Fig. 6: Optical frequencies present in the negative dispersion filter.
From: Gravitational wave detectors with broadband high frequency sensitivity
The gravitational wave (GW) signal sidebands, labelled “1” and “2”, are detuned from the interferometer carrier frequency ω0 by the GW signal frequency Ω. The resonance peak of the interferometer and filter cavity is shown centered around ω0. The filter cavity is pumped by light that is blue detuned from the carrier by the mechanical frequency ωm. Additional noise sidebands “3” and “4” are present at ω0 + 2ωm ± Ω, which couple to the GW signal sidebands “1” and “2”, introducing extra quantum noise at ω0 ± Ω.
