[15p-PB01-1~5] 3.8 Terahertz technologies (formerly 3.9)

▲ [15p-PB01-4] Challenges with Terahertz Magneto-Optic Imaging Scheme

〇Dmitry S Bulgarevich¹, Miezel Talara², Hideaki Kitahara², Makoto Watanabe¹, Masahiko Tani² (1.NIMS, 2.FIR-UF)

Keywords:terahertz, magneto-optic Imaging, spintronic emitters

We continue to improve our magneto optical imaging (MOI) scheme based on THz spintronic emitters with on-chip emitter/detector sensor which was already tested and reported with continuous spintronic film or with uniform diablo antenna pattern and with non-uniform thickness of diabolo-shaped spintronic antenna flares. For the later case, a different MOI contrast of the magnet scanned above MOI chip was observed when compared to a continuous/uniform spintronic emitter. In this work with different MOI schemes, we understood, that such difference in the contrast was originated from Faraday rotation of modulated pump beam initially scattered at the sharp edges of the diabolo antenna gap, then the propagation of such light through ZnTe and its partial reflection into the balanced photodetector. With continuous/uniform spintronic emitters, such pump beam scattering is minimized and main contribution to the MOI contrast is coming from electro optic OE sampling with ZnTe, i.e. our MOI chip works as expected. Examples of MOI with EO sampling and Faraday rotation using ZnTe will be given and discussed in details. Further MOI developments in minimizing scattering effects by increasing of antenna gap size, tighter laser focusing or in use of photoconductive antenna detector will be presented.