[15p-312-1~10] 3.1 Basic optics and frontier of optics

△ [15p-312-7] Measurement of Micro-Sphere Diameter Based on Whispering Gallery Mode Resonance-Construction of the Model for Spheroidal Particle-

〇Kohei Hayashi¹, Buhuai Chu¹, Zheng Zhao¹, Masaki Michihata¹, Kiyoshi Takamasu¹, Satoru Takahashi¹ (1.The Univ. of Tokyo)

Keywords:Whispering Gallery Mode, diameter measurement, micro resonator

It is difficult to evaluate a critical dimension of recently manufactured smaller micro-scale devices. Three dimensional metrology are recently highly dedicated but the calibration is a issue to be addressed, especially a lack of calibration artifacts. We proposed the diameter measurement method of a micro-sphere, which is used for a calibration, utilizing whispering gallery mode resonance in a sphere. Light wave, which well-projected into a sphere, propagates only near the surface of the sphere and this phenomenon is only occurred for the particular incident wavelength. Generalizing the model from a perfect sphere to a spheroidal particle is worth because it not only makes the measurement method more accurate but also able to apply the model to a spheroidal particle. The central equation for measurement, i.e. the discretion equation, is derived by using analytical result for Mie scattering fora spheroidal and is ensured by numerical analysis.