We demonstrate a cross-dispersed spectrometer for Spectral Domain Optical Coherence Tomography (SD-OCT). The resolution of a conventional SD-OCT spectrometer is limited by the available sizes of the linear array detectors. The adverse consequences of this finite resolution is a trade-off between achieving practical field of view (i.e. ranging depth) and maintaining high axial resolution. Inspired by spectrometer designs for astronomy, we take advantage of very high pixel-density 2D CCD arrays to map a single-shot 2D spectrum to an OCT A-scan. The basic system can be implemented using a high-resolution Echelle grating crossed with a prism in a direction orthogonal to the dispersion axis. In this geometry, the interferometric light returning from the OCT system is dispersed in two dimensions; the resulting spectrum can achieve more pixels than a traditional OCT spectrometer (which increases the ranging depth) and maintains impressive axial resolution because of the broad bandwidth of the detected OCT light. To the best of our knowledge, we present the first demonstration of OCT data using an Echelle-based cross-dispersed spectrometer. Potential applications for such a system include high-resolution imaging of the retina or the anterior segment of the eye over extended imaging depths and small animal imaging.

Date Published: 22 March 2013
PDF: 10 pages
Proc. SPIE 8572, Advanced Biomedical and Clinical Diagnostic Systems XI, 85720I (22 March 2013); doi: 10.1117/12.2003865

Published in SPIE Proceedings Vol. 8572:
Advanced Biomedical and Clinical Diagnostic Systems XI
Anita Mahadevan-Jansen; Tuan Vo-Dinh; Warren S. Grundfest M.D., Editor(s)