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7 February 2007 Optical delay line using rotating rhombic prisms
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We propose a robust and efficient delay line using an ensemble of rotating rhombic prisms. Delay lines relying on rotating elements provide fast and stable operation. Optical systems using rhombic prisms are quite easy to align since these prisms are efficient even when slightly misaligned. Optical delay lines with a single rotating element usually have a poor duty cycle and show large nonlinearity in the variation of the optical path lengh with the angular position. Our delay line improves over existing technology by using off-centroid rotation and reinjection. Off-centroid rotation allows the use of multiple prisms and, by optimizing the conditions of operation, the duty cycle is increased and the nonlinearity is decreased. The duty cycle and repetition rate are further increased by reinjecting the incoming ray towards the delay line when it is not first intercepted by the prism ensemble. We have designed and built such a delay line using five prisms. The experimental device was tested at 2000 delay scans per second and provided a duty cycle larger than 80% with about 5% nonlinearity. Higher delay scan rates are easily achievable with this technology. The delay line was introduced in a time-domain optical coherence tomography system and example of imaging of biological tissue is provided.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
G. Lamouche, M. Dufour, B. Gauthier, V. Bartulovic, M. Hewko, and J.-P. Monchalin "Optical delay line using rotating rhombic prisms", Proc. SPIE 6429, Coherence Domain Optical Methods and Optical Coherence Tomography in Biomedicine XI, 64292G (7 February 2007);


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