Effects of F2 Color Center Spatial Distribution on the Emission Properties of Optical Microcavities Based on LiF Films

Highly stable F2 color centers are very efficiently produced in lithium fluoride (LiF) by electron beam irradiation at room temperature. We have fabricated optical microcavities in which the active medium is a low-energy electron beam irradiated LiF film, whose optical thickness is comparable with the peak wavelength (∼668nm) of the F2 broad photoluminescence band. By selecting the proper electron beam energy, one can control the F2 color center depth distribution. This distribution influences the photoemission angular distribution of the microcavity, whose resonance properties are determined by the coupling of the depth profile of the defects with the pump electromagnetic field and microcavity modes.