Optical EngineeringHigh-resolution optic displacement measurement using a dual photodiode sensor
|Format||Member Price||Non-Member Price|
Comparative displacement measurements are made using laser diode (LD) and light emitting diode sources, fiber optic collimators, and a dual-photodiode detector (DPD). It is shown that a relative displacement resolution < 2 nm is possible with the LD source. This result is interpreted to indicate that the coherent LD sources illuminating the DPD temporally correlates the mutual irradiation function of the signals between each photodiode segment and significantly reduce electronic (shot) noise, reduces the variance, and thereby enhances resolution.