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Displaying 51 - 75 of 235

Tight real-time synchronization of a microwave clock to an optical clock across a turbulent air path

April 15, 2016
Author(s)
Hugo Bergeron, Laura C. Sinclair, William C. Swann, Craig Nelson, Jean-Daniel Deschenes, Esther Baumann, Fabrizio R. Giorgetta, Ian R. Coddington, Nathan R. Newbury
The ability to distribute the precise time and frequency from an optical clock to remote platforms could enable future precise navigation and sensing systems. Here we demonstrate tight, real-time synchronization of a remote microwave clock to a master

Dual-comb spectroscopy

April 14, 2016
Author(s)
Ian R. Coddington, Nathan R. Newbury, William C. Swann
Dual-comb spectroscopy is an emerging new spectroscopic tool that exploits the frequency resolution, frequency accuracy, broad bandwidth, and brightness of frequency combs for ultra-high resolution, sensitive broadband spectroscopy. By use of two coherent

Optical system design for femtosecond-level synchronization of clocks

February 13, 2016
Author(s)
Laura C. Sinclair, William C. Swann, Jean-Daniel Deschenes, Hugo Bergeron, Fabrizio R. Giorgetta, Esther Baumann, Michael A. Cermak, Ian R. Coddington, Nathan R. Newbury
Synchronization of optical clocks via optical two-way time-frequency transfer across free-space links can result in time offsets between the two clocks below tens of femtoseconds over many hours. The complex optical system necessary to support such

Femtosecond synchronization of optical clocks over free-space links

December 11, 2015
Author(s)
Jean-Daniel Deschenes, Laura C. Sinclair, Fabrizio R. Giorgetta, William C. Swann, Esther Baumann, Hugo Bergeron, Michael A. Cermak, Nathan R. Newbury
The use of optical clocks/oscillators in future ultra-precise navigation, gravitational sensing, and relativity experiments will require time comparison and synchronization over terrestrial or satellite free-space links. Here we demonstrate full

Broadband phase spectroscopy over turbulent air paths

September 4, 2015
Author(s)
Fabrizio R. Giorgetta, Greg B. Rieker, Esther Baumann, William C. Swann, Laura C. Sinclair, Jonathan Kofler, Ian R. Coddington, Nathan R. Newbury
Broadband atmospheric phase spectra are measured at sub-milliradian uncertainty corresponding to a 10-13 refractive index change, despite strong decoherence from atmospheric turbulence. A phase-sensitive dual-comb spectrometer acquires spectra over 233 cm

A compact optically coherent fiber frequency comb

August 18, 2015
Author(s)
Laura C. Sinclair, Jean-Daniel Deschenes, Lindsay I. Sonderhouse, William C. Swann, Isaac H. Khader, Esther Baumann, Nathan R. Newbury, Ian R. Coddington
We describe design and operation of a robust self-referenced, optically coherent frequency comb. The system robustness is derived from a combination of an optics package based on polarization-maintaining fiber, high signal-to-noise ratio (SNR) detection of

Mid-Infrared Optical Frequency Combs based on Difference Frequency Generation for Dual-Comb Spectroscopy

May 10, 2015
Author(s)
Flavio Caldas da Cruz, Daniel I. Maser, Todd Johnson, Gabriel G. Ycas, Andrew M. Klose, Fabrizio R. Giorgetta, Ian R. Coddington, Nathan R. Newbury, Scott A. Diddams
Mid-infrared femtosecond optical frequency combs at 2.8 - 3.5 υm were produced by difference frequency generation of the spectral components of a near-infrared comb in a 3-mm long MgO:PPLN crystal. We observe strong pump depletion and 9.3 dB parametric

