Patent ID: 8199331

Claim:
A vibrometer for optic oscillation measurements of an object ( 12 ), comprising a radiation source for creating a source beam, a beam splitter for splitting the source beam into a measuring beam and a reference beam ( 10 ), an optic interference device for interfering the reference beam with the measuring beam ( 9 ), at least partially reflected by the object ( 12 ), and a detector, with the interference device and the detector being embodied cooperating such that the measuring beam ( 9 ) and the reference beam ( 10 ), at least partially reflected by the object ( 12 ), interfere on the detector, the vibrometer comprises a heterodyne vibrometer, an optic frequency shift unit is arranged in an optical path of the vibrometer, to form a carrier frequency by creating a frequency difference between the measuring beam and the reference beam ( 10 ), the beam splitter and the frequency shift device are embodied as an acousto-optic modulator in an optic component to deflect the source beam, with the acousto-optic modulator being embodied such that the source beam ( 8 ) entering the acousto-optic modulator can be split into at least two diffraction beams: a first diffraction beam of the order of 1, and a second diffraction beam of the order of −1, and the acousto-optic modulator is arranged in the optical path of the vibrometer such that one of the two diffraction beams is the measuring beam ( 9 ) and the other of the diffraction beams is the reference beam ( 10 ), the acousto-optic modulator comprises a slow shear mode Bragg cell ( 2 ), and the radiation source is embodied such that it creates a monochromatic beam of a predetermined wavelength and the acousto-optic modulator is embodied such that an optimal light angle for a maximum intensity of the diffraction beam of the order of 1 is identical to a light angle for a maximum intensity of the diffraction beam of the order of −1, at least for an incoming beam having the predetermined wavelength.