Lensing cosmic drift

As the Universe expands, redshift of distant sources changes with time. Here we discuss gravitational lensing phenomena that are consequence drift between lensed source, lens, and observer. When source is located very close to drifting caustics, a pair images could occur (or disappear) because cosmological expansion. Furthermore, systems act as signal converters drift. The angular position, magnification, distortion, time delay already existing multiple change. We estimate expected frequency these prospects observe them in era deep large surveys. detection image separation be within reach next generation surveys $\mu$arcsec resolution.