The optical setup typically consists of an interferometer (Fig. The principle OCT is white light or low coherence interferometry. En face imaging (C-scan) at an acquired depth is possible depending on the imaging engine used.
#SMART PIXEL DETECTOR ARRAY SERIES#
A cross-sectional tomograph (B-scan) may be achieved by laterally combining a series of these axial depth scans (A-scan). This reflectivity profile, called an A-scan, contains information about the spatial dimensions and location of structures within the item of interest. Any light that is outside the short coherence length will not interfere. Areas of the sample that reflect back a lot of light will create greater interference than areas that don't. By scanning the mirror in the reference arm, a reflectivity profile of the sample can be obtained (this is time domain OCT). The combination of reflected light from the sample arm and reference light from the reference arm gives rise to an interference pattern, but only if light from both arms have travelled the "same" optical distance ("same" meaning a difference of less than a coherence length). Light in an OCT system is broken into two arms - a sample arm (containing the item of interest) and a reference arm (usually a mirror). White light is also a broadband source with lower powers. Light with broad bandwidths can be generated by using superluminescent diodes (superbright LEDs) or lasers with extremely short pulses (femtosecond lasers). In OCT, this interference is shortened to a distance of micrometres, thanks to the use of broadband light sources (sources that can emit light over a broad range of frequencies). In conventional interferometry with long coherence length (laser interferometry), interference of light occurs over a distance of meters. OCT is based on low-coherence interferometry. Medical ultrasonography, magnetic resonance imaging (MRI) and confocal microscopy are not suited to morphological tissue imaging: the first two have poor resolution the last lacks millimeter penetration depth. OCT has critical advantages over other medical imaging systems. OCT has also been used for various art conservation projects, where it is used to analyze different layers in a painting. 3.2.1 Smart detector array for parallel TD-OCTįirst devised in 1991 by Huang et al., optical coherence tomography (OCT) with micrometer resolution and cross-sectional imaging capabilities has become a prominent biomedical tissue-imaging technique it is particularly suited to ophthalmic applications and other tissue imaging requiring micrometer resolution and millimeter penetration depth.2.2.2 Time Encoded Frequency Domain OCT (also swept source OCT).2.2.1 Spatially Encoded Frequency Domain OCT (also Fourier Domain OCT).
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