The performace of (TbBiCa)3Fe5O12 magneto-optical films at 1064 nm after hydrogen atmosphere annealing and ion beam polishing

Abstract

The laser damage properties of magneto-optical (MO) materials are the most important constraint for their application in high-power laser systems in the near-infrared (NIR) band. Rare-earth ion doped garnet (RIG) materials are widely used in optical communication systems and compact laser systems due to their superior MO properties —— small size and low driving magnetic field. In this study, high-quality (TbBiCa)3Fe5O12 films with hundreds of microns thickness were fabricated by liquid phase epitaxy (LPE) method. These films have lower optical absorption than conventional (TbBi)3Fe5O12 films after annealing in reducing atmosphere while possessing outstanding magneto-optical properties and their optical and MO properties are investigated in detail, which has a high specific faraday rotation angle of 1413 deg/cm at 1310 nm and 2647 deg/cm at 1064 nm, and transmittance is 51.2 % at 1064 nm and 71.6 % at 1310 nm. After that, ion beam polishing (IBP) treated the samples at different depths, and atomic force microscopy (AFM) was used to observe their surface morphology. Finally, the laser-induced damage threshold (LIDT) of samples was tested by a multi-frequency laser in different frequencies using the R-on-1 method. The LIDT of (TbBiCa)3Fe5O12 irradiated by a multi-frequency at 50 kHz is 10.92 J/cm2. Scanning electron microscopy (SEM) and optical microscopy were used to observe the surface morphology of the sample after the damage.