arXiv subjects

David C. Garrett

Publications and source records attributed to David C. Garrett.

5 recordsLinked to original sources

arXiv2026

An Ingestible Light Source for Deep Photoacoustic Imaging

Photoacoustic tomography leverages ultrasound's deep tissue penetration to retrieve optical absorption contrast well beyond the optical diffusion limit. Conventional photoacoustic systems rely on externally delivered light and are therefore constrained by optical attenuation, limiting imaging depths to several centimeters. Here, we overcome this constraint using a compact, acoustically powered device that provides optical excitation directly from within the target medium. By exploiting the weak attenuation of low-MHz ultrasound, acoustic energy is transmitted through tissue to wirelessly power a pulsed laser diode. The emitted light pulses generate photoacoustic signals that encode local optical absorption at clinically relevant depths, which could enable imaging in regions such as the gastrointestinal tract that are inaccessible to surface-based illumination. We demonstrate this approach by imaging through a 12 cm thick phantom, establishing a pathway toward deep-tissue photoacoustic imaging.

physics.optics↗

arXiv2025

Whole Cross-Sectional Human Ultrasound Tomography

Ultrasonography is a vital component of modern clinical care, with handheld probes routinely used for diagnostic imaging and procedural guidance. However, handheld ultrasound imaging is limited by factors such as the partial-cross-sectional field of view, operator dependency, contact-induced distortion, and lack of transmission contrast. Here, we demonstrate a new system enabling whole cross-sectional ultrasound tomography of humans in reflection and transmission modes. We generate 2D images of the entire in vivo human cross-section with uniform in-plane resolution using a custom 512-element circular ultrasound receiver array and a rotating ultrasonic transmitter. We demonstrate this technique in regions such as the abdomen and legs in healthy volunteers. To address unmet clinical needs, we explore two key applications. First, we readily observe abdominal adipose distributions in our images, enabling adipose thickness assessment over the body without ionizing radiation or mechanical deformation. Second, we demonstrate an approach for video-rate (30 frame-per-second) biopsy needle localization with respect to internal tissue features. These capabilities make whole cross-sectional ultrasound tomography a potential practical tool for clinical needs not currently met by other modalities.

physics.med-ph↗

arXiv2023

Numerical modeling of the multi-stage Stern$\unicode{x2013}$Gerlach experiment by Frisch and Segrè using co-quantum dynamics via the Bloch equation

We numerically study the spin flip in the Frisch$\unicode{x2013}$Segrè experiment, the first multi-stage Stern$\unicode{x2013}$Gerlach experiment, within the context of the novel co-quantum dynamics theory. We model the middle stage responsible for spin rotation by sampling the atoms with the Monte Carlo method and solving the dynamics of the electron and nuclear magnetic moments numerically according to the Bloch equation. Our results show that, without using any fitting parameters, the co-quantum dynamics closely reproduces the experimental observation reported by Frisch and Segrè in 1933, which has so far lacked theoretical predictions.

quant-ph↗

arXiv2023

Numerical modeling of the multi-stage Stern$\unicode{x2013}$Gerlach experiment by Frisch and Segrè using co-quantum dynamics via the Schrödinger equation

We use a theory termed co-quantum dynamics (CQD) to numerically model spin flip in the multi-stage Stern$\unicode{x2013}$Gerlach (SG) experiment conducted by R. Frisch and E. Segrè. This experiment consists of two Stern$\unicode{x2013}$Gerlach apparatuses separated by an inner rotation chamber that varies the fraction of spin flip. To this day, quantum mechanical treatments inadequately predict the Frisch$\unicode{x2013}$Segrè experiment. Here, we account for electron-nuclear interactions according to CQD and solve the associated Schrödinger equation. Our simulation outcome agrees with the Frisch$\unicode{x2013}$Segrè experimental observation and supports CQD as a potential model for electron spin evolution and collapse.

quant-ph↗

arXiv2023

Quantum imaging of biological organisms through spatial and polarization entanglement

Quantum imaging can potentially provide certain advantages over classical imaging. Thus far, however, the signal-to-noise ratios (SNRs) are poor; the resolvable pixel counts are low; biological organisms have not been imaged; birefringence has not been quantified. Here, we introduce quantum imaging by coincidence from entanglement (ICE). Utilizing spatially and polarization entangled photon pairs, ICE exhibits higher SNRs, greater resolvable pixel counts, imaging of biological organisms, and ghost birefringence quantification; it also enables 25 times greater suppression of stray light than classical imaging. ICE can potentially empower quantum imaging towards new applications in life sciences and remote sensing.

quant-ph↗