The Rise of the Brown-Twiss Effect

Despite the simplicity of flux collecting hardware, robustness to misalignments and immunity to seeing conditions, Intensity Correlation Imaging arrays using the Brown-Twiss effect to determine two-dimensional images have been burdened with very long integration times. The root cause is that the essential phase retrieval algorithms must use image domain constraints, and the traditional Signal-to-Noise calculations do not account for these. Thus the conventional formulations are not efficient estimators. Recently, the long integration times have been emphatically removed by a sequence of papers. This paper is a review of the previous theoretical work that removes the long integration times, making the Intensity Correlation Imaging, a practical and inexpensive method for high resolution astronomy.