Description
AlGaAs/GaAs crystalline coatings are promising for future gravitational-wave detectors due to their low mechanical loss and superior optical properties. However, their high optical absorption at 532 nm precludes the use of conventional arm-length stabilization schemes based on 532 nm auxiliary lasers.
We present an alternative arm-length stabilization scheme employing an auxiliary laser at 1596 nm, where the absorption of AlGaAs/GaAs coatings is sufficiently low. The 1596 nm light is converted to 532 nm via single-pass third-harmonic generation, enabling phase locking to the
second harmonic of the main 1064 nm interferometer laser. The resulting phase-locked loop stabilizes the frequency difference between the two systems.
We demonstrate ~Hz linewidth in the beat signal between the two 532 nm fields. Furthermore, arm-length stabilization is experimentally realised using a rigid tabletop cavity, confirming the viability of this scheme for future gravitational-wave detectors incorporating crystalline coatings
| I am the presenting author | Yes |
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