22 September 1999 3D-FDTD and experimental analysis of a resonant microcavity probe for high-resolution SNOM
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A simple novel probe for Scanning Near-field Optical Microscope (SNOM) is proposed. The probe consists of a small protrusion on a micro resonator. The resonator and protrusion is a spherical micro sphere with diameter of 50-70 μm, 1.5 μm, respectively. The resonator is a polystyrene latex sphere and the protrusion is a polymethyl methacrylate sphere. The s-polarized laser (Ti:Sapphire laser) beam, which illuminates the resonator through an evanescent wave, can be tuned to the resonant frequencies. The resonance occurred in the sphere is a traveling wave resonance, which is called MDRs (Morphology Dependent Resonances) or WGMs (Whispering Gallery Modes). The internal resonant wave could generate an intensive evanescent field on the surface of the resonator. The small protrusion on the resonator combines with the evanescent field and could acts as a high sensitive probe for SNOM. A clear image of the protrusion illuminated by the evanescent field on the resonator was observed with the cooled CCD detector. The brightness of the image of the protrusion depends on the laser wavelength. The optical characteristics of the resonant probe is also studied by a Finite-Difference Time- Domain method.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yasushi Oshikane, Yasushi Oshikane, Hirofumi Nakagawa, Hirofumi Nakagawa, Toshihiko Kataoka, Toshihiko Kataoka, Katsuyoshi Endo, Katsuyoshi Endo, Haruyuki Inoue, Haruyuki Inoue, Takayuki Hirai, Takayuki Hirai, } "3D-FDTD and experimental analysis of a resonant microcavity probe for high-resolution SNOM", Proc. SPIE 3791, Near-Field Optics: Physics, Devices, and Information Processing, (22 September 1999); doi: 10.1117/12.363862; https://doi.org/10.1117/12.363862

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