Light Triggering CCD To Capture Phase Shift Hologram To Eliminate The Interference

Comparing with the original optical holography, digital holography can achieve the effective separation of reconstruction, and calculate the value of wave-front reconstruction accurately. Specific to the characteristic of digital holography, this research has investigated the disturbance for the vibration existed in the digital phase shift holography. Computer is used to control the spatial light modulator, in order to make multiple raster patterns with fixed phase difference moving repeatedly inside, this achieves the modulation of holographic reference light. Accordingly, light triggered technology can control CCD to achieve the alternating of the images and the synchronous triggered shooting of CCD, thus eliminate the interference from external vibrations to the procedure of holographic recording.This article is mainly engaged several researches as below:(1) Established system of digital phase shift holographic recording, the accurate phaseshifting of reference wave was achieved by adding the spatial light modulator to the reference light.(2) The recording mode of using light to trigger CCD is proposed to make the acquisition of digital phase shift holograms, hologram corresponded to each phase value is collected accurately and effectively. Using the commutative transmit of the grating phase shift image in the light modulator, the high and low voltage generated by its diffractive beam can make the triggered shooting of CCD. This achieves that one phase diagram has only one hologram corresponding to it, thus improved the accuracy and credibility of this experiment and reduced a bunch of workload during post process.(3) Crafted a program to process the digital phase shift holograms, the phase value corresponded to each hologram is calculated by this program. The best phase value and its corresponding hologram can be acquired after statistics of these values by histogram and its fitted curve.(4) A satisfactory result is gained after comparing the best phase value with the one set at the beginning, thus proved the validity of light triggering CCD to capture phase shift hologram to eliminate the interference.