Rh6G Dye Research Articles

Wavelength-modulation of a dye laser with a low voltage device; Application to signal transmission and analog-to-digital conversion

A specially designed low voltage transverse modulator is used to achieve tunable operation of a cw Rh6G dye laser. The system exhibits a tuning rate 20 times greater than had been reported previously (25 Å/V). Operation of the system is demonstrated in experiments dealing with transmission of signals by wavelength modulation, bistability in wavelength and in A/D conversion. The system can also be used for tuning styril-9 dye lasers.

Dye laser pumped by Nd:YAG laser pulses frequency doubled in a glass optical fiber

Efficient frequency doubling of a cw Q-switched and mode-locked Nd:YAG laser has been observed in commercial single-mode optical glass fibers. Pulses of duration ~55 psec and intensities as high as ~0.55 kW were produced at 0.53 microm. The maximum peak power-conversion efficiency measured was ~3%. The frequency-doubled light generated in the glass fibers was sufficient to pump a commercial Rh6G dye laser with ~19% efficiency at 570 nm.

FM dye lasers

We have investigated the detailed operation of a frequency modulated dye laser (FML). The FML consists of a standing wave Rh6G dye laser with an intracavity transverse ADP phase modulator which is driven at a frequency close to the cavity mode spacing. An ideal FML output consists of a laser beam which is constant in amplitude but sinusoidally varying in frequency. This provides a source of many laser modes which are equally spaced by the modulation frequency. Several dye laser configurations have been investigated. Measurements of the mode intensities, total power, amplitude modulation and rf beat amplitudes have been made as a function of the rf driving frequency of the phase modulator. The FM laser obtained has been frequency stabilised by locking it to a reference interferometer and also by frequency offset locking it to a single-frequency dye laser.

Synchronous mode-locking of a dye laser using an optical bias technique

Abstract We have demonstrated the generation of pulses of 1.4 ps duration by the synchronous mode-locking of a Rh6G dye laser using as little as 10 mW average pump power from the frequency doubled output of a CW mode-locked Nd:YAG laser. The dye laser was optically biased using an argon ion laser in a manner analogous to the mode-locking of semiconductor laser diodes. Applications of this technique to the pumping of dyes in different spectral regions are discussed.

Infrared–optical double resonance spectroscopy of the NH2 radical

Vibration-rotation transitions of NH2 in the à 2A1 state were observed with sub-Doppler resolution, by using a Rh 6G dye laser and a CO2/N2O laser combined with the laser magnetic resonance technique. When the dye laser pumped the à 2A1 (0,9,0) 220←X̃ 2B1(0,0,0) 110 transition, 39 MJ components of (0,10,0) 211←(0,9,0) 220, and 5 MJ components of (0,10,0) 111←(0,9,0) 220 in à were observed by sweeping the magnetic field. Four additional lines which corresponded to changes in fluorescence intensity opposite in sign to those for the transitions mentioned above, were also observed and assigned to transitions from à 2A1(0,9,0) to a highly excited vibrational state of X̃ (“u’’ level). The rotational quantum numbers N and J and the spin splitting of the u level were determined as well as the interaction term between the u and à (0,10,0) 211 states. The u level is tentatively assigned to a rotational level in X̃(2,8,0), however, the observed spin splitting does not agree with that for X̃(0,8,0) calculated by Jungen, Hallin, and Merer.

Investigation of Passively Mode Locking Condition for a CW Dye Laser

We have investigated the operational parameters of a passively mode-locked Rh-6G dye laser, having a cavity with five mirrors and two jet streams, in order to generate stable subpicosecond pulses. The optimum concentration of saturable absorber (DODCI) was found to be 6.0×10-6M. The ratio of pumping power Pp to the threshold power Pth (Pp/Pth) falls in a range of 1.08±0.01, in order to obtain good mode-locking. The optimum value Pp/Pth is independent of the DODCI concentrations. Under this optimum condition, the narrowest pulses of 0.69ps were generated at 614nm. The time-bandwidth product of the pulse was calculated to be 0.78 indicating that the pulse was close to being transform-limited. The lasing-wavelength was tunable in the range of 604-613nm by using a Lyot filter. A nearly transform-limited pulse of 1.54ps with the time-bandwidth product of 0.40was obtained at 605.5nm.

High Power Efficient Dye Laser Pumped by a Copper Vapor Laser

A high power efficient dye laser pumped by a copper vapor laser was developed with longitudinally pumped geometry and using a jet stream. An average output power of 0.86 W for the Rh6G dye was obtained with an efficiency of 31%.

Picosecond injection mode-locking of the XeCl laser

Ultrashort pulse generation has been achieved in a UV-preionized transverse discharge XeCl laser by injection mode-locking using the second harmonic of a passively mode-locked Rh 6G dye laser tuned to the XeCl gain bandwidth. Temporal measurements using a Photochron II streak camera showed pulse durations ∼7 ps with single-pulse peak power of ∼150 MW.

Characteristics of an opto-galvanic effect in cesium and other gas discharge plasmas*

The change in the voltage between the electrodes of a gas discharge plasma when illuminated at wavelengths corresponding to allowed transitions in the gas atoms has been measured for cesium, uranium, argon, neon, hydrogen, and mercury plasmas. Using this effect, high signal-to-noise absorption spectra were obtained with a mechanically scanned cw Rh6G dye laser. Magnitude, polarity, and saturation of the induced voltage charges were determined; a 30% decrease in the operating voltage of a cesium discharge tube was the largest effect observed.

Continuous wave uv radiation tunable from 285 nm to 400 nm by harmonic and sum frequency generation

Broadly tunable cw uv radiation has been generated by frequency doubling and sum frequency mixing in ADP, ADA, and RDP, using the output of a Kr laser, a Rh6G dye laser, and an oxazine 1 dye laser. Continuous tunable uv radiation has been obtained from 285 nm to 400 nm with a maximum power of 750 microW at 313 nm and with powers in excess of 5 microW from 290 nm to 390 nm.

Tunable dye laser pulse converter for production of picosecond pulses

An open flowing Rh6G dye laser, cavity length tuned to a mode-locked Ar+ laser, has been used to generate continuous pulse trains tunable from 5600 to 6100 Å over the dye lasing bandwidth. Interferometric pulsewidth measurement using second harmonic generation yields a pulsewidth of 2.8 ps.