High performance [Bi3Fe5O12/Sm3Ga5O12]m magneto-optical photonic crystals.

We report the properties of one-dimensional heteroepitaxial all-garnet magneto-optical (MO) photonic crystals (MOPCs) composed of alternating MO-active Bi3Fe5O12 (BIG) and transparent Sm3Ga5O12 (SGG) quarter-wavelength layers grown by rf-magnetron sputtering on Ca,Mg,Zr:Gd3Ga5O12(111) and Gd3Sc2Ga3O12(001) crystals. MOPCs’ spectra, as designed, exhibit a stop band structure and a band gap with the transmittance central peak at 750 nm caused by light localization in the half-wavelength BIG cavity. A series of MOPCs with different numbers of [BIG/SSG]m reflectors (m=4, 5, and 6) has been fabricated to optimize the specific Faraday rotation θF (deg/μm) and MO-quality factor Q(deg)=2|θF|/absorption coefficient. A close BIG-to-SGG lattice match enabled significant improvement of [Bi3Fe5O12/Sm3Ga5O12]m properties compared to previously reported [Bi3Fe5O12/Y3Fe5O12]m [S. Kahl and A. M. Grishin, Appl. Phys. Lett. 84, 1438 (2004)] and [Bi3Fe5O12/Gd3Ga5O12]m [S. I. Khartsev and A. M. Grishin, Appl. Phys. Lett. 87, 122504 (2005)] pulsed laser deposited photonic crystals. At the resonance wavelength λ=750 nm, θF=-20.5 deg/μm and Q=66 deg represent the highest MOPC performance achieved so far. Respectively, these are 470% and 31% enhancements compared to a single layer Bi3Fe5O12 film Faraday rotator with equivalent thickness. [ABSTRACT FROM AUTHOR]