Full-field cavity enhanced microscopy techniques

Quantum enhanced microscopy allows for measurements at high sensitivities and low damage. Recently, multi-pass microscopy was introduced as such a scheme, exploiting the sensitivity enhancement offered by multiple photon-sample interactions. Here we theoretically and numerically compare three different contrast enhancing techniques that are all based on self-imaging cavities: CW cavity enhanced microscopy, cavity ring-down microscopy and multi-pass microscopy. We show that all three schemes can lead to sensitivities beyond the standard quantum limit.