共查询到20条相似文献,搜索用时 31 毫秒
1.
S. Chénais F. Druon F. Balembois G. Lucas-Leclin P. Georges A. Brun M. Zavelani-Rossi F. Augé J.P. Chambaret G. Aka D. Vivien 《Applied physics. B, Lasers and optics》2001,72(4):389-393
We demonstrate that Yb-doped Ca4GdO(BO3)3 (GdCOB) crystals are suitable for the development of high-power diode-pumped lasers emitting at around 1.04 μm. A 15%-doped
Yb:GdCOB crystal was longitudinally pumped with a cw fiber-coupled diode emitting 10 W at 976 nm. While 5.2 W of diode power
was absorbed, we obtained 3.2 W of 1043-μm laser light, with a beam quality factor M2 equal to 3, and 2.5 W in a diffraction-limited beam. Furthermore, the laser is continuously tunable between 1018 and 1086 nm.
Thermal effects have been investigated with a Shack–Hartmann wavefront analyser: although thermal lensing is not negligible,
it does not affect the performance of the laser with the resonator design we used.
Received: 1 August 2000 / Revised version: 18 September 2000 / Published online: 21 February 2001 相似文献
2.
Laser-diode-pumped Cr4+, Nd3+:YAG self-Q-switched laser with high repetition rate and high stability 总被引:4,自引:0,他引:4
A diode end-pumped self Q-switched Cr4+, Nd3+: YAG laser was established with 30-ns pulse width (FWHM) and 0.5-μJ pulse energy output. In normal pulse pumping operation,
the lasing threshold changed greatly from 122 mJ to 2.4 mJ as the pump pulse frequency varied from 1 Hz to 500 Hz due to pumping-induced
thermal effect. A pre-pumping method was proposed and the change of the lasing threshold was reduced; programmable Q-pulse
output with maximum frequency of 16 kHz and high stability was achieved.
Received: 16 January 2001 / Revised version: 21 May 2001 / Published online: 19 September 2001 相似文献
3.
We present the first photoacoustic spectrometer for gas sensing employing both the fundamental and the frequency-doubled radiation
of a continuously tunable high-pressure CO2 laser with room temperature operation. A quasi-phase-matched diffusion-bonded GaAs crystal is used in the system for second-harmonic
generation. A pulsed photoacoustic detection scheme with a non-resonant cell, equipped with an 80-microphone array, is employed.
The wide continuous tuning range in the fundamental (9.2–10.7 μm) and the frequency-doubled (4.6–5.35 μm) regimes, together
with the narrow linewidth of 540 MHz (0.018 cm-1) for the 10-μm region and of 1050 MHz (0.0315 cm-1) for the 5-μm region, allow the measurement of gas mixtures, individual species and isotope discrimination. This is illustrated
with measurements on NO and CO2. The measured isotope ratio 15
NO/14
NO=(3.58±0.55)×10-3 agrees well with the literature (3.700×10-3) and demonstrates the good selectivity of the system.
Received: 30 April 2002 / Revised version: 10 June 2002 / Published online: 2 September 2002
RID="*"
ID="*"Corresponding author. Fax: +41-1/633-1077, E-mail: sigrist@iqe.phys.ethz.ch 相似文献
4.
S.T. Sanders 《Applied physics. B, Lasers and optics》2002,75(6-7):799-802
A swept-wavelength source is created by connecting four elements in series: a femtosecond fiber laser at 1.56 μm, a non-linear
fiber, a dispersive fiber and a tunable spectral bandpass filter. The 1.56-μm pulses are converted to super-continuum (1.1–2.2 μm)
pulses by the non-linear fiber, and these broadband pulses are stretched and arranged into wavelength scans by the dispersive
fiber. The tunable bandpass filter is used to select a portion of the super-continuum as a scan-wavelength output. A variety
of scan characteristics are possible using this approach. As an example, an output with an effective linewidth of approximately
1 cm-1 is scanned from 1350–1550 nm every 20 ns. Compared to previous scanning benchmarks of approximately 1 nm/μs, such broad,
rapid scans offer new capabilities: a gas sensing application is demonstrated by monitoring absorption bands of H2O, CO2, C2H2 and C2H6O at a pressure of 10 bar.
Received: 5 August 2002 / Revised version: 23 September 2002 / Published online: 22 November 2002
RID="*"
ID="*"Corresponding author. Fax: +1-608/265-2316, E-mail: ssanders@engr.wisc.edu 相似文献
5.
