谱在传输方向上衰减越慢,在离轴方向上衰减越快,能量越向光轴集中。相比无高斯光阑限制,带高斯光阑限制时,光谱在传输方向上衰减更快,在离轴方向上衰减更慢,且在离轴方向上,红移量和谱宽压缩量均明显减小。随着传输距离增大,轴上光谱蓝移,且在远场趋近于高斯分布,中心频率趋近于一个渐进值。
The numerical simulation method was used to study the spectral characteristics of chirped Gaussian pulses constrained by Gaussian aperture in a dispersive medium. A model of chirped Gaussian pulses constrained by Gaussian aperture in a dispersive medium was established. The expression of the power spectrum was derived. Based on the power spectrum expression, the influence of factors such as the Gaussian aperture radius, chirped parameters, the distance of propagation , and off-axis radius on the spectral characteristics was simulated and analyzed. The results show that the influence of the chirped parameter on the spectrum depends only on its absolute value, the chirped parameter deviates the near-field spectrum from the Gaussian distribution, and the limitation of Gaussian aperture can effectively suppress this deviation. The larger the absolute value of the chirped parameter, the slower the spectrum in the far field is attenuated in the direction of propagation,the faster the attenuation in the off-axis direction, and the more concentrated the energy is on the optical axis. The spectrum attenuates faster in the direction of propagation with the limitation of Gaussian aperture than that without it, while slower in the off-axis direction, and the red-shift and the spectral width compression are significantly reduced in the off-axis direction. As the distance of propagation increases, the spectrum shifts blue on the axis and approaches the Gaussian distribution in the far field and the center frequency of the spectrum approaches a asymptotic value.
作者
孙春霞
郭杰
王小鹏
邹其徽
Sun Chunxia;Guo Jie;Wang Xiaopeng;Zou Qihui(School of Electronic and Information Engineering ,Lanzhou Jiaotong University ,Lanzhou,Gansu 730070,China;School of Science ,Southwest Petroleum University ,Chengdu,Sichuan 610500,China)
出处
《应用激光》
CSCD
北大核心
2019年第2期305-312,共8页
Applied Laser
基金
国家自然科学基金资助项目(项目编号:61761027)
兰州交通大学研究生教育改革项目(项目编号:1600120101)
关键词
光学工程
光谱变化特性
数值模拟
高斯光阑
啁啾
色散介质
optical engineering
spectral change characteristics
Gaussian aperture
numerical simulation
chirped
dispersive media
