  A laser-diode-pumped intracavity frequency-doubled Nd:YAP/KTP laser is
presented. Over 110 mw of TEM00 single-frequency output power at 540-nm
wavelength was obtained. The output green laser was employed to pump a
semimonolithic nondegenerate optical parametric oscillator to produce intensity
quantum correlated twin beams at 1080 nm, and the maximum quantum noise
squeezing of 74 %(5.9 dB) on the intensity difference fluctuation between the
twin beams is observed. The threshold was reduced and the stability was
increased significantly when compared with similar lamp-pumped systems.
