A5046182395- Digital Holography and Microscopy
- Atmospheric aerosols and clouds
- Microfluidic and Bio-sensing Technologies
- Atmospheric chemistry and aerosols
- Coagulation and Flocculation Studies
- Particle Dynamics in Fluid Flows
- Orbital Angular Momentum in Optics
- Optical Polarization and Ellipsometry
- Planetary Science and Exploration
- Advanced Optical Imaging Technologies
- Laser Material Processing Techniques
- Aeolian processes and effects
- Atmospheric and Environmental Gas Dynamics
- Advanced Surface Polishing Techniques
- Characterization and Applications of Magnetic Nanoparticles
- Solar Thermal and Photovoltaic Systems
- Geophysical and Geoelectrical Methods
- Thermal Radiation and Cooling Technologies
- Near-Field Optical Microscopy
- Soil Geostatistics and Mapping
- Material Science and Thermodynamics
- Aerodynamics and Acoustics in Jet Flows
- Quantum Mechanics and Applications
- Radiative Heat Transfer Studies
- Photonic and Optical Devices
Kansas State University
2010-2024
Brown University
2020-2022
Université de Toulouse
2021
Xiamen University of Technology
2020
John Brown University
2020
University of Central Florida
2019-2020
China University of Mining and Technology
2019
Centre National de la Recherche Scientifique
2019
Aix-Marseille Université
2019
Weber State University
2018
Abstract The lack of quantitative characterization aerosol particles and their loading in the atmosphere is one greatest uncertainties climate-change science. Improved instrumentation capable determining size shape needed efforts to reduce this uncertainty. We describe a new instrument carried by an unmanned aerial vehicle (UAV) that images free-floating atmosphere. Using digital holography, obtains non-contact manner, resolving larger than ten micrometers sensing volume approximately three...
We study the extinction caused by a single particle and present conceptual phase-based explanation for related optical theorem. Simulations of energy flow particle's presence in collimated beam light demonstrate how process occurs. It is shown that does not necessarily cause reduction along exact forward direction. Implications regarding measurement single-particle cross section are discussed. This work extended to noninteracting interacting multiparticle groups Part II [J. Opt. Soc. Am....
This work combines digital holography with spatial filtering at two wavelengths to record the hologram and light-scattering pattern for a single particle using color sensor. Particles 30-100 μm in size various shapes are considered. The results demonstrate ability unambiguously associate complicated scattering size, shape, orientation.
The nature of structural changes nanosecond laser modification inside silicon is investigated. Raman spectroscopy and transmission electron microscopy measurements cross sections the modified channels reveal highly localized crystal deformation. prove existence amorphous induced modifications, percentage calculated based on spectrum. For first time, high-resolution images directly show appearance which corroborates indirect from spectroscopy. channel consists a small amount embedded in...
Small particles that are trapped, deposited, or otherwise fixed can be imaged by digital holography with a resolution approaching of optical microscopy. When such in motion as an aerosol, comparable is challenging to achieve. Using simplified bi-telecentric lens system, we demonstrate 1µm free-flowing aerosol at the single-particle level using in-line holography. The imaging demonstrated polystyrene latex microspheres and ragweed pollen aerosol.
An alternative to using the traditional scattering angle θ describe light from a uniform dielectric sphere is dimensionless parameter qR, where R radius of sphere, q = 2k sin(θ/2), and k wavenumber incident light. Simple patterns appear in scattered intensity if qR used place θ. These are characterized by envelopes approximating distributions quantified phase-shift ρ 2kR | m − 1 |, real refractive index sphere. Here we find new these when normalized Rayleigh differential cross section. Mie...
The extinction due to a group of identical particles in fixed orientation is studied. An analytical description based on the Maxwell volume integral equation presented, describing interference energy flow noninteracting particles. As compared single particle, effect multiple shown narrow angular region around forward direction over which dominant contribution group's cross section occurs. fully interacting nonspherical studied using discrete dipole approximation. Interparticle interactions...
Abstract We incorporate optics and an ICCD to record the two‐dimensional angular optical scattering (TAOS) patterns retrieved from single aerosolized cells. analyze these by performing autocorrelations demonstrate that we are able retrieve cell size locations of secondary maxima. Additional morphological information is contained in autocorrelation functions decay rate heights peaks. techniques with C6 Y79 cells, which readily distinguishable. One key advantage this methodology there no...
Coarse mode atmospheric aerosol particles are abundant in agricultural, desert, and urban environments. Accurate characterisation of these particles' morphology is an important need scientific applied contexts, especially to advance our understanding for how such aerosols influence solar radiative forcing the atmosphere. Elastic light scattering a standard method study contact-free manner, wherein measured patterns interpreted infer particle morphology. Due part absence wave-phase...
Thermal-to-electrical energy conversion was demonstrated using an oscillating heat pipe (OHP) filled with ferrofluid and equipped annular-type solenoid. The OHP subjected to a 100 °C axial temperature difference allowing the passively oscillate through solenoid, thus accomplishing electromagnetic induction. measured solenoid voltage consisted of aperiodic pulses dominant frequencies between 2 5 Hz peak-to-peak amplitudes approaching 1 mV. Despite exposure thermal phase change cycling within...
Internal modification of silicon is important for wafer stealth dicing. In this paper, the authors report experimental and simulation results three-dimensional inside wafers using laser pulses with 1.55 μm wavelength 3.5 ns pulse duration. Permanent generated by tightly focusing continuously scanning beam samples, without damaging front back surface. Cross sections these modifications are observed after cleaving samples further analyzed mechanical polishing followed chemical etching. The...
The authors demonstrate a method for transverse writing of optical waveguides in crystalline silicon wafer using nanosecond laser with shaped beam profile that is formed by pair cylindrical lenses. In contrast to traditional methods, this avoids forming asymmetric waveguide profiles. Both straight and curved are written nearly circular guide found support single-mode propagation 1550 nm wavelength light. loss also measured.
We demonstrate, for the first time, direct writing of curved optical waveguides in monocrystalline silicon with curve radii from 2 mm to 6 cm. The bending loss is measured and a good agreement theoretical values found. Raman spectroscopy measurements suggest formation inhomogeneous amorphous polycrystalline phases laser-modified region. This laser-writing method may advance fabrication capabilities integrated 3D photonic devices.