Frequency-Comb-Based Remote Sensing of Greenhouse Gases over Kilometer Air Paths

October 29, 2014
Author(s)
Greg B. Rieker, Fabrizio R. Giorgetta, William C. Swann, Jonathan Kofler, Alexander M. Zolot, Laura C. Sinclair, Esther Baumann, Christopher L. Cromer, G. Petron, Colm Sweeney, P P. Tans, Ian R. Coddington, Nathan R. Newbury
We demonstrate frequency comb tooth-by-tooth measurements of atmospheric gas absorption across a 2-km, turbulent, open-air path through coherent dual-comb spectroscopy. High accuracy, high signal-to-noise transmission spectra are acquired spanning 5990 to

Comb-calibrated laser ranging for three-dimensional surface profiling with micrometer-level precision at a distance

October 6, 2014
Author(s)
Esther Baumann, Fabrizio R. Giorgetta, Jean-Daniel Deschenes, William C. Swann, Ian R. Coddington, Nathan R. Newbury
Non-contact surface mapping at a distance is interesting in diverse applications including industrial metrology, manufacturing, forensics, and artifact documentation and preservation. Frequency modulated continuous wave (FMCW) laser detection and ranging

Precision limitations in coherent laser ranging due to speckle phase noise

August 15, 2014
Author(s)
Esther Baumann, Jean-Daniel Deschenes, Fabrizio R. Giorgetta, William C. Swann, Ian R. Coddington, Nathan R. Newbury
The ultimate precision of coherent laser three-dimensional mapping of a diffusely scattering surface will be determined by speckle noise. Speckle phase noise gives rise both to apparent range outliers and to excess range noise during lateral scans

Speckle phase noise in coherent laser ranging: fundamental precision limitations

August 8, 2014
Author(s)
Esther Baumann, Jean-Daniel Deschenes, Fabrizio R. Giorgetta, William C. Swann, Ian R. Coddington, Nathan R. Newbury
Frequency-modulated continuous-wave laser detection and ranging (FMCW LADAR) measures the range to a surface through coherent detection of the backscattered light from a frequency-swept laser source. The ultimate limit to the range precision of FMCW LADAR

Time-domain stabilization of carrier-envelope phase in femtosecond light pulses

May 7, 2014
Author(s)
Young-Jin Kim, Ian R. Coddington, William C. Swann, Nathan R. Newbury, Joohyung Lee, Seungchul Kim, Seung-Woo Kim
We report a time-domain method of stabilizing the carrier-envelope phase (CEP) of femtosecond pulses. Temporal variations of the pulse envelope and the carrier electric-field phase were separately detected with the aid of intensity cross-correlation and

Operation of an optically coherent frequency comb outside the metrology lab

March 13, 2014
Author(s)
Laura C. Sinclair, Ian R. Coddington, William C. Swann, Archita Hati, Kana Iwakuni, Nathan R. Newbury
Frequency combs can support cutting-edge measurements in areas that include optical clocks and oscillators, high-accuracy frequency and time transfer, precision spectroscopy from the UV to THz regimes, high-accuracy LIDAR, precise microwave photonics, and

High Resolution Frequency Comb Molecular Spectroscopy.

November 3, 2013
Author(s)
Ian R. Coddington, Alexander M. Zolot, Esther Baumann, Fabrizio R. Giorgetta, Greg B. Rieker, Jeffrey W. Nicholson, William C. Swann, Nathan R. Newbury
Frequency combs serve as an extremely high accuracy reference across broad portions of the optical spectrum. Dual frequency combs harness this accuracy and allow for fast and highly fidelity molecular spectroscopy.

High-performance free-space photonic links for frequency/time transfer

September 8, 2013
Author(s)
Nathan R. Newbury, Fabrizio R. Giorgetta, William C. Swann, Laura C. Sinclair, Esther Baumann, Ian R. Coddington
We discuss optical two-way time and frequency transfer over air to connect remote optical clocks/oscillators. This method can link remote sites with a residual timing noise of femtoseconds and a residual fractional accuracy below 10^-18.

