Experimental Generation of Multimode Squeezing in an Optical Parametric Amplifier

We experimentally demonstrate that HG₀₁ (Hermit–Gauss) and HG₁₀ squeezed states can be generated simultaneously in an optical parametric amplifier. The HG₀₁ mode is a bright squeezed state and the HG₁₀ mode is a vacuum squeezed state. The squeezing of the HG₀₁ mode is -2.8 dB, and the squeezing of the HG₁₀ mode is -1.6 dB. We also demonstrate that the output field is also continuous-variable entanglement with orbital angular momentum.