Evanescent fields with subwavelength features: Their behaviour and application to atom optics

Abstract

This paper presents a theoretical discussion of the behaviour of the evanescent field produced when light is totally internally reflected from a surface onto which a metallic lamellar diffraction grating has been patterned. In particular, gratings with a period significantly less than the wavelength of light are considered. As expected, it is found that the period of the intensity of the evanescent field is equal to that of the grating and is completely independent of the wavelength of the incident radiation in this limit. It is also shown that the field contains a component which has a decay rate away from the grating which increases as the grating spacing decreases for a fixed incident wav..