Single picosecond UV pulse generation by mode-locking of an excimer laser-pumped dye laser

A single picosecond ultraviolet pulse has been generated based on mode-locking of a dye laser pumped by a long pulse XeCl laser to serve as the input source for a high-power ps KrF laser system. A short-pulse uv dye laser (BBQ) pumped by an additional XeCl laser was used to selectively amplify a single pulse from a mode-locked pulse train with the pulse separation of 3.2 ns. The amplified single pulse was frequency-doubled to 248 nm with the pulse duration of 20 ps.     

Subpicosecond pulse generation in synchronously pumped and hybrid ring dye lasers

Subpicosecond pulse generation has been examined in synchronously pumped mode-locked ring dye laser systems. These include hybrid and composite absorber/gain media arrangements as well as a simple synchronous cavity. The shortest pulses recorded were 0.3 ps for the hybrid system, and this has been shown to be critically dependent on the positioning of the absorber jet in the centre of the cavity to better than 50 m. Stable operation for subpicosecond pulse generation has been achieved in the ring configuration with greater wavelength tunability and higher average power conversion efficiency than with conventional cavity arrangements.     

A single-mode KrF laser

Single-mode operation of a KrF laser oscillator has been achieved for the first time. The laser medium is pumped by an electron beam which allows excitation for a much longer duration than with discharge pumping. The long excitation time, together with the use of a short oscillator cavity with a low single-pass gain, allows many roundtrips before saturation is reached. This makes line-narrowing easier and single-mode operation has been achieved using only two intracavity etalons.Technical Research Centre of Finland, Helsinki, Finland     

Influence of circuit and UV prioniser parameters on the performance of a discharge pumped KrF laser

The influence of the preioniser and main discharge circuit parameters on the performance of a high pressure UV preionised KrF laser using NF₃ as the fluorine donor has been investigated. Output laser energy densities of 1.7J·1⁻¹ based on the mode volume have been obtained under optimised conditions.     

Production of intensities of ∼ 1019 W/cm2 by a table-top KrF laser

We report on the generation of intensities of 10¹⁹ W/cm^–2 by focusing the output beam of a table-top hybrid dye-excimer laser system operating at 248 nm. The laser system uses a pulsed dye laser and a single, commercially available excimer gain module. Considerations and optical arrangements for the optimization of the phase-front and the beam homogeneity of ultraviolet excimer amplifiers are presented.Prof. F.P. Schäfer on the occasion of his 65th birthday.     

Tunable picosecond pulse generation from the passively mode-locked coumarin 6 dye laser

Using the saturable absorber 2-(p-Dimethylaminostyryl)-benzothiazolylethyl iodide, coumarin 6 has been passively mode-locked for the first time to give fully modulated trains of pulses of 4 ps duration and with peak powers of 3 MW tunable over the spectral range 526–547 nm.     

Influence of cavity configuration on the pulse energy of a high-pressure molecular fluorine laser

We report an investigation of a high-pressure molecular fluorine laser operating at 158 nm. Several cavity configurations were studied, including one employing a roof prism as the high reflector. A maximum VUV pulse energy of 237 mJ, corresponding to a specific output of 3.3 J/1 was obtained when the laser was operated as a double-ended device. With single-ended operation the largest output energy was 176 mJ at a specific output of 2.5 J/1.     

KrF laser system with corrected pulse front and compressed pulse duration

A high-power KrF laser system is presented providing 45 mJ, 150 fs pulses at the position of a target. Pulse front distortion is avoided by specially designed refractive optics. Pulse compression is done after final amplification using a simplified compressor.Dedicated to Prof. Dr. Herbert Welling on the occasion of his 60th birthdayPolska Akademia Nauk, Instytut Chemii Fizycznej, Kasprzaka 44/52, PL-01-224 Warszawa, Poland     

Formation of diffraction-free beams by laser generation of conical radiation in a Kerr medium

Received: 16 June 1998     

Highly efficient synchronous amplification of a picosecond dye laser at a kHz repetition rate

A short pulse, high energy, high repetition rate dye amplifier with superior conversion efficiency is reported. The dye amplifier is composed of three single-pass dye cells, longitudinally pumped by a frequency doubled 1 kHz Nd: YLF regenerative amplifier. The dye amplifier yields 3.5 ps, 150 J pulses at 595 nm, corresponding to a 12% conversion efficiency. The ASE is 1% or less, and the transverse mode quality is near-Gaussian.In absentia from the Department of Chemistry, Princeton University, Princeton, NJ 08544, USA     

Efficient amplification of sub-picosecond pulses of a non-CW dye laser

Efficient amplification in a dye laser amplifier is investigated theoretically and experimentally. A five-level rate equation approach is considered including rotational relaxation of the dye molecules. The effects of the pump pulse duration and of the parameters of the input pulse are discussed. The results are compared with experimental data for 0.5 ps pulses of a pulsed dye laser. Conversion efficiencies >10% are achieved for a single pass amplifier using Nd:YAG pump pulses of 2 ns while an effective fluorescence lifetime of 1.7±0.2 ns is determined for the gain medium rhodamine 6G. The triple pass amplifier stage of the laser system achieves an energy conversion of 4% with 40 J output pulses.     

