A5030230122- Spectroscopy and Laser Applications
- Atmospheric Ozone and Climate
- Atmospheric and Environmental Gas Dynamics
- Advanced Fiber Laser Technologies
- Atomic and Subatomic Physics Research
- Gas Sensing Nanomaterials and Sensors
- Potato Plant Research
- Climate change impacts on agriculture
- Crop Yield and Soil Fertility
- Laser Design and Applications
- Remote Sensing in Agriculture
- Plant Water Relations and Carbon Dynamics
- Atmospheric chemistry and aerosols
- Photonic and Optical Devices
- Bioactive Natural Diterpenoids Research
- Spectroscopy and Quantum Chemical Studies
- Scientific Measurement and Uncertainty Evaluation
- Analytical Chemistry and Sensors
- Advanced Frequency and Time Standards
- Greenhouse Technology and Climate Control
- Quantum optics and atomic interactions
- Mechanical and Optical Resonators
- Laser-Matter Interactions and Applications
- Chemical Thermodynamics and Molecular Structure
- Light effects on plants
National Institute of Standards and Technology
2013-2024
Material Measurement Laboratory
2006-2023
University of Surrey
2019-2022
National Institute of Standards
2021
California Institute of Technology
2017
Wesleyan University
2017
University of Colorado Boulder
2017
Physical Sciences (United States)
2017
Stanford University
2017
Cameron University
2017
We present low uncertainty measurements of line parameters for 15 rotation-vibration transitions water vapor in the wave number range $7170.27--7183.02\text{ }{\text{cm}}^{\ensuremath{-}1}$. These experiments incorporated frequency-stabilized cavity ring-down spectroscopy and a primary standard humidity generator which produced stable accurately known amount nitrogen carrier gas stream. Intensities shape factors were derived by fitting high-resolution spectra to spectral models that account...
Intensities of lines in the near-infrared second overtone band (3-0) ^{12}C^{16}O are measured and calculated to an unprecedented degree precision accuracy. Agreement between theory experiment better than 1‰ is demonstrated by results from two laboratories involving independent absorption- dispersion-based cavity-enhanced techniques. Similarly, Fourier transform spectroscopy measurements stronger this yield mutual agreement consistency with at level. This set highly accurate intensities can...
A single-mode cavity ring-down spectrometer, which incorporates a stabilized and tuneable comb of resonant frequencies continuous-wave external-cavity diode probe laser, was used to study rovibrational absorption line shapes within the vibrational bands water vapor. This has noise-equivalent coefficient frequency resolution , enables high-precision measurements line-shape effects pressure shifting relatively weak transitions. We investigated room-temperature dependence over range from two...
We discuss the use of single-mode cavity ringdown spectroscopy with pulsed lasers for quantitative gas density and line strength measurements. The approach to gives single exponential decay signals without mode beating, which allows measurements uncertainties near shot-noise limit. technique is demonstrated a 10-cm-long pulsed, frequency-stabilized optical parametric oscillator as light source. A noise-equivalent absorption coefficient 5 x 10(-10) cm(-1) Hz(-1/2) demonstrated, relative...
Traditional electro-optic frequency comb spectrometers rely upon the use of an acousto-optic modulator (AOM) to provide a differential shift between probe and local oscillator (LO) legs interferometer. Here we show that these modulators can be replaced by phase (EOM) which is driven sawtooth waveform induce serrodyne modulation. This approach enables direct spectroscopy performed with single dual-drive Mach–Zehnder (DD-MZM), allowing for lower noise. Further, this method allows simpler...
Main text We present primary spectroscopic measurements of line intensities in the 3-0 vibrational band 12 C 16 O. This international measurement campaign was organized under auspices Consultative Committee for Amount Substance (CCQM) and involved six laboratories carrying out independent more than forty rotation-vibration transitions. A total three techniques on samples pure carbon monoxide were applied this intercomparison, including Fourier transform spectroscopy, cavity ring-down mode...
The quantification of radiation‐use efficiency (RUE), the amount dry matter produced per unit intercepted photosynthetically active radiation, is important for yield modeling and determination potentials in different environments. This study was conducted to determine mean RUE value potato ( Solanum tuberosum L.) its stability across diverse Radiation use computed with growth analysis data from a field experiment four cultivars Hawaii at elevations, experimentation Washington Oregon,...
