Regular Paper

[OPTICAL REVIEW Vol. 21, No. 5 (2014) 560-562]
© 2014 The Japan Society of Applied Physics

Improvement of Focusing Characteristics of a Spiral Plasmonic Lens

Shinpei OKUDA1, Naoyuki KIMURA1, Minoru TAKEDA2*, Tsutomu INOUE3, and Kento AIZAWA3

1Department of Electronics, Kyoto Institute of Technology, Kyoto 606-8585, Japan
2Department of Mathematical and Physical Sciences, Kyoto Institute of Technology, Kyoto 606-8585, Japan
3Spectroscopy Engineering Division, JASCO Corporation, Hachioji, Tokyo 192-8537, Japan

(Received November 29, 2013; Revised May 7, 2014; Accepted May 30, 2014)

We designed and fabricated a spiral plasmonic lens (PL) with multi-circular grooves to increase light intensity in a far-field region via the constructive interference of the light scattered by the multi-circular grooves. To compare the beam focusing characteristics of a spiral PL with multi-circular grooves with those of a conventional spiral PL, we simulated the electric field distribution of the PLs operating at a 405 nm wavelength. We confirmed that the light intensity increased about twofold at 0.75 μm above the PL surface owing to the effect of the multi-circular grooves. Furthermore, the circular grooves negligibly affect the full width at half-maximum of the focal spot, keeping the subwavelength size (∼200 nm) of incident light.

Key words: surface plasmon, plasmonic lens, far-field focusing, FDTD simulation


*E-mail address: takeda@kit.ac.jp

 

© 1994-2014 The Japan Society of Applied Physics
Produced, Developed, and Maintained by The Optical Society of Japan (An Affiliate of the Japan Society of Applied Physics)
Printed in Japan by Komiyama Printing Co., Ltd.

mail to Editorial Office, OPTICAL REVIEW