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Based on the measurement principle of laser hatched method,an equipment for measure plasma shield was set up.The shielding of NS pulse laser induced breakdown in water was studied.Laser induced plasma shield images were recorded.Linear relation between the effect and laser energy was found.Linear break phenomenon by the NS pulse laser was observed for the first time.These research results will provide the theoretical and experimental references for laser processing underwater,laser medicine and corresponding hydromechanics.

Aiming at measurements of glass material inner-stress,a new high precision measurement method is proposed using the Magnetic-Optic Modulation technique for the stress birefringence.The proposed method has the strong points that simple theory,high precision and so on.The theory derivation is also given using the Jones Matrix,and the results show that the two methods to improve measurement efficiency are feqsible when the testing sample is much bigger.

Based on femtosecond laser inscription technology,a novel method for femtosecond laser micromachining system is proposed to fabricate a microfiber Fabry-Perot (F-P) cavity on the fiber end surface.This technique can solve the parallelism problem of the traditional fiber F-P sensors inscribed by femtosecond laser.The F-P interferometric sensor made by the proposed technique shows over 20 dB fringe visibility.This technique is parameter-controllable and easy to implement.It is a promising candidate of strain measurement in the case of extreme temperature circumstances.

The development of a novel push-type ultrasonic endoscope is described in which probe rotation is accomplished by a small motor situated near the transducer. A digital FPGA-based ultrasound imaging system is implemented which uses coded excitation to increase the SNR and penetration depth, with probe rotation accomplished by a small motor situated near the transducer replacing the external motor and the long steel wire used in other ultrasonic endoscopes. The apparatus is tested continuously for 300 hours with no obvious problems. The coded excitation, digital quadrature demodulation imaging system can obtain ultrasonic images of higher quality and more information of the echo is preserved compared with the analog imaging system, because the analog digital conversion is moved to the first step of the signal processing.The digital imaging system possesses a higher SNR resulting in a sharp image. Locating the motor near the probe improves the consistency of rotational speed in comparison with external guide-wire rotation, and increases the image quality and life-span of these devices.