Passive mode locking of a continuous-wave energy-transfer dye laser operating in the near infrared around 750 nm

Fluorescent pseudorotaxanes of a quinodicarbocyanine dye with gamma cyclodextrin

Spectrophotometric titration of buffered solutions of gamma cyclodextrin (γCD) and 1,1'-diethyl,2,2'-dicarbocyanine (DDI) demonstrates extension of the known 1:2 host:guest complex to form a previously unreported 2:2 complex near the γCD solubility limit. Though DDI is predominantly hosted as a non-fluorescent H-aggregate, both complexes exist in respective equilibria with two secondary complexes hosting unaggregated DDI as 1:1 and 2:1 complexes. The 2:1 complex exhibits significant fluorescence emission, with a quantum yield six times that of DDI in organic solvents, but ten times lower than that of an analogous indodicarbocyanine. Fragment Molecular Orbital calculations suggest that the 2:1 complex has the tail-to-tail conformation, and that solvent access to the dye strongly favors photoisomerization. In the host-guest complex, γCD limits solvent access to the dye and hinders rotation of the quinolyl terminal groups, but nevertheless pairwise rotation of methine carbons within the γCD cavity likely remains as a significant nonradiative relaxation pathway for the excited state.

Potential and limitations of energy-transfer processes in pulsed and cw dye laser mixtures: comparison of theory and experiments

A comprehensive energy-transfer dye laser (ETDL) simulation model and the premise on which it is based are examined and reviewed. The model permits theoretical predictions of the total transfer efficiency and hence identification of the appropriate mechanisms that are responsible for energy transfer as well as predicting fluorescence spectra of dye mixtures. Using concentration regimes that are generally applicable to laser action, we also show that the model is capable of predicting gain line shapes (and hence tunability) for pulsed ETDL's. An extension of the model also predicts the gain spectrum of cw laser-pumped ETDL's as a function of donor and acceptor concentrations, their spectral data, energytransfer parameters, pump power and wavelength, and dimensions of the active region. Model simulation results are checked against experimental results for pulsed and cw ETDL's with laser outputs in the visible and near-IR spectral regions. The results lead to a better and more detailed understanding of ETDL mec hanisms and the role that the triplet states play in these mechanisms.

Experimental verification of a theoretical model for continuous wave energy transfer dye mixture lasers in the near infrared

We report the experimental verification of a simulation model for cw energy transfer dye lasers. Experimentals results obtained with Rhodamine 610 (donor) and Nile Blue 690 (acceptor) confirm theoretical model predictions.

Generation of 36-fsec pulses near 775 nm from a colliding-pulse passively mode-locked dye laser

We report the passive mode locking of a cw Rhodamine 700 dye laser using the saturable absorber DDI. Pulses as short as 36 fsec near 775 nm have been produced in a colliding-pulse mode-locked dye laser with adjustable intracavity group-velocity dispersion.

Passive mode locking of a cw energy-transfer dye laser operating in the infrared near 800 nm

The cw tuning range, and subsequent passive mode locking of a new argon-ion-pumped energy-transfer dye laser operating in the near IR, is reported for the first time to our knowledge. The gain medium, consisting of an energytransfer mixture of Pyridin 1 as the donor dye and Rhodamine 800 as the acceptor dye, has been found to lase continuous waves from 742 to 823 nm. Passively mode locked with bis-4-(1-ethylquinoline) [gamma-4'-(1'-ethylquino-line)] pentamethine cyanine diiodide dye, this active medium yielded sub-500-fsec pulses from 783 to 815 nm in a linear cavity, with pulses as short as 260 fsec being generated.

Generation of sub-100-fsec pulses tunable near 497 nm from a colliding-pulse mode-locked ring dye laser

A colliding-pulse mode-locked ring dye laser with Coumarin 102 passively mode locked by 3,3'-diethyloxacarbocyanine iodide has been developed. Pulses of less than 100-fsec duration have been obtained from 493 to 502 nm at a repetition rate of 160 MHz. A similar operation has also been obtained with alternative saturable absorbers.