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1.
Mid-infrared trace gas detection using continuous-wave difference frequency generation in periodically poled RbTiOAsO4 总被引:1,自引:0,他引:1
A tunable mid-infrared continuous-wave (cw) spectroscopic source in the 3.4–4.5 μm region is reported, based on difference
frequency generation (DFG) in a quasi-phase-matched periodically poled RbTiOAsO4 (PPRTA) crystal, DFG power levels of 10 μW were generated at approximately 4 μm in a 20-mm long PPRTA crystal by mixing two
cw single-frequency Ti:Al2O3 lasers operating near 713 nm and 871 nm, respectively, using a laser pump power of 300 mW. A quasi-phase-matched infrared
wavelength-tuning bandwidth (FWHM) of ∼12 cm-1 and a temperature tuning rate of 1.02 cm-1/°C were achieved. Experimental details regarding the feasibility of trace gas detection based on absorption spectroscopy
of CO2 in ambient air using this DFG radiation source are also described.
Received: 23 October 2000 / Revised version: 22 January 2001 / Published online: 27 April 2001 相似文献
2.
Hsiang-Chen Chui Ming-Sheng Ko Yi-Wei Liu Tyson Lin Jow-Tsong Shy Sen-Yen Shaw Rostislav V. Roussev Martin M. Fejer 《Optics and Lasers in Engineering》2006,44(5):479-485
A 197.2 THz (1520.2 nm) ITU-T grid distributed feedback (DFB) diode laser is frequency stabilized at 197.198 THz by 1ocking its second harmonic (SH) signal on the rubidium 5S1/2→7S1/2 two-photon transition at 394.396 THz (760.1 nm). With 100 mW from the DFB diode laser and amplifying by an erbium-doped fiber amplifier, we obtain an SH power of 15 mW using a periodically poled lithium niobate (PPLN) waveguide frequency doubler. The stability was 2×10−11 (10 s), corresponding to a frequency variation of 4 kHz at 1520.2 nm. Our scheme provides a compact and high performance frequency reference in the communication band. 相似文献
3.
L. S. Pan H. P. Lee C. Lu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,50(1):27-33
We report the synthesis and measurement of an
ultra-precise and extremely stable optical frequency in the
telecommunications window around 1543 nm. Using a fibre-based femtosecond
frequency comb we have phase-stabilised a fibre laser at 194 THz to an
optical frequency standard at 344 THz, thus transferring the properties of
the optical frequency standard to another spectral region. Relative to the
optical frequency standard, the synthesised frequency at 194 THz is
determined to within 1 mHz and its fractional frequency instability is
measured to be less than 2×10-15 at 1 s, reaching 5×
10-18 after 8000 s. We also measured the synthesised frequency against
a caesium fountain clock: here the frequency comparison itself contributes
less than 4 mHz (2×10-17) to the uncertainty. Our results
confirm the suitability of fibre based frequency comb technology for
precision measurements and frequency synthesis, and enable long-distance
comparison of optical clocks by using optical fibres to transmit the
frequency information. 相似文献
4.
S. D. Zhuang X. D. Xu Z. P. Wang D. Z. Li H. H. Yu J. Xu L. Guo L. J. Chen Y. G. Zhao X. G. Xu 《Laser Physics》2011,21(4):684-689
Continuous-wave (CW) and passively Q-switched performance of a Nd-doped oyorthosilicate mixing crystal, (Nd0.005Lu0.4975Y0.4975)2SiO5 (Nd:LYSO), were reported. As a result, new dual-wavelength all-solid-state lasers at 1075 and 1079 nm were achieved. When
the absorbed pump power was 3.87 W, the CW laser produced 1.1 W output, corresponding to an optical conversion efficiency
of 28.4% and a slope efficiency of 32.4%. By using a Cr4+:YAG wafer as the saturable absorber, we achieved Q-switching operation of Nd:LYSO crystal. The maximal average output power,
shortest pulse width, largest pulse energy and highest peak power were measured to be 294 mW, 27.5 ns, 34.3 μJ and 1.18 kW,
respectively. By difference frequency, these dual-wavelength lasers have potential applications for the generation of a broadband
coherent radiation from 0.7–1.3 THz. 相似文献
5.
