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.     

An interferometrically tuned and actively modelocked cw dye laser

An interferometer of the Michelson type is used to tune and to actively modelock an argon ion laser pumped cw dye laser. The interferometer constitutes a resonator mirror with a modulated reflecting coefficient. This modulation corresponds to a transient Fourier spectrum containing the whole emission band of the dye. In the center of this spectrum, a mode-locked train of picosecond pulses is generated. These pulses are tunable throughout the tuning range of the employed lasing medium in a simple and convenient way. Due to the inherent characteristic broad band output of the cw dye laser, the modulation envelope extends only for a fraction of the entire lasing period. Means of extending the said envelope to cover the complete laser output are discussed.     

Bistability in wavelength using an electro-optically tuned dye laser

Bistability in wavelength is demonstrated using a Rh 6 G dye laser tuned electro-optically with an intra-cavity modulator. Laser emission occurs on two wavelengths that can be switched between them by a change in the level of light input. Multistable mode is also possible. The characteristics of the system are discussed. They show that the discrimination between the two wavelengths attached to the stable states can be performed easily. Further prospects deal with bulk systems operating with low driving voltages.     

Direct absorption spectroscopy using a rapidly tunable CW dye laser

Using a recently developed electronically tunable cw dye laser, the spectrum of an absorption sample could be obtained and repeatedly scanned every 10 μsec. The system is potentially capable of monitoring spectral changes in times as short as 10^?7 sec.     

Laser Compton scattering for a linearly polarized laser

Laser Compton light sources are potential candidates for the next generation of high-brightness X or γ-ray sources. When increasing the laser power to obtain intense X-ray laser, nonlinear Compton scattering happens. Nonlinear Compton scattering of linearly polarized laser beam is discussed in this paper. A complete transition probability formula is introduced and the polarization properties of final photons are discussed for different conditions.     

Laser Compton scattering for a linearly polarized laser

Laser Compton light sources are potential candidates for the next generation of high-brightness X or γ-ray sources. When increasing the laser power to obtain intense X-ray laser, nonlinear Compton scattering happens. Nonlinear Compton scattering of linearly polarized laser beam is discussed in this paper. A complete transition probability formula is introduced and the polarization properties of final photons are discussed for different conditions.     

Fast mode-hop-free acousto-optically tuned laser with a simple laser diode

A mode-hop-free tunable external-cavity Littrow diode laser with intracavity acousto-optic modulators (AOMs) has been built. The modes of the red laser diode without a special antireflection coating are shifted by varying the injection current. The external resonator modes and the grating selectivity are independently electrically alterable by two AOMs. Thus, a tuning of the external resonator over up to 1900 GHz is possible. A precise computer control of laser diode and AOMs allowed a single-mode tuning of the whole laser with a tuning range of 225 GHz in 250 s. Additionally, we demonstrated fast tuning over 90 GHz in 190 micros and a repetition rate of 2.5 kHz.     

Laser system based on a picosecond dye laser with combined feedback for spectroscopy

A laser system comprising a synchronously pumped picosecond dye laser with combined cavity-distributed feedback and a two-stage dye amplifier is described. The dependence of the laser pulse duration on the detuning of the cavity length, the pumping level of the active medium, and the pulse number in the pulse train was investigated. It is shown that the combination of the two types of feedback provides more than ten-fold shortening of the dye laser ultrashort pulse duration. B. I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 1, pp. 47–55, January–February, 1998.     

Stimulated raman scattering of rapidly amplified short laser pulses

The theory of transient forward stimulated Raman scattering (FSRS) of rapidly amplified short laser pulses is put forth to complement the classical theory for FSRS of stationary pulses. Quantitative conditions for FSRS suppression are identified. In particular, it is shown quantitatively how the limitation imposed by pumped pulse FSRS on the output laser intensity in plasma-based ultrapowerful backward Raman amplifiers can be overcome through a selective detuning of the Stokes resonance.     

Laser intracavity absorption: A numerical and experimental study with a pulsed dye laser

A flash pumped dye laser (Rh6G+Methanol) has been used to study the intra-cavity absorption of I₂ vapour over a wide range of extinctions and over a selected range of laser energies. A computer model based on the characteristics of the experimental laser provides values for quantitative comparison with the experimental ones. Reasonable agreement exists between the numerical computations and the experimental findings.     

Color center laser pumped with a DCM dye laser

A CW, DCM dye laser has been used to pump a RbCl:Li crystal in a color center laser. The DCM dye laser was pumped by the 488 nm and 514.5 nm lines of an argon ion laser. When used in a broad band configuration the dye laser had a power output in the TEM₀₀ mode in excess of 600 mW at a wavelength of 655 nm. An output power in excess of 10 mW at 2.73 μm was possible from the RbCl:Li crystal in a Burleigh FCL for an input power of 600 mW at 655 nm. This method of pumping for the RbCl:Li alleviates the need for both argon ion and krypton ion laser pumps for the Burleigh FCL. All three crystals can be pumped to the specification power levels with a single argon ion laser.     

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 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.     

Broadband coherent anti-Stokes Raman scattering spectroscopy of nitrogen using a picosecond modeless dye laser

Broadband picosecond coherent anti-Stokes Raman scattering (CARS) spectroscopy of nitrogen is demonstrated using 145-ps pump and probe beams and a 115-ps Stokes beam with a spectral bandwidth of 5 nm. This is, to our knowledge, the first demonstration of broadband CARS using subnanosecond lasers. The short temporal envelope of the laser pulses and the broadband spectral nature of the Stokes beam will enable nonresonant-background-free, single-shot, or time-dependent spectroscopy in high-pressure or hydrocarbon-rich environments. Successful correlation of room-temperature broadband picosecond N2 CARS with a theoretical spectrum is presented.     

A distributed feedback dye laser based on higher order Bragg scattering

A distributed feedback dye laser based on second order Bragg scattering due to a sinusoidal susceptibility modulation is reported. Rhodamine 6G dye solution in three different solvents; methanol, ethanol and benzyl alcohol is pumped by interference fringes produced by two beams from the second harmonic of Nd:YAG laser. Output power is plotted as a function of the pump power. The spectrum of dye laser shows a new type of modulation.     

Opto-acoustic spectroscopy with a visible CW dye laser

The first use of a tunable visible laser in conjunction with an opto-acoustic cell is described. By using a longitudinal resonance of the gas cell NO₂ can be detected around 10 p.p.b., the same order of detectivity as in the infrared. The use of the technique for studying photodissociation in the visible and u.v. is discussed.