Holography can be divided into two processes of recording and reproduction. The recording process is to superimpose the reference light and the reflected light on the subject onto the holographic plate to generate interference fringes. After processing the plate in the dark environment, the interference pattern on the sensor plate is reproduced to be exactly the same as the original object by diffraction. Compared with ordinary photography, holography not only records the amplitude of the light field of the object being photographed, but also records the relative phase of the reflected light wave. It is widely used in holographic microscopy, holographic anti – counterfeiting, data storage, deformation measurement and holographic interferometry.
Theotry
The main components of device are:
Gain medium - Nd: YVO4
The working medium of the laser is Nd: YVO4, which has the characteristics of high gain, low threshold, high energy efficiency and low loss at 1342nm. We use it to emit a near-infrared laser with a wavelength of 1342nm.
Electro-optic Q methods is used, through the accurate control of the voltage, we can control phase difference between fast light and slow light after light transmits the crystal to control the polarization direction of the output light, here, the Q switch crystal is Cr4+: YAG crystal, its application range is 900-1200 nm and 1350-1600 nm, damage threshold overs 500 MW/cm2.
Q switch - Cr：YAG
LBO Frequency conversion
The frequency multiplier adopts LBO crystal, which can be used for frequency doubling to generate high energy red light of 671 nm. LBO has wide transmission band (169-2600 nm), large effective second harmonic generation (SHG) coefficient and high frequency conversion efficiency.
Feature
- The reconstructed stereoscopic images are conducive to preserve precious art materials for collection.
- Each point is recorded at any point on the hologram, it is no matter even if the picture is damaged.
- Holographic images have strong stereoscopic and vivid images, which can be displayed in various exhibitions with the help of lasers, and very good results can be obtained.
Application
- Holographic microscopy
- Holographic anti-counterfeiting
- Data storage
- Deformation measurement
- Holographic interferometry
Leave a Reply