NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.

Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.

U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: Joseph T. Hodges (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 51 - 75 of 112

High-Accuracy Measurements of the Vapor Pressure of Ice Referenced to the Triple Point

December 6, 2013
Author(s)
Katarzyna E. Bielska, Daniel K. Havey, Gregory E. Scace, D Lisak, Allan H. Harvey, Joseph T. Hodges
The vapor pressure of hexagonal (Ih) ice was measured over the temperature range 175 K to 253.4 K and referenced to the value at the triple point of water. This experiment combined a highly accurate humidity generation system containing an ice-coated

Spectral line shapes investigation with Pound-Drever-Hall-locked frequency-stabilized cavity ring-down spectroscopy

October 23, 2013
Author(s)
A. Cygan, S. Wojtewicz, J. Domyslawska, Piotr Maslowski, Katarzyna E. Bielska, M. Piwinski, K. Stec, R.S. Trawinski, F Ozimek, C. Radzewicz, Hisashi Abe, T. Ido, Joseph T. Hodges, D Lisak, R. Ciurylo
A review of recent experiments involving a newly developed Pound-Drever-Hall-locked frequency-stabilized cavity ring-down spectroscopy (PDH-locked FS-CRDS) system is presented. By comparison to standard FS-CRDS, the PDH lock of the probe laser to the ring

Rapid scan absorption spectroscopy using a waveform-driven electro-optic phase modulator in the 1.6- 1.65 ym region

September 25, 2013
Author(s)
Kevin O. Douglass, Stephen Maxwell, Gar W. Truong, Roger D. van Zee, Joseph T. Hodges, David Long, David F. Plusquellic
A method is reported for performing fast optical frequency scans over a bandwidth of 36.9 GHz and at a sweep rate of 40 kHz using a single second-order sideband from an electro-optic phase modulator driven by an arbitrary waveform generator. Single

Direct measurements of mass-specific optical cross sections of single component aerosol mixtures

July 22, 2013
Author(s)
James Radney, Xiaofei Ma, Keith A. Gillis, Michael R. Zachariah, Joseph T. Hodges, Christopher D. Zangmeister
The optical properties of atmospheric aerosols vary widely, being dependent upon particle composition, morphology and mixing state. This diversity and complexity of aerosols motivates measurement techniques that can discriminate and quantify a variety of

Differential cavity ring-down spectroscopy

May 9, 2013
Author(s)
Jeremie B. Courtois, Katarzyna E. Bielska, Joseph T. Hodges
We present a technique called differential cavity ring-down spectroscopy (D-CRDS) for reducing etaloning effects in a ring-down spectrometer. The method relies on alternately measuring and then subtracting intra-cavity losses associated with pairwise TEM00

Frequency-agile, rapid scanning spectroscopy

April 28, 2013
Author(s)
Gar W. Truong, Kevin O. Douglass, Stephen E. Maxwell, Roger D. van Zee, David F. Plusquellic, Joseph T. Hodges, David A. Long
Challenging applications in trace gas analyses require high precision and acquisition rates.1-4 Many continuous-wave laser spectroscopy techniques exhibit significant sensitivity and potential;5 however, their scanning rates are slow because they rely upon

Coupled-cavity ring-down spectroscopy technique

August 6, 2012
Author(s)
Jeremie B. Courtois, Joseph T. Hodges
We present a technique called coupled-cavity ring-down spectroscopy (CC-RDS) for controlling the finesse of an optical resonator. Applications include extending the sensitivity and dynamic range of a cavity-enhanced spectrometer, as well as widening the

Frequency-stabilized cavity ring-down spectroscopy

March 21, 2012
Author(s)
David A. Long, A. Cygan, Roger D. van Zee, Mitchio Okumura, C. E. Miller, D Lisak, Joseph T. Hodges
This Frontiers article describes frequency-stabilized cavity ring-down spectroscopy (FS-CRDS), an ultraprecise refinement of conventional cw-CRDS. We review the technique and highlight some recent studies which have utilized FS-CRDS to perform precision

