We propose a strain measurement method utilizing light scattered by a pair of nano-disks onto an elastomer sheet. Such nanoparticle pairs exhibit a scattering spectrum that is dependent on the gap distance and the incident light polarization. We utilized this behavior by forming nano-disk pairs with a diameter of 105 nm and a gap of 20?50 nm on a polydimethylsiloxane (PDMS) sheet so that the gap could be altered with strain. The axial direction of the nano-disk pair could be identified by finding the peak wavelength maximum while rotating the polarization angle. Under tensile strain, the peak wavelength decreased from 674 nm at a strain of 0% to 637 nm at a strain of 9.5%, with a peak-shift sensitivity of ? 3.4 nm/% strain. Under compression strain, the peak wavelength increased from 681 nm at a strain of 0% to 705 nm at a strain of ? 3.8%, and the peak-shift sensitivity was ? 16 nm/% strain for strains of 0 to ? 1%. These experimentally determined peak scattering wavelength positions and peak-shift directions are consistent with the simulation results. This method offers wireless measurements of in situ strain on a nanometric scale.

References :
Tetsuo Kan, Kiyoshi Matsumoto, and Isao Shimoyama, “Optical measurement of directional strain by scattering from nano-disk pairs aligned on an elastomer,” Nanotechnology, vol. 23, no. 31, article no. 315201, 2012. [Proceedings]

Tetsuo Kan, Kiyoshi Matsumoto, and Isao Shimoyama, “Optial measurement of strain using scattering from nanoparticle pairs on elastomer,” The 16th International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers2011), Beijing, China, 5-9 June, 2011. [Proceedings]

Asuto Koyama, Tetsuo Kan, Eiji Iwase, Kiyoshi Matsumoto, Isao Shimoyama, “Force Sensor Based on Metal Nanoparticle,” IEEE 23rd International Conference on Micro Electro Mechanical Systems (MEMS '10), pp.428-431, Hong Kong, China, Jan. 25-28, 2010． [Proceedings]