Effect of mechanical stress on optical properties of polydimethylsiloxane

The deformation affects the optical transmittance and the refractive index so strongly that it is necessary to take it into account when the PDMS is used as a medium for optical applications. The transmittance at the wavelength of 1700 nm and for the relative stress −0.5 decreases about three times and the change of the refractive index at the wavelength of around 1500 nm reaches a value of about 0.05. These values imply that it is possible to utilize the PDMS for constructing optical sensors that could be used for measuring stress or mechanical displacement.