Spectroscopic optical coherence tomography at 1200 nm for lipid detection

Significance: Spectroscopic analysis of optical coherence tomography (OCT) data can yield added information about the sample's chemical composition, along with high-resolution images. Typical commercial OCT systems operate at wavelengths that may not be optimal for identifying lipid-containing samples based on absorption features. Aim: The...

Integrated SiGe Detectors for Si Photonic Sensor Platforms

In this work, we present the results of integrated Ge detectors grown on a Si photonic platform for sensing applications. The detectors are fabricated on a passive photonic circuit for maximum coupling efficiency. Measurement results at 1300 nm wavelength show a responsivity of 0.2 A/W and very low dark current levels. For a voltage range...

Development of a Retinal Eye Tracker for 3D Optical Coherence Tomography

Several eye diseases appear in the posterior part of the eye, i.e. the retina or fundus. Retinal images therefore provide valuable information to identify eye diseases. Optical Coherence Tomography (OCT) is a 3D imaging technique that can image the retina with a resolution and depth penetration that can not be achieved by any other non-invasive...

An Evaluation of Silicon Carbide Based Bimorph Actuators for Optical Coherence Tomography Applications

Optical coherence tomography (OCT) probes rely on MEMS micro-scanners to provide fast and reproducible scans covering as much area as possible. A popular choice of actuators employed in this role are electrothermal bimorph actuators. They comprise of two layers of different materials which are rigidly joined together. Differential expansion...

Optical coherence tomography complemented by hyperspectral imaging for the study of protective wood coatings

Optical coherence tomography (OCT) is a contactless and non-destructive testing (NDT) technique based on lowcoherence interferometry. It has recently become a popular NDT-tool for evaluating cultural heritage. In this study, protective coatings on wood and their penetration into the wood structure were measured with a customized infrared fiber...

Ultra-compact silicon photonic integrated interferometer for swept-source optical coherence tomography

We demonstrate an ultra-compact silicon integrated photonic interferometer for swept-source optical coherence tomography (SS-OCT). The footprint of the integrated interferometer is only 0.75×5??mm2. The design consists of three 2×2 splitters, a 13 cm physical length (50.4 cm optical length) reference arm, and grating couplers. The photonic...

Optical coherence elastography for measuring the deformation within glass fiber composite

Optical coherence elastography (OCE) has been applied to the study of microscopic deformation in biological tissue under compressive stress for more than a decade. In this paper, OCE has been extended for the first time, to the best of our knowledge, to deformation measurement in a glass fiber composite in the field of nondestructive testing. A...

Examination of historical paintings by state-of-the-art hyperspectral imaging methods: From scanning infra-red spectroscopy to computed X-ray laminography

The development of advanced methods for non-destructive selective imaging of painted works of art at the macroscopic level based on radiation in the X-ray and infrared range of the electromagnetic spectrum are concisely reviewed. Such methods allow to either record depth-selective, element-selective or species-selective images of entire...

Effect of temperature and fixation on the optical properties of atherosclerotic tissue: A validation study of an ex-vivo whole heart cadaveric model

Atherosclerotic plaque composition can be imaged using the optical attenuation coefficient derived from intravascular optical coherence tomography (OCT) data. The relation between optical properties and tissue type has been established on autopsy tissues. In this study, we validate an ex-vivo model for the effect of temperature and tissue...

Signal processing in optical coherence tomography for aerospace material characterization

Based on a customized time-domain optical coherence tomography (OCT) system, a series of signal processing approaches have been designed and reviewed. To improve demodulation accuracy and image quality, demodulation approaches such as median filter, Hilbert transform, and envelope detector were investigated with simulated as well as experimental...

Image processing of optical coherence tomography for image guided dental drilling

In the past two decades, dental implants have been an essential component of the public health. However, lack of a reliable and safe dental surgery imaging modality remains a major problem. Optical coherence tomography (OCT) is an interferometic optical imaging modality that is somewhat similar to B-mode ultrasound but utilizes infrared light...

Demonstration of PECVD SiC thermal delay lines for optical coherence tomography in the visible

Optical Coherence Tomography (OCT) has found applications in many fields of medicine and has a large potential for the optical biopsy of tumors. One of the technological challenges impairing faster adoption of OCT is the relative complexity of the optical instrumentation required, which translates into expensive and bulky setups. In this paper...

Excitation and readout of a thermally driven time-domain optical coherence tomography system

This system presented in this thesis report will be put into practice in a sensory system for dental drilling. The aim of this system is to provide real-time feedback to the practitioner about the anatomical structure in close vicinity of the drill bit. Therefore, the system has to deal with in vivo, in situ bone tissue, bone tissue within a...