Date of Graduation


Document Type


Degree Name

Doctor of Philosophy in Physics (PhD)

Degree Level





Yong Wang

Committee Member

Chen, Jingyi

Second Committee Member

Li, Jiali

Third Committee Member

Kumar, Pradeep


bacteria, kinetics, lasers, motility, nanoparticles, photoluminescence


This dissertation has two focus areas: nanoparticle nanowelding and bacteria motility in the presence of micrometer sized structures. There are two main projects for the nanoparticle nanowelding studies: “Real-time imaging of laser-induced nanowelding in solution” and “Two-color laser-induced nanostructure shape modulation.” For the real-time imaging project, I used a fluorescence microscope, a 405 nm laser, and various python packages to quantify the average size of nanowelded nanostructures as a function of time and found that the average nanostructure growth over time fit the parameters of A¯(t) ∝ c0(1−e−t/τ), where c0 represents the initial concentration of nanoparticles in the solution and τ is a parameter that depends on the power of my laser. For the two-color laser-induced nanostucture project, I used a combination of a 405 nm lase rand a 532 nm laser to see how nanostructure shape depends on the combination of laser wavelengths. Bacteria motility connects to my nanoparticle nanowelding projects through the research processes I used and the practical applications in various fields like energy generation and environmental remediation. I will discuss three projects related to bacterial motility in this paper: two simulation projects and one microscopy project that is still in progress. For the simulation projects, I looked at bacteria in the presence of micrometer-sized Tesla valves and bacteria in the presence of micro-pillars with different surface structures. For the microscopy project I started looking at what I will refer to as ‘potential wells’ to see how bacteria motility effects their ability to be trapped-in and escape from micrometer-sized well structures.

Included in

Biophysics Commons