formation of a fluorescent-dye layer on the surface of porous alumina, the porous alumina substrate was dipped in an ethanol solution containing 20 wt.-% dendrimer [13] and 4 × 10 M pyrromethene 597 (EXITON) for 1 min and then dried. The thickness of the fluorescent-dye layer was approximately 1 lm. Optically pumped lasing experiments were performed using a frequency doubled Nd:yttrium aluminum...

Subpicosecond vacuum-ultraviolet radiation at 155 nm with pulse energies above 0.2 mJ has been obtained by near-resonant four-wave difference-frequency mixing in a Xe gas jet. Laser fields for the mixing process have been generated by a short-pulse KrF dye excimer laser system and a Raman converter. The process permits tuning in a broad vacuum-ultraviolet range and can be scaled up to higher ou...

The temporal profiles of the emission from titania particle suspensions in Rhodamine 640 perchlorate dye solutions excited by 10-ps pulses of 527-nm radiation were measured over a wide range of particle and dye concentrations and laser powers. The dynamics of stimulated emission from random media is modeled by a random walk of photons within the colloid and rate equations for molecular excitati...

We report the demonstration of low order distributed feedback DFB optofluidic dye lasers with reduced threshold. The laser chips were realized in polydimethylsiloxane using replica molding with two masters. A comparison between first, second, and third order DFB dye lasers was performed, while the second order DFB dye laser exhibited the lowest pump threshold of 78 nJ/pulse. Compared to previou...

The influence of self-phase modulation (SPM) and group-velocity dispersion (GVD) on pulse development in a passive mode-locked dye laser is investigated numerically by using fast Fourier transformations. The situation of positive SPM is considered. Four regions of laser performance may be distinguished: (i) In the positive GVD region pulse broadening by GVD must be balanced by the pulse-shorten...

Pulse-shortening and pulse broadening effects in passively mode-locked lasers are analysed. A steady-state pulse duration limit is calculated and compared with round-trip simulations. The numerical calculations apply to a picosecond N d : glass laser. Methods of short-pulse generation are discussed. PACS: 42.55R, 42.60D, 42.65 In passively mode-locked pulsed lasers the statistical spontaneous e...

S u m m a r y . Methods of generation and measurement of tunable ultrashort light pulses from c.w. synchronously pumped dye-lasers are described. Conditions for optimal pulse shape are discussed and experiments to determine absolute dye-laser cavity length, pulse-to-pulse reproducibility and pulse substructure arc described. Methods of applying synchronously pumped dye-lasers to time-resolved e...

Synchronized trains of picosecond laser pulses of two different wavelengths constitute a powerful tool to study fast processes in materials. In the last several years this scheme was used to study vibrational dephasing of molecular monolayers on surfaces,’ optical nonlinearities in the polydiacetylene PTS conjugated polymer,“‘3 and the solvent dependance of the rotational diffusion of Cresyl Vi...

Laser-induced fluorescence measurements of OH have been performed in an atmospheric stoichiometric CH(4)/air flame and in a highly sooting propane flame. The measurements were realized with a single 6-nsec pulse from a frequency-doubled dye laser pumped by a Nd:YAG laser and with a spatial resolution of ~25 microm. This was achieved by imaging through a suitably chosen filter set a section of t...