Lifetime Measurement of Polarization Gratings in Polymer Thin Films by Spectral Analysis of the Distributed Feedback Laser Emission
Denis Gindre, Jean-Michel Nunzi and Adrien Vesperini
We study the dynamics of the emission spectrum of a distributed Feedback Dye Laser in Rhodamine 6G doped polymer films. The optical feedback is provided by Bragg gratings formed in the film by interference patterns created by the pump beams. In this experiment the sample is pumped by two beams in a Lloyd mirror interferometer configuration. Both the delay and the angle between the two beams can be varied. The analysis of the emission spectrum as a function of the delay between the pumps allows measurement of the lifetime of the polarization modulation in the material. The coherent superposition of the pulses produces five laser lines in the emission spectrum.