DeepLightSeekdefinition:
A linear optical resonant cavity used to introduce dispersion.
Gires-TournoisInterferometer is similar to Fabry Perot-A standing wave resonant cavity of the Perot interferometer, but utilizing the reflection effect to generate dispersion. The front mirror is partially reflective, while the back mirror has a high reflectivity. If there is no loss in the resonant cavity, then the power reflectivity is consistent at all wavelengths, but the phase of the reflected light is frequency dependent due to the resonance effect, resulting in dispersion. The phase variation and dispersion (including group delay dispersion and high-order dispersion) of reflected light vary periodically with frequency, while ignoring material dispersion. At this point, there is no second-order dispersion that is resonant or anti resonant, and there is no normal or anomalous dispersion between these points.
pictureone：Gires-TournoisSchematic diagram of interferometer.
picturetwo: From5μm Thick quartz layer prepared on high reflection mirrorGTIThe group delay dispersion curve that varies with wavelength.
Tunable dispersion can be achieved by adjusting the air gap between two mirrors, but it needs to be carefully fixed to avoid unnecessary movement. Adopting a single-chip design can achieve more stable but non adjustableGDDUsing cladding dielectric materials, such asTiO2andSiO2Especially suitable for femtosecond lasers.
GTIThe main drawback is its limited bandwidth (compared to the givenGDDThe square root of the amplitude is proportional and has little control over high-order dispersion. Dispersive mirrors with larger bandwidth can be used as chirped mirrors.
