  In this work we suggest a phenomenological theory of photogalvanic phenomena
in superconducting materials and structures revealing the diode effect.
Starting from a generalized London model including the quadratic nonlinearity
in the relation between the supercurrent and superfluid velocity we show that
the electromagnetic wave incident on the superconductor can generate a
nontrivial superconducting phase difference between the ends of the sample.
Being enclosed in a superconducting loop such phase battery should generate a
dc supercurrent circulating in the loop. Increasing the electromagnetic wave
intensity one can provoke the switching between the loop states with different
vorticities.
