Polycarbazoles microcavities:: towards plastic blue lasers

With the aim of developing a plastic blue laser emitting around 400 nm, we have investigated the luminescence and lasing possibilities of recently designed new polymeric materials based on carbazole chromophores. Our carbazole compounds are used either as doping organic dyes in usual polymer cast films (e.g. PMMA) or as thin layers deposited onto a quartz substrate. In both cases, by using different interferometric methods, periodic patterning of surfaces has been realised and compared. Efficient relief gratings are produced by laser irradiation at 193 nm of a phase mask (A = 1090 nm) in contact onto carbazolic films. We demonstrate that such patterning allows photopumping of doped PMMA films in a planar waveguide configuration with distributed feedback (DFB) even for high Bragg grating order (m = 6). Monomode stimulated emission is observed for rhodamine doped PMMA film. Preliminary results concerning UV photopumping of carbazolic films are presented. (C) 2002 Elsevier Science B.V. All rights reserved.