Highly Sensitive Cavity-Enhanced Sub-Doppler Spectroscopy of a Molecular Overtone Band with a 1.66 µm Tunable Diode Laser

Ishibashi, Chikako; Sasada, Hiroyuki

doi:10.1143/jjap.38.920

Cited by 43 publications

(23 citation statements)

References 19 publications

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“…In particular, methods and problems associated with the conversion of absorption information into concentrations are addressed. This is important because firstly, while [1][2][3][4] absorption sensitivity values are excellent tools for comparing different sensors, they do not give a good idea of the utility of a specific sensor for a particular analyte. Secondly, two different sensors having the same absorption sensitivity may not yield the same possible concentration sensitivities because of logistical differences in sensor operation.…”

Section: Layoutmentioning

confidence: 99%

“…i (#) is the absorption cross-section in cm 2 /molecule of the i th chemical at ν, N i is its number density in molecules/cm 3 , and the sum is over all chemicals present. For gas samples, it is often convenient to use an alternate expression for !…”

Section: Sensitivity and Figures Of Meritmentioning

confidence: 99%

“…This is the typical regime for Pound-Drever-Hall (PDH) laser-cavity locking [12][13][14], and for the resonant sideband detection of NICE-OHMS. [1][2][3] On the other hand, when the modulation frequency Ω is less than or of the order of the linewidth of the features being detected, the optimum value of the frequency modulation depth ! "# approaches a value that is approximately the same as the linewidth, the exact value depending again on the demodulation technique.…”

Section: -11mentioning

confidence: 99%

“…The next step we have taken in the development of cavity-enhanced sensors was to use the technique of resonant sideband detection, or NICE-OHMS [1][2][3], discussed theoretically in Section 2.5. Figure 3.9 shows the NICE-OHMS experimental arrangement.…”

Section: Cavity-enhanced Sensors Using Nice-ohmsmentioning

confidence: 99%

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Ultra-Trace Chemical Sensing with Long-Wave Infrared Cavity-Enhanced Spectroscopic Sensors

Taubman¹,

Myers²,

Cannon³

et al. 2003

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Sensors for most of these missions will require extreme chemical sensitivity and selectivity because the signature chemicals of importance are expected to be present in low concentrations or have low vapor pressures, and the ambient air is likely to contain pollutants or other chemicals with interfering spectra. Cavity-enhanced chemical sensors (CES) that draw air samples into optical cavities for laser-based interrogation of their chemical content promise real-time, in-situ chemical detection with extreme sensitivity to specified target molecules and superb immunity to spectral interference and other sources of noise.PNNL is developing CES based on quantum cascade (QC) lasers that operate in the midwave infrared (MWIR -3 to 5 microns) and long-wave infrared (LWIR -8 to 14 microns), and CES based on telecommunications lasers operating in the short-wave infrared (SWIR -1 to 2 microns). All three spectral regions are promising because smaller molecular absorption cross sections in the SWIR are offset by the superior performance, maturity, and robustness of SWIR lasers, detectors, and other components, while the reverse is true for the MWIR and LWIR bands. PNNL's research activities include identification of signature chemicals and quantification of their spectroscopy, exploration of novel sensing techniques, and experimental sensor system construction and testing. In FY02, experimental QC laser systems developed with DARPA funding were used to explore continuous-wave (cw) CES in various forms culminating in the NICE-OHMS technique [1-3] discussed below. In FY02 PNNL also built an SWIR sensor to validate utility of the SWIR spectral region for chemical sensing, and explore the science and engineering of CES in field environments. The remainder of this report is devoted to PNNL's LWIR CES research.iv During FY02 PNNL explored the performance and limitations of several detection techniques in the LWIR including direct cavity-enhanced absorption, cavity-dithered phase-sensitive detection and resonant sideband cavity-enhanced detection. This latter technique is also known as NICE-OHMS, which stands for Noise-Immune CavityEnhanced Optical Heterodyne Molecular Spectroscopy. This technique, pioneered in the near infrared (NIR) by Dr J. Hall and coworkers at the University of Colorado, is one of the most sensitive spectroscopic techniques currently known. In this report, the first demonstration of this technique in the LWIR is presented. The noise-equivalent absorption sensitivities (NEAS) achieved in these experiments are promising, but must be translated into parts-per-billion volume sensitivities to specific chemicals at the air intake in the presence of interferents to assess practical LWIR CES capabilities and identify the most promising CES techniques, configurations, and modus operandi. While NEAS are relatively easy to measure in the laboratory, the translation to practical sensitivity and selectivity limits involves numerous challenging science and engineering questions. PNNL's goals for FY03 include improving the...

