Continuous wave optical parametric oscillator for quartz-enhanced photoacoustic trace gas sensing

Ngai, A.K.Y.; Persijn, Stefan; Lindsay, I.D.; Kosterev, Anatoliy A.; Groß, P.; Lee, Chris; Cristescu, Simona M.; Tittel, Frank K.; Boller, Klaus J.; Harren, F.J.M.

doi:10.1007/s00340-007-2755-y

Cited by 46 publications

(30 citation statements)

References 24 publications

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“…The total length of each of the two μR tubes is 5.1 mm (close to λ/2 for a sound wave of 32.8 kHz in air or N 2 ). This is approximately twice longer than have been used in earlier sensor versions [2,3] and was experimentally found to produce higher photoacoustic signals at >500 Torr gas pressure. The gaps between each of the μR tubes and a QTF surface were in the 30-50 μm range.…”

Section: Qepas-based Sensor Descriptionmentioning

confidence: 90%

“…Since the discovery of QEPAS several years ago [1], it has been demonstrated with several simple molecules using a single rovibrational line in fundamental mid-IR absorption bands [2,3] (e.g., CO, N 2 O, H 2 CO, C 2 H 6 ) or in near-IR combination bands (e.g., NH 3 [4], CO 2 [5], HCN [6], H 2 S [7]). More recently, QEPAS has also been implemented with larger molecules with broad, unresolved absorption spectra, such as acetone and freons [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Performance evaluation of a near infrared QEPAS based ethylene sensor

Schilt¹,

Kosterev

Tittel

2008

Appl. Phys. B

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A sensor based on quartz-enhanced photoacoustic spectroscopy (QEPAS) was evaluated for the detection of trace levels of ethylene at atmospheric pressure using a fiber coupled DFB diode laser emitting in the 1.62 μm spectral range. A noise-equivalent QEPAS signal of ∼4 ppm C 2 H 4 was achieved for a 0.7 s data acquisition time using wavelength-modulation with a second-harmonic detection scheme on the strongest C 2 H 4 absorption peak at 6177.14 cm −1 with an average optical power of ∼15 mW. Improved detection sensitivity of 0.5 and 0.3 ppm C 2 H 4 (1σ ) was demonstrated using longer averaging time of 70 and 700 s, respectively. Important characteristics for the QEPAS based sensor operation in real-world conditions are presented, particularly the influence of external temperature variations. Furthermore, the response time of the ethylene sensor was measured in different configurations and it is shown that the QEPAS technique can provide a response time in a few seconds range even without active gas flow.

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Section: Qepas-based Sensor Descriptionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Performance evaluation of a near infrared QEPAS based ethylene sensor

Schilt¹,

Kosterev

Tittel

2008

Appl. Phys. B

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“…The output of the fiber amplifier (7.5 W) is used to pump the OPO. To suppress stimulated Brillouin scattering inside the fiber amplifier, a fast modulation (≥2 MHz) was applied to the gain section of the DBR laser, which resulted in a broadening of the output linewidth of this pump system to 100 MHz [8,9].…”

Section: Methodsmentioning

confidence: 99%

“…As many gases have strong absorptions in the midinfrared region, we chose to tackle this problem by using the well-developed tuning and modulation abilities of diode lasers in the near-infrared region and transfer these to the 3-4 µm range, by using a continuous wave SinglyResonant Optical Parametric Oscillator (SR-OPO) [7][8][9][10][11]. Such a combination is an ideal basis for trace gas detection by means of laser spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Rapid and sensitive trace gas detection with continuous wave Optical Parametric Oscillator-based Wavelength Modulation Spectroscopy

et al. 2010

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A fiber-amplified Distributed Bragg Reflector diode laser is used to pump a continuous wave, singly resonant Optical Parametric Oscillator (OPO). The output radiation covers the 3-4 µm with ability of rapid (100 THz/s) and broad mode-hop-free tuning (5 cm −1 ). Wavelength Modulation Spectroscopy is combined with the OPO to take optimal advantage of the spectral scan speed. The sensitivity of the system was determined as 0.8 ppbv (parts-perbillion by volume) for ethane (C 2 H 6 ) for the absorption peak at 2996.9 cm −1 recorded in 1.3 seconds, corresponding to a noise equivalent absorption sensitivity (NEAS) of 1.2 × 10 −9 cm −1 /Hz 1/2 . A comparison between results using the 1 st , 2 nd and 4 th harmonic derivative signal from wavelength modulation was performed. The broad continuous tunability was demonstrated by covering 35 cm −1 while recording absorption features of ethane, methane and water.

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“…Tuning ranges in the order of 1000 cm −1 in combination with output powers of more than 1 watt have been achieved [4][5][6]. Their high output power renders them ideal as a source for photoacoustic spectroscopic techniques [7,8] while their narrow line width makes them also a useful source for highresolution spectroscopy [9,10]. Recently, several reviews have appeared that focus on developments in the design, operation, and spectroscopic applications of tunable OPOs [11,12].…”

Section: Introductionmentioning

confidence: 99%

Quantitative gas measurements using a versatile OPO-based cavity ringdown spectrometer and the comparison with spectroscopic databases

2010

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A versatile OPO-based cavity ringdown spectrometer is reported for quantitative and sensitive gas measurement down to nmol/mol levels. The system is based on cavity ringdown spectroscopy (CRDS) in combination with a continuous wave optical parametric oscillator tunable from 2693 to 3505 nm. Using a single set of CRDS mirrors, spectra were recorded of methane, ethane, benzene, propane, water, acetone and formaldehyde. Gas mixtures were gravimetrically prepared in cylinders or via dynamic generation using diffusion tubes (formaldehyde). Results were compared with data from the Hitran, PNNL and NIST databases. Good agreement was found with PNNL and NIST data for most molecules while agreement with Hitran was less for ethane and formaldehyde.

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Continuous wave optical parametric oscillator for quartz-enhanced photoacoustic trace gas sensing

Cited by 46 publications

References 24 publications

Performance evaluation of a near infrared QEPAS based ethylene sensor

Performance evaluation of a near infrared QEPAS based ethylene sensor

Rapid and sensitive trace gas detection with continuous wave Optical Parametric Oscillator-based Wavelength Modulation Spectroscopy

Quantitative gas measurements using a versatile OPO-based cavity ringdown spectrometer and the comparison with spectroscopic databases

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