Abstract
A scanning Fabry-Perot interferometer with capacitive aluminium mesh mirrors, which can roughly estimate the oscillation frequency of far-infrared (FIR) laser for its direct frequency measurement, has been developed. The mesh-mirror separation is measured by using a visible laser interferometer (He-Ne 633nm) of frings counting type which is associated with the FIR interferometer. Using the Fabry-Perot interferometer, wavelengths of three FIR oscillation lines have been measured for evaluating its measurement error. It has been found that uncertainties in the wavelength measurements are estimated to be less than ± 0.1μm. This vale is small enough to carry out the direct frequency measurement.
