Distance measurement by multiple-wavelength interferometry

Absolute metrology for space interferometers

“…This can be done with the help of a common reference length in the form of a Fabry-Pérot resonator. Absolute accuracy is obtained by stabilizing the Fabry-Pérot with respect to a frequency stabilized master laser 4 , e.g. a laser stabilized on an atomic absorption line, as shown in Fig.…”

“…4. A new concept of a multiple-wavelength source was developed recently for which the calibration of the different synthetic wavelengths is obtained by beatfrequency measurements 5,6 . This concept may be useful to stabilize and calibrate synthetic wavelengths between 1 mm and 200 mm.…”

Quantum-Noise Limited Distance Resolution of Optical Range Imaging Techniques

“…Using (15) and (17), we obtain the following expression for the low-pass filtered flux function (18) in which the parameters and are related to and of (15) in the following way: (19) If at least three different sample values, , within the same period are known, then the sought parameters and in (18) can be determined [10]. Because of the simplicity of the involved calculations, a preferred method for the determination of and is to employ four equidistant sample points , within the function's period , so that the distance between subsequent sample points is .…”

Absolute distance measurement with an unraveled femtosecond frequency comb

“…To relax the limitations of single-wavelength interferometry, multi-color schemes have been developed using 2 or more lasers with different wavelengths. This increases the range of nonambiguity at the expense of increased complexity [1]. Alternatively, a displacement can be measured, instead of an arbitrary distance, but in this case a linear guidance must be available.…”