Continuous real-time optical homodyne detection

Optical homodyne detection is a powerful method for measuring the statistical properties of light, including coherent, stochastic, and quantum properties of optical fields. However, the use of this method in applied research and industry to generate the feedback signal is hindered by the significant delay required for data analysis. In this work, we demonstrate a combination of software and hardware solutions that perform calculations of an array of light field quadrature amplitudes, i.e., the primary and most labor-intensive part of data processing with low latency. This enables us to conduct real-time second-order correlation measurements, with the complete signal accumulation and processing cycle happening over 1000 times per second. Moreover, the time allocated for signal accumulation and processing is almost evenly distributed. The real-time measurements demonstrated pave the way for automated feedback loops that meet the requirements of research and industry.