Sol-gel silica laser tunable in the blue

Abstract

Doped and undoped silica slabs were fabricated through the use of the sol-gel technique. Extended UV transmission was observed for HCl-catalyzed sol-gel silica. Under transverse pumping with a XeCl laser, narrow-linewidth 1,0.9-nm2 laser oscillation from silica slabs doped with coumarin 460 1C4602 was achieved in a grating-resonator cavity configured in the grazing-indicence geometry. Tuning of the C460-doped silica laser extended from 468 to 494 nm. The conversion efficiency of the narrow-linewidth blue laser was 5.5%.Dye-doped inorganic matrixes derived through the sol-gel route-a new glass-making technologyconstitute a new class of tunable solid-state laser materials that offer tuning capabilities ranging from the UV to the near infrared. Previously, polymeric materials such as poly1methylmethacrylate2 1PMMA2 and modified PMMA 1MPMMA2 have been used with some success as host materials for organic dyes. Because of the low temperatures that are employed during the sol-gel process, organic dopants, which will otherwise be destroyed in conventional glassforming processes, can be introduced into sol-gel glasses to serve as optically active centers. In view of the many potentials of dye-doped sol-gel-derived glasses, research interest regarding this class of tunable solid-state-laser materials has been considerable. Rhodamine-and coumarin-doped silicates have been characterized spectroscopically and the mechanical properties ascertained. 1,2 Gain measurements, broadband lasing, and frequency tuning have been performed with a liquid-dye laser or a frequencydoubled YAG laser as the pump source. [3][4][5] Our group has studied XeF-laser-induced emission properties of 10 dyes in a sol-gel silica matrix that covers the spectral range from 400 to 800 nm. 6,7 Most of the recent studies on dye-doped sol-gel lasers has been with the green-to-red spectral regions because pumping can be provided conventiently with frequency-doubled Nd:YAG lasers at 532 nm. 8 Recently, Ferrer et al. 9 also reported having lased dye-doped PMMA in the blue-green range. Applications in fields like optical storage, underwater communication, etc., however, call for efficient tunable lasers in the blue. Excimer lasers in the UV are powerful pump sources for liquid-dye lasers. 10 They are in fact most useful when one pumps dyes in the blueto-UV spectral regions. Silica glass formed by means of the sol-gel route, however, usually transmits poorly in the UV. Porous sol-gel silica glass supplied by a commercial vendor 1Geltech, Alachua, Fla.2, for instance, has UV cutoffs that vary from 300 to 500 nm, depending on the pore sizes. Hence, excimer-laser pumping of dye-doped sol-gel glass that exhibits poor UV transmission could lead to a shortened of laser lifetime and eventually to the destruction of the sample. When HCl was used as the catalyst during the sol-gel process, UV transmission of the undoped sol-gel silica was found to extend down to 260 nm, which thus permitted safe XeCl-laser pumping at 308 nm. 11 Wideband tuning of silica slabs that were do...

Solid-state dye lasers based on modified rhodamine 6G dyes copolymerized with methacrylic monomers

“…As a result, over the last decade there has been a renewed interest in the use of solid matrices containing laser dyes, 2,3 and significant advances have been made towards the development of practical tunable solidstate dye lasers. [4][5][6][7][8][9][10][11][12][13] A solid host for lasing dyes is an attractive alternative to their liquid solutions, with obvious technical advantages such as compactness, manageability, lack of toxicity and flammability, and suppression of flow fluctuations, solvent evaporation, etc. Very recently, Duarte 11 has described a compact solid-state multiple prism grating dye laser oscillator with a cavity length as short as 55 mm.…”

Lasing characteristics of Rhodamine B and Rhodamine 6G as a sensitizer in sol–gel silica

“…In the present work, dye-doped sol-gel silica samples have been fabricated following the sol-gel process of acid catalyzed hydrolysis/polycondensation [24][25][26][27][28][29][30][31][32][33][34][35]. Sol-gel silica samples of high optical homogeneity have been obtained.…”

Sol–Gel Processed Lasers and Related Optical Materials

“…Blue laser operation was reported by Lam et al (1995). This was achieved by silica slabs doped by coummarine 460 (C460).…”