Resonant photoacoustic detection of NO2 traces with a <i>Q</i>-switched green laser

Slezak, V.; Codnia, Jorge; Peuriot, A.; Santiago, Guillermo

doi:10.1063/1.1518570

Cited by 8 publications

(7 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Nitrogen dioxide was supplied from a calibrated gas mixture (2000 ppmv NO 2 buffered in Ar) and was further diluted in argon by means of a mass flow controller to obtain the desired concentrations. A constant flow through the PA cell (typically 50 mL/min) was maintained during measurements to avoid adsorption effects [8]. The total pressure inside the PA cell was also maintained at 980 mbar.…”

Section: Methodsmentioning

confidence: 99%

“…To the best of our knowledge, this third case has not been treated theoretically yet. On a few occasions, it has been applied as an alternative to continuous-wave (cw) lasers [7][8][9]. In this work, we compare the modulated resonant mode to the pulsed resonant mode under similar experimental conditions such as the wavelength, the average power or the diameter of the laser beam.…”

mentioning

confidence: 99%

“…For comparison purposes, we chose NO 2 , for it strongly absorbs at 532 nm where both cw and pulsed laser sources are available. Furthermore, NO 2 is a pollutant of current interest that plays an important role in atmospheric chemistry [8,10,11].…”

mentioning

confidence: 99%

See 2 more Smart Citations

Modulated resonant versus pulsed resonant photoacoustics in trace gas detection

Bartlomé

Kaucikas²,

Sigrist

2009

Appl. Phys. B

View full text Add to dashboard Cite

Modulated resonant photoacoustics is a sensitive technique widely used for trace gas sensing. Generally, a continuous-wave laser is modulated at a frequency corresponding to an acoustic resonance of a photoacoustic cell. Another mode of operation-which we propose to call the pulsed resonant mode-consists in matching the frequency repetition rate of a pulsed laser to an acoustic resonance of the cell. We present a theoretical model to compare the performance of these two configurations. For a given average power of the incoming light inside the cell, the pulsed resonant mode of operation (nanosecond pulses or shorter) produces π/2 times higher photoacoustic signals than the modulated resonant scheme (the latter is optimized for a 50% duty cycle). This result agrees with experiments during which both cases were investigated at 532 nm using the same photoacoustic cell containing trace concentrations of NO 2 .

show abstract

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Modulated resonant versus pulsed resonant photoacoustics in trace gas detection

Bartlomé

Kaucikas²,

Sigrist

2009

Appl. Phys. B

View full text Add to dashboard Cite

show abstract

“…Specifically, nitrogen dioxide (NO 2 ) light absorption can play an important role in the ultraviolet (UV) and visible radiation budget of the atmosphere (Intergovernmental Panel on Climate Change [IPCC], 2007;VasilKov et al, 2009). Photoacoustic measurements can be used for the sensitive characterization of NO 2 absorption coefficients and concentrations (e.g., Terhune and Anderson, 1977;Slezak et al, 2003); in addition, NO 2 is commonly used to calibrate photoacoustic measurements of aerosol light absorption (Adams et al, 1989;Arnott et al, 2000). For all of these applications, absorption and photolysis of NO 2 need to be better understood.…”

Section: Introductionmentioning

confidence: 99%

Influence of photolysis on multispectral photoacoustic measurement of nitrogen dioxide concentration

Tian

Moosmüller

Arnott

2013

Journal of the Air & Waste Management Association

View full text Add to dashboard Cite

Multispectral photoacoustic instruments are commonly used to measure aerosol and nitrogen dioxide (NO 2 ) light absorption coefficients to determine the radiation budget of the atmosphere. Here a new photoacoustic system is developed to explore the effect of photolysis on the measured signal in a multispectral photoacoustic spectrometer. In this system, a 405-nm laser is used primarily as light source for photolysis. Additionally, a well-overlapped 532-nm laser, modulated at the resonant frequency of the photoacoustic instrument, is used to probe the NO 2 concentration. As a result, the photolysis effect at 405 nm can be observed by the photoacoustic instrument through the 532-nm laser. This work determines an 11% reduction of the photoacoustic signal caused by the photolysis effect for typical conditions, which needs to be taken into account when calibrating multispectral photoacoustic spectrometers with NO 2 .Implications: Multispectral photoacoustic instruments are commonly used to measure aerosol and nitrogen dioxide (NO 2 ) light absorption coefficients to determine the radiation budget of the atmosphere. A 405-nm laser is often used in these multispectral photoacoustic instruments. Although NO 2 absorbs strongly at 405 nm, it also has a strong photolysis pathway that is accessible by light of the same wavelength. Photolysis reduces the photoacoustic signal, necessitating special care when interpreting photoacoustic measurements. This paper offers a method for the multispectral photoacoustic instrument user to quantify the influence of the 405-nm NO 2 photolysis effect on the photoacoustic signal.

show abstract

“…[3][4][5] Owing to the simplicity of the system, it is well suited to perform in situ measurements, especially when complemented with data acquisition through the standard sound system of a PC. A signal generator ͑Stanford Research DS 340͒, controlled by a personal computer ͑PC͒, provided a variable frequency, low-level signal that served as a reference for the LED driving circuit.…”

Section: Introductionmentioning

confidence: 99%

Novel optical method for background reduction in resonant photoacoustics

González

Santiago

Slezak

et al. 2007

Review of Scientific Instruments

Self Cite

View full text Add to dashboard Cite

We report a new way of reducing the background originated by window absorption in resonant photoacoustics. The technique employs a secondary light source that is absorbed by the window but not by the gas sample. This auxiliary source is modulated 180 degrees apart from the one used to probe the gas. This way the window is heated almost uniformly during each cycle, thus lessening the associated background signal. We tested the scheme on a photoacoustic setup, conceived to measure NO(2), which is excited by an array of blue light-emitting diodes. Another array of near-infrared, light-emitting diodes served as the secondary light source. With the addition of this cancelling method, the detection limit was decreased to 4% of the previous reached without it.

show abstract

Resonant photoacoustic detection of NO2 traces with a Q-switched green laser

Cited by 8 publications

References 2 publications

Modulated resonant versus pulsed resonant photoacoustics in trace gas detection

Modulated resonant versus pulsed resonant photoacoustics in trace gas detection

Influence of photolysis on multispectral photoacoustic measurement of nitrogen dioxide concentration

Novel optical method for background reduction in resonant photoacoustics

Contact Info

Product

Resources

About