Linear and Nonlinear Optical constants of BiFeO_3

TL;DR

This paper reports the linear and nonlinear optical constants of BiFeO_3, including refractive index, absorption, band-gap, and second harmonic generation coefficients, providing comprehensive optical characterization of this multiferroic material.

Contribution

The study provides detailed measurements of both linear and nonlinear optical properties of BiFeO_3 using spectroscopic ellipsometry and second harmonic generation techniques.

Findings

BiFeO_3 has a direct band-gap at 442 nm (2.81 eV).

Nonlinear optical coefficients were quantified, e.g., |d_22| = 298.4 pm/V.

Specific ratios of nonlinear coefficients were determined.

Abstract

Using spectroscopic ellipsometry, the refractive index and absorption versus wavelength of the ferroelectric antiferromagnet Bismuth Ferrite, BiFeO_3 is reported. The material has a direct band-gap at 442 nm wavelength (2.81 eV). Using optical second harmonic generation, the nonlinear optical coefficients were determined to be d_15/d_22 = 0.20 +/- 0.01, d_31/d_22 = 0.35 +/- 0.02, d_33/d_22 = -11.4 +/- 0.20 and |d_22| = 298.4 +/- 6.1 pm/V at a fundamental wavelength of 800 nm.