用空间滤波方法制作θ调制全息物片

Study of fabrication of holographic θ modulation board based on spatial filtering method

给出了一种制作θ调制全息物片的新方法.在空间滤波光学系统的频谱面上放置只允许±1级频谱通过的滤波器,当单色平行光垂直照射物平面上的一维光栅时,将在像平面上得到两个重叠的一维光栅像,同时在成像区域形成光强按余弦规律变化的干涉条纹.用装有镂空模板和全息干版的可旋转组合干版夹对干涉条纹进行3次等时曝光,记录下3种不同干涉条纹方向的图案,即可制作出θ调制全息物片.

A new method of fabricating holographic θ modulation board is proposed. The filter is available to allow only ±1 frequency spectrum to pass in the spatial filtering optical system, thus two overlapping one-dimensional grating images and the sinusoidal interference fringes on the output plane are obtained when a parallel monochromatic beam of laser light focuses on the input plane. Three-equal-time exposal is necessary to record the figures of interference fringes with three different directions by using a rotatable bracket with hollow template and holographic plate, thus the θ modulation board is done.