| 摘要 |
A device for the non-contacting measurement of an object to be measured, particularly for distance and/or vibration measurement, has at least one laser light source, optical devices for splitting the light into object light (4) and reference light (5) for interacting with the object to be measured and for superimposing object light and reference light following the interaction of the object light with the object to be measured, preferably a frequency shift device in the form of a Bragg cell for producing a frequency shift between the object light and the reference light and a detecting device (15) for converting reference light and object light into electrical signals suitable for further processing. The detecting device has at least two series-connected optoelectronic transducers in the form of photodiodes (30, 31). Between the transducers is located a tap (32) for tapping a difference signal which, for further processing, is supplied to a transimpedance circuit (33) associated with one of the transducers. Thus, there is a subtraction of photodiode currents prior to processing in an amplifier circuit in a balanced detection arrangement. This inexpensively permits measurements at high reference light power with resolutions in the quantum noise limit range.
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