Bright squeezed-light generation by a continuous-wave semimonolithic parametric amplifier.

Continuous-wave amplitude-squeezed light at 1064 nm has been generated with excellent long-term stability by use of a dual-port type I degenerate optical parametric amplifier pumped by a frequency-doubled Nd:YAG laser. A seed wave at 1064 nm is resonantly injected through the low-transmission cavity port, whereas the parametrically deamplified and squeezed output wave is extracted from the high-transmission port. Amplitude noise reduction of as much as 4.3 dB is observed directly at an output power of 0.15 mW. Stable noise suppression exceeding 3.8 dB is obtained for several hours by phase locking of the pump wave. The longterm stability and simplicity make this device suitable for sub-shot-noise metrology.