About

David W. Hahn is a professor and Eminent Scholar in the Department of Aerospace and Mechanical Engineering at the University of Arizona, where he also serves as the dean of the College of Engineering. He specializes in thermal sciences and laser-based diagnostics, with research interests that include renewable energy and biophotonics. Hahn has over twenty years of experience in higher education, working with national agencies and laboratories, and is dedicated to ensuring engineering is accessible to everyone. Prior to his current role, Hahn spent two decades at the University of Florida, where he served as the chair of mechanical and aerospace engineering. During his tenure, he contributed to the development of a significant student design center, expanded student enrollment in his department, and increased the representation of female students in mechanical and aerospace engineering to 20%, which is about 50% above the national average. He has been recognized as the Herbert Wertheim College of Engineering Teacher/Scholar of the Year and Advisor/Mentor of the Year, and received the Outstanding Support of Women in Engineering Award from the UF Society of Women Engineers. Hahn is a fellow of the American Society of Mechanical Engineers, the Optical Society, and the Society for Applied Spectroscopy. His research career began as an NRC postdoctoral associate in the electro-optics branch of the U.S. Food and Drug Administration Center for Devices and Radiological Health. He also spent four years at Sandia National Laboratories as a postdoctoral researcher and member of the technical staff. He studied mechanical engineering at Louisiana State University, earning his bachelor's degree in 1986 and his doctorate in 1992. In 2014, he received the Alumni Achievement Award from his home department.

Research topics

• Environmental chemistry
• Chemistry
• Optics
• Atomic physics
• Materials science

Selected publications

• Effects of Ablative Laser Energy Deposition on Supersonic Flow Structure

  2026-01-08

  articleSenior author

  Ablative laser energy deposition on aluminum targets was performed in a Mach 4 vacuum-driven wind tunnel (freestream unit Reynolds Number of Re' = 4.34 × 10^6 m^-1), aiming to disrupt the high-speed laminar boundary layer and flow structures. Schlieren imaging, pressure measurements, and atomic emission spectroscopy were utilized for diagnostics of the flow structures, laser ablation of the target, high-speed and temperature interactions, and the ensuing flow phenomena. Laser ablation of the targets was performed with up to thirty consecutive 6-ns, 2.0-J laser pulses from a 1064-nm, Nd:YAG laser operating at 10 Hz. The interaction of high-speed fluid flow generated by the wind tunnel and the laser-induced phenomena created complex and transient phenomena that included shock-boundary layer interactions, laser-induced shock waves and oblique shocks, advection of the laser-induced plasma, interaction between the leading-edge oblique shock and the laser-induced plasma and the laser-induced shock waves, and shock-shock interactions. The deposition of laser energy caused a significant disruption of the laminar boundary layer upstream and downstream from the ablation site that resembled turbulent spot. Pressure measurements showed the presence of two main laser-induced pressure spikes that decayed over time and approached the speeds of the fast and slow acoustic waves. Simultaneous laser-induced flow disruption and laser-induced plasma spectroscopy were demonstrated. Atomic and ionic plasma emissions were detected via an atomic emission spectroscopy probe to investigate the laser-induced plasma. The results showed the potential of pulsed lasers as an effective means of control and disruption of air flow around supersonic vehicles.

  PublisherDOI

• Laser-induced breakdown spectroscopy for the characterization of certified reference materials containing rare earth elements

