Investigation of spatial Einstein-Podolsky-Rosen aspects in the degenerateoptical parametric oscillator

We present a study of quantum spatial correlations in the transverse cross- section of the beam emitted by a degenerate optical parametric oscillator w ith spherical mirrors and finite-size pump. We show that these correlations are at the origin of efficient quantum noise reduction in proper combinati ons of field quadratures detected over symmetrical regions in the beam tran sverse section; moreover they offer the possibility of investigating EPR as pects for continuous variables. We discuss different regimes and show that EPR correlations arise over a broad range of values for the frequency spaci ng among adjacent transverse modes and for realistic values of the waist of the pump beam. (C) 2000 Elsevier Science B.V. All rights reserved.