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1.
A. Marcinkevičius V. Mizeikis S. Juodkazis S. Matsuo H. Misawa 《Applied Physics A: Materials Science & Processing》2003,76(2):257-260
We studied the peculiarities of femtosecond laser microfabrication in silica glass with a refractive index that did not exactly
match the value for which the focusing optics is designed. Spherical aberrations resulting from a small refractive index mismatch
were found to increase the size and distort the shape of photodamaged regions, thus reducing the spatial resolution of the
microfabrication. However, these undesirable effects can be minimized, providing that the focusing depth inside the glass
is not too large, and the laser intensity is kept close to the light-induced damage threshold.
Received: 3 December 2001 / Accepted: 11 April 2002 / Published online: 10 September 2002
RID="*"
ID="*"Corresponding author. Fax: +81-88/656-7598, E-mail: misawa@eco.tokushima-u.ac.jp 相似文献
2.
E. Majkova S. Luby R. Senderak Y. Chushkin M. Jergel I. Zergioti D. Papazoglou A. Manousaki C. Fotakis 《Applied Physics A: Materials Science & Processing》2003,76(5):763-766
The sub-picosecond laser microstructuring of multilayer gratings is presented in this paper. A micromachining system operating
with a 0.5 ps KrF laser at 248 nm was used to etch grating structures with a groove width of 1–2 μm in Mo/Si and Si/Mo multilayers.
Atomic force microscopy, scanning electron microscopy and X-ray reflectivity were used to characterize the microetched patterns.
The ω-scans around the 1st Bragg maximum show symmetric satellites up to 3rd order, with positions corresponding to the grating
period. The use of sub-picosecond laser pulses minimizes the thermally affected zone and enhances the quality of the etched
features. Short pulse laser processing is advantageous for the fabrication of high spatial resolution microstructures required
in X-ray optics.
Received: 21 May 2002 / Accepted: 19 August 2002 / Published online: 15 January 2003
RID="*"
ID="*"Corresponding author. Email: dpapa@iesl.forth.gr 相似文献
3.
We report the observation of light filaments produced by a picosecond laser pulse in the visible. The pulse trapped in the
filamentary mode experiences large-scale self-phase modulation, with almost 100-fold spectral broadening along with apparent
shortening of the leading edge. Spatial-temporal properties of the light filament reveal rather complex propagation dynamics.
Received: 7 August 2002 / Revised version: 12 September 2002 / Published online: 11 December 2002
RID="*"
ID="*"Corresponding author. Fax: +370-2/3660-06, E-mail: audrius.dubietis@ff.vu.lt 相似文献
4.
Modification of the fused silica glass network associated with waveguide fabrication using femtosecond laser pulses 总被引:1,自引:0,他引:1
J.W. Chan T.R. Huser S.H. Risbud D.M. Krol 《Applied Physics A: Materials Science & Processing》2003,76(3):367-372
Atomic-scale structural changes have been observed in the glass network of fused silica after modification by tightly focused
800-nm, 130-fs laser pulses at fluences between 5 and 200 J cm-2. Raman spectroscopy of the modified glass shows an increase in the 490 and 605-cm-1 peaks, indicating an increase in the number of 4- and 3-membered ring structures in the silica network. These results provide
evidence that densification of the glass occurs after exposure to fs pulses. Fluorescence spectroscopy of the modified glass
shows a broad fluorescence band at 630 nm, indicating the formation of non-bridging oxygen hole centers (NBOHC) by fs pulses.
Waveguides that support the fundamental mode at 633 nm have been fabricated inside fused silica by scanning the glass along
the fs laser beam axis. The index changes are estimated to be approximately 0.07×10-3.
Received: 17 December 2001 / Accepted: 9 July 2002 / Published online: 25 October 2002
RID="*"
ID="*"Corresponding author. Fax: +1-925/423-2463, E-mail: dmkrol@ucdavis.edu 相似文献
5.
Photofabrication of periodic microstructures in azodye-doped polymers by interference of laser beams 总被引:4,自引:0,他引:4
Volume holographic gratings and two-dimensional periodic microstructures in azodye-doped polymethylmethacrylate were fabricated,
respectively, by interference of two coherent beams of a femtosecond laser and by interference of three coherent beams of
a nanosecond laser. The dependence of the first-order Bragg diffraction efficiency and the photoinduced refractive-index modulation
of the gratings on the intensity of the writing light was investigated. The measurements of the absorption spectra before
and after irradiation with the writing light suggest that the photoinduced gratings were refractive-index-modulated gratings,
which arose from a photoinduced decomposition reaction of the azodye molecules through multiphoton absorption. In the experiments
involving the interference of three beams, the period of the two-dimensional periodic microstructures was changed by adjusting
the angle between the three writing beams.
