The invention discloses a device and method for detecting the no reflection objects in liquid using backward stimulated
Brillouin scattering. The device comprises a single
longitudinal mode laser, reflector M1, 1 / 2 wave plate, glan
prism, faraday 45 degree activizer, reflector M2, divergent lens, convergent lens,
liquid cell containing the objects to be detected and photo
detector. The
laser from the single
longitudinal mode laser converges in the
liquid cell by the above
system. When the
light intensity of the convergence point reaches to the threshold of the stimulates
Brillouin scattering, the backward stimulated
Brillouin scattering is generated and returns at the original path, and output at the reflection port of the glan
prism and received using the photo
detector. When there is object at the laser convergence point in liquid, the laser is blocked and the backward stimulated Brillouin scattering is not generated, therefore there is no
signal to output. The presentation of the object in liquid and the depth thereof can be detected by detecting whether there is backward stimulated Brillouin scattering
signal or not at different depth of laser converging.