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1.
Portable difference-frequency laser-based cavity leak-out spectrometer for trace-gas analysis 总被引:1,自引:0,他引:1
We report a portable mid-infrared spectrometer for trace-gas analysis which is based on an all-solid-state difference-frequency-generation
laser. The spectrometer provides in situ absorption path lengths of more than 3 km by means of the cavity leak-out method,
a cw variant of the cavity ring-down technique. The design, performance, and application of this spectrometer are presented.
The light source utilizes difference-frequency generation in a periodically poled lithium niobate (PPLN) crystal pumped by
two single-frequency solid-state lasers. A maximum power of 27 μW in the wavelength region near 3.3 μm is achieved using a
pump power of 20 mW at 808 nm, a signal power of 660 mW at 1064 nm, and a 50-mm-long PPLN crystal. This corresponds to a conversion
efficiency of 0.42 mW/(W2 cm). We demonstrate that this portable laser system is suitable as a light source in a cavity leak-out spectrometer. We achieved
a minimum detectable absorption coefficient of 1×10-8/cm (integration time: 2 s), corresponding, for example, to a detection limit of 1 part per billion ethane. This compact trace-gas
analyzer with high sensitivity and specificity is promising for various environmental and medical applications.
Received: 8 April 2002 / Revised version: 28 May 2002 / Published online: 21 August 2002
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ID="*"Corresponding author. Fax: +49-211/811-3121, E-mail: muertz@uni-duesseldorf.de 相似文献
2.
A compact, diode-based difference-frequency laser system combined with a photoacoustic detection scheme is presented for trace-gas
sensing. It features a broad, continuous tuning range (3.2–3.7 μm), a narrow line width (154 MHz), and room-temperature operation,
and thus allows numerous gas species to be measured both isolated and in mixtures of different gases. Several trace-gas species
of environmental interest were detected, and gas mixtures were analysed. The detection limits are in the low-ppmV range, e.g.
1.3 ppmV for methane, 1.8 ppmV for ethane, and 1.2 ppmV for hydrogen chloride.
Received: 10 April 2002 / Revised version: 5 June 2002 / Published online: 12 September 2002
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ID="*"Corresponding author. Fax: +41-1/633-1077, E-mail: Sigrist@iqe.phys.ethz.ch 相似文献
3.
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
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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
4.
T.J. Kulp S.E. Bisson R.P. Bambha T.A. Reichardt U.-B. Goers K.W. Aniolek D.A.V. Kliner B.A. Richman K.M. Armstrong R. Sommers R. Schmitt P.E. Powers O. Levi T. Pinguet M. Fejer J.P. Koplow L. Goldberg T.G. McRae 《Applied physics. B, Lasers and optics》2002,75(2-3):317-327
Quasi-phase-matched (QPM) materials allow the generation of spectroscopically useful infrared radiation in an efficient and
broadly tunable format. Here, we describe several applications of QPM-based light sources to remote and local chemical sensing.
The remote systems are gas imagers that employ a fiber-pumped continuous-wave optical parametric oscillator or a microlaser-pumped,
diode-seeded optical parametric amplifier as the illumination source. Technology described for local sensing includes a cavity
ring down spectrometer that employs a novel optical parametric generator–amplifier to achieve ≥350 cm-1 of contiguous tuning and a long-wave infrared light source based on QPM GaAs. In each case the use of QPM materials in conjunction
with effective pump sources instills simplicity and ruggedness into the sensing systems.
Received: 15 April 2002 / Revised version: 6 June 2002 / Published online: 12 September 2002
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ID="*"Corresponding author. Fax: +1-925/294-2595, E-mail: tjkulp@sandia.gov
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ID="**"Present address: Corning Inc., Corning, NY 14831, USA
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ID="*"Present address: Corning Inc., Corning, NY 14831, USA
RID="**"
ID="**"Present address: Blue Leaf Networks, Sunnyvale, CA 94086, USA
RID="***"
ID="***"Present address: Sandia National Laboratories, Albuquerque, NM 87185, USA 相似文献
5.
V.S. Yakovlev P. Dombi G. Tempea C. Lemell J. Burgdörfer T. Udem A. Apolonski 《Applied physics. B, Lasers and optics》2003,76(3):329-332
Compressing pulses of a mode-locked extended-cavity Ti:sapphire laser using a standard single-mode fiber and tilted-front-interface
chirped mirrors yields phase-stabilized 4-fs, 3-nJ light pulses at the full, 24-MHz, repetition rate. The demonstrated source
paves the way towards exploring interactions sensitive to the carrier-envelope-offset phase, such as, for example, photoemission
from solid targets at moderate intensities (∼1012 W/cm2).
