Heterodyne Wavefront Sensor for High-Speed and Low-Light Applications

Accurate and fast wavefront sensing is crucial to ensure real-time correction of turbulence in laser propagation through the atmosphere. We present a device for this purpose which we call the heterodyne wavefront sensor. It works by frequency shifting an unperturbed reference beam and combining it with the beam that has propagated through the atmosphere. The heterodyne detection process results in a time-varying intensity pattern containing the wavefront phase which can be spatially sampled using an array detector. We present experimental results to demonstrate the feasibility and performance of this wavefront sensor.