Spectroscopic Measurement of the Vapour Pressure of Ice

January 1, 2012
Author(s)
Katarzyna E. Bielska, Daniel K. Havey, Gregory E. Scace, D Lisak, Joseph T. Hodges
We present a laser absorption technique to measure the vapor pressure of ice. This method is referenced to the triple point state of water and uses frequency-stabilized cavity ring-down spec- troscopy to probe four rotation-vibration transitions of H16 2 O

Construction of a High Power OPO Laser system for Differential Absorption LIDAR

September 13, 2011
Author(s)
Kevin O. Douglass, Stephen E. Maxwell, David F. Plusquellic, Joseph T. Hodges, Roger D. van Zee, Daniel V. Samarov, James R. Whetstone
Our goal is to develop and characterize optical measurement technology to enable accurate quantification of greenhouse-gas emissions to meet the needs of industry and regulators. A 1064 nm pumped high energy optical parametric oscillator (OPO) operating

PDH-locked, frequency-stabilized cavity ring-down spectrometer

June 16, 2011
Author(s)
Joseph T. Hodges, A. Cygan, Piotr Maslowski, Katarzyna E. Bielska, S. Wojtewicz, J. Domyslawska, Hisashi Abe, R.S. Trawinski, R. Ciurylo
We describe a high sensitivity and high spectral resolution laser absorption spectrometer based upon the frequency-stabilized cavity ring-down spectroscopy (FS-CRDS) technique. We used the Pound-Drever-Hall (PDH) method to lock the probe laser to the high

Amplification of the optical absorption cross section for aerosols of soot with a nonabsorbing coating from photoacoustic measurements

May 13, 2011
Author(s)
Pedro Bueno, Daniel K. Havey, George W. Mulholland, Joseph T. Hodges, Keith A. Gillis, Russell R. Dickerson, Michael R. Zachariah
A quantitative understanding of the absorption and scattering properties of mixed soot and aerosol particles is necessary for evaluating the Earth's energy balance. Uncertainty in the net radiative forcing of atmospheric aerosols is relatively large and

Standard Photoacoustic Spectrometer: Model and Validation using O2 A-Band Spectra

June 30, 2010
Author(s)
Keith A. Gillis, Daniel K. Havey, Joseph T. Hodges
We model and measure the absolute response of an intensity-modulated photoacoustic spectrometer comprising a 10 cm long resonator and having a Q-factor of approximately 30. We present a detailed theoretical analysis of the system and predict its response

A Second-Generation NIST Gravimetric Hygrometer

April 1, 2010
Author(s)
Christopher W. Meyer, Joseph T. Hodges, Gregory E. Scace, James R. Whetstone, R W. Hyland
A second-generation primary hygrometer has been completed at the National Institute of Standards and Technology (NIST). A gravimetric hygrometer measures humidity by separating the water from the carrier gas using desiccants and afterwards independently

Ultra-Sensitive Optical Measurements of High-J Transitions in the O2 A-band

November 24, 2009
Author(s)
Daniel K. Havey, Joseph T. Hodges, David A. Long, Mitchio Okumura, Charles E. Miller
We report frequency-stabilized cavity ring-down spectroscopy measurements of high-J O2 A-band magnetic dipole line parameters. Our goals were to measure intensities and line shape parameters for the primary isotopologue of O2 in the A-band region and to

Calibration of Hygrometers with the Hybrid Humidity Generator

December 14, 2008
Author(s)
Christopher W. Meyer, Joseph T. Hodges, Peter H. Huang, W Wyatt Miller, Dean C. Ripple, Gregory E. Scace
We describe here the calibration of customer hygrometers using a new humidity generator that has been commissioned at the National Institute of Standards and Technology. The NIST Hybrid Humidity Generator (HHG) generates frost/dew points from –70 °C to +85
Was this page helpful?