High-performance magnetostatic backward volume waves-based guided-wave magnetooptic Bragg cells with application to wide-angle light beam scanning

Abstract

The magnetostatic backward volume waves (MSBVW) possess the following inherent advantages(1) over the magnetostatic forward volume waves (MSFVW) in terms of the performances of the resulting guidewave magnetooptic (MO) Bragg cells(2): (1) The MSBVW of significantly higher carrier frequency can be excited at the same dc magnetic field, (2) The first passband in which the MO Bragg cell commonly operates is located at the high frequency end for the MSBVW, but at the low frequency end for the MSFVW. For example, we have calculated and concluded that for the same dc magnetic field, the operating band of the MSBVW is located higher than that of the MSFVW by at least 4.90 GHz for the pure-YIG (saturation magnetization 4πMs=1750 Oe) and 5.04 GHz for the Bi-YIG (4πMs=1800 Oe) samples. It is therefore desirable to realize guided-wave MO Bragg cells that utilize the MSBVW. Guidedwave MO interaction with the MSBVW was first studied using a Bi Lu-YIG-GGG waveguide.3 However, to the best of our knowledge, neither study on guided-light beam scanning by the MSBVW nor construction of MSBVW-based MO Bragg cells has been reported heretofore. In this paper, we report the first realization of high-performance MSBVW-based MO Bragg cells in pure and Bismuth-doped yttrium iron garnet-gadolinium gallium garnet (YIG-GGG) waveguides, and the first demonstration of wide-angle light beam scanning using such MO Bragg cells. A detailed comparison of the measured performance figures for the MSBVW- and the MSFVW-based MO Bragg cells is also presented.