Received: 10 July 2002 / Revised version: 5 September 2002 / Published online: 20 December 2002
RID="*"
ID="*"Corresponding author. Fax: +81-774/955206, E-mail: jhsi@photon.jst.go.jp 相似文献
6.
N. Yasumaru K. Miyazaki J. Kiuchi 《Applied Physics A: Materials Science & Processing》2003,76(6):983-985
We report observation of nanostructures formed on thin TiN and DLC films that were irradiated by 800- and 267-nm, femtosecond
(fs) Ti:sapphire laser pulses at an energy fluence slightly above the ablation threshold. On the ablated thin-film surfaces,
the linearly polarized fs pulses produce arrays of fine periodic structures that are almost oriented to the direction perpendicular
to the laser polarization, while the circularly polarized light forms fine-dot structures. The size of these surface structures
is 1/10–1/5 of the laser wavelength and decreases with a decrease in the laser wavelength.
Received: 3 September 2002 / Accepted: 4 September 2002 / Published online: 17 December 2002
RID="*"
ID="*"Corresponding author. Fax: +81-778/62-3306, E-mail: yasuma@fukui-nct.ac.jp 相似文献
7.
Random deflection of the white light beam during self-focusing and filamentation of a femtosecond laser pulse in water 总被引:1,自引:0,他引:1
W. Liu O. Kosareva I.S. Golubtsov A. Iwasaki A. Becker V.P. Kandidov S.L. Chin 《Applied physics. B, Lasers and optics》2002,75(4-5):595-599
Ti:sapphire femtosecond laser pulse filamentation in competition with optical breakdown in condensed matter is studied both
experimentally and numerically using water as an example. Strong random deflection and modulation of the supercontinuum under
tight focusing conditions were observed. They manifest the beginning of the filamentation process near the highly disordered
plasma created by optical breakdown at the geometrical focus.
Received: 13 June 2002 / Revised version: 16 August 2002 / Published online: 25 October 2002
RID="*"
ID="*"Corresponding author. Fax: +1-418/656-2623, E-mail: wliu@phy.ulaval.ca 相似文献
8.
V.G. Savitski A.M. Malyarevich K.V. Yumashev B.D. Sinclair A.A. Lipovskii 《Applied physics. B, Lasers and optics》2003,76(3):253-256
Diode-pumped Nd:YVO4 and Nd:KGW lasers passively Q-switched with PbS-quantum dot-doped phosphate glass were demonstrated. For the Nd:YVO4 laser, pulses 110 ns in duration with a 13% Q-switching efficiency were obtained. The absorption recovery time of the PbS-doped
glass was measured to be 27±4 ps. Some recommendations for more efficient use of PbS-doped glasses for Q-switching of diode-pumped
lasers are suggested on the basis of our analysis.
Received: 29 July 2002 / Revised version: 18 September 2002 / Published online: 12 February 2003
RID="*"
ID="*"Corresponding author. Fax: +375-17/232-6286, E-mail: savitski@eudoramail.com 相似文献
9.
Rapid formaldehyde monitoring in ambient air by means of mid-infrared cavity leak-out spectroscopy 总被引:1,自引:0,他引:1
H. Dahnke G. von Basum K. Kleinermanns P. Hering M. Mürtz 《Applied physics. B, Lasers and optics》2002,75(2-3):311-316
We report the spectroscopic detection of formaldehyde in ambient air using cavity leak-out spectroscopy, a cw variant of cavity
ring-down spectroscopy. This technique proved to be suitable for a real-time quantitative analysis of polluted air without
any preprocessing of the air sample. Using a tunable CO-overtone sideband laser for the λ=3 μm spectral region and a ring-down
cell with R=99.95% mirrors, we achieved a detection limit of 2 parts per billion formaldehyde in ambient air, corresponding
to a minimum detectable absorption coefficient of 7×10-9/cm (sampling time: 2 s). Calibration problems arising from the polarity of the molecule and due to HITRAN database uncertainties
are discussed.
Received: 28 March 2002 / Revised version: 7 June 2002 / Published online: 21 August 2002
RID="*"
ID="*"Corresponding author. Fax: +49-211/811-3121, E-mail: muertz@uni-duesseldorf.de 相似文献
10.
100-W average-power, high-energy nanosecond fiber amplifier 总被引:5,自引:0,他引:5
J. Limpert S. Höfer A. Liem H. Zellmer A. Tünnermann S. Knoke H. Voelckel 《Applied physics. B, Lasers and optics》2002,75(4-5):477-479
We report on the fiber-based amplification of a Q-switched Nd:YAG thin-disk laser. At repetition rates between 3 and 50 kHz
output powers up to 100 W are generated. Pulse energies up to 4 mJ, with diffraction-limited beam quality, are generated in
a 30-μm Yb-doped large-mode-area fiber, furthermore pulse energies up to 8 mJ are achieved from a multimode fiber amplifier.
