Nanoplasmonics and surface enhanced spectroscopy
Modification of optical spectra of materials with metal  nanoparticles at deformation of media
Onykienko Ye.V.1, Goliney I.Yu.1
1 Department of Theoretical Physics, Institute for Nuclear Research of the NAS of Ukraine. Prospect Nauki, 47, Kyiv-03680, Ukraine. 
E-mail: zhorzhonyk@gmail.com

Frequencies of localized plasmons excited by light in metal nanoparticles depend on the their shape and the distance between them.  The resonant interaction beween nanoparticles may be changed by the deformation of the medium into which they are embedded. In a strongly uniaxially stretched medium, the distance between some of the nanoparticles would decrease due to the Poisson contraction in the direction perpendicular to the strain axis. This allows modification of the scattering and absorption spectra by stretching.  The plasma resonance in such  systems can be switched on and off.
The change of the dielectric function of the medium with embedded nanoparticles with deformation is described in the spirit of the Maxwell Garnett approach[1] modified with an account for the closest pairs of particles. The change of the distribution of the smallest interparticle distance is evaluated. The dependence of the spectra on the polarization of the incident light with respect to the deformation axis is demonstrated.

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