Michael L. Dennis

“They Don’t Give You No Note If It’s Got Fentanyl”: Using Cognitive Interviews to Understand Self-report and Urine Drug Screen Discrepancies

Dennis P. Watson, Katie A.J. Clark, Michael L. Dennis, Christine E. Grella et autres

Background: Fentanyl, a highly potent synthetic opioid, is now involved in the majority of drug overdose deaths in the United States. Discrepancies between substance use self-reports and urine drug screens (UDS) are common, especially when users are unaware of fentanyl adulteration. Objectives: …

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Recent Incarceration and Minoritized Racial Status as Barriers to the Effectiveness of Recovery Management Checkups

Jeffrey H. Kahn, M. Kate Hart, Dennis P. Watson, Caroline B. Allen et autres

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Tradeoff between the Brillouin and transverse mode instabilities in Yb-doped fiber amplifiers

Joshua T. Young, A. J. Goers, David M. Brown, Michael L. Dennis et autres

The Brillouin instability (BI) due to stimulated Brillouin scattering (SBS) and the transverse (thermal) mode instability (TMI) due to stimulated thermal Rayleigh scattering (STRS) limit the achievable power in high-power lasers and amplifiers. The pump power threshold for BI increases as the …

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Accurate and efficient modeling of the transverse mode instability in high-energy laser amplifiers using the phase-matched model

Curtis R. Menyuk, Joshua T. Young, Jonathan Hu, Andrew J. Goers et autres

We review recent work in which we developed a phase-matched model to study the transverse mode instability (TMI) in high-energy laser amplifiers. The standard models for TMI have contributions that vary rapidly compared to the beat period between the fundamental mode and …

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Accurate and efficient modeling of the transverse mode instability in high energy laser amplifiers

Curtis R. Menyuk, Joshua T. Young, Jonathan Hu, A. J. Goers et autres

We study the transverse mode instability (TMI) in the limit where a single higher-order mode (HOM) is present. We demonstrate that when the beat length between the fundamental mode and the HOM is small compared to the length scales on which the …

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Accurate and Efficient Modeling of the Transverse Mode Instability in\n High Energy Laser Amplifiers

Curtis R. Menyuk, Joshua T. Young, Jonathan Hu, A. J. Goers et autres

We study the transverse mode instability (TMI) in the limit where a single higher-order mode (HOM) is present. We demonstrate that when the beat length between the fundamental mode and the HOM is small compared to the length scales on which the …

Progress in Photonic Digital Radio Transceivers

Thomas R. Clark, Jean H. Kalkavage, Natalie Bos, Robert L. Schmid et autres

Utilizing direct radio frequency photonic downsampling and upsampling, photonic digital radio transceiver architectures are promising systems for the realization of frequency agile software-defined radios in the microwave and millimeter wave frequency bands. We will explore recent progress and discuss system design issues …

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Comparison of Optical Frequency Comb and Sapphire Loaded Cavity Microwave Oscillators

Justin W. Zobel, Michele Giunta, Andrew J. Goers, Robert L. Schmid et autres

The single-sideband phase noise power spectral density and Allan deviation of a portable microwave oscillator system based on an optical frequency comb stabilized to an ultra-low expansion Fabry-Perot reference cavity is characterized at carrier frequencies of 4.0, 8.0, and 16.0 GHz. Compared …

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Future State Plane Coordinate System for the United States

Michael L. Dennis, W. A. Stone, Donna J. Caccamise

Precision Microwave Frequency Transfer over Dual Free-Space Optical Links

Eric J. Adles, N.G. Bos, Brice M. Cannon, Michael L. Dennis et autres

We have developed a complete system for the transfer of an X-band microwave reference frequency over two independent free-space optical links. The links use optical frequency combs, linear optical sampling, and two-way time transfer techniques to derive femtosecond precision correction signals for …

Synchronization of clocks through 12 km of strongly turbulent air over a city

Laura C. Sinclair, William C. Swann, Hugo Bergeron, Esther Baumann et autres

We demonstrate real-time, femtosecond-level clock synchronization across a low-lying, strongly turbulent, 12-km horizontal air path by optical two-way time transfer. For this long horizontal free-space path, the integrated turbulence extends well into the strong turbulence regime corresponding to multiple scattering with a …

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Enhanced link availability for free space optical time-frequency transfer using adaptive optic terminals

Keith G. Petrillo, Michael L. Dennis, Juan C. Juarez, Katherine T. Souza et autres

Optical time and frequency transfer offers extremely high precision wireless synchronization across multiple platforms for untethered distributed systems. While large apertures provide antenna gain for wireless systems which leads to robust link budgets and operation over increased distance, turbulence disrupts the beam …

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