0021-3640/02/7608- $22.00 © 2002 MAIK “Nauka/Interperiodica” 0527 JETP Letters, Vol. 76, No. 8, 2002, pp. 527–531. Translated from Pis’ma v Zhurnal Éksperimental’noœ i Teoreticheskoœ Fiziki, Vol. 76, No. 8, 2002, pp. 609–613. Original Russian Text Copyright © 2002 by Fedyanin, Yoshida, Nishimura, Marowsky, Inoue, Aktsipetrov. Magnetization-induced second harmonic genera- tion (MSHG) is one of the fundamental phenomena in nonlinear magneto-optics. It is associated with the involvement of the spin subsystem and the spin–orbit interaction in the formation of the electronic quadratic nonlinear optical response of magnets [1]. This phe- nomenon was used to develop an efficient method of studying magnetic surfaces and thin films [2]. The sen- sitivity of this method is caused by the symmetry selec- tion rule for MSHG in the bulk of centrosymmetric media; many important magnetic materials belong to such media. Magnetization-induced changes in the parameters of SH radiation such as its amplitude (inten- sity), polarization, and phase in typical experimental situations prove to be several orders of magnitude larger than in the magnetooptical Kerr effect and the Faraday effect. Since the first observation of MSHG in ferrite garnet films [3] and its theoretical prediction in [4], the magnetization-induced SH was extensively studied at metal surfaces and thin films [5– 8], as well as in thin films of magnetic insulators, primarily, of yttrium–iron garnets [9, 10]. In last years, much atten- tion has been given to studying MSHG in magnetic nanoparticles [2, 11, 12]. The methods developed in the last years for manu- facturing structures with an artificial photonic band gap {photonic crystals and microcavities (MC) [13]} made it possible to study nonlinear optical phenomena which are associated with the specificity of light propagation in such microstructures [14]. For example, in the case of MC, the spatial localization of resonant electromag- netic radiation in the vicinity of microcavity layer strengthens the generation of optical harmonics, as was recently observed experimentally for the second and third harmonics in microcavities based on porous sili- con [15, 16]. Of special interest is the study of nonlin- ear optical effects in magnetic microstructures with photonic band gap because of the expected enhance- ment of their magnetization-induced response. How- ever, methods of growing such objects were developed only recently [17, 18]. In this work, the enhancement of MSHG was stud- ied experimentally in magnetic microcavities based on photonic crystals. A high quality of the nonmagnetic Bragg reflectors grown from silicon oxide and tantalum oxide layers causes strong localization of electromag- netic field in a ferromagnetic yttrium–iron garnet MC layer and enhances the gain in MSHG, which manifests itself in a many-fold amplification of the rotation of SH polarization. Magnetophotonic MC samples were composed of a half-wave 190-nm-thick bismuth-doped polycrystalline yttrium–iron garnet (Bi:YIG) layer surrounded by two Bragg reflectors consisting of five pairs of alternating quarter-wave SiO 2 and Ta 2 O 5 layers 135 and 95 nm in thickness, respectively. The expected spectral position of the microcavity mode in the grown MC was about 850 nm at the normal incidence, and the center of the photonic band gap and its width were about 780 and 200 nm, respectively. When manufacturing MC, SiO 2 /Ta 2 O 5 photonic crystal was first grown on a fused silica substrate by magnetron sputtering. Then a Magnetization-Induced Second Harmonic Generation in Magnetophotonic Microcavities Based on Ferrite Garnets A. A. Fedyanin 1 , T. Yoshida 2 , K. Nishimura 2 , G. Marowsky 3 , M. Inoue 2 , and O. A. Aktsipetrov 1, * 1 Moscow State University, Vorob’evy gory, Moscow, 119992 Russia * e-mail: aktsip@shg.ru 2 Toyohashi University of Technology, 441-8580 Toyohashi, Japan 3 Laser-Laboratorium Göttingen, D-37077 Göttingen, Germany Received September 25, 2002 Magnetization-induced second harmonic generation was observed in magnetophotonic microcavities consist- ing of a ferromagnetic yttrium–iron garnet layer surrounded by nonmagnetic photonic crystals (Bragg reflec- tors). At resonance between the fundamental radiation and the microcavity mode in the geometry of polar mag- netooptical Kerr effect, the polarization rotation for the second harmonic was found to be (18.5 ± 0.5)°/μm for the fundamental radiation with a wavelength of 825 nm. © 2002 MAIK “Nauka/Interperiodica”. PACS numbers: 42.65.Ky; 42.70.Qs; 75.75.+a