Spectroscopic measurement of the refractive index of ion-implanted diamond

TL;DR

This study measures how ion implantation alters the complex refractive index of single-crystal diamond across a broad wavelength range, revealing non-linear effects at high damage densities and potential for photonic device fabrication.

Contribution

It provides detailed spectroscopic data on refractive index changes in diamond due to ion damage, including depth profiles and non-linear damage effects, enabling advanced microfabrication applications.

Findings

Refractive index increases with damage density.

Non-linear relationship at high damage levels.

Up to 5% increase in real part of index.

Abstract

We present the results of variable-angle spectroscopic ellipsometry and transmittance measurements to determine the variation of the complex refractive index of ion implanted single-crystal diamond. An increase is found in both real and imaginary parts at increasing damage densities. The index depth variation is determined in the whole wavelength range between 250 and 1690 nm. The dependence from the vacancy density is evaluated, highlighting a deviation from linearity in the high-damage-density regime. A considerable increase (up to 5%) in the real part of the index is observed, attributed to an increase in polarizability, thus offering new microfabrication possibilities for waveguides and other photonic structures in diamond.