The spectral shape of a source is of prime importance in optical coherence imaging because it determines several aspects of image quality, especially longitudinal resolution. Wide spectral bandwidth, which provides short coherence length, is sought to obtain high-resolution imaging. To estimate longitudinal resolution, the spectral shape of a source is usually assumed to be Gaussian, although the spectra of real sources are typically non-Gaussian. We discuss the limit of this assumption regarding the estimation of longitudinal resolution. To this end, we also investigate how coherence length is related to longitudinal resolution through the evaluation of different definitions of the coherence length. To demonstrate our purpose, the coherence length for several theoretical and real spectral shapes of sources having the same spectral bandwidth and central wavelength is computed. The reliability of coherence length computations toward the estimation of longitudinal resolution is discussed.
© 2002 Optical Society of America
Original Manuscript: October 22, 2001
Revised Manuscript: February 20, 2002
Published: September 1, 2002
Ceyhun Akcay, Pascale Parrein, and Jannick P. Rolland, "Estimation of longitudinal resolution in optical coherence imaging," Appl. Opt. 41, 5256-5262 (2002)