Received: 13 December 2002 / Published online: 26 February 2003
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ID="*"Corresponding author. Fax: +43-1/58801-38799, E-mail: apolonski@tuwien.ac.at 相似文献
6.
T. Ohtsubo T. Azuma M. Takaura T. Higashiguchi S. Kubodera W. Sasaki 《Applied Physics A: Materials Science & Processing》2003,76(2):139-141
We have demonstrated the non-thermal removal of oxygen atoms from an oxidized silicon surface (SiO2) on a silicon wafer by the use of a low-power (0.3 mW cm-2) incoherent vacuum ultraviolet (VUV) light source at 126 nm. X-ray photoelectron spectroscopy (XPS) has shown that a maximum
Si concentration of 80% appears at the surface after a 20-h irradiation with 9.8 eV photons, as a result of oxygen removal
from the SiO2 matrix. The surface morphology, however, indicates no damage or melting on the surface even after the irradiation.
Received: 15 April 2002 / Accepted: 17 April 2002 / Published online: 10 September 2002
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ID="*"Permanent address: Nano-Tech Photon Inc., Shimotomita 4132-1, Shintomi, Miyazaki, 889-1404, Japan
RID="**"
ID="**"Corresponding author. Fax: +81-985/583-899, E-mail: kubodera@opt.miyazaki-u.jp 相似文献
7.
A.G. Berezin O.V. Ershov A.I. Nadezhdinskii 《Applied physics. B, Lasers and optics》2002,75(2-3):203-214
The goal of the present paper was to develop an experimental technique to detect trace concentrations of complex molecules
in the atmosphere using near-IR diode lasers. Ethanol and propane were chosen as model species. New optical, hardware, instrument-operation-mode
and data-processing approaches for detection of trace complex molecules were developed. Different physical processes limiting
the sensitivity of trace molecule detection were considered and solutions were developed to reduce the influence of these
mechanisms on instrument operation. An absorption sensitivity of αmin=2.5×10-5 for 4.5 ms measurement time was achieved, which is comparable with the sensitivity of “small” molecule detection. The first
results utilizing this technique for in-field monitoring of trace complex molecules are presented.
Received: 25 April 2002 / Revised version: 29 May 2002 / Published online: 21 August 2002
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ID="*"Corresponding author. Fax: +7-095/135-8281, E-mail: anber@nsc.gpi.ru 相似文献
8.
Spectroscopic sensing of gases can be performed with high sensitivity and photometric precision by cavity ringdown (CRD) absorption
spectroscopy. Our cavity ringdown spectrometer incorporates continuous-wave (cw) tunable diode lasers, fibre-optic coupling
and standard photonics and optical telecommunications components. It comprises a rapidly swept optical cavity in a single-ended
optical heterodyne transmitter–receiver configuration, enabling optical absorption of gases to be recorded either as single-frequency
scanned spectra or as simultaneous, multi-wavelength tailored spectra. By measuring weak near-infrared rovibrational spectra
of carbon dioxide gas (CO2), with high resolution in the vicinity of 1.53 μm, we have realised a noise-limited absorption sensitivity of 2.5×10-9 cm-1 Hz-1/2. Analytical sensitivity limits (both actual and projected) and prospective gas-diagnostic applications are discussed. Our
approach to cw-CRD spectroscopy offers high performance in a relatively simple, low-cost, compact instrument that is amenable
to chemical analysis of trace gases in medical, agricultural, industrial and environmental situations.
Received: 16 May 2002 / Revised version: 3 June 2002 / Published online: 21 August 2002
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ID="*"Corresponding author. Fax: +61-2/9850-8313, E-mail: brian.orr@mq.edu.au 相似文献
9.
S. Pereira J.E. Sipe M.A. Bader S. Soria G. Marowsky 《Applied physics. B, Lasers and optics》2002,75(6-7):635-640
We theoretically demonstrate the feasibility of using a grating-waveguide structure (GWS) as a loss-tolerant, narrow-band
reflector in the UV. We simulate device operation using a Green-function technique. Our numerical simulations indicate that
a GWS with a 25-nm grating can be used as a 95% reflector for 157-nm light, even in the presence of intensity absorptions
of 50 cm-1.
Received: 23 July 2002 / Published online: 22 November 2002
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ID="*"Corresponding author. Fax: +49-551/5035-99, E-mail: mbader@llg.gwdg.de 相似文献
10.
A portable modular gas sensor for measuring the 13C/12C isotopic ratio in CO2 with a precision of 0.8‰(±1σ) was developed for volcanic gas emission studies. This sensor employed a difference frequency generation (DFG)-based spectroscopic
source operating at 4.35 μm (∼2300 cm-1) in combination with a dual-chamber gas absorption cell. Direct absorption spectroscopy using this specially designed cell
permitted rapid comparisons of isotopic ratios of a gas sample and a reference standard for appropriately selected CO2 absorption lines. Special attention was given to minimizing undesirable precision degrading effects, in particular temperature
and pressure fluctuations.
