Ultrafast Faraday Rotation In Magnetophotonic Microcavities Alexandr I. Musorin (1), Margarita I. Sharipova (1), Artem V. Chetvertukhin (1), Tatyana V. Dolgova (1), Mitsuteru Inoue (2), Andrey A. Fedyanin (1) (1) Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia (2) Toyohashi University of Technology, Toyohashi, Aichi 441-8580, Japan musorin@nanolab.phys.msu.ru Faraday effect is a non-reciprocal optical phenomenon that can be greatly enhanced in multilayered structures due to multiple reflection interference [1]. A layered optical material can modulate electric field amplitude and phase of a femtosecond pulse in space and time. If a multilayered medium is illuminated by short laser pulses, non-steady behavior of Faraday rotation can be found on the timescale of pulse duration [2]. For example, Faraday rotation of the leading part of the pulse can differ from that of its tail and from a steady-state value. Moreover, Faraday rotation can both increase and decrease in time depending on interference conditions for a particular pulse central wavelength. In this work femtosecond dynamics of Faraday rotation is demonstrated experimentally in magnetophotonic microcavities (MMC) and thin magnetic films. The experimental technique used in Ref. [3] was modified for time-resolved magnetooptical measurements. Fig. 1 shows spectral characteristics of time dependences of Faraday rotation in the MMC (a) and 16-µm-thick iron garnet film (b). The MMC was formed from a /2 magnetic Bi:YIG cavity layer placed between two Bragg reflectors consisted of 5 pairs of /4 alternate SiO2/Ta2O5 layers.