We have fabricated and characterized polymeric slab asymmetric waveguides doped with a near-infrared-emitting dye, 2-(6-(p-dimethylaminophenyl)-2,4-neopentylene-1,3,5-hexatrienyl)-3-ethylbenzothiazolium perchlorate. Upon nanosecond photopumping, the waveguides have shown a small-signal gain coefficient of 37.2 ± 2.1 cm-1 at 820 nm for a pump fluence of 1.57 mJ/cm2 (314 kW/cm2). The loss coefficient and transparency fluence have been found to be 7.3 ± 1.0 cm-1 at 820 nm and 0.14 mJ/cm2 (28 kW/cm2), respectively. It is shown that a small-signal gain of 19.7 ± 2.3 dB is achievable in a 1.2-mm-long waveguide. Furthermore, near-infrared laser emission from self-assembled luminescent polymer microcavities has been demonstrated. The microrings are formed around silica optical fibers of varying diameters (80, 125, and 200 μm) and the larger microresonators have an overall quality factor of ~2 × 103, which is limited by surface roughness and scattering. We illustrate how the laser threshold varies inversely with both the quality factor and the inner diameter of the microrings. The free spectral range and the intensity variation of the laser output are also presented.
We demonstrate laser emission in polymer-based microrings doped with a near infrared emitting dye, 2-(6-(4-Dimethylaminophenyl)-2,4-neopentylene-1,3,5-hexatrienyl)-3-methyl-benzothiazolium perchlorat. We fabricate our poly(1-vinyl-2-pyrrolidone)-based microrings containing 0.5 wt % of the dye. They exhibit lasing at around 840 nm under transverse nanosecond photoexcitation at 532 nm. Optical feedback is provided by total internal reflection. The threshold for lasing is found to be 311 μJ/cm2. The cavity has a Q-factor larger than 2000, which is limited by the resolution of our detection system.
We study light amplification and laser emission in polymer gain media containing a near-infrared emitting dye, 2-(6-(4-dimethylaminophenyl)-2,4-neopentylene-1,3,5-hexatrienyl)-3-methyl-benzothiazolium perchlorat, with a view to the development of polymer amplifiers and lasers operating in the 800-nm region of the spectrum. Nanosecond gain spectroscopy is carried out by use of amplified spontaneous emission. Multimoded poly(1-vinyl-2-pyrrolidone)-base planar waveguides, 50 μm in thickness, doped with 0.5 wt% dye show a moderate net small-signal gain coefficient of 2.6±0.3 cm-1 (11.3±1.3 dB/cm) at 820 nm for the pump fluence of 115 μJ/cm2 (23.1 kW/cm2). Moreover, we have fabricated polymer microring cavities 200 μm in diameter with the same material composition. The moderate optical gain in the material allows laser emission to occur at around 840 nm under transverse nanosecond photoexcitation at 532 nm. The threshold for lasing is found to be 311 μJ/cm2 (62.2 kW/cm2).