![2D regular optical pattern thumbnail](https://opn-web-afd-d3bfbkd5bcc5asbs.z02.azurefd.net/opn/media/images/afterimages/2021/21jan-01.jpg?t=638430689192634910)
2D regular optical pattern
2D regular optical pattern formed by a 632.8-nm Gaussian beam propagating through a 10-mm length of Fe-doped lithium niobate crystal, and registered by a CMOS camera after 140 seconds of illumination.
—L. Tsarukyan, A. Badalyan, F. Devaux, M. Chauvet and R. Drampyan, Institute for Physical Research, National Academy of Sciences, Armenia