1. The Fourier transform characteristics of off-axis hololens was discussed, which was made by using a dot light source and an inclined parallel light.

2. A newest recording path system for gecnerating the four focus hololens is presented.

3. A method of parallel optical processing of double exposure specklegram or particle image using hololens array is presented.

4. And adopting a method of eight light beam exposure at the same time forms four focus hololens so that diffraction efficiency is increased. Real optical path system and experimental results are given.

5. The Fourier transform power spectrum of input object can be obtained when the input image is placed at the front or back of the hololens.

6. As an example, experimental results of multi-image storage with speckle encoding using the hololens is given.