Large third-order nonlinear optical susceptibility of Au-Al2O3 composite films near the resonant frequency 总被引:2,自引:0,他引:2
2 O3 composite films with high Au concentrations (30%–60% in volume fraction) were prepared by reactive co-sputtering and post
rapidly thermal annealing. The structure of the films and the size distributions of the Au nanoclusters were examined by TEM,
and the third-order nonlinear optical susceptibility χ(3) was measured by degenerated four-wave mixing using a 70-ps pulse laser at 532 nm. The maximum value of the χ(3) was about 1.2×10-6 esu in the annealed films and occurred at around 45% Au concentration. The figure of merit, χ(3)/α (α is the absorption coefficient), has a value of 7×10-12 esu cm over a wide range of Au concentrations.
Received: 23 July 1997 相似文献
6.
V.L. Kasyutich C.E. Canosa-Mas C. Pfrang S. Vaughan R.P. Wayne 《Applied physics. B, Lasers and optics》2002,75(6-7):755-761
We present an application of continuous-wave (cw) cavity-enhanced absorption spectroscopy (CEAS) with off-axis alignment geometry
of the cavity and with time integration of the cavity output intensity for detection of narrow-band and broadband absorbers
using single-mode red diode lasers at λ=687.1 nm and λ=662 nm, respectively. Off-axis cw CEAS was applied to kinetic studies
of the nitrate radical using a broadband absorption line at λ=662 nm. A rate constant for the reaction between the nitrate
radical and E-but-2-eneof (3.78±0.17)×10-13 cm3 molecule-1 s-1 was measured using a discharge-flow system. A nitrate-radical noise-equivalent (1σ≡ root-mean-square variation of the signal)
detection sensitivity of 5.5×109 molecule cm-3 was achieved in a flow tube with a diameter of 4 cm and for a mirror reflectivity of ∼99.9% and a lock-in amplifier time
constant of 3 s. In this case, a noise-equivalent fractional absorption per one optical pass of 1.6×10-6 was demonstrated at a detection bandwidth of 1 Hz. A wavelength-modulation technique (modulation frequency of 10 kHz) in
conjunction with off-axis cw CEAS has also been used for recording 1f- and 2f-harmonic spectra of the RR(15) absorption of the b1Σg
+-X3Σg
- (1,0) band of molecular oxygen at =14553.947 cm-1. Noise-equivalent fractional absorptions per one optical pass of 1.35×10-5, 6.9×10-7 and 1.9×10-6 were obtained for direct detection of the time-integrated cavity output intensity, 1f- and 2f-harmonic detection, respectively,
with a mirror reflectivity of ∼99.8%, a cavity length of 0.22 m and a detection bandwidth of 1 Hz.
Received: 24 June 2002 / Revised version: 12 August 2002 / Published online: 15 November 2002
RID="*"
ID="*"Corresponding author. Fax: +44-1865/275410, E-mail: vlk@physchem.ox.ac.uk 相似文献
7.
K.J. Siemsen J.E. Bernard A.A. Madej L. Marmet 《Applied physics. B, Lasers and optics》2001,72(5):567-573
A cw carbon dioxide laser operating on the 10 μm R(0)I transition (28.832 THz) was frequency stabilized by a servo lock to the saturated absorption dip of the Q(15) transition
of 188OsO4. The laser frequency was measured with a cesium-clock-based frequency chain. In addition, the absorption line frequencies
Q(14) of 188OsO4 and sQ(4,3) of 15NH3, were measured relative to the frequency of Q(15).
