School of Physical Sciences

Scanning, Noise and Distortions

Modulators and scanning methods for OCT

Using two RF modulators, we demonstrated simultaneous acquisition of two C-scans at two different depths: A. Gh.Podoleanu, G. M. Dobre, D. J. Webb, D. A. Jackson, Simultaneous En-face Imaging of Two Layers in Human Retina,Opt. Lett., Vol. 22, No. 13, pp. 1039-1041, (1997)

Using a Mach Zehnder integrated modulator with independent RF excitation in each arm, we demonstrated simultaneous acquisition of two C-scans at two different depths (collaboration with University of Besancon):
A.Gh. Podoleanu, J. A. Rogers, R. C. Cucu, D. A. Jackson, B Wacogne, H. Porte T. Gharbi, Simultaneous Low Coherence Interferometry Imaging at Two Depths Using an Integrated Optic Modulator, Optics Communications, 191(1-2): 21-30, May, 1, 2001.

We demonstrated a novel scanning delay line for fast A-scan but with less loss:
C. C. Rosa, J. Rogers, A.Gh. Podoleanu, Fast Scanning Transmissive Delay Line Optical Coherence Tomography,Opt. Lett. 30, 3263-3265 (2005)

Using two coupled interferometers we devised a novel method for measuring eye length:
A. Gh.Podoleanu, G. M. Dobre, D. J. Webb, D. A. Jackson, Fiberised Set-up for Eye Length Measurement, Full length article in Optics Commun., 137, pp. 397-405, (1997)

Signal to noise ratio analysis

Comparative noise analysis in the two channels of an OCT/SLO system:
A. Gh.Podoleanu, D. A. Jackson, Noise Analysis of a Combined Optical Coherence Tomograph and a Confocal Scanning Ophthalmoscope, Republished in "Selected Papers on Optical Low-Coherence Reflectometry & Tomography", B. R. Masters and B. J. Thompson eds., SPIE Milestone Series, vol. MS165, SPIE Optical Engineering Press, Washington, 2000, USA, pp. 511-526., Appl. Optics, Vol. 38, (1999), No. 10, pp. 2116 - 2127.

This reports shows that fast OCT systems have to work in excess photon noise regime limitation and not in shot noise regime:
A.Gh.Podoleanu, Unbalanced versus balanced operation in an OCT systemAppl. Opt., 2000, Vol. 39, No. 1, pp. 173-182.

Two novel noise bandwidth definitions are introduced to consider the excess photon noise in balanced OCT under wide bandwidth excitation:
C. C. Rosa, A. Podoleanu, Limitation of the achievable signal to noise ratio in OCT due to mismatch of the balanced receiver, Applied Optics, 43 (25): 4802-4815, 2004

Corrections of distortions in OCT images

We make distinction between scanning and refractive type distortions in OCT. This report also predicts a distorted elevation of the RPE layer in the fovea in the OCT images of the retina, due to differences in the indices of refraction of vitreous and retina (collaboration with University of Central Florida, School of Optics / CREOL and New York Eye and Ear Infirmary):
A. Podoleanu, I. Charalambous, L. Plesea, A. Dogariu, R. Rosen, Correction of distortions in OCT imaging of the eye,Physics in Medicine and Biology, 49, 2004, 1277-1294.

 

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Last Updated: 15/07/2011