提出一种集合浮雕和折射率周期分布调制的复合型衍射光栅,并利用角谱表示和严格的模式理论研究了线偏振高斯光束通过这种复合型衍射光栅的传输特性.数值计算结果表明,在光栅的同一透射深度处复合型衍射光栅光强的起伏频率要比浮雕型光栅光强的起伏频率小.最后使用复合型衍射光栅模型,研究了亚波长体积相位全息光栅的表面起伏和入射光束的束腰宽度对衍射效率的影响.
A new type of diffraction grating called the compound modulated diffraction grating is proposed, which incorporates both surface relief and periodic refractive index modulation. Based on the angular spectrum representatign and strict modal theory, the propagation of linearly polarized Gaussian beam through the compound-modulated diffraction grating whose characteristic size is comparable with the wavelength is studied. It is shown that the propagation of beam in each layer is different and the intensity fluctuation frequency in the compound-modulated grating is smaller than that in the conventional relief grating at the same transmission depth. Using the compound modulated grating model, the influence of surface fluctuation of the sub-wavelengthvolume phase holographic grating and waist width of the incident beam on the diffraction efficiency is analyzed.