Prospects for vapor-phase dye lasers

This review covers the field of vapor-phase dye lasers (VPDL) with special emphasis on prospects of gas lasers with optical pumping. Some peculiarities of the gaseous active medium and a possibility to control its density near the critical point are discussed. High specific laser energies (0.3J/cm^–3), low thresholds, and high efficiencies (20–40%) made it possible to construct a powerful tunable VPDL.     

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.     

A narrowband single-mode dye laser

The linewidth of a cw-single-mode tunable dye laser has been investigated. It was found that the linewidth is determined by microscopic velocity fluctuations of the turbulent flow within the dye cell of the laser and by fluctuations of the pump power. The linewidth is further influenced by mechanical disturbances and by temperature fluctuations of the dye solution. The results of the investigations made it possible to achieve a reduction of the velocity fluctuations. It is shown that under adequate operating conditions the free-running dye laser has a linewidth of 2 MHz.     

多波长染料激光系统

本文报道由四台染料激光器组成的四波长染料激光系统、测量了四个波长激光合束后的激光参量和时间特性,简要地讨论了影响有效染料激光功率的诸因素.本系统输出总功率8.9W.     

A double-wavelength nitrogen-laser-pumped dye laser

A narrow-band tunable double-wavelength dye laser with a bandwidth of 0.1 cm⁻¹ is described. The output at one of the wavelengths is found to be completely linearly polarized in the plane of incidence.     

A single mode flashlamp-pumped dye laser

A flashlamp-pumped dye laser capable of single transverse and longitudinal mode operation is described. The maximum untuned power output is 2 MW cm^-2, TEM₀₀ mode. By employing three intracavity Fabry—Pérot etalons, a minimum spectral width of 4 MHz, stable to within 12 MHz, has been obtained.     

A high-efficiency carbazine-122 dye laser

Highly efficient operation of a carbazine-122 dye laser has been achieved by pumping longitudinally with the second harmonic of a Nd:YAG laser. An overall energy conversion efficiency of 44% was obtained for the experimental conditions described.     

A grating tuned cw dye laser

We report on the operation of a rhodamine 6G cw dye laser involving a simple tuning mechanism capable of achieving high output powers (～500 mW) and resolving power (0.004 nm) close to the Doppler limit for a range of light gases. The system employs a 600 line/mm diffraction grating external to, but coupled with a high Q laser cavity; continuous tuning over 50 nm of the fluorescence spectrum of the dye was obtained.     

A reliable thyratron-switched flashlamp-pumped dye laser

A thyratron-switched flashlamp-pumped dye laser capable of an average power of approximately 1 watt operating at 40 pulses/sec with a bandwidth of several GHz is described. The lamps are run in a high-current simmering mode to decrease lamp inductance and extend lamp life. In heavy use the laser system has proven to be very reliable with lamp life-times in excess of 10⁷ shots and half-power dye lifetimes of better than 10⁶ J/1 for Rhodamine 6G.     

A narrowband jet stream dye laser

The dependence of the optical quality of water and of higher viscosity jet streams on the flow velocity and the geometry of the nozzle is investigated. It was found that disturbing thickness fluctuations can be reduced by the use of thin jet streams with solvents of high viscosity and by working at an experimentally determined optimum flow velocity. The linewidth of a cw jet stream dye laser with a water-Ammonyx and an ethylene glucol solution was measured to be 9 MHz and 3.3 MHz, respectively. The linewidths were independent of the pump power.     

A high-resolution cw dye laser spectrometer

The construction and utilization of a high-resolution cw dye laser spectrometer is described. The laser incorporates pressure tuned intra-cavity etalons enabling the single mode output laser frequency to be tuned more than one nm in a continuous scan. In the scan the laser jumps from one cavity mode to the next in ～ 50 MHz steps. In comparison to molecular Doppler widths this mode jumping is negligible. As an example of the use of the instrument, a high-resolution absorption spectrum of molecular iodine between the sodium D lines is presented. A unique frequency counter provides the calibration of the absorption spectrum.     

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.     

A mode-locked dye laser pumped by a xenon ion laser

Passive mode-locking of a rhodamine 6G dye laser has been achieved, using a pulsed xenon ion laser as a pumping source. A pulse width of 5 ps and a peak power of 4 kW have been obtained. Thermal problems were encountered, which adversely affected the operation of the dye laser. Work is in progress to improve these results.     

A dye laser with a polyurethane matrix

A dye laser with a polyurethane matrix cured by polycondensation is studied. An increase in the conversion efficiency, service life, optical stability, and tuning range in comparison with lasing media produced by radical polymerization is demonstrated.     

A powerful broad band tunable dye laser

Perchloric acid solutions of 4 methylumbelliferone pumped by a second harmonic of ruby provide a high efficiency (20% conversion yield of pumping source) broad band (5600-4600 Å) tunable dye laser. Some effects of chemical quenching on the efficiency of this protonic exciplex laser were investigated.     

A simple and reliable short-pulse dye laser

A simple technique is described that allows the generation of a short pulses (1 ns) from dye lasers pumped by a much longer (7 ns) N₂-laser pulse. Dye-laser pulses, either with a narrow bandwidth or a short duration, can thus be obtained with the same N₂-laser pump.     

A dye laser with a transverse-flow cuvette

A new type of transverse-flow dye laser is described which features a number of technical advantages; among these are a beam divergence of less than 6 mrad and stable operational characteristics even at 50 hz. The low Fresnel number of the cavity results in low-order emission modes.     

A simple,efficient plastic dye laser

A simple efficient plastic dye laser is described. A conversion efficiency of 47% was obtained from Rhodamine 6G doped PMMA, when pumped by the second harmonic of a Q-switched Nd: YAG laser in a near longitudinal pumping configuration. Lifetime tests performed on 0.3 cm² surface area of plastic, indicates a drop in efficiency from an initial 47% to 25% after 3.2 × 10⁴ shots. By defocusing the pump beam and doubling the sample thickness, the lifetime increases to 1 million shots before the dye laser efficiency drops from an initial 35% to 25%, for a scanned area of 2 cm², similar results have been obtained with rhodamine B.     

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 reliable high average power dye laser

A flashlamp-pumped dye laser with an average output power of 6.6 W at 100 Hz repetition rate is described, which utilizes thyristors as switching elements instead of the normally used spark gaps. Using a simmering-mode operation of the flashlamps, no high voltage sparks are required to initiate the discharge even at low capacitor voltages. In this way the amplitude and time jitter of the laser output pulse are decreased and the life and reliability of the laser considerably increased.