Project:	Sonic-Speed, Light-Speed, and Quantum Imaging/Physics
Disciplines:	Physics, Electrical Engineering
Mentor:	Lihong Wang, Bren Professor, (EAS), lvw@caltech.edu, Phone: 6263951970
Mentor URL:	https://coilab.caltech.edu/  (opens in new window)
Background:	We develop sonic-speed photoacoustic tomography (PAT) to peer deep into biological tissue. PAT offers functional, metabolic, molecular, and histologic imaging across scales from organelles to entire organisms. We also develop light-speed compressed ultrafast photography (CUP), which records up to 219 trillion frames per second, far exceeding the capabilities of commercially available cameras. CUP can capture real-time images of the fastest phenomena in nature, such as light propagation, and can be slowed down to record slower events, such as neural conduction. In parallel, we explore quantum entanglement for imaging and quantum physics. PAT physically couples pulsed optical excitation with ultrasonic detection. Conventional high-resolution optical imaging of scattering tissue is confined to depths within the optical diffusion limit (~1 mm). PAT overcomes this limit, providing centimeter-scale penetration with high ultrasonic resolution and high optical contrast by sensing molecules. Its broad applications include early cancer detection and brain imaging. Since 2010, the annual PAT conference at SPIE Photonics West (about 20,000 attendees) has been the largest conference at that meeting. With a single exposure, CUP can image transient events on time scales as short as tens of femtoseconds. Like traditional photography, CUP is receive-only and does not require specialized active illumination, unlike many other single-shot ultrafast imagers. CUP can be coupled to front-end optics ranging from microscopes to telescopes, enabling widespread applications in both fundamental and applied sciences, from biology to astrophysics and cosmology. We study quantum entanglement, quantum imaging, and atomic physics. Entangled photons exhibit nonclassical characteristics and can be used for quantum imaging. Unlike classical optical imaging, quantum imaging has achieved super-resolution beyond the diffraction limit through coincidence detection. Because photons originate from atoms and molecules, we also investigate atomic physics at the interface between classical and quantum descriptions. For example, we found, perhaps surprisingly, that the Bloch equation, conventionally regarded as classical, yields the von Neumann and Schrödinger equations. We also developed a theory that models the multistage Stern–Gerlach experiment suggested by Heisenberg and Einstein more accurately than existing treatments.
Description:	Upon joining the lab, students will refine their initial project ideas, developed after reviewing our publications and background information, and align them with ongoing team efforts. They will collaborate closely with lab members, contributing to both the conceptual foundations and practical implementation of active projects. This integrated, team-based model has consistently been highly productive and intellectually rewarding for participants.
References:	https://coilab.caltech.edu/
Student Requirements:	Physics/Applied Physics/Electrical Engineering
Programs:	This AO can be done under the following programs:   Program    Available To        SURF    both Caltech and non-Caltech students  Click on a program name for program info and application requirements.