Feature Of The Week 2/28/10: Multichannel optical coherence tomography using a high-power telescope-less polygon-based swept laser in dual-amplifier configuration
Feature Of The Week 2/28/10: Researchers at the University of Toronto, Ontario Cancer Institute and Ryerson University have been actively advancing Optical Coherence Tomography (OCT) in several areas, including application of Doppler OCT (DOCT) and advancing the underlying technology to expand and improve the applications and capability of this imaging modality. The group, led by Dr. Alex Vitkin and Dr. Victor Yang, has clinical experience in circulation imaging of the gastrointestinal tracts, the prostate, the colons, the lungs, and more. This group also developed a microvasculature imaging technique called speckle variance OCT (SV-OCT) that can capture, with high sensitivity, the presence of flow, and have applied the technique to preclinical models of rodents.
Here, the recent development of a 6-channel OCT imaging system is reported. The light source is a wavelength-swept laser based on a compact telescope-less polygon-based filter in Littman arrangement. To enable simultaneous multichannel imaging, high output power is achieved by using two serial semiconductor optical amplifiers in Fourier domain mode-locked configuration. The measured wavelength tuning range of the laser is 111 nm centered at 1329 nm. It has a coherence length of 5.5 mm, and total average output power of 131 mW at 43 kHz sweeping rate. Imaging with 6-channels, the effective A-scan speed is 258 kHz.
Multichannel acquisition has the following advantages: (1) Using an array of channels focused at a fixed depth, increased effective frame rate is achieved without raising the laser tuning speed. This is beneficial for volumetric imaging. (2) Utilizing unique scan patterns, DOCT and SV-OCT may be improved. (3) Split acquisition of data among multiple channels reduces the detector bandwidth requirements, hence signal-to-noise ratio is increased.
Courtesy Michael Leung. Click "Full Screen" for better viewing.