Abstract:This paper provides a review of advances in conjugated polymer lasers. High photoluminescence efficiencies and large stimulated emission cross-sections coupled with wavelength tunability and low-cost manufacturing processes make conjugated polymers ideal laser gain materials. In recent years, conjugated polymer lasers have become an attractive research direction in the field of organic lasers and numerous breakthroughs based on conjugated polymer lasers have been made in the last decade. This paper summarizes … Show more
“…It is noteworthy that the thickness of PFO is much thinner than that used in previous reports (100–300 nm). , After applying enough pump energy, all PFO films crystallized at different temperatures show the narrowing of PL spectra at 0–1 bands, accompanied by the dramatic increase of the peak and overall emission intensity, reflecting the presence of ASE (Figures S13–S15). Similar to PL spectra, the ASE peak of PFO-120 (460 nm) displays an obvious blue shift compared with those of PFO-80 and PFO-100 (466 nm) (Figure d). Additionally, the oriented PFO films show a waveguide laser pattern with a double-lobed profile after spectral narrowing, arising from an anti-symmetric near-field phase (inset of Figure d). , We can clearly see from Figure e that the different light output directions exhibit substantially various ASE thresholds for PFO-100, which can also be observed for other films crystallized at different temperatures (Figures S16 and S17).…”
Neat
thin films of semiconducting polymers are attractive as efficient
gain media toward optically pumped lasers. However, the optical loss
and out-coupling of isotropic polymer thin films are far from being
rationally regulated from the perspective of chain orientation and
crystal form. Herein, we accomplished a simultaneous control of both
chain orientation and crystal form in large-area highly ordered poly(9,9-dioctylfluorene)
(PFO) thin films through epitaxial crystallization. The well-arranged
PFO lamellae naturally shape a low-loss, graded-index waveguide to
provide spatially distributed optical feedback. Moreover, much more
horizontally oriented dipoles significantly enhance the light out-coupling
efficiency. Thus, the only 65 nm-thickness oriented PFO films demonstrate
excellent amplified spontaneous emission with a low excitation threshold
(7.1 μJ/cm2) and a narrow full width at half-maximum
(2.2 nm) measured in the perpendicular direction of PFO chains. This
strategy opens an effective pathway to prepare high-performance polymer
thin-film lasers and electrically pumped polymer lasers.
“…It is noteworthy that the thickness of PFO is much thinner than that used in previous reports (100–300 nm). , After applying enough pump energy, all PFO films crystallized at different temperatures show the narrowing of PL spectra at 0–1 bands, accompanied by the dramatic increase of the peak and overall emission intensity, reflecting the presence of ASE (Figures S13–S15). Similar to PL spectra, the ASE peak of PFO-120 (460 nm) displays an obvious blue shift compared with those of PFO-80 and PFO-100 (466 nm) (Figure d). Additionally, the oriented PFO films show a waveguide laser pattern with a double-lobed profile after spectral narrowing, arising from an anti-symmetric near-field phase (inset of Figure d). , We can clearly see from Figure e that the different light output directions exhibit substantially various ASE thresholds for PFO-100, which can also be observed for other films crystallized at different temperatures (Figures S16 and S17).…”
Neat
thin films of semiconducting polymers are attractive as efficient
gain media toward optically pumped lasers. However, the optical loss
and out-coupling of isotropic polymer thin films are far from being
rationally regulated from the perspective of chain orientation and
crystal form. Herein, we accomplished a simultaneous control of both
chain orientation and crystal form in large-area highly ordered poly(9,9-dioctylfluorene)
(PFO) thin films through epitaxial crystallization. The well-arranged
PFO lamellae naturally shape a low-loss, graded-index waveguide to
provide spatially distributed optical feedback. Moreover, much more
horizontally oriented dipoles significantly enhance the light out-coupling
efficiency. Thus, the only 65 nm-thickness oriented PFO films demonstrate
excellent amplified spontaneous emission with a low excitation threshold
(7.1 μJ/cm2) and a narrow full width at half-maximum
(2.2 nm) measured in the perpendicular direction of PFO chains. This
strategy opens an effective pathway to prepare high-performance polymer
thin-film lasers and electrically pumped polymer lasers.
“…Alternative dye molecules, e.g. Disperse Orange 11, with recoverable photodegradation properties 48 and conjugated polymers 49 could be evaluated for their photostability in the presented slot-waveguide SiNOH DFB laser geometry.Figure 6Decay of the SiNOH laser emission pulse energy over the number of optical excitation pulses. The pump intensity at 150 kW cm is twice as high as the lasing threshold.…”
One of the major barriers for a widespread commercial uptake of silicon nitride photonic integrated circuits for cost-sensitive applications is the lack of low-cost monolithically integrated laser light sources directly emitting into single-mode waveguides. In this work, we demonstrate an optically pumped organic solid-state slot-waveguide distributed feedback laser designed for a silicon nitride organic hybrid photonic platform. Pulsed optical excitation of the gain medium is achieved by a 450 nm laser diode. The optical feedback for lasing is based on a second-order laterally coupled Bragg grating with a slot-waveguide core. Optimized material gain properties of the organic dye together with the increased modal gain of the laser mode arising from the improved overlap of the slot-waveguide geometry with the gain material enable single-mode lasing at a wavelength of 600 nm. The straightforward integration and operation with a blue laser diode leads to a cost-effective coherent light source for photonic integrated devices.
“…The cross-section is calculated to be 1.5 × 10 −16 cm 2 with N ph = 33.75 × 10 12 cm −2 . This value is comparable to the one of high gain organic molecules [41]. In order to further investigate the optical gain properties of F4TPA we also performed PL measurements with a rectangular excitation spot size as a function of the excitation density both under ultrafast (150 fs) and QSS (3 ns) pumping.…”
The development of high performance optically pumped organic lasers operating in the deep blue still remains a big challenge. In this paper, we have investigated the photophysics and the optical gain characteristics of a novel fluorene oligomer functionalized by four triphenylamine (TPA) groups. By ultrafast spectroscopy we found a large gain spectral region from 420 to 500 nm with a maximum gain cross-section of 1.5 × 10−16 cm2 which makes this molecule a good candidate for photonic applications. Amplified Spontaneous Emission measurements (ASE) under 150 fs and 3 ns pump pulses have revealed a narrow emission at 450 nm with a threshold of 5.5 μJcm−2 and 21 μJcm−2 respectively. Our results evidence that this new fluorene molecule is an interesting material for photonic applications, indeed the inclusion of TPA as a lateral substituent leads to a high gain and consequently to a low threshold blue organic ASE.
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