zyxw zyxwvutsr zyxwvuts zyxwvu Elaboration and characterization of a novel material for laser in blue region S. Sanaur, A. J. Anias, M. Lefebvre and E. Rosencher Office National d'Etudes et de Recherches Airospaliales Chemin de la Hunikre, 91 761 Palaiseau Cedex, France sanaur@onera.fr Abstract :Design and characterization of novel self-frequency-doubling organic materials for blue laser emission have been developped in liquid phase. Non Linear Optics (NLO) coefficient efficiency is studied as a function of wavelength and density of molecular species. zyxwvut zyxwvutsrqp Multifunctionnal materials have recently attracted much attention for very compact and cheap optical sources. Organic materials exhibit nonlineafities of hundreds of p m N and are particularly interesting for lasers into the blue [l]. The versatility of the chemistry of functional polymers allows to modulate their properties. Moreover, polymeric materials are suitable to fabricate waveguides thin films for quasi-phase-matching second harmonic generation (QPM SHG) devices and DFB lasers. Our main goal is at first to realize a self-frequency-doubling organic material tested in liquid phase. The absorption at the self-frequency-doubled wavelength must he minimized. Two strategies have been adopted to study the absorption contribution : 1) In a first case, we study the possibility to fmd a combination of organic materials in which the lasing radical at w does not absorb the SHG signal at 2w of a NLO radical. Different combinations of laser dye and NLO chromophore are separately tested using two different cells : the laser dye is contained within a cell transversaly pumped by a doubled Nd3+:YAG laser (lo&, 10 ns long-pulses) which is placed in an optical cavity whereas the chromophore is introduced in an EFISHG cell to measure the SHG efficiency at output wavelength of the dye laser (see figure 1). The SHG efficiency has been measured versus three parameters : dye emission wavelength, density and molecular species. Results are reported in Figure 2. A fast EFISHG signal amplitude decay for Disperse Orange 3 chromophore is due to a large absorption whereas a constant response for LDS720 laser dye is due to a negligible absorption. 2) In a second case, we limit the absorption effect with a material constituted by an unique molecule grouping fluorescence emission and NLO quadratic response. We synthetized a new type of molecule based on 3,3' hipyridine. These have an NLO quadratic efficiency at least comparable to Disperse Red One [2]. Figure 3 shows emission laser and laser oscillation threshold; these molecules are two times less intense than Coumarin 540A. To conclude, the design of the cell generating the self-doubling-fr 532 nm , I I ' mluer dye I I dye laser I EFISHG zyxwvut E , I . Fieure 1 I r I i Firmre 2 Laser Vlrerhold zyxwvutsrqp Figure 3 [ I ] : A. Otomo, G. Stegeman, J . Opt. Soc. Am. B, 15,759-772 (1998) [2] : N. Lemaitre, A. J. Attias, I. Ledoux et J. Zyss, Chem. Mat., 13(4), 1420-1427 (2001) 0-7803-7734-6/03/$20.00 2003 IEEE 399 Authorized licensed use limited to: ECOLE DES MINES DE SAINT ETIENNE. Downloaded on April 02,2010 at 12:08:47 EDT from IEEE Xplore. Restrictions apply.