An all-optical ultrasonic detection device based on photo-induced ultrasound and laser interference

Abstract

The invention relates to an all-optical ultrasonic detection device based on photoinduced ultrasound and laser interference. The first laser of the device is connected to the optical switch through an optical fiber; the optical switch is connected to the dielectric film through multiple optical fibers, and the light-absorbing film is located on the outgoing light path of the dielectric film; the second laser generates reference light and multiple probe lights; the reference light passes through the acoustic After the optical frequency shifter and the second optical fiber coupler, the first frequency-shifted reference light and multiple beams of second frequency-shifted reference light are generated; the first frequency-shifted reference light passes through the third optical fiber coupler and reaches the first photodiode to generate a carrier signal; After the light is reflected by the dielectric film, it interferes with the second frequency-shifted reference light, and the interfering light reaches the second photodiode after passing through the fourth optical fiber coupler to generate a frequency modulation signal, and the frequency modulation signal and carrier signal are input to the mixer to generate a frequency mixing signal; The collection unit is used to collect the mixed frequency signals output by multiple mixers, and obtain the vibration signal generated by the object to be measured. The invention can improve the flexibility and bandwidth of ultrasonic detection.

Description

technical field [0001] The invention relates to the field of ultrasonic detection, in particular to an all-optical ultrasonic detection device based on photoinduced ultrasound and laser interference. Background technique [0002] Ultrasonic detection technology is widely used in many fields such as non-destructive testing, biomedical imaging and marine reconnaissance, and is one of the most important detection technologies at present. The core of ultrasonic detection technology is the ultrasonic sensor. Traditional ultrasonic sensors are mostly made of piezoelectric materials. This kind of sensor cannot take into account high sensitivity and wide bandwidth at the same time. In addition, there is strong electromagnetic interference, which greatly limits its application. [0003] Ultrasonic sensing based on laser interference has good anti-electromagnetic interference ability, and can still ensure high sensitivity under a wide bandwidth. It is a very promising ultrasonic detec...

AI Technical Summary

Problems solved by technology

So far, the existing optical ultrasonic detection systems only generate ultrasonic waves based on the principle of photoinduced ultrasound or detect ultrasonic waves based on laser interference, and cannot realize all-optical ultrasonic detection.

Moreover, the ultrasonic detection system based on the fiber optic ultrasonic sensor is difficult to realize the array integration of multiple sensors, which greatly limits its further application.

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