Multi-dimensional laser Doppler velocimeter
First Claim
1. A multidimensional laser Doppler velocimeter using the reference beam method for emitting not less than two probe beams to an object to be measured at a predetermined angle to multi-dimensionally measure a velocity or displacement vector of the object due to Doppler shift of beams reflected by the object, comprising:
- laser beam source for generating a laser beam having a single frequency,frequency shifting means for dividing said laser beam into a plurality of beams, and for shifting the frequency of said laser beam by a predetermined frequency difference, one of the beams having the same frequency as that of said laser beam and the other each having different frequencies,beam splitting means for splitting each of the beams into a probe beam and a reference beam, the probe beam being used together with the reference beam whose frequency is different from that of the probe beam,photodetecting means on which a light beam is incident to obtain a detection current, anda bandpass filter means through which said detection current passes for eliminating a crosstalk component from said detection current,wherein the probe beam is radiated to the object to produce a scattered beam from the object, the scattered beam being directed to the photodetecting means, andthe reference beam is directed through the beam splitting means to the photodetecting means thereby mixed with the scattered beam.
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Accused Products
Abstract
A reference beam type optical laser Doppler velocimeter for emitting two or more probe beams to an object to be measured at a predetermined angle to multi-dimensionally measure a velocity and/or a displacement vector of the object due to Doppler shifts of beams reflected by the object. This velocimeter includes a frequency shifting means for dividing a laser beam from a single light source into two or more beams, and shifting optical frequencies of the beams each by a predetermined shift amount, a photodetecting means for receiving the reflected and reference beams to obtain a detection current, and a bandpass filter for causing the detection current to pass therethrough to obtain a required signal.
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Citations
10 Claims
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1. A multidimensional laser Doppler velocimeter using the reference beam method for emitting not less than two probe beams to an object to be measured at a predetermined angle to multi-dimensionally measure a velocity or displacement vector of the object due to Doppler shift of beams reflected by the object, comprising:
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laser beam source for generating a laser beam having a single frequency, frequency shifting means for dividing said laser beam into a plurality of beams, and for shifting the frequency of said laser beam by a predetermined frequency difference, one of the beams having the same frequency as that of said laser beam and the other each having different frequencies, beam splitting means for splitting each of the beams into a probe beam and a reference beam, the probe beam being used together with the reference beam whose frequency is different from that of the probe beam, photodetecting means on which a light beam is incident to obtain a detection current, and a bandpass filter means through which said detection current passes for eliminating a crosstalk component from said detection current, wherein the probe beam is radiated to the object to produce a scattered beam from the object, the scattered beam being directed to the photodetecting means, and the reference beam is directed through the beam splitting means to the photodetecting means thereby mixed with the scattered beam. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification