摘要
基于Kogelnik的体光栅耦合波理论,推导了超短激光脉冲照射下透射型体光栅的耦合波方程,并由此得到了衍射光场和瞬时衍射光强的表达式。研究结果发现,体光栅的瞬时衍射光强分布与体光栅的结构参数,如体光栅的光栅周期、光栅厚度以及体光栅材料的折射率调制度密切相关。通过调节这些光栅结构参量,就可以对体光栅衍射脉冲进行控制和调节,以实现脉冲整形。研究还发现衍射脉冲光相对于入射光脉冲,在时间轴方向有负的平移,这个平移量和体光栅的光栅周期与厚度相关。结合群速度概念,从群时延的角度给出了对这一时间平移量的定量分析。
Based on Kogelnik′s coupled-wave theory,we derive the coupled-wave equations of a volume holographic grating（VHG） illuminated by ultra-short pulsed laser,and obtain its diffraction electric field and instantaneous diffraction intensity.It is found instantaneous diffraction intensity of volume grating is affected by the VHG′s structural parameters,such as the grating spacing,grating thickness,and the refractive-index modulation of the VHG.By changing these parameters,diffracted characteristics could be controlled and this may be used in the pulse shaping.In simulation,we also find group time delay of the diffracted beam with respect to the readout pulse in the negative time axis and this time delay are affected by the grating spacing and thickness.With the concept of group velocity,we give a quantitative analysis about this time delay.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2011年第5期24-29,共6页
Acta Optica Sinica
基金
国家自然科学基金(60908007
10974132)
上海市重点学科基金(S30105)资助课题
关键词
超快光学
超短脉冲
体光栅
耦合波理论
衍射
群时延
ultrafast optics
ultrashort pulse
volume holographic grating
coupled-wave theory
diffraction
group time delay