The impact of turbulence on high accuracy time-frequency transfer across free space

June 26, 2013
Author(s)
Laura C. Sinclair, Fabrizio R. Giorgetta, William C. Swann, Esther Baumann, Ian R. Coddington, Nathan R. Newbury
Atmospheric optical path-length variations are measured across a 2-km optical link through a frequency comb-based system with femtosecond-level precision. Without mitigation, the turbulent piston effect will severely restrict time-frequency transfer from

A comb-calibrated FMCW LADAR for absolute distance measurements

June 15, 2013
Author(s)
Esther Baumann, Fabrizio R. Giorgetta, Ian R. Coddington, Laura C. Sinclair, Kevin O. Knabe, William C. Swann, Nathan R. Newbury
We present a comb calibrated frequency-modulated continuous wave (FMCW) LADAR system for absolute distance measurements to diffuse or specular surfaces. The FMCW LADAR uses a MEMS-based external cavity laser that is swept quasi-sinusoidally over 1 THz at a

Free-space optical time-frequency transfer over 2 km

June 9, 2013
Author(s)
William C. Swann, Fabrizio R. Giorgetta, Laura C. Sinclair, Esther Baumann, Ian R. Coddington, Nathan R. Newbury
Precision free-space time-frequency transfer could advance fields where present microwave-based transfer is inadequate. We demonstrate an optical free-space link with femtosecond timing deviation and residual instability below 10 −18 at 1000 seconds.

Open-Path Dual-Comb Spectroscopy of Greenhouse Gases

June 9, 2013
Author(s)
Greg B. Rieker, Fabrizio R. Giorgetta, William C. Swann, Ian R. Coddington, Laura C. Sinclair, Christopher L. Cromer, Esther Baumann, Alexander M. Zolot, Nathan R. Newbury
Frequency-comb spectroscopy in the near-infrared is used to measure atmospheric CO2 and H2O concentrations over a 2-km outdoor open-air path. This technique shows promise for measurements over length scales between point sensors and satellite systems.

Precision metrology with coherent dual frequency combs

May 12, 2013
Author(s)
Nathan R. Newbury, Esther Baumann, Ian R. Coddington, Fabrizio R. Giorgetta, Greg B. Rieker, Laura C. Sinclair, William C. Swann, Alexander M. Zolot
Frequency combs have enabled a wide range of applications because of their unique combination of coherence and broad bandwidth. The comb provides 100,000's of comb teeth at precise, well-known optical frequencies that can support broadband accurate

Optical two-way time and frequency transfer over free space

April 28, 2013
Author(s)
Fabrizio R. Giorgetta, William C. Swann, Laura C. Sinclair, Esther Baumann, Ian R. Coddington, Nathan R. Newbury
The transfer of high-quality time-frequency signals between remote locations underpins many applications, including precision navigation and timing, clock-based geodesy, long-baseline interferometry, coherent radar arrays, tests of general relativity and

Absolute spectroscopy of N2O near 4.5 um with a comb-calibrated, frequency-swept quantum cascade laser spectrometer

January 14, 2013
Author(s)
Kevin O. Knabe, Paul A. Williams, Fabrizio R. Giorgetta, Michael Radunsky, Chris Armacost, Sam Crivello, Nathan R. Newbury
We present absolute line center frequencies for 24 fundamental nu-3 ro-vibrational P-branch transitions near 4.5 um in N2O with an absolute frequency uncertainty of 800 kHz. The spectra were acquired with a swept laser spectrometer consisting of an

Broad-band frequency references in the near-infrared: accurate dual comb spectroscopy of methane and acetylene

December 1, 2012
Author(s)
Alexander M. Zolot, Fabrizio R. Giorgetta, Esther Baumann, William C. Swann, Ian R. Coddington, Nathan R. Newbury
The Doppler-limited spectra of methane between 176 THz and 184 THz (5870-6130 cm −1) and acetylene between 193 THz and 199 THz (6430-6630 cm −1) are acquired via comb-tooth resolved dual comb spectroscopy with frequency accuracy traceable to atomic