Quantum tomography and intracavity dynamics with a biased optical parametric oscillator

We propose and experimentally demonstrate a method to study intracavity quantum states and their dynamics in an optical parametric oscillator (OPO). By measuring the OPO steady state’s sensitivity to an external bias field, we show how intracavity quantum states can be reconstructed. Our method includes precise control over the pump phase, facilitating arbitrary quadrature reconstruction and enabling complete visualization of cavity states using Husimi Q-function representations. We experimentally demonstrate the quantum tomography of an intracavity squeezed vacuum state generated by an OPO pumped below threshold. Additionally, by controlling the bias time delay and amplitude relative to the pump it allows for the reconstruction of the intracavity state at various times, offering insights into the temporal evolution of the OPO intracavity state. This approach provides a powerful tool for exploring and understanding the intricate behavior of quantum states within optical cavities.