Abstract Two cavity ring‐down spectrometers were employed to accurately measure line intensities in a series of near‐infrared carbon dioxide bands including (30012) ← (00001), (30013) and (30014) (00001) near 1.6 μm. Relative combined standard uncertainties for these band less than 0.1% showed significant, percent‐level deviations with respect many existing spectroscopic databases (although close agreement was observed the HITRAN 2016 database bands). Further, resulting utilized Total Carbon...
We report Doppler-free two-photon absorption of N$_2$O at $\lambda$ = 4.53 $\mu$m, measured by cavity ring-down spectroscopy. High power was achieved optical self-locking a quantum cascade laser to linear resonator finesse $F$ 22730, and accurate detuning over 400 MHz range relative an frequency comb. At sample pressure p 0.13 kPa, we large cross-section $\sigma_{13}^{(2)}$ 8.0 $\times$ 10$^{-41}$ cm$^4$ s molecule$^{-1}$ for the $Q$(18) rovibrational transition resonant $\nu_0$ 66179400.8 MHz.
Abstract The ability to precisely model methane absorption in the R(6) manifold of 2ν 3 band at atmospheric pressure and temperature conditions is a key technical requirement German‐French, Methane Remote Sensing Lidar (MERLIN) space mission. To this end, 27 high‐resolution high‐signal‐to‐noise‐ratio spectra air‐broadened 12 CH 4 were recorded using variable‐temperature frequency‐stabilized cavity ring‐down spectroscopy apparatus. measurement corresponded sample temperature, pressure, molar...
Using cavity ring-down spectroscopy to probe R-branch transitions of CO in N_{2}, we show that the spectral core line shapes associated with first few rotational quantum numbers, J, can be accurately modeled using a sophisticated profile, provided pressure-dependent area is introduced. This correction vanishes as J increases and always negligible CO-He mixtures. The results are supported by molecular dynamics simulations attributing effect non-Markovian behavior collisions at short times....
ABSTRACT Potato plant dry matter and nutrient accumulation partitioning patterns into various parts of the are important to fine tune management practices that optimize uptake efficiency tuber production-dates printpubdate="07/01/2002". Accumulation nitrogen (N) during growing period were evaluated in this four year study for two potato cultivars high yielding printpubdate="07/01/2002" conditions Columbia Basin region Washington, under irrigated farming. Studies conducted on a Quincy sand,...
The soil and climate conditions prevalent in the Pacific Northwest region are favorable for production of high potato (Solanum tuberosum L.) yields. Much this occurs on coarse, low organic matter, sandy soils which can be subject to wind water erosion, excessive leaching soluble agrichemicals below root zone, particularly when irrigation is not managed adequately. Tuber quality adversely impacted potatoes stress. Therefore, optimal scheduling important support good tubers minimize potential...
Electromagnetically induced transparency (EIT) in K39 and K41 was probed using electro-optic frequency combs generated by applying chirped waveforms to a phase modulator. The carrier tone of the comb served as pump beam necessary optical cycling. Comb tooth spacings narrow 20 kHz were used probe potassium both buffer gas evacuated cells at elevated temperatures. Atomic absorption features 33(5) observed, allowing for lower-state hyperfine splitting be optically measured with fit uncertainty...
Abstract Site‐specific crop management (SSCM) requires that simulation models be applied to subareas of a field test or develop practices. When the number is sufficiently large, should linked with geographic information system (GIS) for ease input data preparation and output analysis. An interface between PC ARC/INFO (a GIS) SIMPO‐TATO potato growth simulator) was developed study ( Solanum tuberosum L.) yield N leaching distributions. The most important distributed parameters were identified...
The effect of finite beam extinction ratio on the precision and accuracy cavity ring-down decay time constant measurements was examined using frequency-agile, rapid scanning, spectroscopy (FARS-CRDS) technique. This new approach to CRDS uses a waveguide-based electro-optic phase modulator (EOM) provide laser as high 80 dB: value that is ≈30 dB greater than typically achieved with acousto-optic-modulator- based switches. We find observed measurement scales inversely ratio, such an EOM...
Retrievals of atmospheric composition from near-infrared measurements require airmass to better than the desired precision composition.The oxygen bands are obvious choices quantify since mixing ratio is fixed over full range conditions.The OCO-2 mission currently retrieving carbon dioxide concentration using A-band for normalization.The 0.25% accuracy has pushed required state-of-the-art spectroscopy.To measure O 2 cross-sections with such through pressure requires a sophisticated line-shape...