CEFERINO LÓPEZ FERNÁNDEZ INSTITUTO DE CIENCIA DE MATERIALES DE MADRID, CSIC, ESPAÑA

Ordinary lasers comprise a pumping systems, a cavity and a gain medium. The cavity provides feed back and selects working modes and therefore set the colour of the emission. On the other hand random lasers are typically formed by a random assembly of optical scatters with optical gain added. Multiple light scattering replaces the standard optical cavity of traditional lasers and the interplay between gain and scattering determines its unique properties. Random lasers studied to date, consisted of irregularly shaped or sized polydisperse scatters, with some average scattering strength roughly constant over the gain frequency window and therfore emit at the peak of the gain curve. We consider the case where the scattering is resonant by using photonic glasses that can sustain scattering resonances [1]. These resonances manifest as variations in scattering mean free path and can thus be thought of as the loss/gain knob. The unique resonant balance in this material allows to control the laser emission via the diameter of the particles and their refractive index. The system is therefore a random laser with a priori designed lasing frequency [2].

With this material it is possible to create random lasers in which the lasing wavelength can be decoupled from the gain profile and selected at will.

Recent advances in the light loss and gain balance, new light sources and new highly scattering photonic structures will be reviewed.

Seminarios Internacionales de Fronteras de la Ciencia de Materiales Aula de Seminarios Departamento de Ciencia de Materiales E. T. S. de Ingenieros de Caminos, UPM C/ Profesor Aranguren s.n. 28040 Madrid

Para más información contactar con: Dr. José Ygnacio Pastor (+34) 913 366 684. [email protected].

Vídeo Realizado por el Gabinete de Tele-Educación de la Universidad Politécnica de Madrid, grabado por el departamento ciencia de los materiales.