A laboratory astrophysics platform to investigate gravitational lensing diffraction

We have developed a table-top optical system to reproduce the conditions of gravitational lensing. We use lasers, spatial light modulation, and optical imaging techniques to set up the conditions that produce gravitational lensing. The control of spatial and temporal coherence of the lensed light has allowed us to observe the diffraction of gravitationally lensed light, not possible in astrophysical observations due to spatial and temporal decoherence. We observed patterns consistent with a 2D Bessel function for symmetric objects and lenses. When the lens deviates from spherical symmetry, we observe interference patterns bound by a caustic envelope, such as an astroid. The separations between interference maxima and minima are wavelength-dependent, whereas the caustic envelope is wavelength-independent. Recent work includes investigating the patterns produced by a binary lens as a function of the masses, their separation, and the axial location of the observation. In this case, the caustics are hypocycloids.