We report on a passively Q-switched diode-pumped Nd:YVO4 laser polarized along the a axis (corresponding to the smallest value of emission cross section at 1064 nm), generating 157-μJ
pulses with 6.0-ns time duration (>20 kW peak power) and 3.6 W of average power at 1064 nm with good beam quality (M2<1.4). The selection of the polarization was performed by a novel technique relying on the birefringence of the laser crystal
and on the misalignment sensitivity of the resonator.
Received: 30 September 2002 /
Revised version: 22 November 2002 / Published online: 19 March 2003
RID="*"
ID="*"Corresponding author. Fax: +39-382/422583, E-mail: agnesi@ele.unipv.it 相似文献
6.
V.G. Savitski N.N. Posnov P.V. Prokoshin A.M. Malyarevich K.V. Yumashev M.I. Demchuk A.A. Lipovskii 《Applied physics. B, Lasers and optics》2002,75(8):841-846
Passive mode locking and saturable absorber Q-switching of neodymium lasers at 1.3 μm with PbS-doped phosphate glasses are
demonstrated. Q-switched pulses of 120 ns (0.1 μJ) in duration (energy) and the average output power of 3 mW from a quasi-cw
diode-pumped Nd3+:KGW laser and ultrashort pulses of a maximum of 250 μJ in energy and 150 ps in duration from a Nd3+:YAP laser were obtained. The bleaching decay rate of the samples was found to increase with the Quantum Dot’s size decreasing
due to the enhancement of quantum confinement effects for smaller dots and stronger overlapping of the electron and trap state
wave functions.
Received: 23 January 2002 / Revised version: 2 April 2002 / Published online: 20 December 2002
RID="*"
ID="*"Corresponding author. Fax: +375-17/232-6286, E-mail: savitski@eudoramail.com 相似文献
7.
Nonlinear absorption properties of Co2+:MgAl2O4 crystal 总被引:2,自引:0,他引:2
K.V. Yumashev I.A. Denisov N.N. Posnov P.V. Prokoshin V.P. Mikhailov 《Applied physics. B, Lasers and optics》2000,70(2):179-184
The differential absorption spectra of Co2+: MgAl2O4 (MALO) crystal were studied with a picosecond pump-probe technique under excitation of the 4A2→4T1(4P) and 4A2→4T1(4F) transitions of the tetrahedral Co2+ ion. The difference spectra of stimulated emission (SE) and excited state absorption (ESA) were derived from the measured
differential absorption spectra. The 4T1(4P)→4A2 SE band around 660 nm was observed. The ESA bands were assigned to the 4T2→4T1(4P) transition and to transitions from the thermally populated 2E(2G) excited state to doublet levels arising from the 2F free-ion level of the tetrahedrally coordinated Co2+ ion. Absorption saturation measurements were performed at 1.34 μm and 1.54 μm. Passive Q-switching of 1.34-μm Nd3+:YAlO3 and 1.54-μm Er3+:glass lasers was realized using the Co2+:MALO crystal as saturable absorber. The Q-switched laser pulses of 38 ns (110 ns) in duration and up to 2.7 mJ (10 mJ) in
energy at 1.54 μm (1.34 μm) were obtained.
Received: 3 March 1999 / Revised version: 30 June 1999 / Published online: 30 November 1999 相似文献
8.
4 I13/2 and 4I11/2 of erbium is measured in a fluorozirconate fiber in the wavelength range 780–840 nm. Using a pump- and probe-beam technique
and choosing the pump wavelength such that the perturbation by pump ESA is minimized in the measurement, it is possible to
determine the effective ESA cross sections, despite the fact that the excitation is distributed among two metastable levels.
The derived ESA cross sections at 793 nm of 1.4×10-21 cm2 from the 4I13/2 level and less than 0.1×10-21 cm2 from the 4I11/2 level are in reasonable agreement with former results obtained from a rate-equation simulation of the erbium 3-μm laser.
The corresponding ESA spectrum under 3-μm lasing conditions is derived. At the strongest ground-state absorption around 799 nm,
decreasing ESA from the 4I13/2 level is compensated by increasing ESA from the 4I11/2 level, i.e., ESA losses cannot be avoided when pumping around 800 nm. This result is of relevance for possible high-power
diode pumping of an erbium 3-μm double-clad fiber laser.
