High Frequency Holographic Grating Fabrication And Superlattice Technique In Optical Mesomechanics Study

A novel method for SHG (Second Harmonic Generation) of Ar~+ laser, temperature phase-matching of ADP crystal, is presented in this paper. The quartz crystal temperature measurement sensor, the thermoelectric cooling module, the PID real— time control algorithm and other new devices are applied in the intelligent precise temperature measurement and control system. The apparatus with the temperature— controlling accuracy of 0.05℃ is developed. Based on the above devices, the system of extracavity SHG of Ar~+ laser is developed successfully. The ultraviolet coherent light with the wavelength of 257.3nm is obtained.Three new methods for fabricating high frequency holographic gratings are presented and realized. They are grating- fabrication by the ultraviolet coherent light of SHG of Ar~+ laser, grating- fabrication by the pulse light output from modulatable dye laser with the wavelength of 243nm and grating—fabrication in the high refractive index medium. High frequency gratings with the density of over 5000 lines / mm are fabricated.Refractive index medium is introduced into moire interferometry. The sensitivity of conventional moire interferometry is significantly increased up to 0.16μm. This new technique is developed for mesomechanics research.Zero-thickness specimen grating etching techniques are developed. High frequency zero-thickness gratings are fabricated on the surfaces of different materials via chemical etching technique and RIE ( Reacting ion etching) technique seperately.High frequency gratings fabricated by optical methods are employed in superlattice method in order to replace mechanical method. Mesomechanical characteristics of the short-fibre reinforced composite and shape memory alloy under loads are investigated. Experimental results demonstrate that thecombination of optical etching technique and lattice method provides promising techniques for the further research of mesomechanics.