IR‐SNOM on lithium fluoride films with regular arrays based on colour centres

Abstract

LiF films have been grown on silicon substrate, irradiated with soft x-rays to create fluorescent regular micrometric-spaced arrays based on colour centres, and studied by Scanning Near-field Optical Microscope (SNOM). Strong variations in the local reflectivity have been observed in the infrared region between 6.1 and 9.2 µm and tentatively ascribed to a modulated variation of the refractive index of the coloured zone with respect to that of the uncoloured LiF matrix.

Scanning near‐field optical microscopy (SNOM)

“…In fact, we would expect the same topographical contribution at all the three different wavelengths. It is worth to point out that this conclusion is also supported by results obtained on topography-free samples [23], thus excluding any topographic induced artifact in the optical images.…”

A novel tapping SNOM: Specifications and performances

“…3 topography and fluorescence measurements on a Lithium Fluoride film are shown [10]. A LiF layer (~800 nm thick) was thermally deposited on a clean Si surface and irradiated with soft X-rays (energy = 700 eV; penetration depth 1-5 µm) producing optically active color centers due to aggregate F 2 and F 3 + defects.…”

Infrared near-field microscopy with the Vanderbilt free electron laser: overview and perspectives

“…3 shows the results of a third series of materials-science tests, dedicated to lithium fluoride films on silicon substrates. The objective in this case was not the lateral distribution of different chemical species but the lateral changes in the refractive index induced by X-ray bombardment [26].…”