Abstract

In the earlier work by one of the authors,¹ the self-bending (or self-deflecting) effect was predicted, where a beam with an asymmetrical intensity profile follows a curvilinear trajectory in a nonlinearly refractive material. This effect was later observed in a bulk nonlinear crystal.² With the advent of superlattices and quantum well structures with strong optical nonlinearities, very thin films may be used to replace bulk materials. Here we consider the theory and make computer simulations of the self-deflection effect induced in thin nonlinear films (where undesirable effects such as catastrophic self-focusing can be avoided). In our analysis the general integral solution for the far-field area is the Fourier transform of the incident field distribution with an intensity-dependent phase distribution. The analytical solution for a beam with a right-triangular intensity distribution results in an undistorted deflection in the far field, consistent with the geometric-optics result.¹ Computer simulations were performed for many asymmetrical profiles, e.g., semi-Gaussian, all of which demonstrated an expected self-deflection. The simulation for a symmetrical 2-D Gaussian beam reveals a surprising result: instead of the expected self-focused (or self-defocused) single beam at high intensities, we observed two symmetrically self-deflected beams in the far field. The thin-film self-deflection effect may be useful for radiation protection devices and beam scanners.

© 1986 Optical Society of America