Received: 20 January 1998 相似文献
9.
Continuous-wave tunable Cr2+:ZnS laser 总被引:1,自引:0,他引:1
I.T. Sorokina E. Sorokin S. Mirov V. Fedorov V. Badikov V. Panyutin A. Di Lieto M. Tonelli 《Applied physics. B, Lasers and optics》2002,74(6):607-611
We report the first continuous-wave tunable over ∼280 nm around 2.3 μm room-temperature operation of a chemical vapor transport-grown
and diffusion-doped Cr2+:ZnS laser, pumped by a Co:MgF2 laser at 1.67 μm and generating over 100 mW of output power at 16% slope efficiency. The self-consistent results of the laser
and spectroscopic analysis demonstrate a large potential of this crystal as an active medium for diode-pumped tunable mid-infrared
sources.
Received: 7 January 2002 / Revised: 14 March 2002 / Published online: 2 May 2002 相似文献
10.
J.C. Bermudez Gutierrez M.J. Damzen V.J. Pinto-Robledo A.V. Kir’yanov J.J. Soto-Bernal 《Applied physics. B, Lasers and optics》2003,76(1):13-16
The analysis of compact CW diode-side-pumped grazing-incidence-geometry Nd:YVO4 laser designs is presented. An output power of 5 W (λ=1064 nm) was produced at 17 W of diode pump (conversion efficiency
of 30%) in single transverse TEM00 mode operation at high laser beam quality (Mx
2≈1.05 and My
2≈1.01). The resonator geometry was analyzed by applying generalized 4×4 matrix modeling of the spatial mode size, including
the impact on the laser operation of cavity astigmatism and a thermal lens in the laser slab. The simplicity and compactness
of the laser cavities allow their use for technological applications.
Received: 31 July 2002 / Published online: 22 January 2003
RID="*"
ID="*"Corresponding author. Fax: +44-20/7594-7744, E-mail: m.damzen@ic.ac.uk 相似文献
11.
A.R. Präg F. Löwenthal R. Tommasini J.E. Balmer 《Applied physics. B, Lasers and optics》1998,66(5):561-566
2 . By using a 0.7% prepulse that precedes the main pulse by 5 ns and applying a total pump energy of 100 J or less, the J=0-1
lasing is at least one order of magnitude higher than the non-lasing background. For the 32.6-nm line of Ti, the 25.5-nm line
of Fe, and the 23.1-nm line of Ni, gain coefficients of (±) 4.20.4cm-1, (±) 3.90.3cm-1, and (±) 3.60.6cm-1, respectively, were measured for 2.4-cm-long curved targets, resulting in gain–length products of ∼10. Angle-resolved spectra
indicate a beam divergence of 3 mrad (FWHM), typically. The space-resolved spectra show that the J=0-1 lasing lines are emitted
from an approximately 60-μm-wide (FWHM) plasma region, whereas the nearby continuum emission is produced in a considerably
broader plasma region of ∼250 μm. Lasing at 25.5 nm in neon-like iron was observed at a pump power as low as 180 GW (∼9 TW/cm2), with, however, considerable shot-to-shot scatter in the absolute laser output.
Received: 5 September 1997/Revised version: 10 November 1997 相似文献
12.
S.A. Starostin I.V. Kochetov P.J.M. Peters Y.B. Udalov W.J. Witteman A.P. Napartovich 《Applied physics. B, Lasers and optics》2000,71(4):491-494
The performance of a RF excited cw atomic xenon laser at wavelengths of 2.03 μm and 2.65 μm was studied theoretically and
experimentally as a function of electrode distance. Results for inter-electrode distances from 2 to 0.25 mm are presented.
A high pumping rate resulted in strong 40 mW cw amplified spontaneous emission at 2.65 μm wavelength from the configuration
with the smallest distance of 0.25 mm between the electrodes. The maximum laser output of 2.7 W (0.24 W/cm3) was obtained with an active medium volume of 2×15×370 mm3 whereas the maximum specific output of 1.9 W/cm3 was received for an active medium volume of 0.25×2.25×370 mm3. A fluid model of the RF discharge was developed to analyze the laser behavior for different distances between the electrodes.
Received: 30 November 1999 / Revised version: 21 April 2000 / Published online: 6 September 2000 相似文献
13.
