Effect of optical diffraction on laser heating of a field emitter

Abstract

The wavelength of the illuminating radiation used in studies of photofield emission is comparable to the diameter of the shank of the field emitter. Under these conditions, diffraction is expected to play an important role in determining the absorption of energy from the electromagnetic field. The complicated geometry of the field emitter has so far prevented an exact calculation of this effect. By considering the diffraction of a plane wave by an idealized model of a field emitter, we have calculated the absorption of energy from an incident focussed laser beam. Calculations based on the present results yield accurate predictions of the magnitude of the temperature rise and its dependence on the position of the focal spot and on the direction of polarization of the incident beam.