Generation of a stable low-frequency squeezed vacuum field with periodically poled KTiOPO4 at 1064 nm.
We report the generation of a stable continuous-wave low-frequency squeezed vacuum field with a squeezing level of 7.4+/-0.1 dB at 1064 nm, the wavelength at which laser-interferometric gravitational wave (GW) detectors operate, using periodically poled KTiOPO4 (PPKTP) in a subthreshold optical parametric oscillator. The squeezing was observed in a broad band of frequencies above 700 Hz where the sensitivity of the currently operational GW detectors is limited by shot noise. PPKTP has the advantages of higher nonlinearity, smaller pump-induced seed absorption, and wider temperature tuning range than alternative nonlinear materials such as MgO-doped or periodically poled LiNbO3, and is, therefore, an excellent material for generation of squeezed vacuum fields for application to laser interferometers for GW detection.
Goda
Keisuke
K
LIGO Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Mikhailov
Eugeniy E
EE
Miyakawa
Osamu
O
Saraf
Shailendhar
S
Vass
Stephen
S
Weinstein
Alan
A
Mavalvala
Nergis
N