scholarly journals Absorption Measurements in Liquid Core Waveguides Using Cavity Ring-Down Spectroscopy

2013 ◽  
Vol 85 (9) ◽  
pp. 4328-4334 ◽  
Author(s):  
Klaus Bescherer ◽  
Jack A. Barnes ◽  
Hans-Peter Loock
Keyword(s):  
Liquid Core ◽  
Cavity Ring Down Spectroscopy ◽  
Liquid Core Waveguides ◽  
Absorption Measurements ◽  
Cavity Ring Down

scholarly journals Absorption detection using optical waveguide cavities

2010 ◽  
Vol 88 (5) ◽  
pp. 401-410 ◽  
Author(s):  
Hans-Peter Loock ◽  
Jack A. Barnes ◽  
Gianluca Gagliardi ◽  
Runkai Li ◽  
Richard D. Oleschuk ◽  
...  
Keyword(s):  
Optical Cavity ◽  
Spectroscopic Method ◽  
Optical Loss ◽  
Wavelength Shift ◽  
Cavity Ring Down Spectroscopy ◽  
Mode Spectrum ◽  
Waveguide Cavities ◽  
High Finesse ◽  
Absorption Measurements ◽  
Cavity Ring Down

Cavity ring-down spectroscopy is a spectroscopic method that uses a high quality optical cavity to amplify the optical loss due to the light absorption by a sample. In this presentation we highlight two applications of phase-shift cavity ring-down spectroscopy that are suited for absorption measurements in the condensed phase and make use of waveguide cavities. In the first application, a fiber loop is used as an optical cavity and the sample is introduced in a gap in the loop to allow absorption measurements of nanoliters of solution at the micromolar level. A second application involves silica microspheres as high finesse cavities. Information on the refractive index and absorption of a thin film of ethylene diamine on the surface of the microresonator is obtained simultaneously by the measurements of the wavelength shift of the cavity mode spectrum and the change in optical decay time, respectively.

scholarly journals Toward real-time measurement of atmospheric mercury concentrations using cavity ring-down spectroscopy

2010 ◽  
Vol 10 (6) ◽  
pp. 2879-2892 ◽  
Author(s):  
X. Faïn ◽  
H. Moosmüller ◽  
D. Obrist
Keyword(s):  
Temporal Resolution ◽  
Time Resolution ◽  
Pulse Repetition Frequency ◽  
Ambient Air ◽  
Atmospheric Mercury ◽  
Dye Laser ◽  
High Temporal Resolution ◽  
Cavity Ring Down Spectroscopy ◽  
Absorption Measurements ◽  
Cavity Ring Down

Abstract. Cavity ring-down spectroscopy (CRDS) is a direct absorption technique that utilizes path lengths up to multiple kilometers in a compact absorption cell and has a significantly higher sensitivity than conventional absorption spectroscopy. This tool opens new prospects for study of gaseous elemental mercury (Hg0) because of its high temporal resolution and reduced sample volume requirements (<0.5 l of sample air). We developed a new sensor based on CRDS for measurement of (Hg0) mass concentration. Sensor characteristics include sub-ng m−3 detection limit and high temporal resolution using a frequency-doubled, tuneable dye laser emitting pulses at ~253.65 nm with a pulse repetition frequency of 50 Hz. The dye laser incorporates a unique piezo element attached to its tuning grating allowing it to tune the laser on and off the Hg0 absorption line on a pulse-to-pulse basis to facilitate differential absorption measurements. Hg0 absorption measurements with this CRDS laboratory prototype are highly linearly related to Hg0 concentrations determined by a Tekran 2537B analyzer over an Hg0 concentration range from 0.2 ng m−3 to 573 ng m−3, implying excellent linearity of both instruments. The current CRDS instrument has a sensitivity of 0.10 ng Hg0 m−3 at 10-s time resolution. Ambient-air tests showed that background Hg0 levels can be detected at low temporal resolution (i.e., 1 s), but also highlight a need for high-frequency (i.e., pulse-to-pulse) differential on/off-line tuning of the laser wavelength to account for instabilities of the CRDS system and variable background absorption interferences. Future applications may include ambient Hg0 flux measurements with eddy covariance techniques, which require measurements of Hg0 concentrations with sub-ng m−3 sensitivity and sub-second time resolution.

scholarly journals Toward a real-time measurement of atmospheric mercury concentrations using cavity ring-down spectroscopy

2009 ◽  
Vol 9 (5) ◽  
pp. 22143-22175
Author(s):  
X. Faïn ◽  
H. Moosmüller ◽  
D. Obrist
Keyword(s):  
Temporal Resolution ◽  
Time Resolution ◽  
Pulse Repetition Frequency ◽  
Elemental Mercury ◽  
Atmospheric Mercury ◽  
Dye Laser ◽  
High Temporal Resolution ◽  
Cavity Ring Down Spectroscopy ◽  
Absorption Measurements ◽  
Cavity Ring Down

Abstract. A new sensor based on cavity ring-down spectroscopy (CRDS) has been developed for the measurement of gaseous elemental mercury (Hg0) mass concentration with sub-ng m−3 detection limit and high temporal resolution. Cavity ring-down spectroscopy is a direct absorption technique that utilizes path lengths of up to multiple kilometers in a compact absorption cell and has a significantly higher sensitivity than conventional absorption spectroscopy. Our prototype uses a frequency-doubled, tuneable dye laser emitting pulses at ~253.65 nm with a pulse repetition frequency of 50 Hz. The dye laser incorporates a unique piezo element attached to its tuning grating allowing it to tune the laser on and off the Hg0 absorption line on a pulse to pulse basis to facilitate differential absorption measurements. Hg0 absorption measurements with this CRDS laboratory prototype are highly linearly related to Hg0 concentrations determined by a Tekran 2537B analyzer over a Hg0 concentration range of four orders of magnitude, from 0.2 ng m−3 to 573 ng m−3 implying excellent linearity of both instruments. The current CRDS instrument has a~sensitivity of 0.10 ng m−3 at 10 s time resolution. This tool opens new prospects for the study of Hg0 because of its high temporal resolution and reduced limited sample volume requirements (<0.5 l of sample air). Future applications may include ambient Hg0 flux measurements with eddy covariance techniques, which require measurements of Hg0 concentrations with sub-ng m−3 sensitivity and sub-second time resolution.

On Electronic Type Cavity Ring-Down Spectroscopy

2014 ◽  
Vol 134 (8) ◽  
pp. 243-246
Author(s):  
Yuki Hirabayashi ◽  
Hirokazu Tanimoto ◽  
Yoshinobu Maeda
Keyword(s):  
Cavity Ring Down Spectroscopy ◽  
Cavity Ring Down
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