Search results for "Laser pumping"
showing 10 items of 35 documents
Temporal Control of Pulses from a High-Repetition-Rate Tunable Ti:Sapphire Laser by Active Q-switching
2003
We investigated the lasing characteristics of a Ti:sapphire laser pumped by a pulsed high-repetition-rate Nd:YAG laser. The pump laser has a pulsewidth of 450 ns, while the Ti:sapphire laser shows a significantly shorter pulse width of 25 ns for suitably intense pumping. The energy conversion efficiency of the laser is more than 10%. To synchronize different lasers and to avoid multiple spiking during one pump pulse, we use a Brewster-cut Pockels cell in the resonator for Q-switching. The temporal profile and conversion efficiency are determined and compared to theoretical estimates.
Demonstration of an efficient pumping scheme for a 7.36-nm Ni-like samarium soft x-ray laser
2010
The demonstration of a 7.36 nm Ni-like Sm soft x-ray laser pumped by 36 J of a Nd:glass chirped pulse amplification laser is presented. Double-pulse single-beam non-normal incidence pumping was applied for the efficient soft x-ray laser generation. Here the applied technique included a new single optic focusing geometry for large beam diameters, a single-pass grating compressor traveling-wave tuning capability and an optimized high energy laser double-pulse. This scheme has the potential for even shorter wavelength soft x-ray laser pumping.
A distributed model for continuous-wave erbium-doped fiber laser
2011
Abstract A distributed model of a continuous-wave erbium-doped fiber laser is discussed. The model is based on two contra-propagated traveling laser waves, and includes inhomogeneous pumping, excited state absorption at the pump and the laser wavelengths, amplified spontaneous emission and radial distribution of populations of erbium levels. It is shown that excited state absorption is a main limiting factor to the laser's efficiency. Moreover, consideration of radial distributions of erbium levels' populations in the model reduces laser efficiency and decreases optimal reflection of the laser output coupler. The modeling results are in excellent agreement with the experimental study on the…
High-efficiency Q-switched erbium fiber laser using a Bragg grating-based modulator
2002
Abstract In this work we analyze the behavior of an erbium-doped fiber laser which is based on a simple scheme. Excitation of the active medium is performed in the 980 nm pump band with a CW semiconductor laser source. Two fiber Bragg gratings acting as mirrors of the Fabry–Perot laser cavity were used. One of these gratings was mounted over a piezoelectric (PZT) element. By applying voltage pulses to the piezoelectric, the laser cavity was temporally modulated and Q-switched laser pulses up to 530 mW peak powers at 3 kHz were obtained. Typical laser emission of 2–3 μs temporal widths and 0.1 nm of optical bandwidth have been achieved when the system was operated at 18.5 kHz repetition rate…
Dual-kind Q-switching of erbium fiber laser
2014
Two different regimes of Q-switching in the same implementation of an actively Q-switched erbium-doped fiber laser are demonstrated. Depending on the active fiber length and repetition rate of an intracavity Q-cell (acousto-optic modulator), the laser operates either in the regime of common, rather long and low-power, pulses composed of several sub-pulses or in the one of very short and powerful stimulated Brillouin scattering-induced pulses. The basic physical reason of the laser system to oscillate in one of these two regimes is the existence or absence of CW narrow-line “bad-cavity” lasing in the intervals when the Q-cell is blocked.
Vibrational relaxation of Na2 molecules in a triplet state: collisional transfer from a mixed A 1Σu+ − b3Πu gateway level to long-lived levels of b 3…
1997
Abstract Collision-induced vibrational transitions of Na2 within the b 3Π1u state have been observed in a free jet expansion, using two CW dye lasers for the pump and probe steps. The b-state is entered by the pump laser using a low mixed ( A 1 Σ u + − b 3 Π u ) level as a gateway. The occupations of various v′,J′-levels are studied as functions of the position in the flowing gas. The radiative lifetimes of Na2 in levels which had been populated by vibrational relaxation are found to be very long (> 4 μs). Cross-sections are estimated for vibrationally inelastic collisions with Na and Ar atoms.
Electrostrictive limit in the detection of weak stimulated Raman signals in gases
1997
0377-0486; It is shown experimentally that, in stimulated Raman spectroscopy, electrostriction induced by the pump laser gives rise to a non-resonant signal detected on the probe laser. This phenomenon limits the detectivity of the experiment. A qualitative interpretation is given. (C) 1997 by John Wiley & Sons, Ltd.
Application of sol-gel and laser evaporation methods to obtain thin gas sensitive films
2005
New type resistive/capacitative gas sensitive structures were obtained by using a specially prepared substrate- glass, covered by thin conducting In/sub 2/O/sub 3/ layer, cutted into a comb teeth-type electrodes by help of laser beam. Such laser processed gap in the layer of conducting material was a prototype of excellent humidity sensor, especially at high values of relative humidity (RH). Different additional coatings onto a laser processed gap were examined for humidity sensing. Sol-gel, vacuum thermal evaporation and laser evaporation methods were used to obtain a thin layers of different materials.
Triple resonant four-wave mixing: A microwatt continuous-wave laser source in the vacuum ultraviolet region at 120 nm
2012
We present a vacuum ultraviolet laser source by four-wave mixing in mercury vapour based on solid-state laser systems. Maximum powers of 6μW were achieved with an increase of four orders of magnitude in efficiency.
Observability of the Risken–Nummedal–Graham–Haken instability in Nd:YAG lasers
2003
Multilongitudinal mode instability in ring Nd:YAG lasers is theoretically analyzed. After we review the way in which the standard two-level laser theory applies to this laser we extend the theoretical treatment to include transverse effects. We do this by taking into account the finite transverse section of the active medium and by assuming a Gaussian transverse distribution for the intracavity field. Finally we demonstrate that multimode emission develops whenever the intracavity field waist diameter is almost equal to the active rod diameter. We conclude that continuous-wave diode-pumped Nd:YAG lasers with low cavity losses are good candidates for the observation of the Risken–Nummedal–Gr…