Received: 8 May 2002 / Revised version: 10 July 2002 / Published online: 25 October 2002
RID="*"
ID="*"Corresponding author. Fax: +49-3641/65-7680, E-mail: Jens.Limpert@uni-jena.de 相似文献
11.
Internal modification of transparent materials such as glass can be carried out using multiphoton absorption induced by a femtosecond (fs) laser. The fs‐laser modification followed by thermal treatment and successive chemical wet etching in a hydrofluoric (HF) acid solution forms three‐dimensional (3D) hollow microstructures embedded in photosensitive glass. This technique is a powerful method for directly fabricating 3D microfluidic structures inside a photosensitive glass microchip. We used fabricated microchips, referred to as a nanoaquarium, for dynamic observations of living microorganisms. In addition, the present technique can also be used to form microoptical components such as micromirrors and microlenses inside the photosensitive glass, since the fabricated structures have optically flat surfaces. The integration of microfluidics and microoptical components in a single glass chip yields biophotonic microchips, in other words, optofluidics, which provide high sensitivity in absorption and fluorescence measurements of small volumes of liquid samples. 相似文献
12.
The progress in the development of a sensor for the detection of trace air constituents to monitor spacecraft air quality
is reported. A continuous-wave (cw), external-cavity tunable diode laser centered at 1.55 μm is used to pump an optical cavity
absorption cell in cw-cavity ringdown spectroscopy (cw-CRDS). Preliminary results are presented that demonstrate the sensitivity,
selectivity and reproducibility of this method. Detection limits of 2.0 ppm for CO, 2.5 ppm for CO2, 1.8 ppm for H2O, 19.4 ppb for NH3, 7.9 ppb for HCN and 4.0 ppb for C2H2 are calculated.
Received: 3 April 2002 / Revised version: 3 June 2002 / Published online: 21 August 2002
RID="*"
ID="*"Corresponding author. Fax: +1-202/994-5873, E-mail: Houston@gwu.edu 相似文献
13.
K. Wang A. Chelnokov S. Rowson J.-M. Lourtioz 《Applied Physics A: Materials Science & Processing》2003,76(7):1013-1016
We show the very particular behavior of focused-ion-beam etching in macroporous silicon. We demonstrate that, contrary to
bulk samples, a porous substrate allows extremely high-aspect-ratio patterns to be etched at submicrometer scales. Thanks
to the pre-introduced porosity, the secondary effects that limit the pattern depth in bulk-sample etching, namely the sputtered
material redeposition as well as the beam ‘self-focusing’ effects, are strongly reduced in a porous sample. In this case the
walls between the pores are sputtered in an almost independent way. The etching of deep and straight patterns is feasible.
Combined with photoelectrochemical etching that generates the initial macropores, three-dimensional (3D) lattices can be obtained,
as demonstrated by 3D photonic crystal fabrication.
Received: 21 August 2002 / Accepted: 21 August 2002 / Published online: 12 February 2003
RID="*"
ID="*"Corresponding author. Fax: +33-1/6915-6086, E-mail: wang@lps.u-psud.fr 相似文献
14.
E.C. Richard K.K. Kelly R.H. Winkler R. Wilson T.L. Thompson R.J. McLaughlin A.L. Schmeltekopf A.F. Tuck 《Applied physics. B, Lasers and optics》2002,75(2-3):183-194
We describe a near-infrared in situ tunable diode laser spectrometer developed for atmospheric measurements of CH4 in the upper troposphere and lower stratosphere (UT/LS). The instrument is designed to provide fast-response (0.5–1 Hz) measurements
and operate autonomously on the NASA WB-57F high-altitude aircraft. A single-mode InGaAsP distributed feedback laser diode
operating at 1.6537 μm scans continuously over the R(3) rotation–vibration transition in the 2ν3 band. We use a direct absorption technique incorporating a custom-designed long path length (252 m) low-volume (3.6 L) astigmatic
Herriott cell. The present detection sensitivity is 5×1010 molecules cm-3, corresponding to ∼20 ppbv in the UT/LS, with the main limit to instrument precision being background optical interference
fringes. In-flight performance is demonstrated by presentation of recent data.
Received: 25 January 2002 / Revised version: 5 April 2002 / Published online: 21 August 2002
RID="*"
ID="*"Corresponding author. Fax: +1-303/497-5373, E-mail: richard@al.noaa.gov 相似文献
15.
Calculation of the temperature and thermal expansion of a STM tip heated by a short laser pulse 总被引:1,自引:0,他引:1
A mathematical model for the calculation of the temperature field in a scanning tunneling microscope (STM) tip under laser
illumination is developed. The duration of the laser pulse is a few nanoseconds or shorter. A Gaussian distribution of the
laser light intensity in time and space is assumed. Two different mechanisms of tip heating are taken into account: 1. due
to an enhanced electric field on the tip; 2. due to heating of the side surface of the tip by the focused spot of laser light.
