Nonlinear optical microscopies provide a flexible, inexpensive, and useful way to do medical imaging. Among the imaging modalities, pump-probe microscopy is a versatile technique that shows great potential to image melanomas (a skin cancer) for which there is still a great need for improved early clinical diagnosis. But image analysis often suffers from an incomplete understanding of the signal properties. In this dissertation, I discuss several unusual properties observed in pump-probe signals using model samples (e.g., gold nanoparticles, natural and synthesized melanin particles, historic artwork pigments) and an upgraded pump-probe microscope. The experiments improve understanding in pump-probe signals and help for better data analysis.Chapter 2 demonstrates my experimental results regarding the directional dependence of pump-probe signals. I upgrade imaging system for angle-resolved measurements, and use melanin particles and gold nanoparticles to study the role of scattering in the generation of pump-probe signals. The results show the reason for signal discrepancy between transmission (for thin sliced samples) and backward (for in-vivo imaging) detections observed in melanoma imaging. Chapter 3 discusses an intrinsic polarization anisotropy in the pump-probe signal of melanin. I develop a formalism based on transition dipole moments to model this polarization anisotropy, and use it to decompose pump-probe signals in several pigments (melanin, historic artwork pigments). I improve the imaging system to accurately control and calibrate the polarization angle of the lasers for polarization measurements. The polarization angle serves as a useful imaging parameter. Combined with the directional dependence discussed in chapter 2, a global fitting is performed on the melanin signals to extract strengths and decays of the various components in the signal. Chapter 4 discusses studies on remaining puzzles observed in melanoma imaging, including depth dependence, signal dynamics change due to particle aggregation, and a long-lived signal component of unclear origin. While these anomalies are not fully understood, their properties are presented for future studies. Chapter 5 summarizes the key achievements presented in this dissertation, and discusses new questions that should be explored in the future.
","abstract_html":"<p>Nonlinear optical microscopies provide a flexible, inexpensive, and useful way to do medical imaging. Among the imaging modalities, pump-probe microscopy is a versatile technique that shows great potential to image melanomas (a skin cancer) for which there is still a great need for improved early clinical diagnosis. But image analysis often suffers from an incomplete understanding of the signal properties. In this dissertation, I discuss several unusual properties observed in pump-probe signals using model samples (e.g., gold nanoparticles, natural and synthesized melanin particles, historic artwork pigments) and an upgraded pump-probe microscope. The experiments improve understanding in pump-probe signals and help for better data analysis.Chapter 2 demonstrates my experimental results regarding the directional dependence of pump-probe signals. I upgrade imaging system for angle-resolved measurements, and use melanin particles and gold nanoparticles to study the role of scattering in the generation of pump-probe signals. The results show the reason for signal discrepancy between transmission (for thin sliced samples) and backward (for in-vivo imaging) detections observed in melanoma imaging. Chapter 3 discusses an intrinsic polarization anisotropy in the pump-probe signal of melanin. I develop a formalism based on transition dipole moments to model this polarization anisotropy, and use it to decompose pump-probe signals in several pigments (melanin, historic artwork pigments). I improve the imaging system to accurately control and calibrate the polarization angle of the lasers for polarization measurements. The polarization angle serves as a useful imaging parameter. Combined with the directional dependence discussed in chapter 2, a global fitting is performed on the melanin signals to extract strengths and decays of the various components in the signal. Chapter 4 discusses studies on remaining puzzles observed in melanoma imaging, including depth dependence, signal dynamics change due to particle aggregation, and a long-lived signal component of unclear origin. While these anomalies are not fully understood, their properties are presented for future studies. Chapter 5 summarizes the key achievements presented in this dissertation, and discusses new questions that should be explored in the future.</p>","abstract_has_math":false,"creators":["Jia, Xiaomeng"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Warren, Warren"],"committee_chairs":[],"committee_members":[],"year":2021,"date_issued":"2021","date_published":"2021","updated_at":"2026-07-24T02:07:10Z","subjects":["Physics","Optics","directional dependence","polarization anisotropy","pump-probe microscopy"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/10161/22959","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Warren, Warren"]},{"key":"dc:creator","label":"Author","values":["Jia, Xiaomeng"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2021-05-19T18:07:34Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2022-05-17T08:17:10Z"]},{"key":"dc:date.issued","label":"Date","values":["2021"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Physics","Optics","directional