Linear negative dispersion with a gain doublet via optomechanical interactions

Optical cavities containing a negative dispersion medium have been proposed as a means of improving the sensitivity of laser interferometric gravitational wave detectors through the creation of white-light signal recycling cavities. Here we demonstrate that negative dispersion can be realized using an optomechanical cavity pumped by a blue detuned doublet. We used an 85-mm cavity with an intracavity silicon nitride membrane. Tunable negative dispersion is demonstrated, with a phase derivative 푑휑/푑푓 from −0.14  Deg·Hz−1 to −4.2×10−3  Deg·Hz−1.