Two-wavelength operation of a femtosecond ring dye laser

We report on two-wavelength operation of a CPM ring dye laser employing Rhodamine 6G as gain medium and a new styryl dye as saturable absorber. Two trains of femtosecond pulses at different wavelengths are simultaneously generated under proper alignment of the laser. The secondary pulse train is attributed to the laser action of the absorber dye. Auto- and cross-correlation measurements are performed to determine the temporal characteristics of the laser in the double mode-locking regime.     

Novel achromatic distributed feedback dye laser for subpicosecond operation

The optical pump arrangement of distributed feedback dye lasers (DFDLs) having a grating beam splitter is analyzed in detail. The upper limit of the pump spectral bandwidth and beam divergence are given as a function of the length of the excited volume. A novel achromatic pump arrangement is reported which is capable of producing a short, high visibility interference pattern even if a divergent pump source of several nm bandwidth is used. The DFDL pulse duration has an estimated lower limit of 200 fs.     

连续波环形染料激光器的单向运转特性

本文讨论了连续波环形染料激光器的单向运转特性。采用改进的Ganiel速率方程模型,分析了在单向运转条件下泵浦光通量、染料分子密度等参量对激光光通量、激发单重态粒子集居数密度以及增益的影响;揭示了在连续波环形染料激光器中单向运转条件下存在粒子集居数密度的非对称性、激光光通量与激活介质内空间位置的相关性和增益峰值波长的扫描现象。本文给出了数值计算结果。     

Simultaneous two-line operation of a CW CO laser with arbitrary choice of laser transitions

An experimental scheme is discussed, by which we can operate a CO laser at two individually selectable lines from the same gain tube. There are virtually no restrictions on the wavelength separation of the two lines within the manifold of the available lasing transitions. Experimental verifications of this scheme are described and the mutual influence of the simultaneous laser operation is discussed.Dedicated to Professor Siegfried Penselin on the occasion of his 60th birthday     

Nitrogen-laser-pumped single-mode dye laser

Single-mode operation of a N₂-laser-pumped'dye laser has been obtained in a short laser cavity consisting of a diffraction grating used near grazing incidence and an uncoated resonant reflector. The dye laser pulse has a spectral linewidth of 420±30 MHz and a pulse width of 1.1±0.1 ns, giving a time-bandwidth of 0.46±0.07 close to the Fourier transform limit for Gaussian pulse.     

An investigation of laser-induced fluorescence for measuring velocity distributions of neutral atoms using a CW dye laser

The velocity distribution of evaporated Zr atoms has been measured by means of laser-induced fluorescence using a cw dye laser by scanning the laser line across the Doppler-broadened absorption line profile of the atoms. It is shown that the experimental data can be explained on the basis of an excitation theory for a three-level system developed from basic principles. It was calculated that the probability for an atom to be in the excited state mainly depends on the radiation-power density of the laser and on the residence time of the atom in the exciting laser light. It was found that the laser frequency must be well stabilized in order to meet the assumptions in the excitation calculation. Otherwise deviations to the theoretical predictions appear in the experimental results due to the jitter of the dye laser.     

Picosecond laser amplification system with 93 W high average power

A high average power picosecond laser amplification system with diode-end-pumped Nd:YVO₄ and diode-side-pumped Nd:YAG is described. Laser with power up to 92.7 W, repetition frequency of 73.3 MHz, pulse duration of 26.5 ps, and beam quality of M² < 3.5 is generated in the amplification system. Thermal-birefringence-induced depolarization in the Nd:YAG rod laser head amplifier is measured to be 21.9 W though birefringence compensation is performed.     

Prism tuner for single frequency operation of CW dye laser

A cw dye laser capable of single longitudinal mode operation and linear reproducible wavelenght tuning over a relatively wide spectral range is described. By employing a novel scheme of four intracavity highly dispersive Abbe prisms output powers of 5 mW with a linewidth less than 30 MHz for an input power of 700 mW have been obtained.     

A 1 MWP-terphenyl dye laser

P-terphenyl in cyclohexane, has been pumped by a KrF laser in a longitudinal configuration. Dye laser pulses of 11 mJ, 1 MW were obtained with over 10% conversion efficiency. N₂ purge of the dye solution is shown to increase the conversion efficiency. The tuning curve between 321.8 nm and 365.3 nm is presented.     

Generation of powerful one-picosecond dye laser pulses at two independently tunable wavelengths

Generation of powerful 1-ps pulses at two independently and continuously tunable wavelengths with precisely controllable delays between them is obtained in a compact dye laser device using a single standard nanosecond Nd:YAG pump laser.     

