Interferometry works on the principle of wave interference, where coherent waves (usually light or radio waves) are combined to create interference patterns that can be analyzed to extract information about the sources or medium by which they travel. The fundamental principle of interferometry relies on the superposition of waves, where the resulting intensity at any time is determined by the sum of the amplitudes of the individual waves and the phase difference between them. This phase difference, which can result in constructive or destructive interference, is very sensitive to changes in the length or characteristics of the wave path, allowing interferometers to measure parameters such as distance, wavelength, displacement or surface profile with high precision. Interferometric techniques find applications in astronomy, optics, radar and other fields requiring precise measurement and analysis of wave properties.
A heterodyne interferometer works on the principle of heterody, which involves mixing the signal of interest with a reference signal of slightly different frequency (often called a local oscillator). The key principle behind heterodyment is the generation of a beat frequency equal to the difference between the frequencies of the two signals. In a heterodyne interferometer, this beat frequency is used to extract phase information from the interference pattern. By detecting and analyzing the beat frequency, the interferometer can measure small phase shifts with high precision. This approach is particularly advantageous in applications requiring extremely precise measurements of distance, displacement, vibration or surface irregularities. Heterodyne interferometers are widely used in fields such as metrology, laser variation, optical testing and semiconductor inspection, taking advantage of the higher resolution and sensitivity achieved by heterodying compared to detection methods. direct.