Comparison of gas temperatures measured by coherent anti-Stokes Raman spectroscopy (CARS) of O_2 and N_2

Reichardt, Thomas A.; Schrader, Paul E.; Farrow, Roger L.

doi:10.1364/ao.40.000741

Cited by 25 publications

(21 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The great flexibility of the CARS technique makes it a popular instrument for performing thermometry measurements for various gases: nitrogen and oxygen [11][12][13], carbon dioxide [14], as well as methane and hydrogen [15]. CARS techniques allow concentration and temperature measurements in harsh environments and at high temperature during the combustion process [16,17].…”

Section: Introductionmentioning

confidence: 99%

Collinear FAST CARS for Chemical Mapping of Gases

et al. 2017

View full text Add to dashboard Cite

Featured Application: remote spectroscopic mapping of gas emissions and leaks. Abstract:We examine the concentration dependence of the Coherent Anti-Stokes Raman Scattering (CARS) signal obtained for gas mixtures at various conditions using the Femtosecond Adaptive Spectroscopic Technique (FAST). We use the CARS signal of the Q-branch vibrational oscillation of molecular oxygen (1556 cm −1 ) to confirm the quadratic dependence of the coherent signal on the number of molecules in a test volume. In addition, we demonstrate multi-shot FAST CARS imaging of a gas flow in free space by raster-scanning the area of interest.

show abstract

Section: Introductionmentioning

confidence: 99%

Collinear FAST CARS for Chemical Mapping of Gases

et al. 2017

View full text Add to dashboard Cite

show abstract

“…CARS spectra are similar to spontaneous Raman spectra, and CARS has been demonstrated in forward scattering [68], as well as backscattered geometries in Si and other solid-state materials [69,70]. To our knowledge, CARS has never been exploited for solid-state thermometry, but has been extensively used for gas-phase temperature measurements at Sandia and elsewhere [28,[71][72][73].…”

Section: Coherent Anti-stokes Raman Scattering (Cars)mentioning

confidence: 79%

Noncontact surface thermometry for microsystems: LDRD final report.

Abel

Beecham

Graham

et al. 2006

View full text Add to dashboard Cite

We describe a Laboratory Directed Research and Development (LDRD) effort to develop and apply laser-based thermometry diagnostics for obtaining spatially resolved temperature maps on working microelectromechanical systems (MEMS). The goal of the effort was to cultivate diagnostic approaches that could adequately resolve the extremely fine MEMS device features, required no modifications to MEMS device design, and which did not perturb the delicate operation of these extremely small devices. Two optical diagnostics were used in this study: microscale Raman spectroscopy and microscale thermoreflectance. Both methods use a low-energy, nonperturbing probe laser beam, whose arbitrary wavelength can be selected for a diffraction-limited focus that meets the need for micron-scale spatial resolution. Raman is exploited most frequently, as this technique provides a simple and unambiguous measure of the absolute device temperature for most any MEMS semiconductor or insulator material under steady state operation. Temperatures are obtained from the spectral position and width of readily isolated peaks in the measured Raman spectra with a maximum uncertainty near ±10 K and a spatial resolution of about 1 micron. Application of the Raman technique is demonstrated for V-shaped and flexure-style polycrystalline silicon electrothermal actuators, and for a GaN high-electron-mobility transistor. The potential of the Raman technique for simultaneous measurement of temperature and inplane stress in silicon MEMS is also demonstrated and future Raman-variant diagnostics for ultra spatiotemporal resolution probing are discussed. Microscale thermoreflectance has been developed as a complement for the primary Raman diagnostic. Thermoreflectance exploits the small-but-measurable temperature dependence of surface optical reflectivity for diagnostic purposes. The temperaturedependent reflectance behavior of bulk silicon, SUMMiT-V polycrystalline silicon films and metal surfaces is presented. The results for bulk silicon are applied to silicon-on-insulator (SOI) fabricated actuators, where measured temperatures with a maximum uncertainty near ±9 K, and 0.75-micron inplane spatial resolution, are achieved for the reflectance-based measurements. Reflectance-based temperatures are found to be in good agreement with Raman-measured temperatures from the same device. Constructive peer-reviews of this report were provided by Ed Piekos and Carlton Brooks. 4 ACKNOWLEDGEMENTS5

show abstract

“…We used oxygen for the temperature determination since a lean oxy-fuel flame is investigated. Additionally, the vibrational CARS process for diatomic molecules is still easier to model and therefore such CARS signals are simpler to evaluate [25]. A detailed description of the CARS process can be found, e.g.…”

Section: Cars Setupmentioning

confidence: 99%