Bismuth-substituted Lutetium Iron Garnet Films with Giant Visible-Range Magneto-Optical Sensitivity

TL;DR

This paper reports the growth and characterization of bismuth-substituted lutetium iron garnet films with exceptionally high Verdet constants in the visible range, advancing magneto-optical material performance for sensing and quantum technologies.

Contribution

The study introduces LuBiIG films with record-high Verdet constants near 520nm, combining bismuth's spin-orbit coupling with lutetium iron garnet's stability, and demonstrates their potential for sensitive magneto-optical applications.

Findings

Verdet constant up to -0.120 deg/um/mT in visible range

Films grown by pulsed laser deposition with 80-220nm thickness

Potential for cryogenic detection and quantum applications

Abstract

Magneto-optical materials are indispensable across modern physics, serving as the foundation for precision magnetic sensing, nonreciprocal photonics, and optical isolation technologies. The continual pursuit of materials with high Verdet constants has driven the development of garnet-based compounds exhibiting extreme magneto-optical sensitivity. In this work, we report the growth and comprehensive magneto-optical characterization of bismuth-substituted lutetium iron garnet (LuBiIG), a material that combines the large spin-orbit coupling of bismuth with the lattice stability of lutetium iron garnet. The films exhibit an exceptionally high Verdet constant of up to -0.120 deg/um/mT, peaking in the visible spectral range near 520nm. LuBiIG films with thicknesses between 80 and 220nm were grown by pulsed laser deposition and characterized at room temperature over the 500-820nm wavelength range. These results position LuBiIG as a highly sensitive magneto-optical material suitable for advanced cryogenic detection and hybrid quantum applications.