Distributed feedback lasing from dye-doped glass films using photopatterned gold nanoparticles

We found a tunable lasing action of dye-doped glass films using a distributed feedback (DFB) resonator composed of gold (Au) nanoparticles. The Au-DFB resonators having various periodic spacings of 400–600 nm were fabricated by photoreduction of chloroauric ions doped in silica/titania (SiO2∕TiO2) sol-gel films using two-beam interference of a He-Cd laser. After lamination of a SiO2∕TiO2 film containing Rhodamine B (RB), the device was pumped with a frequency-doubled yttrium aluminum garnet laser. As compared to the amplified spontaneous emission [full width at half maximum (FWHM) ∼20nm] from a RB-doped film without DFB, the laminated device indicated feedback-gained narrowing of the emission (FWHM∼1nm). Moreover, their peak wavelengths were shifted according to the tuned spacing of the Au-DFB resonator.