Optical and magneto-optical properties of bismuth-substituted neodymium iron gallium garnet films on glass substrates at the 1310-nm and 1550-nm wavelengths

Abstract

We describe measured results of optical and magneto-optical (MO) properties of bismuth-substituted neodymium iron gallium garnet (Bi1Nd2Fe4Ga1O12, Bi1:NIGG) films prepared by spin coating on glass substrates and crystallized by metal–organic decomposition (MOD) method in the near-infrared (NIR) wavelengths of 1310 nm and 1550 nm. The optical constants of the Bi1:NIGG films were determined with a spectrophotometer measurement. The measured refractive index and absorption coefficient were about 1.835 and 55.8 cm−1, respectively, at the 1310 nm wavelength and about 1.837 and 29.8 cm−1 at the 1550 nm wavelength. The MO properties of the films were determined by measuring the Faraday rotation in the saturated magnetization region. The measured maximum Faraday rotation of the Bi1:NIGG film of about 1055-nm thickness was 0.032 °/μm and 0.016 °/μm at 1310-nm and 1550-nm wavelengths, respectively. The corresponding Figure-of-Merits (FoMs) were 5.64 deg/dB and 5.22 deg/dB at each wavelength. Our measured result indicates that the Bi1:NIGG films prepared by the MOD method are useful for integrated optical isolator and MO sensor applications because of relatively good optical transparency and MO characteristics.