dependence","polarization anisotropy","pump-probe microscopy"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10161/22959"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Nonlinear optical microscopies provide a flexible, inexpensive, and useful way to do medical imaging. Among the imaging modalities, pump-probe microscopy is a versatile technique that shows great potential to image melanomas (a skin cancer) for which there is still a great need for improved early clinical diagnosis. But image analysis often suffers from an incomplete understanding of the signal properties. In this dissertation, I discuss several unusual properties observed in pump-probe signals using model samples (e.g., gold nanoparticles, natural and synthesized melanin particles, historic artwork pigments) and an upgraded pump-probe microscope. The experiments improve understanding in pump-probe signals and help for better data analysis.Chapter 2 demonstrates my experimental results regarding the directional dependence of pump-probe signals. I upgrade imaging system for angle-resolved measurements, and use melanin particles and gold nanoparticles to study the role of scattering in the generation of pump-probe signals. The results show the reason for signal discrepancy between transmission (for thin sliced samples) and backward (for in-vivo imaging) detections observed in melanoma imaging. Chapter 3 discusses an intrinsic polarization anisotropy in the pump-probe signal of melanin. I develop a formalism based on transition dipole moments to model this polarization anisotropy, and use it to decompose pump-probe signals in several pigments (melanin, historic artwork pigments). I improve the imaging system to accurately control and calibrate the polarization angle of the lasers for polarization measurements. The polarization angle serves as a useful imaging parameter. Combined with the directional dependence discussed in chapter 2, a global fitting is performed on the melanin signals to extract strengths and decays of the various components in the signal. Chapter 4 discusses studies on remaining puzzles observed in melanoma imaging, including depth dependence, signal dynamics change due to particle aggregation, and a long-lived signal component of unclear origin. While these anomalies are not fully understood, their properties are presented for future studies. Chapter 5 summarizes the key achievements presented in this dissertation, and discusses new questions that should be explored in the future.
"]},{"key":"dc:title","label":"Title","values":["Directional Dependence and Polarization Anisotropy in Pump-probe Microscopy"]}]}],"canonical_facts":{"dc:contributor.advisor":["Warren, Warren"],"dc:creator":["Jia, Xiaomeng"],"dc:date.accessioned":["2021-05-19T18:07:34Z"],"dc:date.available":["2022-05-17T08:17:10Z"],"dc:date.issued":["2021"],"dc:description.abstract":["Nonlinear optical microscopies provide a flexible, inexpensive, and useful way to do medical imaging. Among the imaging modalities, pump-probe microscopy is a versatile technique that shows great potential to image melanomas (a skin cancer) for which there is still a great need for improved early clinical diagnosis. But image analysis often suffers from an incomplete understanding of the signal properties. In this dissertation, I discuss several unusual properties observed in pump-probe signals using model samples (e.g., gold nanoparticles, natural and synthesized melanin particles, historic artwork pigments) and an upgraded pump-probe microscope. The experiments improve understanding in pump-probe signals and help for better data analysis.Chapter 2 demonstrates my experimental results regarding the directional dependence of pump-probe signals. I upgrade imaging system for angle-resolved measurements, and use melanin particles and gold nanoparticles to study the role of scattering in the generation of pump-probe signals. The results show the reason for signal discrepancy between transmission (for thin sliced samples) and backward (for in-vivo imaging) detections observed in melanoma imaging. Chapter 3 discusses an intrinsic polarization anisotropy in the pump-probe signal of melanin. I develop a formalism based on transition dipole moments to model this polarization anisotropy, and use it to decompose pump-probe signals in several pigments (melanin, historic artwork pigments). I improve the imaging system to accurately control and calibrate the polarization angle of the lasers for polarization measurements. The polarization angle serves as a useful imaging parameter. Combined with the directional dependence discussed in chapter 2, a global fitting is performed on the melanin signals to extract strengths and decays of the various components in the signal. Chapter 4 discusses studies on remaining puzzles observed in melanoma imaging, including depth dependence, signal dynamics change due to particle aggregation, and a long-lived signal component of unclear origin. While these anomalies are not fully understood, their properties are presented for future studies. Chapter 5 summarizes the key achievements presented in this dissertation, and discusses new questions that should be explored in the future.
"],"dc:identifier.uri":["https://hdl.handle.net/10161/22959"],"dc:subject":["Physics","Optics","directional dependence","polarization anisotropy","pump-probe microscopy"],"dc:title":["Directional Dependence and Polarization Anisotropy in Pump-probe Microscopy"],"dc:type":["Dissertation"]},"updated_at":"2026-07-24T02:07:10Z"}