  The study of light lensed by cosmic matter has yielded much information about
astrophysical questions. Observations are explained using geometrical optics
following a ray-based description of light. After deflection the lensed light
interferes, but observing this diffractive aspect of gravitational lensing has
not been possible due to coherency challenges caused by the finite size of the
sources or lack of near-perfect alignment. In this article, we report on the
observation of these wave effects of gravitational lensing by recreating the
lensing conditions in the laboratory via electro-optic deflection of coherent
laser light. The lensed light produces a beam containing regularities,
caustics, and chromatic modulations of intensity that depend on the symmetry
and structure of the lensing object. We were also able to observe previous and
new geometric-optical lensing situations that can be compared to astrophysical
observations. This platform could be a useful tool for testing
numerical/analytical simulations, and for performing analog simulations of
lensing situations when they are difficult to obtain otherwise. We found that
laboratory lensed beams constitute a new class of beams, with long-range, low
expansion, and self-healing properties, opening new possibilities for
non-astrophysical applications.
