Lei Tian
Bond-selective intensity diffraction tomography
Recovering molecular information remains a grand challenge in the widely used holographic and computational imaging technologies. To address this challenge, we developed a computational mid-infrared photothermal microscope, termed Bond-selective Intensity Diffraction Tomography (BS-IDT). Based on a low-cost brightfield microscope with an add-on pulsed light source, BS-IDT recovers both infrared spectra and bond-selective 3D refractive index […]
Metasurface Photodetectors for Computational Imaging
Traditional image sensors used in photography and microscopy can only visualize the intensity distribution of the incident light, whereas all information related to the local direction of light propagation and phase profile is lost in the image acquisition process. To address this limitation, the proposed research will develop a new class of image sensors based […]
Computational Miniature Mesoscope for Cortex-wide, Cellular resolution Ca2+ Imaging in Freely Behaving Mice
Scale is a fundamental obstacle in linking neural activity to behavior. While perception and cognition arise from interactions between diverse brain areas separated by long distances, neural codes and computations are implemented at the scale of individual neurons. An integrative understanding of brain dynamics thus requires cellular-resolution measurements across sensory, motor, and executive areas spanning […]
High-content High-speed Chemical Imaging of Metabolic Reprogramming by Integration of Advanced Instrumentation and Data Science
The goal of this project is to develop two complementary stimulated Raman scattering imaging platforms that will allow high-speed, high-content, and high-sensitivity mapping of cell metabolism by synergistic integration of advanced instrumentation and data science.
Reflection-mode Computational 3D Phase and Polarization Imaging for Semiconductor Wafer Metrology and Inspection
The goal of this project is to prototype a reflection-mode computational microscope to 1) provide wide field-of-view (FOV) and high-resolution phase reconstruction using a new reflection-mode Fourier ptychography (FP) algorithm; 2) enable 3D phase reconstruction based on a new reflection-mode multi-slice beam-propagation method (MS-BPM) model; and 3) investigate the utility of polarization sensitive contrast in […]
Local neuronal drive and neuromodulatory control of activity in the pial neurovascular circuit
We seek to understand the nature of the pial neurovascular circuit, whose dynamics is characterized by ultralow frequency oscillations near 0.1Hz that parcellate into separate coherent regions across cortex. We will use this knowledge to form a mathematical relation between the hemodynamic patterns observed in optical and functional magnetic resonance imaging experiments and the underlying […]
A novel method for volumetric oxygen mapping in living retina
It is widely accepted that oxygen deficiency is a culprit and a marker of several major retinal diseases, including diabetic retinopathy, age-related macular degeneration, glaucoma etc. However, it remains to be extremely challenging to measure oxygen in vivo in the eye, and no tools currently exist that can provide 3D oxygen distributions in the retina […]
A Computational Miniature Mesoscope for Large-Scale Brain Mapping in Behaving Mice
Scale is a fundamental obstacle in linking neural activity to behavior. While perception and cognition arise from interactions between diverse brain areas separated by long distances, neural codes and computations are implemented at the scale of individual neurons. An integrative understanding of brain dynamics thus requires cellular-resolution measurements across sensory, motor, and executive areas spanning […]
CAREER: Optical Intensity Diffraction Tomography with Multiple Scattering
Tomography is a powerful technique that has found wide applications in life science and medical diagnosis. Optical tomography is particularly attractive since it is noninvasive and uses non-ionizing radiation. Recent development to optical tomography focuses on pushing the imaging depth, as motivated by many important needs including deep tissue imaging and brain photostimulations. However, existing […]
CIF: Small: Collaborative Research: Signal Processing for Nonlinear Diffractive Imaging: Acquisition, Reconstruction, and Applications
There is a growing need in biomedical research to observe biological structure and processes on the length scales smaller than 100nm. Conventional optical systems cannot effectively provide such information, however, due to the infamous diffraction limit. The formulation of the diffraction limit fundamentally relies on the presumed linearity in the interaction between the illuminating light […]