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Section: Layoutmentioning

confidence: 99%

Section: Sensitivity and Figures Of Meritmentioning

confidence: 99%

Section: -11mentioning

confidence: 99%

Section: Cavity-enhanced Sensors Using Nice-ohmsmentioning

confidence: 99%

See 2 more Smart Citations

Ultra-Trace Chemical Sensing with Long-Wave Infrared Cavity-Enhanced Spectroscopic Sensors

Taubman¹,

Myers²,

Cannon³

et al. 2003

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show abstract

“…The experimental setup is similar to that of our previous work (11). Briefly, the extended-cavity semiconductor laser used as a radiation source is continuously tunable from 1.63 to 1.67 m and has a typical output power of 1 mW.…”

mentioning

confidence: 99%

Near-Infrared Laser Spectrometer with Sub-Doppler Resolution, High Sensitivity, and Wide Tunability: A Case Study in the 1.65-μm Region of CH3I Spectrum

Ishibashi

Sasada

2000

Journal of Molecular Spectroscopy

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Laser Spectrometric Techniques in Analytical Atomic Spectrometry

Axner

Galbács

2012

Encyclopedia of Analytical Chemistry

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The main purpose of this article is to describe the theory, instrumentation, and analytical performance of laser analytical atomic spectrometry, focusing on absorption, fluorescence, and ionization techniques. The structure of the article is such that it first provides an outline of the theory of light‐matter interactions that prevail for each type of technique as well as of the most common modulation techniques, primarily, wavelength modulation (WM). This is followed by a section that covers the most important types of instrumentation used. The article finally provides a detailed discussion on the specific instrumentation, mode of operation, use, performance, and applications (both analytical and diagnostic) of each technique. In terms of laser atomic absorption, the focus of the discussion is on the use of approaches to enhance the detection capability by either reducing the amount of noise (as is done by the wavelength modulation absorption spectrometry (WMAS) technique) or by providing an extended interaction length (giving rise to cavity‐enhanced absorption spectrometry (CEAS) techniques in general, and cavity ring‐down spectrometry (CRDS) in particular). Laser atomic fluorescence techniques (often referred to as laser‐excited atomic fluorescence spectrometry ( LEAFS )) as well as laser ionization techniques (termed either laser‐enhanced ionization ( LEI ) or resonance ionization spectrometry ( RIS )) are also covered in some detail. It is shown that several of these techniques are capable of detecting a variety of elements in liquid samples down to low picogram per milliliter (pg mL −1 ) or parts‐per‐trillion (ppt) concentrations and in low femtogram amounts. Also other properties of the techniques, e.g. selectivity and linear dynamic range (LDR), are in general superior to those of conventional (nonlaser‐based techniques).

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Highly Sensitive Cavity-Enhanced Sub-Doppler Spectroscopy of a Molecular Overtone Band with a 1.66 µm Tunable Diode Laser

Cited by 43 publications

References 19 publications

Ultra-Trace Chemical Sensing with Long-Wave Infrared Cavity-Enhanced Spectroscopic Sensors

Ultra-Trace Chemical Sensing with Long-Wave Infrared Cavity-Enhanced Spectroscopic Sensors

Near-Infrared Laser Spectrometer with Sub-Doppler Resolution, High Sensitivity, and Wide Tunability: A Case Study in the 1.65-μm Region of CH3I Spectrum

Laser Spectrometric Techniques in Analytical Atomic Spectrometry

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