2 and two diode lasers as pump sources are presented. A single-mode Fabry–Pérot-type tunable diode laser (TDL) and an external-cavity
diode laser (ECL) were combined to generate radiation in the mid-infrared region near 7.2 μm. With a TDL at a wavelength of
approximately 1290 nm and an ECL emitting between 1504 and 1589 nm it was possible to carry out spectroscopic experiments
concerning SO2 at five different phasematching points between 1350 and 1400 cm-1 by fixing the wavelength of one pump laser and tuning the wavelength of the other. With an input power of 8 mW for the single-mode
Fabry–Pérot-type diode laser and 6 mW for the external-cavity laser an output power of about 10 nW was generated. Using the
tuning capabilities of the external-cavity laser a spectral region up to 5 cm-1 could be covered within one scan. Measurements of SO2 absorption lines at low pressure demonstrate the high-resolution features of the spectrometer. Moreover, these data provide
new direct experimental phasematching data for the rarely investigated spectral region at 7.2 μm.
Received: 27 October 1997/Revised version: 8 May 1998 相似文献
14.
A.V. Podlipensky K.V. Yumashev N.V. Kuleshov H.M. Kretschmann G. Huber 《Applied physics. B, Lasers and optics》2003,76(3):245-247
Spectroscopic data of a V3+:YAG passive Q-switch crystal were measured. The absorption recovery time was determined to be of 37±7 ns and the ground state
absorption cross section was estimated to be 0.7×10-18 cm2 at 1.44 μm and 3.5×10-18 cm2 at 1.34 μm. Passively Q-switched operation of diode pumped 1.44 μm and 1.3 μm Nd:YAG lasers was demonstrated using this crystal
as saturable absorber. Average output powers of 1.42 W (1.44 μm) and 1.56 W (1.34 μm) and pulse energies of 24 μJ (1.44 μm)
and 25 μJ (1.34 μm) were observed, respectively.
Received: 19 August 2002 / Published online: 12 February 2003
RID="*"
ID="*"Corresponding author. Fax: +49-40/42838-6281, E-mail: kretschmann@physnet.uni-hamburg.de 相似文献
15.
The possible construction of a self-contained and compact pulsed chemical HF-laser based on an auto-wave photon-branched chain
reaction initiated in a gaseous disperse medium composed of H2-F2-O2-He and Al particles by focused external IR radiation is theoretically substantiated. It is shown that an autonomous system
and minimization of the parameters of the main pulsed HF-laser units are achievable due to both the effect of ignition of
the laser-chemical reaction in an auto-wave regime under the condition of external beam focusing and the effect of a huge
laser energy gain of 1011. These effects provide strong reduction of the input pulse energy necessary for initiation up to ∼10-8 J, and make it possible to construct a self-contained laser with kilojoule output energy, which can be initiated by a small
submicrojoule master oscillator powered by an accumulator. Due to an increase in the general pressure of working gases up
to P=2.3 bar and optimization of the parameters of the dispersed component (Al particles with radius r0=0.09 μm and concentration N0=1.4×109 cm-3) and the composition of the working mixture, the HF-laser system will ensure an output energy up to ∼1.5 kJ in a pulse from
the rather small volume of ∼2 L of the active medium.
Received: 18 April 2000 / Revised version: 21 August 2000 / Published online: 8 November 2000 相似文献
16.
Ito S. Ishikawa H. Miura T. Takasago K. Endo A. Torizuka K. 《Applied physics. B, Lasers and optics》2003,76(5):497-503
We present a 7-TW Ti:sapphire laser system operating at 50 Hz for laser Compton femtosecond X-ray generation. This laser system
delivers 8.4 W of average output power at a repetition rate of 50 Hz with a pulse width of 24 fs. It demonstrates successful
management using a dynamically stable resonator in the regenerative amplifier and compensation for thermal lensing by a convex
mirror in a ring-type four-pass power amplifier. We also present the results of closed-loop corrections for distorted wavefronts
of amplified and compressed laser pulses, using an adaptive optical system consisting of a Shack–Hartmann-type wavefront sensor
and a deformable mirror. This closed-loop correction results in dramatic improvements, reducing wavefront distortions below
0.05 λ rms.
Received: 31 October 2002 / Revised version: 3 March 2003 / Published online: 5 May 2003
RID="*"
ID="*"Corresponding author. Fax: +81-298/61-3349, E-mail: ito@festa.or.jp 相似文献
17.