  Spectrochimica Acta Part B Atomic Spectroscopy · 2025-12-03 · 3 citations

  articleSenior author
  PublisherDOI

• Laser Communication Relay Demonstration (LCRD) Optimetrics Experiment

  2024-03-02 · 2 citations

  article

  Within this paper, we report on an Optimetrics experiment conducted on the National Aeronautics and Space Administration (NASA) Laser Communication Relay Demonstration (LCRD) mission. The high precision two-way ranging is conducted on the optical communications link between the LCRD space terminal in a geosynchronous orbit and the Optical Ground Station 1 (OGS-1) at Table Mountain, California, and is referred to as optimetrics ranging.The receiver to transmitter clock loopback is implemented in the LCRD space modem. A digital dual mixer time difference phase meter (DDMTD) is implemented in the OGS-1 ground modem. The round-trip light time is measured by counting the frame and data clock ticks between transmitter and receiver frame synchronization markers for coarse range, and the relative phase of the transmit and receive clock for high precision range. This approach provides coverage for all potential ranges with no ranging ambiguity. The flight modem FPGA code was modified for frame and data clock loopback and the OGS-1 FPGA code was modified for the DDMTD phase meter implementation.The experiment team conducted a 36-hour continuous ranging measurement. Preliminary two-way optimetrics ranging data show a noise floor of 3 mm (rms). It shows the same performance as our theoretical noise analysis and ground-based tests with spare flight modems.For reference and comparison, traditional Radio Frequency (RF) ranging between LCRD and OGS-1 was conducted at the same time and indicates a ranging noise floor of 30 cm (rms). Other telemetry and relevant environmental parameters, such as weather and atmosphere temperature, were also collected for the offline data processing.The high precision range measurements from the laser communications data link clock and clock phase are performed simultaneously with the continuous optical communication. No extra hardware was added to the existing system. This high precision optimetrics measurement implementation provides alternative ranging measurements for orbit determination (OD) and flight dynamics calculations with higher precision. We foresee a significant OD improvement for accurate navigation upon implementation in future optical communication systems.

  PublisherDOI

• Landmark Publications in Analytical Atomic Spectrometry: Fundamentals and Instrumentation Development

  Applied Spectroscopy · 2024-06-16 · 2 citations

  articleOpen access

  The almost-two-centuries history of spectrochemical analysis has generated a body of literature so vast that it has become nearly intractable for experts, much less for those wishing to enter the field. Authoritative, focused reviews help to address this problem but become so granular that the overall directions of the field are lost. This broader perspective can be provided partially by general overviews but then the thinking, experimental details, theoretical underpinnings, and instrumental innovations of the original work must be sacrificed. In the present compilation, this dilemma is overcome by assembling the most impactful publications in the area of analytical atomic spectrometry. Each entry was proposed by at least one current expert in the field and supported by a narrative that justifies its inclusion. The entries were then assembled into a coherent sequence and returned to contributors for a round-robin review. A total of 48 scientists participated in this endeavor, contributing a combined list of 1055 individual articles spanning 17 sub-disciplines of spectrochemical analysis into what the current community views as "key" publications. Of these cited articles, 60 received nominations from four or more scientists, establishing them as the most indispensable reading materials. The outcome of this collaborative effort is intended to serve as a valuable resource not only for current practitioners in atomic spectroscopy but also for present and future students who represent coming generations of analytical atomic spectroscopists.

  PublisherOA PDFDOI

• Analysis of Copper and Lead in Aerosols with Laser-Induced Breakdown Spectroscopy

  Photonics · 2024-11-25 · 5 citations

  articleOpen accessSenior author

  Laser-induced breakdown spectroscopy (LIBS) was applied to the analysis of aerosolized Cu- and Pb-bearing particles generated from aqueous solutions. A nitrogen-driven nebulizer was utilized to aerosolize Cu- and Pb-spiked solutions. The liquid matrix of the aqueous droplets was evaporated before the LIBS analysis, and the remaining gas-phase analyte-rich aerosols were analyzed in a LIBS system that featured a 1064 nm Nd:YAG laser, a Czerny–Turner spectrometer, and an ICCD camera. The Cu and Pb concentrations in the aerosol streams were 0.26–1.29 ppm and 0.40–1.19 ppm, respectively. Laser diffraction and the particle size distributions of the aqueous aerosols were obtained to indirectly demonstrate the evaporation of the liquid matrix. Highly linear calibration curves (R2 = 0.995 for Cu and R2 = 0.987 for Pb) and acceptable limits of detection (2 ppb for Cu and 9 ppb for Pb) and quantification (5 ppb and 28 ppb) were obtained. The applications of the presented methodology include the near-real-time and in situ analysis of wastewater and gas-phase aerosols contaminated with heavy metals.

  PublisherDOI

• Quantitation of total antibody (tAb) from antibody drug conjugate (ADC) PYX-201 in rat and monkey plasma using an enzyme-linked immunosorbent assay (ELISA) and its application in preclinical studies

  Journal of Pharmaceutical and Biomedical Analysis · 2023-05-08 · 10 citations

  article
  PublisherDOI

• Flame stabilizer for stagnation flow reactor

  OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 2023-01-23

  articleOpen access1st authorCorresponding

  A method of stabilizing a strained flame in a stagnation flow reactor. By causing a highly strained flame to be divided into a large number of equal size segments it is possible to stablize a highly strained flame that is on the verge of extinction, thereby providing for higher film growth rates. The flame stabilizer is an annular ring mounted coaxially and coplanar with the substrate upon which the film is growing and having a number of vertical pillars mounted on the top surface, thereby increasing the number of azimuthal nodes into which the flame is divided and preserving an axisymmetric structure necessary for stability.