Received: 16 April 2002 / Revised version: 28 May 2002 / Published online: 21 August 2002
RID="*"
ID="*"Corresponding author. Fax: +1-713/5245237, E-mail: fkt@rice.edu 相似文献
11.
Sensitive absorption measurements in the near-infrared region using off-axis integrated-cavity-output spectroscopy 总被引:3,自引:0,他引:3
A novel instrument that employs a high-finesse optical cavity as an absorption cell has been developed for sensitive measurements
of gas mixing ratios using near-infrared diode lasers and absorption-spectroscopy techniques. The instrument employs an off-axis
trajectory of the laser beam through the cell to yield an effective optical path length of several kilometers without significant
unwanted effects due to cavity resonances. As a result, a minimum detectable absorption of approximately 1.4×10-5 over an effective optical path of 4.2 km was obtained in a 1.1-Hz detection bandwidth to yield a detection sensitivity of
approximately 3.1×10-11 cm-1 Hz-1/2. The instrument has been used for sensitive measurements of CO, CH4, C2H2 and NH3.
Received: 6 May 2002 / Revised version: 31 May 2002 / Published online: 2 September 2002
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ID="*"Corresponding author. Fax: +1-650/965-7074, E-mail: d.baer@lgrinc.com 相似文献
12.
M. Luennemann U. Hartwig G. Panotopoulos K. Buse 《Applied physics. B, Lasers and optics》2003,76(4):403-406
The electrooptic effect in lithium niobate crystals (LiNbO3) for extremely high externally applied electric fields of up to 65 kV/mm is investigated. Homogeneous electrooptic refractive-index
changes of up to 4.8×10-3 are found for ordinarily polarized light. No quadratic electrooptic effect is observed. An upper bound for the quadratic
electrooptic coefficient of |s13|≤2.3×10-21 m2/V2 is determined. Electrooptic, angular, and wavelength tuning of the Bragg condition of a thermally fixed hologram are demonstrated.
Received: 29 October 2002 / Revised version: 14 January 2003 / Published online: 26 March 2003
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ID="*"Corresponding author. E-mail: ml@uni-bonn.de 相似文献
13.
K. Song H.K. Cha V.A. Kapitanov Yu.N. Ponomarev A.P. Rostov D. Courtois B. Parvitte V. Zeninari 《Applied physics. B, Lasers and optics》2002,75(2-3):215-227
The results of theoretical and experimental studies and the design of a multi-purpose differential Helmholtz resonant photoacoustic
detector (DHRD) and its applications to high-resolution spectroscopy of molecular gases and gas analysis with a room-temperature
diode laser in the near-IR region are summarized. The series of experiments and numerical analysis of the DHRD sensitivity
were performed for both types (single-pass and multi-pass) of DHRDs within a wide pressure range 0.1–101 kPa, including the
regime of a gas flowing through a DHRD cell. The hardware and electronic arrangement of DHRDs for diode laser spectrometers
and gas analyzers providing a limiting absorption sensitivity better than 10-7 Wm-1 are described. The results of measurements of spectral line parameters of H2O near 800 and 1390 nm and CH4 near 1650 nm (intensities, line broadening and shifting by atomic and molecular gases) are presented and discussed. The problems
and the ways of perfection of the methodology and accuracy of DHRD techniques with tunable diode lasers of near-IR and visible
spectral ranges are discussed.
Received: 1 April 2002 / Revised version: 20 June 2002 / Published online: 21 August 2002
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ID="*"Corresponding author. Fax: +7/382-225-8026, E-mail: kvan@asd.iao.ru 相似文献
14.
J. Liao X.J. Zhang F. Xu X.Z. Fan H.T. Wang N.B. Ming 《Applied physics. B, Lasers and optics》2002,75(8):865-869
Optical bistable behavior in a quasi-waveguide containing non-linear film has been experimentally investigated in several
publications in the past years; however, the physical mechanism for optical bistability has not been theoretically explained.
In the present letter, we propose a theoretical model and successfully explain the observed optical bistability of both the
reflected light and the scattered light (m-lines) in a non-linear quasi-waveguide. The optical bistability in the non-linear quasi-waveguide is due to the scattering-type
wavevector mismatch mechanism.
Received: 10 July 2002 / Revised version: 10 September 2002 / Published online: 20 December 2002
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ID="*"Corresponding author. Fax: +86-25/359-5535, E-mail: htwang@nju.edu.cn 相似文献
15.
