Laser interferometric diffractometry for measurements of diffraction grating spacing

Two methods and an experimental setup for the measurement of spacing of diffraction gratings have been developed. These methods depend on interferometric measurements at different wavelengths of the angles of diffraction beams from the grating to be measured. A lower limit for the measured spacing is the half-wavelength of laser radiation. The results of spacing measurements of approximately 0.28, 0.39, and 0.50 μm are presented.