By now, it is still extremely challenging to accurately measure femto-Newton (10^-15 N) optical forces. Here, a simple scheme of a suspended tapered nanofiber coupled with a glass substrate is demonstrated to generate and sense the fN optical force, where the ~10 nm deformation of the nanofiber can be resolved by white light interferometry and an ultra-low stiffness of 0.540 fN/nm is obtained for the suspended nanofiber through Brownian motion. Owing to the ultra-low stiffness of the nanofiber, the scheme provides a cost-effective method to sense and measure ultra-weak (5.2 fN) optical force. Moreover, the scheme also provides a simple way to exploit fN optical forces for implementation of micro-Watt all-optical devices.

Date Published: 14 February 2019
PDF: 5 pages
Proc. SPIE 11048, 17th International Conference on Optical Communications and Networks (ICOCN2018), 1104843 (14 February 2019); doi: 10.1117/12.2520367

Published in SPIE Proceedings Vol. 11048:
17th International Conference on Optical Communications and Networks (ICOCN2018)
Zhaohui Li, Editor(s)