CC BY
1The 30th International Conference on Advanced Laser Technologies ALT'23
B-I-17
Balanced detection spectral-domain optical coherence tomography
with a single line-scan camera
Jun Zhang1
1- School of Artificial Intelligence, Guilin University of Electronic Technology, Guilin 541004, China
junzhang@guet. edu. cn
The spectral interferogram of Fourier domain Optical Coherence Tomography (FD-OCT) incorporates a direct current term (DC), an autocorrelation term (AC), which signifies the mutual interference from reflectors at varying depths of the sample [1], and a cross-correlation interference term (CC). Generally, the reference spectrum is subtracted from the interference spectrum, which acts as the background, in order to mitigate the DC and AC terms. These terms typically cause low frequency noise near the zero-delay line [2,3]. Moreover, balanced detection has been extensively utilized in Time-Domain OCT (TD-OCT) and Swept-Source OCT (SS-OCT) employing balanced photodetectors, providing a more effective approach to remove the DC and AC terms [4,5].
Recently, several balanced detection Spectral Domain OCT (BD-SD-OCT) techniques have been proposed. However, these come with drawbacks such as limited imaging speed, bulky and complex setups, signal loss, and an additional imbalance between the two channels [6,7].
In this study, we have developed a cost-effective and structurally simple dual balanced detection spectral-domain optical coherence tomography (SD-OCT) system. It uses a 4096-pixel single line-scan camera to both reduce auto-correlation (AC) artifacts and improve the signal-to-noise ratio (SNR) in SD-OCT. The system simultaneously detects two interference spectra—each in opposed-phase and incident on the spectrometer at different angles—using 2048 pixels per channel.
The developed dual balanced detection SD-OCT system demonstrated a direct current (DC) term suppression of 10 dB, an AC term suppression of 5-10 dB and SNR enhancement of 5.4 dB in comparison to unbalanced detection configuration.
In vivo imaging of human nail fold and retina also exhibited that the balanced detection SD-OCT technique proposed in this paper is able to suppress AC noise in in vivo imaging and acquire deeper layers of the tissue with more details.
The technique allows for a relatively simple structure, taking advantage of the high acquisition rate of the line-scan camera, and avoids crosstalk between the balanced detection spectra.
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