  PublisherOA PDF

• Method of growing films by flame synthesis using a stagnation-flow reactor

  OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 2023-01-23

  articleOpen access1st authorCorresponding

  A method of stabilizing a strained flame in a stagnation flow reactor. By causing a highly strained flame to be divided into a large number of equal size segments it is possible to stablize a highly strained flame that is on the verge of extinction, thereby providing for higher film growth rates. The flame stabilizer is an annular ring mounted coaxially and coplanar with the substrate upon which the film is growing and having a number of vertical pillars mounted on the top surface, thereby increasing the number of azimuthal nodes into which the flame is divided and preserving an axisymmetric structure necessary for stability.

  PublisherOA PDF

• Detection of Off-Gassed Products From Molten Salts Using Laser-Induced Breakdown Spectroscopy

  Applied Spectroscopy · 2023-07-11 · 7 citations

  articleOpen accessSenior author

  The detection of off-gassed sodium from molten sodium nitrate (NaNO 3 ) at temperatures between 330 °C and 505 °C and off-gassed calcium from molten lithium chloride–potassium chloride eutectic (LKE) mixtures at 510 °C with laser-induced breakdown spectroscopy (LIBS) was demonstrated. NaNO 3 and LKE samples were melted in a custom-built crucible that promoted the generation of off-gassed products from the molten sample. The off-gassed products were analyzed with a LIBS system designed to probe the high-temperature environment. Na D emission lines, Na(I)588.99 nm and Na(I) 589.59 nm, were detected from the NaNO 3 samples after reaching a temperature threshold, which indicated the occurrence of phase change. In LKE mixtures, the detection of Ca impurities at a concentration of 78 mg/kg was possible using the emission lines Ca(II) 393.66 nm and Ca(II) 395.85 nm. This work demonstrates the real-time monitoring capabilities of LIBS in high-temperature environments that simulate the conditions of molten salt reactors.

  PublisherOA PDFDOI

• Quantification of antibody–drug conjugate PYX-201 in rat and monkey plasma via ELISA and its application in preclinical studies

  Bioanalysis · 2023-01-01 · 10 citations

  article

  Aim: PYX-201 is a novel antibody–drug conjugate targeting the extra domain B splice variant of fibronectin in the tumor microenvironment. Accurate quantification of PYX-201 is critical for PYX-201 pharmacokinetics profiling in preclinical studies. Materials & methods: ELISA was performed using reference standard PYX-201, mouse monoclonal anti-monomethyl auristatin E antibody, mouse IgG1, mouse monoclonal anti-human IgG horseradish peroxidase and donkey anti-human IgG horseradish peroxidase. Results: This assay was validated at 50.0–10,000 ng/ml in rat dipotassium EDTA plasma and 250–10,000 ng/ml in monkey dipotassium EDTA plasma. Conclusion: This is the first time for a PYX-201 bioanalytical assay in any matrix to be reported.

  PublisherDOI

Recent grants

• Laser-Induced Plasma Based Diagnostics

  NSF · $300k · 2003–2007

Frequent coauthors

• Meinrad Beer

  University Hospital Ulm

  46 shared

• J Sandstede

  32 shared

• W. Kenn

  32 shared

• Daniel Díaz

  University of Arizona

  29 shared

• Herbert Köstler

  26 shared

• Thomas Pabst

  Universitätsklinikum Würzburg

  23 shared

• Stefan Neubauer

  John Radcliffe Hospital

  19 shared

• Brian T. Fisher

  University of Minnesota

  18 shared

Education

• PhD, Mechanical Engineering

  Louisiana State University

  1992

• BSME, Mechanical Engineering

  Louisiana State University

  1986

Awards & honors

• Herbert Wertheim College of Engineering 2007-2008 Teacher/Sc…
• UF Society of Women Engineers 2016-2017 Outstanding Support…
• Alumni Achievement Award from Louisiana State University (20…