Received: 21 August 2000 / Revised version: 15 January 2001 / Published online: 30 March 2001 相似文献
8.
M. Mamor Y. Fu O. Nur M. Willander S. Bengtsson 《Applied Physics A: Materials Science & Processing》2001,72(5):633-637
We investigate, both experimentally and theoretically, current and capacitance (I–V/C–V) characteristics and the device performance
of Si/SiO2/Si single-barrier varactor diodes (SBVs). Two diodes were fabricated with different SiO2 layer thicknesses using the state-of-the-art wafer bonding technique. The devices have very low leakage currents (about 5×10-2 and 1.8×10-2 mA/mm2) and intrinsic capacitance levels of typically 1.5 and 50 nF/mm2 for diodes with 5-nm and 20-nm oxide layers, respectively. With the present device physical parameters (25-mm2 device area, 760-μm modulation layer thickness and ≈1015-cm-3 doping level), the estimated cut-off frequency is about 5×107 Hz. With the physical parameters of the present existing III–V triplers, the cut-off frequency of our Si-based SBV can be
as high as 0.5 THz.
Received: 9 February 2001 / Accepted: 9 February 2001 / Published online: 23 March 2001 相似文献
9.
J. X. Zhang L. Han Y. Wu N. Zong P. Z. Fu B. S. Wang G. C. Zhang Z. Y. Xu Y. C. Wu 《Applied physics. B, Lasers and optics》2011,103(4):853-856
The self-sum-frequency process was firstly demonstrated in Nd3+-doped La2CaB10O19 (LCB) crystal. In addition, simultaneous participation of the fundamental laser in multi-self-frequency conversion including
the self-frequency doubling was reported. Emissions at five different wavelengths (525, 529, 533.6, 1050 and 1069 nm) were
simultaneously obtained. The output power of the three green visible lasers (525, 529 and 533.6 nm) generated by multi-self-frequency-conversion
of the fundamental laser is up to 26.64 mW, and the light-light conversion efficiency is up to 4.85%. The lasers at 525 and
529 nm are very close to the green primary color G (526.3 nm) defined by the 1964CIERGB system, which has potential applications
in laser-based high brightness display. The large frequency differences of 4–6 THz between 525 and 529 nm, 529 and 533.6 nm,
as well as 1050 and 1069 nm, are also potential useful in generating THz waves by difference frequency generation (DFG) technique
in a nonlinear optical (NLO) crystal. 相似文献
10.
A.M. Malyarevich I.A. Denisov K.V. Yumashev V.P. Mikhailov R.S. Conroy B.D. Sinclair 《Applied physics. B, Lasers and optics》1998,67(5):555-558
gsa =3.0×10-18 cm2 and σesa=1.4×10-19 cm2 at 1064 nm, and σgsa=7.2×10-18 cm2 and σesa=7.4×10-19 cm2 at 1342 nm. Q-switched operation was demonstrated at 1064 nm and 1342 nm from a Nd:YVO4 microchip laser, producing pulses as short as 9.3 ns at 1342 nm with peak powers of 350 W.
Received: 17 March 1998/Revised version: 8 June 1998 相似文献
11.
CW laser emission on the quasi 3-level (4F3/2→4I9/2) transition in Nd:GGG is reported for different pump focusing and resonator dimensions. A nearly hemispherical plano-concave
resonator led at 937.3 nm to a maximum output power of 4.1 W for an incident pump power of 21.7 W, thus corresponding to a
slope efficiency of about 23.5%. Laser operation was also obtained for the first time around 933.6 nm by using a glass etalon
for frequency selection with a maximum output power of 2.3 W and a slope efficiency of 16% with respect to the incident pump
power. Dual-wavelength operation (around 933.6 and 937.3 nm), which offers a potential source to generate THz radiation, is
also reported. 相似文献
12.
