Study On The Application Of Laser Technology In SAW Gas Detecting

Surface acoustic wave(SAW) gas sensor is a novel gas-detecting method in the field of gas exploration. It can give the information on gas strength by means of the sensitive reaction of absorptive film which has been covered on the surface of sample plate. Further more, SAW gas sensor has many excellent properties such as high precision, high resolution, small size and easy integration.Recently.At first, this paper has made a overview summary about the applications of SAW gas detecting technology. On the base of SAW gas detection mechanism, discuss the physical characteristics and diffusibility of surface wave, and introduce the selectivity factor and species of surface wave in detail. In order to use the superior of laser technology fully, the laser-induced technique and detecting technique of integrating the fault detection of laser ultrasound using on the surface of solid, use the thermal elasticit of laser on the solid surface and finite element model to discuss the physical process of laser producing SAW and the design procedure. Discuss the optical detection ways and supply theoretical foundation and support feasibility for finding new SAW methods. On the base of the optical communication technology and the fiber acoustic-optics modulator used for optical signal processing,this text has discussed the basic theory of fiber acoustic-optics modulator, compared the two mechanism between Raman-Nath diffraction and Bragg diffraction. It also made some examples for using acoustic-optics modulator in the end.At the end of this text, the paper try to point out a gas detection system which use fiber acoustic-optics modulator for Detecting the surface wave on the SAW device, and analyze the system mentality of designing and structure of experiment. At the same time by listing the advantages, it has fully analyzed the problems and difficulties.