Direct fabrication of PDMS waveguides via low-cost DUV irradiation for optical sensing

We demonstrate the fabrication of single mode optical waveguides by irradiating polydimethylsiloxane (PDMS) with a low cost Hg lamp through a conventional quartz mask. By increasing the refractive index of the irradiated areas, waveguiding is achieved with an attenuation of 0.47 dB/cm at a wavelength of 635 nm. The refractive index change is stable in ambient air and water for time periods of more than 3 months. The excitation of water-dispersed fluorescent nanoparticles in the evanescent field of the waveguide is demonstrated.