Spectral Domain Optical Coherence Tomography Imaging Performance Improvement Based on Field Curvature Aberration-Corrected Spectrometer

Seung Seok Lee,Woosub Song,Eun Seo Choi

doi:10.3390/app10103657

Abstract

We designed and fabricated a telecentric f-theta imaging lens (TFL) to improve the imaging performance of spectral domain optical coherence tomography (SD-OCT). By tailoring the field curvature aberration of the TFL, the flattened focal surface was well matched to the detector plane. Simulation results showed that the spot in the focal plane fitted well within a single pixel and the modulation transfer function at high spatial frequencies showed higher values compared with those of an achromatic doublet imaging lens, which are commonly used in SD-OCT spectrometers. The spectrometer using the TFL had an axial resolution of 7.8 μm, which was similar to the theoretical value of 6.2 μm. The spectrometer was constructed so that the achromatic doublet lens was replaced by the TFL. As a result, the SD-OCT imaging depth was improved by 13% (1.85 mm) on a 10 dB basis in the roll-off curve and showed better sensitivity at the same depth. The SD-OCT images of a multi-layered tape and a human palm proved that the TFL was able to achieve deeper imaging depth and better contrast. This feature was seen very clearly in the depth profile of the image. SD-OCT imaging performance can be improved simply by changing the spectrometer’s imaging lens. By optimizing the imaging lens, deeper SD-OCT imaging can be achieved with improved sensitivity.

Highlights

Optical coherence tomography (OCT) is a high-resolution optical imaging modality that combines a wide spectral light source-based optical interferometer and a fast point scanning method
Because of its high axial resolution, OCT can be used for the early diagnosis of diseases as it can acquire tomographic images of accessible skin tissues and can detect diseases occurring in the airways, stomach, blood vessels and urethra by using optical probes developed in the form of catheters [2–5]
A method for improving spectral domain optical coherence tomography (SD-OCT) performance based on a spectrometer using an aberration-corrected imaging lens is proposed

Summary

Introduction

Optical coherence tomography (OCT) is a high-resolution optical imaging modality that combines a wide spectral light source-based optical interferometer and a fast point scanning method. The OCT system, which is implemented based on the principle of the basic interferometer, was developed as an optical biopsy technique for non-invasive imaging of various internal diseases. Because of its high axial resolution, OCT can be used for the early diagnosis of diseases as it can acquire tomographic images of accessible skin tissues and can detect diseases occurring in the airways, stomach, blood vessels and urethra by using optical probes developed in the form of catheters [2–5]. OCT is one of the latest optical measurement techniques and it has recently been developed as a diagnostic technique that is capable of providing multiple information beyond simple non-invasive tomographic images [6–9]

Methods

Results

Conclusion