O. Terra G. Grosche K. Predehl R. Holzwarth T. Legero U. Sterr B. Lipphardt H. Schnatz 《Applied physics. B, Lasers and optics》2009,97(3):541-551
We have explored the performance of two “dark fibers” of a commercial telecommunication fiber link for a remote comparison
of optical clocks. The two fibers, linking the Leibniz University of Hanover (LUH) with the Physikalisch-Technische Bundesanstalt
(PTB) in Braunschweig, are connected in Hanover to form a total fiber length of 146 km. At PTB the performance of an optical
frequency standard operating at 456 THz was imprinted to a cw transfer laser at 194 THz, and its frequency was transmitted
over the fiber. In order to detect and compensate phase noise related to the optical fiber link we have built a low-noise
optical fiber interferometer and investigated noise sources that affect the overall performance of the optical link. The frequency
stability at the remote end has been measured using the clock laser of PTB’s Yb+ frequency standard operating at 344 THz.
We show that the frequency of a frequency-stabilized fiber laser can be transmitted over a total fiber length of 146 km with
a relative frequency uncertainty below 1×10−19, and short term frequency instability given by the fractional Allan deviation of σ
y
(τ)=3.3×10−15/(τ/s). 相似文献
13.
Distinctive optical properties of single-wall carbon nanotubes (SWNT) are highly sensitive to variations in the environment.
Here, we have studied SWNT in aqueous suspensions at a low (less than 0.1 μg ml−1) concentration by four-wave mixing (FWM) spectroscopy in the spectral bands of 0.1 to 10 cm−1 (≈300 GHz) and 100 to 250 cm−1 (3 to 7.5 THz). We directly investigated the hydration layers around SWNT. A comparison of the FWM spectra of an SWNT aqueous
suspension and Milli-Q water shows a considerable increase in the intensity of low-frequency Raman modes, which are attributed
to the rotational transitions of H2O2 and H2O molecules. We explain the observed phenomenon by the hydrogen peroxide production and formation of a low-density depletion
layer at the water-nanotube interface. We have observed several SWNT radial breathing modes ω
RBM =118.5, 164.7, and 233.5 cm−1 in an SWNT aqueous suspension and estimated the corresponding SWNT diameters as ≈2.0, 1.5, and 1 nm. 相似文献
14.
International comparisons of I2 stabilized ion lasers operated at 514.5 nm have shown a laser frequency reproducibility of 2·10−10
v to 5·10−12
v. These results encouraged the international acceptance of the wavelength value λvac=514.673467 for thea
3 hyperfine component of the127I2 line 43-0P(13). 相似文献
15.
B. Bodermann M. Klug U. Winkelhoff H. Knöckel E. Tiemann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,11(2):213-225
Frequency measurements of 16 lines of I2 in the near infrared have been performed using different Rb frequency references: diode lasers stabilised to the Rb D1 line
at 377 THz, to the Rb D2 line at 384 THz and to the 5
s
-5
d
two photon transition at 385 THz. The relative uncertainties of the measurements of are limited by the frequency stability of the laser source locked to I2 in the case of the Rb D2 and two photon transition or by the accuracy of the Rb D1 line. The internal consistency of calibrations
of iodine lines is shown to be better than by measurements of the difference frequencies of calibrated iodine lines using four-wave mixing in laser diodes.
Received 12 July 1999 and Received in final form 12 December 1999 相似文献
16.
The generation of standard reference frequencies close to the ITU channels is essential for the calibration and maintenance of DWDM systems. This work describes a method to synthesize frequency references in the range from 187.1 to 205.1 THz (1462-1602 nm). The method is based on the generation of four equispaced frequencies (by the process of four-wave mixing in a semiconductor amplifier) of which two are locked to absorption lines of the acetylene 12C2H2 (1511-1542 nm). 相似文献
17.
