Online monitoring of ethane traces in exhaled breath with a difference frequency generation spectrometer

We report a transportable mid-infrared laser cavity leak-out spectrometer for online detection of trace gases. The laser spectrometer is based on continuous-wave difference-frequency generation in the wavelength region around 3 μm. Sensitive spectroscopic trace gas monitoring was achieved using a high-finesse ring-down cavity. For difference-frequency generation, we use a periodically poled lithium niobate (PPLN) crystal, pumped by a Nd:YAG laser (signal wave) and a diode laser (pump wave) with a tapered amplifier. A maximum power of 280 μW near λ=3.3 μm is achieved using a pump power of 180 mW at 807 nm, a signal power of 890 mW at 1064.46 nm, and a 50-mm-long PPLN crystal. The resulting system proved to be a unique tool with high sensitivity and specificity for rapid and precise breath testing. We demonstrate spectroscopic online monitoring of ethane traces in exhaled human breath with a precision of 270 parts per trillion (1σ) and a time resolution of 1 s.

[1]  A. Fried,et al.  Development of a tunable mid-IR difference frequency laser source for highly sensitive airborne trace gas detection , 2002, Applied physics. B, Lasers and optics.

[2]  Grant A. D. Ritchie,et al.  Difference frequency generation in periodically poled lithium niobate and its use in the detection of atmospheric methane , 2004 .

[3]  Miles J Padgett,et al.  Development of high-resolution real-time sub-ppb ethane spectroscopy and some pilot studies in life science. , 2005, Applied optics.

[4]  Daniel Halmer,et al.  Fast exponential fitting algorithm for real-time instrumental use , 2004 .

[5]  P De Natale,et al.  Combining a difference-frequency source with an off-axis high-finesse cavity for trace-gas monitoring around 3 microm. , 2006, Optics express.

[6]  Markus W. Sigrist,et al.  Trace-gas sensing in the 3.3-μm region using a diode-based difference-frequency laser photoacoustic system , 2002 .

[7]  Michael Hippler,et al.  High-resolution cavity ring-down absorption spectroscopy of nitrous oxide and chloroform using a near-infrared cw diode laser , 1998 .

[8]  T. H. Risby.  CURRENT STATUS OF CLINICAL BREATH ANALYSIS , 2005 .

[9]  M. Mürtz,et al.  High-resolution cavity leak-out absorption spectroscopy in the 10-μm region , 1999 .

[10]  Daniel Halmer,et al.  Parts per trillion sensitivity for ethane in air with an optical parametric oscillator cavity leak-out spectrometer. , 2004, Optics letters.

[11]  P. De Natale,et al.  A 3.5-mW continuous-wave difference-frequency source around 3 μm for sub-Doppler molecular spectroscopy , 2005, EQEC '05. European Quantum Electronics Conference, 2005..

[12]  P. Hering,et al.  Ultra-sensitive mid-infrared cavity leak-out spectroscopy using a cw optical parametric oscillator , 2002 .

[13]  S. Li,et al.  Tuning and stability of a continuous-wave mid-infrared high-power single resonant optical parametric oscillator , 2002 .

[14]  Daniele Romanini,et al.  Two schemes for trace detection using cavity ringdown spectroscopy , 2004 .

[15]  Daniel Halmer,et al.  Online recording of ethane traces in human breath via infrared laser spectroscopy. , 2003, Journal of applied physiology.

[16]  Paul Rabinowitz,et al.  Trace moisture detection using continuous-wave cavity ring-down spectroscopy. , 2003, Analytical chemistry.

[17]  P. Hering,et al.  Portable difference-frequency laser-based cavity leak-out spectrometer for trace-gas analysis , 2002 .

[18]  P. Aadahl,et al.  A Validated Method for Rapid Analysis of Ethane in Breath and its Application in Kinetic Studies in Human Volunteers , 2003, Free radical research.

[19]  F. Tittel,et al.  Portable fiber-coupled diode-laser-based sensor for multiple trace gas detection , 1999, Applied physics. B, Lasers and optics.

[20]  P. Španěl,et al.  The challenge of breath analysis for clinical diagnosis and therapeutic monitoring. , 2007, The Analyst.

[21]  P. Hering,et al.  Real-time monitoring of ethane in human breath using mid-infrared cavity leak-out spectroscopy , 2001 .