Laser dynamics in organic distributed feedback lasers

Abstract

The authors study laser dynamics in a polymer distributed feedback resonator by performing pump-probe experiments. They measured the population kinetics in the device under lasing operation with subpicosecond time resolution. By modeling the system with a set of coupled rate equations, which account for stimulated emission and nonradiative decays, they extract quantitative information on buildup time, photon lifetime, and pulse duration and give evidence of the feedback and loss mechanisms. They also investigate the influence of the grating length in the feedback and loss processes, and they show that lower pump energy thresholds can be achieved with short devices.

Wavelength Conversion from Silica to Polymer Optical Fibre Communication Wavelengths via Ultrafast Optical Gain Switching in a Distributed Feedback Polymer Laser

“…The output pulse shows a peak at about 6 ps after the pump pulse and has a duration of ∼ 10 ps (FWHM). Similar time dynamics have been reported in DFB lasers using other conjugated polymers [17,18] except that the Red F laser output pulses are of longer duration than is typical. With an increase in pump energy, the temporal shape of the lasing pulse and its build-up time remained largely unaffected, an observation in contrast to the results of previous studies.…”

“…With an increase in pump energy, the temporal shape of the lasing pulse and its build-up time remained largely unaffected, an observation in contrast to the results of previous studies. [17,18] This can be explained by the fact that only Figure 2. Streak traces of a) the pump pulse (dotted line) and the DFB laser output (solid line) in a 2 nm window centred at 692 nm when no control pulse is applied, b) the frequency doubled control pulse (dashed line) and the DFB laser output (dotted line) in the same 2 nm window at 692 nm when switched off by the control pulse.…”

Effects of morphology and optical contrast in organic distributed feedback lasers

“…4͒. 12 Therefore, in our long resonator, different short lasers are emitting in parallel, which can explain the linewidth being larger than expected for this pulse duration ͑ϳ1 nm͒, as in each single cavity a different lasing wavelength originates from slight differences in the grating period. 4 Their spacing ⌬ ϳ c /2LЈ, such that the effective length of the cavity LЈ ϳ 40 m. LЈ is thus much shorter than the DFB length L = 500 m, due to scattering losses, as was already observed previously.…”

Organic solid‐state integrated amplifiers and lasers

“…These dyes provide the gain in the structures, producing laser emission in the spectral ranges 615-660 nm and 655-700 nm, respectively. Lasing in these gain media was achieved using Fabry-Perot [54][55][56]129], and DFB [57,78,87,162] resonators. Their attraction lies in that the absorption and emission spectra of the DCM (DCM 2) and Alq 3 , respectively, conveniently overlap to allow for a very efficient fluorescence resonant energy transfer (FRET), also known as Förster energy transfer, from the excited host to the dye dopant [57,58,163].…”