Optical coherence tomography speckle reduction by a partially spatially coherent source.

Area of Science:

• Biomedical Optics
• Medical Imaging Technology
• Coherent Phenomena

Background:

• Speckle in optical coherence tomography (OCT) arises from the high spatial coherence of incident light.
• This coherence leads to interference with light backscattered from heterogeneous biological tissues.
• Speckle degrades image quality and resolution in OCT.

Purpose of the Study:

• To investigate speckle reduction in OCT using a partially spatially coherent light source.
• To compare the performance of single-mode versus multimode fibers for generating partially coherent light in OCT.
• To validate findings through numerical simulation and experimental data.

Main Methods:

• A numerical simulation using a Gaussian-Schell model for a partially spatially coherent source was developed.
• An experiment utilized a broadband light source and a multimode fiber to generate a partially spatially coherent source.
• Low-coherence interferograms of a scattering surface were recorded using both single-mode and multimode fibers.

Main Results:

• Numerical simulations modeled the effect of a partially spatially coherent source on OCT speckle.
• Experimental results showed that interferograms recorded with a single-mode fiber resembled conventional OCT speckle.
• Substantial speckle reduction was observed in OCT images acquired using the multimode fiber, indicating a partially spatially coherent source.

Conclusions:

• Partially spatially coherent light sources effectively reduce speckle in OCT imaging.
• The use of a multimode fiber with a broadband source is a viable method for generating such sources.
• This approach offers a promising strategy for improving OCT image quality.