L.E. Batay A.A. Demidovich A.N. Kuzmin A.N. Titov M. Mond S. Kück 《Applied physics. B, Lasers and optics》2002,75(4-5):457-461
A new laser medium – Yb,Tm:KY(WO4)2 – for diode pumped solid state laser applications operating around 1.9 to 2.0 μm has been investigated and the main laser
characteristics are presented. Diode pumping at 981 nm and around 805 nm was realised. For 981-nm pumping, the excitation
occurs into Yb3+ ions followed by an energy transfer to Tm3+ions. A slope efficiency of 19% was realised. For pumping around 805 nm, the excitation occurs directly into the Tm3+ ions. Here a maximum slope efficiency of 52%, an optical efficiency of 40%, and output powers of more than 1 W were realised.
Using a birefringent quartz plate as an intracavity tuning element, the tunability of the Yb,Tm:KY(WO4)2 laser in the spectral range of 1.85–2.0 μm has been demonstrated. The possibility of laser operation in a microchip cavity
configuration for this material has also been shown.
Received: 12 March 2002 / Revised version: 20 May 2002 / Published online: 25 September 2002
RID="*"
ID="*"Corresponding author. Fax: +49-531/592-4116, E-mail: stefan.kueck@ptb.de 相似文献
18.
M. Jackson E.M. Telles M.D. Allen K.M. Evenson 《Applied physics. B, Lasers and optics》2001,72(7):815-818
A significantly improved far-infrared laser has been used to generate optically pumped laser emissions from 26 to 150 μm for
CD3OH. Using an X–V-pumping geometry, several new laser emissions have been found for CD3OH. In addition, an increase in power, by factors from 10 to 1000, for many of the previously known shorter-wavelength laser
lines, below 100 μm, has been observed. Frequency measurements for several lines have also been performed and have been reported
to a fractional uncertainty up to ±2×10-7, permitting the spectroscopic assignment of the laser transition. One of the frequency-measured lines, 44.256 μm observed
using the 10R34 pump, has confirmed the assignment of the previously reported FIR emission (n,K;J)=(1,7;20)?(0,8;20)A in the
ground vibrational state.
Received: 26 October 2000 / Published online: 7 February 2001 相似文献
19.
M. Stanislawki J. Meister T. Mitra M.M. Ivanenko K. Zanger P. Hering 《Applied physics. B, Lasers and optics》2001,72(1):115-120
The Er:YAG and the CO2 laser are competitors in the field of hard tissue ablation. The use of Er:YAG lasers (2.94 μm, pulse length
L of 100 to 200 μs) show smaller areas of thermal defects then ‘‘superpulsed’’ CO2 lasers with pulse lengths of approximately 100 μs. Only the development of a Q-switched CO2 laser (9.6 μm, τL=250 ns) allowed for similar results. In this paper new results for the Er:YAG and the Q-switched CO2 laser under the influence of water spray will be presented. Several parameters are of special interest for these investigations:
the specific ablation energy, which shows a minimum for the CO2 laser at an energy density of 9 J/cm 2 and a broad shallow minimum in the range of 10 to 70 J/cm2 for the Er:YAG laser, and comparison of the cut-shape and depth. Surface effects and cutting velocity are discussed based
on SEM pictures.
Received: 19 July 2000 / Revised version: 1 November 2000 / Published online: 30 November 2000 相似文献
20.
V.G. Shcherbitsky S. Girard M. Fromager R. Moncorgé N.V. Kuleshov V.I. Levchenko V.N. Yakimovich B. Ferrand 《Applied physics. B, Lasers and optics》2002,74(4-5):367-374
A rigorous approach taking into account both the temporal and spatial distributions of the pulsed probe beam used for transmission
measurements of solid-state saturable absorbers is applied to characterise these absorbers accurately. The use of this method
can significantly influence the resulting value for the ground-state absorption cross section. It also permits us to avoid
the introduction of an artificial excited-state absorption in systems where, according to energy-level diagrams, no such loss
should occur. This is illustrated in the case of passive Q-switchers for 1.5-μm lasers such as Co2+-doped LaMgAl11O19 and MgAl2O4 and Co2+- or Cr2+-doped ZnSe and ZnS.
Received: 21 November 2001 /
Revised version: 22 January 2002 / Published online: 14 March 2002 相似文献