High Sensitive and Spatial-Resolution Atom Sensor Using Two-Step Photoionization with Two-Color Near-Field Lights Generated at a Nano-Slit

Abstract:

We develop a nanoslit to detect a small number of neutral atoms in the ground state. The detection scheme of using two-step photoionization is very sensitive and the use of nanometric near-field lights leads to an ultrahigh spatial resolution. An edge-sharpened nanoslit is fabricated with FIB milling. Considering the case of detecting Rb atoms, the polarization-dependent spatial distribution of near-field light generated at the nanoslit by total-internal reflection of a 476.5-nm Ar-ion laser beam is obtained with a scanning near-field optical microscope. Based on the experimental results, the ionization efficiency is estimated for both s-polarization and p-polarization. We also discuss the discrepancy between the experimental value and the numerical one obtained from the finite difference time domain simulations in the p-polarization case.

• Periodical: Key Engineering Materials (Volume 605)
• Pages: 412-415
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.605.412
• Online since: April 2014
• Authors: Kenta Sagawa, Haruhiko Ito
• Keywords: FDTD, Nanoslit, Radius of Curvature, SNOM, Two-Step Photoionization

References

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