Bi3 Fe4Ga1O 12 Garnet Properties and Its Application to Ultrafast Switching in the Visible Spectrum

We have synthesized Bi₃Fe₄Ga₁O₁₂ (BIGG) films on Gd₃Ga₅O₁₂ and Gd₃(ScGa)₅O₁₂ substrates by a pulsed laser deposition technique. X-ray diffraction and rocking curve analyses confirm the epitaxial quality of the films with a lattice constant close to 12.61 plusmn 0.01 Aring. Compared with that of a bismuth iron garnet Bi₃Fe₅O₁₂ (BIG) film, the bandwidth of the BIGG transmittance (T) spectrum is extended and its left edge shifted down in wavelength by approximately 50 nm. This enables its Faraday rotation and switching speed to be tested at a wavelength of 532 nm. While BIGG film has a Faraday rotation angle slightly less than that of BIG film, its magnetooptical figure of merit, 2|thetas_Fd|/-ln(T%), is greatly improved to a typical value ~1.8 times larger than that of the BIG film. Further, the high-speed pulse response time of the BIGG film reaches 2.4 ns with a 1 mm aperture size at the wavelength of 532 nm.