S. Reinhardt B. Bernhardt R. Holzwarth S. Karpuk W. Nörtershäuser C. Novotny 《Optics Communications》2007,274(2):354-360
We report frequency measurements at the rovibronic transition P(42)1-14 (772 nm) and R(114)2-11 (735 nm) from the electronic transition of the iodine molecule 127I2 with the help of a frequency comb as a reference. By using Doppler-free saturation spectroscopy a frequency precision in the 7 × 10−10 region is reached and two iodine cells both operated at 550-600 °C are compared. To relate our results to other measurements, the absolute transition frequency of the hyperfine structure line P(148)1-14 a1 at 780 nm with an already known transition frequency was also determined. 相似文献
18.
G. Schreiber H. Suche Y.L. Lee W. Grundkötter V. Quiring R. Ricken W. Sohler 《Applied physics. B, Lasers and optics》2001,73(5-6):501-504
Using an FM-mode-locked Ti:Er:LiNbO3 waveguide laser as the fundamental source, wavelength conversion by cascaded χ(2):χ(2)-difference frequency generation with a conversion efficiency of up to +3(-4.6) dB was demonstrated at a pulse repetition
rate of about 2 (10) GHz. In addition, multi-channel conversion was demonstrated with a fully packaged wavelength converter
using a continuous fundamental source.
Received: 29 May 2001 / Revised version: 10 August 2001 / Published online: 2 November 2001 相似文献
19.
G. Zhou Y. Ren D. Wang C. Wang Z. Shao Q. Fang M. Jiang 《Applied physics. B, Lasers and optics》2001,72(8):937-940
Trans-4-[p-(N-hydroxyethyl-N-ethylamino)styryl]-N-methylpyridinium p-toluene sulfonate (abbreviated as HEASPS) is a two-photon-absorption
(TPA) dye newly synthesized by our research group. It possesses a much larger TPA cross-section and much stronger upconversion
fluorescence emission than those of common organic dyes (such as rhodamine) when excited with near-infrared (IR) radiation.
TPA spectrum and upconversion efficiency spectrum of HEASPS solution at different wavelengths have been measured. The largest
molecular TPA cross-section σ2
′ is measured to be 2.06×10-47 cm4 s/photon at 930 nm. At 1064 nm, σ2
′ is 2.71×10-48 cm4 s/photon, which is only one-ninth of that at 930 nm. The upconverted lasing efficiency spectrum has been measured at different
wavelengths. The highest efficiency is 5.1% at 1020 nm, whereas it is 3.5% at 1064 nm. Its optical-power-limiting properties
at 930 nm have also been illustrated.
Received: 30 November 2000 / Published online: 27 April 2001 相似文献
20.
K. Divakara Rao S. Anantha Ramakrishna P.K. Gupta 《Applied physics. B, Lasers and optics》2001,72(2):215-219
We report the results of our studies on the nonlinear optical response of thin films of tetraphenyl porphyrin doped in boric
acid glass for picosecond-duration pulses. The fluence-dependent transmission measurements show that the sample exhibits reverse
saturation behavior at 532 nm and saturable absorber action at 683 nm. By fitting the nonlinear transmission data at these
wavelengths to a rate equation model, values for σS
e and σL the excited singlet and ground state cross sections were obtained. The large value (≈8) for σS
e/σL makes it a potential material for optical limiting at 532 nm, whereas at 683 nm the ratio σL/σS
e≈4.3. Intensity dependence of degenerate forward four-wave mixing at 683 nm was also investigated to establish the order and
magnitude of the nonlinearity. The forward four-wave mixing signal at 683 nm showed a cubic dependence on the input intensity,
establishing the third-order nonlinearity. A value of 4×10-12 esu for the third-order susceptibility |χ(3)| was estimated from the measured efficiency. The time response of the nonlinearity was measured by the pump-probe transmission
experiment, resulting in a decay constant of about 1.8 ns for the repopulation of the ground singlet state at 683 nm.
Received: 13 April 2000 / Published online: 20 September 2000 相似文献