CO laser stabilization using the optogalvanic Lamb-dip

Frequency stabilization of the CO laser using a CO lamb-dip is achieved in the range from 5.0–6.3 m. The CO saturation signal is obtained from a low-pressure discharge in absorption and is detected using optogalvanic, detection. The frequency stability and reproducibility has been verified to be better than 100 kHz; this is an improvement of more than one order of magnitude compared with locking techniques using CO laser gain profiles.Alexander von Humboldt Awardee from National Bureau of Standards, Boulder, Colorado, USA     

Two-wavelength operation of a tunable KrF excimer laser — A promising technique for combustion diagnostics

A KrF excimer laser was operated on two independently tunable lines. This was achieved by a double-resonator configuration with two gratings. Tuning range and gain competition were investigated. The narrow line width (<1 cm^–1) and the independent tunability make this laser ideal for simultaneous spectroscopic detection of two species and temperature measurements in combustion processes.     

Detailed simulation of recombination XUV laser experiments

The detailed simulation of recombination XUV laser experiments is described and the calculation of gain as measured by two different experimental techniques is discussed. It is shown that a reasonable comparison between simulation and experiment can only be obtained if the self-trapping of the Lyman line is neglected.     

Efficient distributed feedback solid state dye laser with a dynamic grating

We present the first operation of a distributed feedback solid state dye laser with a dynamic, pump-induced grating. Broadly tunable, narrow band operation in the region of 616 nm (604–649 nm) has been demonstrated with perylene red laser dye doped in poly(methyl methacrylate) (PMMA), when pumped with a frequency doubled Nd:YAG laser. Conversion efficiencies of 20%, corresponding to 35% optical-to-optical efficiency, have been measured. The laser bandwidth was between 0.01 and 0.04 nm, and smooth tuning over more than 200 GHz has been demonstrated. Received: 29 March 1999 / Published online: 24 June 1999     

Solid-state active media of tunable organic- compound lasers pumped with a laser. II. A copper vapor laser

The lasing properties of organic compounds in a polymethylmethacrylate matrix pumped by a copper vapor laser are studied. The results demonstrate that the transverse pumping scheme of solid-state laser-active media with the copper vapor laser is promising compared to the longitudinal pumping scheme from the viewpoint of the lifetime parameters. Received: 6 February 2002 / Published online: 2 May 2002     

Subpicosecond,widely tunable distributed feedback dye laser

A simple, achromatic, widely tunable distributed feedback dye laser arrangement is described. It makes use of a microscope objective, which images a transmission grating into the active medium. With this arrangement subpicosecond operation and broad tunability (400–760 nm) is reported.     

Two-wavelength self-seeded pulsed tunable laser

A compact self-seeded pulsed tunable laser is described. Its optical cavity comprises a diffraction grating, operating at a grazing angle of incidence as a spectral selector and narrow-band spectral gate. The grating couples two partially overlapping laser channels: a highly selective master laser and a nonselective slave laser. Due to the implemented efficient intracavity self-seeding the laser emits spectrally pure single-longitudinal-mode radiation at two independently tunable wavelengths, with an efficiency and output energy that are typical for nonselective lasers. Results of the experimental investigation of the laser’s output characteristics are presented. Received: 12 March 2001 / Revised version: 10 December 2001 / Published online: 7 February 2002     

A novel double grazing-incidence single-mode dye laser

Using only one grating and plane parallel glass plate in a novel double-grazing incidence configuration, twice higher dispersion is obtained, resulting in twofold narrowing of the single-pass linewidth, compared to the single grazing-incidence scheme. This laser cavity design features several-times improved signal-to-noise ratio and enhanced stability. Single-mode operation of 210±50 MHz is demonstrated.     

20 ps pulse generation by an excimer laser pumped double self-Q-switched distributed feedback dye laser

The behaviour of an excimer-laser-pumped distributed feedback dye laser (ELP DFDL) using a mixture of saturable absorber and laser dye as an active medium was studied. In a DFDL self-Q-switching occurs because of the population inversion dependence of the feedback. If the DFDL contains absorber saturation of the absorption by the leading edge of the created laser pulse also causes Q-switching. As a result of this double self-Q-switching, mixing a saturable absorber into the laser dye, the laser pulses become shorter and more stable. This was demonstrated experimentally. Mixing Rhodamine B into the dye solution of a Coumarin 153 ELP DFDL, a six-fold reduction in the pulse duration and a more than two-fold reduction in the pulse energy instability were observed. The experimental results were in good qualitative agreement with the predictions of a simple rate equation model.