Swept-source optical coherence tomography (SS-OCT) enables volumetric imaging of subsurface structure, but applications requiring wide fields of view, rapid imaging, and higher resolutions have been challenging because of the need for multi-MHz A-scan rates. Until now, achieving multi-MHz A-scan rates has been limited to Fourier-domain mode-locked lasers or stretched-pulse lasers. We describe a microelectromechanical-system, vertical-cavity surface-emitting laser (MEMS-VCSEL) for SS-OCT at A-scan rates of 2.4 and 3.0 MHz using a dual-channel acquisition system. Dual-channel operation enables simultaneous acquisition of Mach-Zehnder interferometer (MZI) fringes for sweep-to-sweep calibration and resampling, overcoming inherent optical clock limitations in state-of-the-art digitizers. We demonstrate ...

In this project, a blood flow quantification technique was developed based on a novel backscattering indicator-dilution approach for intravascular optical coherence tomography (IV-OCT). It achieved the goal of obtaining the flow velocity in a coronary artery of interest by analyzing the backscattering signal from blood after passage of a bolus of Ringer's lactate or another transparent injectate, in parallel to thermodilution coronary flow reserve (CFR). In contrast to thermodilution CFR, the structural OCT image can be used to determine the bolus volume and transit time, as well as used to account for motion and volume change between the two ...

Optical coherence tomography (OCT), an imaging modality based on low coherence interferometry, can be extended to obtain various endogenous functional contrasts. This thesis focuses on the development and translation of angiographic and polarization sensitive (PS) OCT techniques for clinical and preclinical applications. This goal includes four specific aims. The first aim is to develop a clinical imaging system to image the anatomy and microvasculature of human skin. The second aim is to develop a high performance post-processing algorithm for angiographic OCT. Towards this aim, we developed a processing algorithm based on complex differential variance (CDV) and confirmed its performance by ...

The health of the human respiratory system depends critically on airway clearance via motile hair-like structures (cilia), which transport and eliminate unwanted particles trapped within mucus. Impairment of mucociliary clearance (MCC) can lead to life-threatening airway narrowing and lung infections, and is a major cause of morbidity and mortality in patients with cystic fibrosis, primary ciliary dyskinesia and chronic obstructive lung disease. However, no tool for microscopic in-vivo visualization of ciliary function is currently available, limiting studies of disease pathogenesis, refined diagnosis and phenotyping, and the development of novel therapeutics. In this thesis, a novel, 1-pm resolution, optical interferometric imaging ...

A forward viewing fiber optic-based imaging probe device was designed and constructed for use with ultrahigh speed optical coherence tomography in the human gastrointestinal tract. The light source was a MEMS-VCSEL at 1300 nm wavelength running at 300 kHz sweep rate, giving an effective A-line rate of 600 kHz. Data was acquired with a 1.8 GS/s A/D card optically clocked by a maximum fringe frequency of 1 GHz. The optical beam from the probe was scanned by a freely deflecting optical fiber that was mounted proximally on a piezoelectric tubular actuator, which was electrically driven in two ...

Optical coherence tomography (OCT), a diagnostic tool which can perform non-contact, noninvasive, cross-sectional imaging of the retina and anterior eye in real time, has dramatically improved in its resolution and speed in the recent years. In addition to the advancement in hardware, different OCT methods for functional measurements, such as Doppler OCT for quantifying blood flow and generating angiography using OCT phase information, polarization sensitive OCT for measuring intrinsic mechanical / optical tissue property using light of different polarizations, and spectroscopic OCT for measuring blood oxygenation using multiple wavelengths, have been demonstrated and developed. In this thesis, a dual-wavelength spectroscopic OCT ...