Experimental Dynamical Variables Of A Chaotic Co2 Laser With Saturable Absorber

A weak continuous beam of a CO2 laser was used to probe the time changing gain and absorption inside the cavity of a passive Q-switching CO2 laser with SF6 gas in an intracavity saturable absorber cell. The probe variations detected simultaneously with the laser intensity pulses gave experimental projection planes of the chaotic system attractor.55324632466Tachikawa, M., Hong, F.L., Tanii, K., Shimizu, T., (1988) Phys. Rev. Lett., 60, p. 2266Dangoisse, D., Bekkali, A., Papoff, F., Glorieux, P., (1988) Europhys. Lett., 6, p. 335Zambon, B., De Tomasi, F., Hennequin, D., Arimondo, E., (1989) Phys. Rev. A, 40, p. 3782Lefranc, M., Hennequin, D., Dangoisse, D., (1991) J. Opt. Soc. Am. B, 8, p. 239Zambon, B., (1991) Phys. Rev. A, 44, p. 688Papoff, F., Fioretti, A., Arimondo, E., Mindlin, G.B., Solari, H., Gilmore, R., (1992) Phys. Rev. Lett., 68, p. 1128Alcantara Jr., P., Guidoni, L., Barsella, A., Fioretti, A., Arimondo, E., (1995) J. Opt. Soc. Am. B, 12, p. 1326. , and references cited thereinLiu, Y., Rios Leite, J.R., (1992) Opt. Commun., 88, p. 391Liu, Y., Rios Leite, J.R., (1994) Phys. Lett. A, 191, p. 134Sugawara, T., Tachikawa, M., Tsukamoto, T., Shimizu, T., (1994) Phys. Rev. Lett., 72, p. 3502Liu, Y., De Oliveira, P.C., Danailov, M.B., Rios Leite, J.R., (1994) Phys. Rev. A, 50, p. 3464Bobin, B., Borde, Ch.J., Borde, J., Breant, Ch., (1987) J. Mol. Spectrosc., 121, p. 91Di Lorenzo-Filho, O., De Oliveira, P.C., Rios Leite, J.R., (1991) Opt. Lett., 16, p. 1768Witteman, W.J., (1987) The CO2 Laser, , Springer-Verlag, New YorkDangoisse, D., Glorieux, P., Hennequin, D., (1990) Phys. Rev. A, 42, p. 1551Grassberger, P., Procaccia, I., (1983) Phys. Rev. Lett., 50, p. 346Lefranc, M., Hennequin, D., Glorieux, P., (1992) Phys. Lett. A, 163, p. 26

Coherent control of high harmonic generation in a large-volume capillary for seeding of free-electron lasers

FEL-1 at FERMI@Elettra is a seeded free-electron laser using sub-harmonic seeding to generate soft x-rays down to 10 nm. The current seed laser, a standard solid-state laser followed by frequency quadrupling in nonlinear crystals, has a minimum wavelength of 200 nm. Injecting much shorter seed-laser wavelengths, for which high-harmonic generation (HHG) is of high promise, can shorten the laser output wavelength significantly. However, the minimum seed pulse energy required is not readily available with standard approaches to HHG. To increase the energy available in a particular harmonic for seeding, we use a gas-filled capillary with a large diameter (500 μm), pumped by an 8 mJ, 35 fs Ti:Sapphire laser. A wide capillary allows a large gas volume for HHG, thereby increasing the output energy. We also investigate the coherent control of HHG by shaping the spectral phase of the drive laser using an acousto-optic programmable dispersive filter. Here, we use a learning algorithm with the objective to simultaneously tune and selectively enhance an individual harmonic order. We present first results including pressure dependent harmonic output energy, spectrum and beam stability, as these are important for seeding of FELs. Further, we discuss initial experiments with coherent control that has shown selective enhancement up to a factor of 10

Size and density redistribution by a rod obstacle in a cluster jet for quasi-phase matching of high harmonic generation

We investigate the the possibility to realize a fully coherent XUV light source generating wavelengths down to 4 nm by using high-order harmonic generation (HHG) in an ionized medium. Due to the strong ionization, current p We investigate the possibility to realize a fully coherent XUV light source generating wavelengths down to 4 nm by using high-order harmonic generation (HHG) in an ionized medium. Due to the strong ionization, current phase-matching techniques for HHG are not suitable. Instead, we will investigate quasi-phase matching (QPM) over an extended interaction length to increase the output pulse energy. For this, we will prepare a cluster jet from a 5 mm long supersonic nozzle operated at high backing pressure (up to 75 bar). The modulation for QPM is obtained by placing either an array of wires or slits on top of the exit of the nozzle. Here, we report on the characterization of the modulated argon cluster jet. We apply Rayleigh scattering imaging and interferometry to infer the cluster size and total atomic number density distribution in the jet. Initial experiments concern the modulation of the jet by placing a 2 mm rod above the nozzle. The rst results on the cluster size and density distribution will be compared with the simulation results from our 2D fluid dynamics model

Chaotic And Periodic Passive Q Switching In Coupled Co2 Lasers With A Saturable Absorber

The dynamics of two single mode CO2 lasers with intracavity saturable absorber when they were submitted to variable amount of optical coupling were investigated experimentally and numerically. In the experiments, the two lasers were optically coupled by sending part of each output beam into the other laser cavity. It was shown that even for a small amount of coupling, their dynamics altered with a rich variety of possibilities. Periodic or chaotic pulsations were inferred to result from the coupling. The numerical results contained the essential characteristics of the experiments, and it was concluded that the main properties of the dynamics of coupled CO2 lasers with saturable absorber might be understood by a system of coupled rate equations.5043464347