Research & information: general SERS active optical waveguides active waveguide devices diffractive optics flexible photonics glass photonics glass poling glass strengthening glass waveguides integrated photonics ion diffusion ion exchange ion exchange in glass ion-exchange ion-exchanged glass laser active materials lasers luminescence enhancement metal nanoparticles noble metal nanoparticles optical glasses optical sensors phase gratings photo-thermo-refractive glass photovoltaic cell quantum integrated optics rare earths silver silver bromide nanocrystals