Generation of entangled TEM_(01) modes with periodically poled KTiOPO_4 crystal

Spatial quantum optics based on the high-order transverse mode is important for the super-resolution measurement and quantum image beyond the shot noise level. Quantum entanglement of the transverse plane Hermite-Gauss TEM₀₁ mode has been demonstrated experimentally in this paper. Two squeezed TEM₀₁ modes, which are generated by a pair of degenerate optical parametric amplifiers (DOPA) with the nonlinear crystals of periodically poled KTiOPO₄, have been combined to produce TEM₀₁ mode entanglement using a beam splitter. The 1.5 dB for the sum of amplitude and 1.2 dB for the difference of phase below shot-noise level is achieved with the measurement system of a Bell state detection.