Design and Optimization of a Linear Wavenumber Spectrometer with Cylindrical Optics for Line Scanning Optical Coherence Tomography

Samadi, Sevin; Dargahi, Javad; Narayanswamy, Sivakumar

doi:10.3390/s21196463

Cited by 3 publications

(1 citation statement)

References 30 publications

(55 reference statements)

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“…The resolution and bandwidth of the SD-OCT system are often limited by the spectrometer. Grating spectrometers are widely used in SD-OCT [45] and its performance is determined by various physical parameters such as grating length, number of gratings, material used, wavelengths, etc. [46].…”

Section: Discussionmentioning

confidence: 99%

Multirate Spectral Domain Optical Coherence Tomography

Gaur,

Grieco,

Fainman

2023

IEEE Photonics J.

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Optical coherence tomography is state-of-the-art in non-invasive imaging of biological structures. Spectral Domain Optical Coherence Tomography is the popularly used variation of this technique, but its performance is limited by the bandwidth and resolution of the system. In this work, we theoretically formulate the use of phase modulators and delay lines to act as filters on the tomography system and scan multiple channels. Various channels are then combined in a digital computer using filter bank theory to improve the sampling rate. The combination of multiple channels allows for increasing the axial resolution and maximum unambiguous range beyond the Nyquist limit. We then simulate the multirate spectral domain optical coherence tomography with 2 channels. We show that a single delay line can improve the axial resolution while a pair of phase modulators can improve the maximum unambiguous range of the system. We also show the use of multirate filter banks to carry out this process. Thus, by using a few extra components in the spectral domain optical coherence tomography, its performance can be increased manifold depending on the number of channels used. The extra cost is the time taken to perform the extra scans that is trivial for stationary objects like biological tissues.

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Section: Discussionmentioning

confidence: 99%

Multirate Spectral Domain Optical Coherence Tomography

Gaur,

Grieco,

Fainman

2023

IEEE Photonics J.

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Optimization Design of Optical Film System Based on Ant Colony Algorithm

Yang

2024

Lecture Notes in Electrical Engineering

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Design of a Linear Wavenumber Spectrometer for Line Scanning Optical Coherence Tomography with 50 mm Focal Length Cylindrical Optics

Samadi

Mohazzab²,

Dargahi

et al. 2022

Sensors

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Optical coherence tomography (OCT) has a wide range of uses in bioimaging and nondestructive testing. Larger bandwidth light sources have recently been implemented to enhance measurement resolution. Increased bandwidth has a negative impact on spectral nonlinearity in k space, notably in the case of spectral domain OCT (SD-OCT). This nonlinearity reduces the depth-dependent signal sensitivity of the spectrometers. A grating and prism combination is extensively used for linearizing. In an earlier study, we used a combination of the reflective grating and prism, as well as a cylindrical mirror with a radius of 180 mm, to achieve a high SR ratio with low nonlinearity. A creative design for a spectrometer with a cylindrical mirror of radius 50 mm, a light source with a center wavelength of 830 ± 100 nm (μm−1 − 6.756 μm−1 in k-space), and a grating of 1600 lines/mm is presented in this work. The design optimization is performed using MATLAB and ZEMAX. In the proposed design, the nonlinearity error reduced from 157∘× μm to 10.75∘× μm within the wavenumber range considered. The sensitivity research revealed that, with the new design, the SR ratio is extremely sensitive to the imaging optics’ angles. To resolve this, a spectrometer based on Grism is introduced. We present a Grism-based spectrometer with an optimized SR ratio of 0.97 and nonlinearity of 0.792∘× μm (Δθ/Δk). According to the sensitivity study, the Grism-based spectrometer is more robust.

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Design and Optimization of a Linear Wavenumber Spectrometer with Cylindrical Optics for Line Scanning Optical Coherence Tomography

Cited by 3 publications

References 30 publications

Multirate Spectral Domain Optical Coherence Tomography

Multirate Spectral Domain Optical Coherence Tomography

Optimization Design of Optical Film System Based on Ant Colony Algorithm

Design of a Linear Wavenumber Spectrometer for Line Scanning Optical Coherence Tomography with 50 mm Focal Length Cylindrical Optics

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