C. Dölle C. Reinhardt P. Simon B. Wellegehausen 《Applied physics. B, Lasers and optics》2002,75(6-7):629-634
. Investigations of the efficient generation of powerful coherent radiation at 82.8 nm by frequency tripling of short-pulse
KrF laser radiation are presented. Argon gas is selected as nonlinear medium due to the resonantly enhanced 3rd-order susceptibility
χ(3)(-3ω,ω,ω,ω). Pulse energies of 100 μJ at 82.8 nm have been measured for a pump pulse energy of 14 mJ. An upscaling to more
than 500 μJ is expected with available more powerful pump lasers. Features of this XUV source and possible applications are
discussed.
Received: 26 July 2002 / Published online: 15 November 2002
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ID="*"Corresponding author. Fax: +49-511/7622211, E-mail: reinhardt@iqo.uni-hannover.de 相似文献
16.
S. Borri P. Cancio P. De Natale G. Giusfredi D. Mazzotti F. Tamassia 《Applied physics. B, Lasers and optics》2003,76(4):473-477
We analyzed the spectroscopic performance of a difference-frequency source that utilizes a 5-W Yb-fiber amplifier for the
“signal” radiation in order to increase the “idler” power generated around 4.3 μm. The amplifier is seeded by a monolithic-cavity
Nd:YAG laser at 1064 nm. The intensity noise spectral density of the “idler” radiation was characterized. Cavity-enhanced
saturated-absorption spectroscopy was also performed to test the frequency resolution. In particular, we observed the Lamb-dip
spectrum of the ro-vibrational (0000-0001)R(0)transition of 17O12C16O in natural abundance. To our knowledge, this is the first observation of that transition by the Lamb-dip technique.
Received: 19 December 2002 / Revised version: 3 February 2003 / Published online: 16 April 2003
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ID="*"Corresponding author. Fax: +39-055/4572-451, E-mail: mazzotti@inoa.it 相似文献
17.
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
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ID="*"Corresponding author. Fax: +39-382/422583, E-mail: agnesi@ele.unipv.it 相似文献
18.
Crunteanu A. Jänchen G. Hoffmann P. Pollnau M. Buchal C. Petraru A. Eason R.W. Shepherd D.P. 《Applied Physics A: Materials Science & Processing》2003,76(7):1109-1112
We present a method for the selective two- and three-dimensional patterning of sapphire using light ion-beam implantation
to generate severe lattice damage to depths exceeding 1 μm and subsequent selective wet chemical etching of the damaged regions
by hot H3PO4. C-cut sapphire crystals were implanted through contact masks using ion fluences of 1×1016 to 5×1017 He+/cm2 and energies up to 400 keV. The etching process is characterized by a high selectivity and a rate of approximately 19 nm/min.
Whereas an implantation that produces a continuously damaged pathway results in complete etching from the surface, sole in-depth
implantation using only high-energy ions leads to under-etching of the crystalline surface layer. By a combination of these
processes we have fabricated three-dimensional structures such as channels and bridges in sapphire.
Received: 14 October 2002 / Accepted: 15 October 2002 / Published online: 26 February 2003
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ID="*"Corresponding author. Fax +41-21/693-3701, E-mail: aurelian.crunteanustanescu@epfl.ch 相似文献
19.
N.M. Huang C.S. Kan S. Radiman 《Applied Physics A: Materials Science & Processing》2003,76(4):555-559
An in situ technique for the synthesis of CdS nanoparticles in a ternary lyotropic cubic phase liquid crystal has been carried out.
The extremely viscous cubic phase liquid-crystal system consists of poly(oxyethylene)10 nonyl phenol ether as non-ionic surfactant, octane as oil phase and an aqueous phase containing reactant ions (Cd2+ and S2-). Thioacetamide (TAA) has been utilized as a source for slow release of sulfur in the in situ synthesis of CdS. Rheological results show that CdS nanoparticle growth did not disrupt the structure of the cubic phase
liquid-crystal system. This indicates that homogenous synthesis of CdS in the liquid crystal had been achieved. The final
products were characterized using X-ray photoelectron spectroscopy, thermal gravimetric analysis, transmission electron microscopy
and UV-visible spectroscopy. It was found that the CdS nanoparticles formed have a mesoporous structure with a size dependent
on the TAA decomposition aging time.
Received: 29 March 2002 / Accepted: 4 September 2002 / Published online: 17 December 2002
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ID="*"Corresponding author. Fax: +603-8921/3257, E-mail: shahidan@pkrisc.cc.ukm.my 相似文献
20.
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
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ID="*"Corresponding author. Fax: +1-303/497-5373, E-mail: richard@al.noaa.gov 相似文献