A5040619857- Atmospheric chemistry and aerosols
- Atmospheric aerosols and clouds
- Diamond and Carbon-based Materials Research
- Atmospheric Ozone and Climate
- Atomic and Subatomic Physics Research
- Force Microscopy Techniques and Applications
- Particle Dynamics in Fluid Flows
- Air Quality Monitoring and Forecasting
- Orbital Angular Momentum in Optics
- High-pressure geophysics and materials
- biodegradable polymer synthesis and properties
- Advanced Semiconductor Detectors and Materials
- Air Quality and Health Impacts
- German Economic Analysis & Policies
- Photonic and Optical Devices
- Nanofabrication and Lithography Techniques
- Nonlinear Optical Materials Studies
- Dark Matter and Cosmic Phenomena
- Mechanical and Optical Resonators
- Quantum optics and atomic interactions
- Electronic and Structural Properties of Oxides
- Microfluidic and Bio-sensing Technologies
- Silicone and Siloxane Chemistry
- Housing, Finance, and Neoliberalism
- Banking stability, regulation, efficiency
University of Maryland, College Park
2022-2024
Harvard University
2022-2024
ETH Zurich
2015-2020
Charles Humbert 8
2018-2020
Abstract Photochemistry taking place in atmospheric aerosol droplets has a significant impact on the Earth’s climate. Nanofocusing of electromagnetic radiation inside aerosols plays crucial role their absorption behaviour, since flux droplet strongly affects activation rate photochemically active species. However, size-dependent nanofocusing effects photokinetics small have escaped direct observation due to inability measure signatures from single droplets. Here we show that photoacoustic...
All-optical (AO), microwave-free magnetometry using nitrogen-vacancy (NV) centers in diamond is attractive due to its broad sample compatibility and reduced experimental complexity. In this work, we investigate room-temperature AO photoluminescence (PL) at low magnetic fields (<2 mT) diamonds with NV ensembles ppm concentrations. Measured AO-PL contrast features as a function of applied field magnitude direction are correlated near-degenerate electronic spin hyperfine transitions from...
Photoacoustic spectroscopy is widely used to measure the light absorption of aerosols. However, impact key factors such as effect relative humidity and mass exchange on photoacoustic measurements are still poorly understood. We assess measurement biases their physical origin by analysing signal single tetraethylene glycol (TEG) particles at varying humidities. Our results show a decrease in elevated humidities for small (0.8-1.5 μm), while larger sizes (2.2-3.2 μm) trend reversed. model...
Continuing efforts to quantify the influence of aerosol light absorption upon global heat budgets rely on high-quality measurements optical properties. Of available methods, photoacoustic spectroscopy stands out as a sensitive method for with minimal sample modification. Theoretical treatments detection have predicted size-dependent damping signal result particle thermal inertia. We provide experimental confirmation this prediction using single-particle spectrometer, which allows us measure...
Next-generation dark matter (DM) detectors searching for weakly interacting massive particles (WIMPs) will be sensitive to coherent scattering from solar neutrinos, demanding an efficient background-signal discrimination tool. Directional improve sensitivity WIMP DM despite the irreducible neutrino background. Wide-bandgap semiconductors offer a path directional detection in high-density target material. A detector of this type operates hybrid mode. The or neutrino-induced nuclear recoil is...
Nitrogen-vacancy (<a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><a:mrow><a:mrow><a:mi mathvariant="normal">N</a:mi></a:mrow></a:mrow></a:math>-<e:math xmlns:e="http://www.w3.org/1998/Math/MathML" overflow="scroll"><e:mi>V</e:mi></e:math>) centers in diamond enable nuclear magnetic resonance (NMR) spectroscopy of samples at the nano- and microscale. However, typical tesla-scale NMR field strengths, <h:math xmlns:h="http://www.w3.org/1998/Math/MathML"...
We report on the dynamics of aerosol droplets in optical traps under influence additional constant and pulsed external forces. Experimental results are compared with simulations three-dimensional droplet for two types traps, counter-propagating Bessel beam (CPBB) trap quadruple (QBB) trap. Under a gas flow (constant force), QBB is found to be more stable CPBB By contrast, laser excitation pulse durations nanoseconds (pulsed type minor importance stability. It typically needs forces that...
Photoacoustic (PA) spectroscopy enjoys widespread applications across atmospheric sciences. However, experimental biases and limitations originating from environmental conditions particle size distributions are not fully understood. Here, we combine single-particle photoacoustics with modulated Mie scattering to unravel the fundamental physical processes occurring during PA measurements on aerosols. We perform optically trapped droplets of varying sizes at different relative humidity. Our...
Photoacoustics have been widely used for the study of aerosol optical properties. To date, these studies performed on particle ensembles, with minimal ability to control size. Here, we present our singleparticle photoacoustic spectrometer. The sensitivity and stability instrument is discussed, along results from two experiments that illustrate unique capabilities this instrument. In first experiment, a measurement size-dependence response. Our confirm previous models photoacoustics had yet...
The nitrogen vacancy (NV) center in diamond is an increasingly popular quantum sensor for microscopy of electrical current, magnetization, and spins. However, efficient NV-sample integration with a robust, high-quality interface remains outstanding challenge to realize scalable, high-throughput microscopy. In this work, we characterize micro-chip (DMC) containing (111)-oriented NV ensemble; demonstrate its utility high-resolution We perform strain imaging the DMC find minimal detrimental...
The nitrogen-vacancy (NV) center in diamond is an increasingly popular quantum sensor for microscopy of electrical current, magnetization, and spins. However, efficient NV–sample integration with a robust, high-quality interface remains outstanding challenge to realize scalable, high-throughput microscopy. In this work, we characterize micro-chip (DMC) containing (111)-oriented NV ensemble demonstrate its utility high-resolution We perform strain imaging the DMC find minimal detrimental...
In this contribution we present experiments used to control and characterize single optically trapped aerosol particles. These include a counter-propagating optical tweezer, feedback mechanism stabilize the particle in trap two-angle scattering measurement monitor time-evolution of size. Experimental setups results are presented for these experiments.
Nitrogen vacancy (NV) centers in diamond enable nuclear magnetic resonance (NMR) spectroscopy of samples at the nano- and micron scales. However, typical tesla-scale NMR field strengths, NV-NMR protocols become difficult to implement due challenge driving fast NV pulse sequences sensitive Larmor frequencies above a few megahertz. We perform simulations theoretical analysis experimental viability fields using new measurement protocol called DRACAERIS (Double Rewound ACquisition Amplitude...
Next-generation dark matter (DM) detectors searching for weakly interacting massive particles (WIMPs) will be sensitive to coherent scattering from solar neutrinos, demanding an efficient background-signal discrimination tool. Directional improve sensitivity WIMP DM despite the irreducible neutrino background. Wide-bandgap semiconductors offer a path directional detection in high-density target material. A detector of this type operates hybrid mode. The or neutrino-induced nuclear recoil is...