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.     

A quasi double-grating grazing incidence pulsed dye laser

Continuous scanning of a 1 GHz pulsed laser line using only one 5-cm grating as an intracavity selective element is obtained from a pulsed dye laser pumped by a Nd: YAG (8 ns-532 nm) laser. Such a single-grating dye laser operates in the same way as a real double-grating grazing incidence laser and provides an appreciable improvement of the resolution (enhancement factor 2), compared with previous grazing incidence ones. The superiority of this laser cavity has been proved for single-longitudinal-mode operation.Laboratoire associé à l'Université de Paris-Sud     

CW and pulsed FIR-CO2 hybrid laser with improved efficiency and amplitude stability at short FIR wavelengths

For the first time stable cw output of a FIR-CO₂ hybrid laser has been achieved at wavelengths shorter than 300 m. Due to the saturable absorber characteristic of the FIR laser gas, cw or pulsed emission is observed on both, the CO₂ and the FIR laser output, depending on the operating conditions. Results are reported on different resonant lines in CH₃OH and the 67 m Raman line in NH₃. The good efficiency of this laser is also demonstrated by the excitation of two new emission lines in CH₃OH, namely 49 and 56 m, pumped by 9R(22) and 9R(24), respectively.On leave from the Institute of Physics, University of Beograd YU-11000, Beograd, Yugoslavia     

A subpicosecond dye laser pumped by a xenon ion laser

A pulsed xenon ion laser has been used to pump a rhodamine 6G dye laser utilizing a ring resonator. The dye laser has been passively mode-locked; a pulsewidth of 0.5 ps and a 50 kW peak power have been obtained.Work partly supported by Italian C.N.R.     

Fast frequency control of a cw dye jet laser

For frequency stabilization of a cw dye laser a very fast reacting piezo mirror translator with 350 kHz lowest resonance frequency has been developed. If it is driven by appropriate control electronics it allows to suppress efficiently fast frequency changes of the jet stream dye laser. The remaining frequency jitter is 270 kHz rms for full-bandwidth detection; it drops to a few kHz if a filter time constant of 100 μs is used.     

Active mode locking of a high pressure CW waveguide CO2 laser

In this paper, we report on a new concept for active mode locking of lasers. It has been successfully applied to a cw waveguide CO₂ laser and pulse widths as short as 2 ns have been obtained.     

New efficient laser dye for pulsed and CW operation in the UV

A new laser dye for pulsed and cw operation has been synthesized which can be tuned from 362 nm up to 412 nm. For pulsed excitation with a XeCl excimer laser an energy conversion of 18.5% has been measured at the tuning maximum of the dye; this is the highest efficiency for any known dye in the UV. For cw operation a low laser threshold and a goof efficiency have been observed. The range of tuned cw dye lasers is extended by 30 nm to shorter wavelengths. The dye shows high photochemical stability even at high pump laser power.     

Mirror problems of a cw argon-ion laser at high output power

We report upon some experiments done on a continuous-wave argon-ion laser which offers 300 W output power in the visible and 34 W in the ultraviolet region of the spectrum, limited by the degradation of the resonator mirrors. To avoid destruction of the outcoupling mirror, a folded three-mirror instead of a two-mirror cavity was tried, resulting in nearly the same output power.     

CVL-pumped dye laser for spectroscopic application

A spectroscopic dye laser system-pumped by a Copper Vapor Laser (CVL)-has been built and optimized for different dye solutions operating in the spectral range from 530 to 890 nm. Conversion efficiencies up to 40% were reached in broad band operation, 24% with a prism expander grating cavity, and 20% in grazing incidence configuration, which operated at typical band widths of 3 GHz. Second harmonic generation (SHG) of the dye laser output produced tunable uv-radiation between 260 and 408 nm at conversion efficiencies 5%. Fundamental and SHG output were used for resonant ionization experiments in molecular beams.     

Shorter dye laser wavelengths from substitutedp-terphenyls

The spectral and laser characteristics of 14 CH₃-, CF₃-, and F-substitutedp-terphenyls have been investigated. 2,2″-dimethyl-p-terphenyl in cyclohexane solution exhibits a shortest tuned laser wavelength of 311.2 nm, thus extending the range of dye laser emission by 1000 cm⁻¹ in the uv. Peak output powers of 1.5 MW and 14% conversion efficiency at 332 nm were obtained under KrF-laser pumping in an untuned cavity.