An average tip temperature is calculated using the heat conductivity equation. The enhanced electric field on the tip is calculated
by the method of boundary integral equations.
Received: 20 August 2002 / Revised version: 4 December 2002 / Published online: 19 March 2003
RID="*"
ID="*"Corresponding author. Fax: +49-2551/962-490, E-mail: sklein@fh-muenster.de 相似文献
16.
R.T. Wainner B.D. Green M.G. Allen M.A. White J. Stafford-Evans R. Naper 《Applied physics. B, Lasers and optics》2002,75(2-3):249-254
A handheld, battery-powered tunable-diode-laser sensor platform is described. The sensor is based on frequency modulation
(FM) spectroscopy using near-IR diode lasers and passive topographic backscatter from common environmental targets such as
buildings, ground and foliage. A specific application to the detection of methane using a 1.65-micron diode laser is described
in detail, showing a detection sensitivity sufficient to identify typical leaks from buried residential natural gas service
lines at stand-off distances up to 30 m. Signal and noise sources are analyzed in detail, along with laboratory and field-test
data, including known service leaks.
Received: 15 April 2002 / Revised version: 4 June 2002 / Published online: 21 August 2002
RID="*"
ID="*"Corresponding author. Fax: +1-978/689-3232, E-mail: allen@psicorp.com 相似文献
17.
A.S. Grabtchikov A.N. Kuzmin V.A. Lisinetskii V.A. Orlovich A.A. Demidovich M.B. Danailov H.J. Eichler A. Bednarkiewicz W. Strek A.N. Titov 《Applied physics. B, Lasers and optics》2002,75(6-7):795-797
We present a diode-pumped Yb:KYW microchip laser. The passive Q-switchedand CW regimes of operation for the Yb:KYW microchip
laser have been investigated. An efficiency for CW operation of up to 10% with regard to incident pump has been obtained.
Raman self-frequency conversion in the Q-switched regime has been observed.
Received: 27 May 2002 / Revised version: 4 July 2002 / Published online: 15 November 2002
RID="*"
ID="*"Corresponding author. Fax: +375-17/2840-879, E-mail: asg@dragon.bas-net.by 相似文献
18.
We have developed a tunable intense narrow-band 285 nm light source based on frequency doubling of 570 nm light in BBO. At
input powers of 840 mW (including 130 mW used for locking purposes) we generate 99 mW UV radiation with an intensity profile
suitable for laser-cooling experiments. The light is used for laser cooling of neutral magnesium atoms in a magneto-optical
trap (MOT). We capture about 5×106 atoms directly from a thermal beam and find that the major loss mechanism of the magnesium MOT is a near-resonant two-photon
ionization process.
Received: 15 February 2002 / Revised version: 13 August 2002 / Published online: 11 December 2002
RID="*"
ID="*"Corresponding author. Fax: +45-4588/7762, E-mail: dnm@mic.dtu.dk Present address: Mikroelektronik Centret, Technical
University of Denmark, Orsteds Plads, Bldg. 345 East, 2800 Kgs. Lyngby, Denmark 相似文献
19.
A. Camposeo F. Fuso E. Arimondo A. Tuissi 《Applied Physics A: Materials Science & Processing》2003,76(6):927-934
NiTi films deposited by pulsed laser ablation on Si/SiO2 are shown to exhibit structural and functional properties related to the shape-memory effect. Film characterization suggests
that relevant temperatures for the solid-to-solid transformation responsible for the shape memory are in substantial agreement
with those of the bulk target material, demonstrating a good congruency of the deposition process. Besides the technological
interest for this class of thin films, our findings point out the suitability of laser ablation for metal alloy deposition.
An investigation based on in situ ion-mass spectroscopy and covariance mapping analysis allows us to determine the main vapor-phase
processes leading to the formation of stoichiometric clusters expected to play a relevant role in assisting the growth of
NiTi thin films.
Received: 6 August 2001 / Accepted: 11 April 2002 / Published online: 4 November 2002
RID="*"
ID="*"Corresponding author. Fax: +39-50/2214-333, E-mail: fuso@df.unipi.it 相似文献
20.
J. Botero M.A. Cirone J.P. Dahl F. Straub W.P. Schleich 《Applied physics. B, Lasers and optics》2003,76(2):129-133
We express the commutation relation between the operators of the momentum and the radial unit vectors in D dimensions in differential
and integral form. We connect this commutator with the quantum fictitious potential emerging in the radial Schr?dinger equation
of an s-wave.
Received: 6 August 2002 / Revised version: 30 October 2002 / Published online: 26 February 2003
RID="*"
ID="*"Corresponding author. Fax: +49-731/502-3086, E-mail: markus.cirone@physik.uni-ulm.de 相似文献