#Y2021 #光学测量 A Gires–Tournois interferometer is an optical standing-wave resonator similar to a Fabry–Pérot interferometer, which however is operated in reflection and with the purpose of generating chromatic dispersion. The front mirror is partially reflective, whereas the back mirror has a high reflectivity. If no losses occur in the resonator, the power reflectance is unity at all wavelengths, but the phase of the reflected light is frequency-dependent due to the resonance effect, causing chromatic dispersion. The phase change of reflected light and the dispersion (including group delay dispersion and higher-order dispersion) change periodically with the optical frequency, if material dispersion is negligible. There is no second-order dispersion exactly on-resonance or anti-resonance, and positive or negative dispersion between these points.  Figure 1: Schematic setup of a Gires–Tournois interferometer.  Figure 2: Wavelength-dependent group delay dispersion of a GTI made of a 5-μm thick silica layer on a high reflector.