TY - JOUR
T1 - A Compact Linear-in-Wavenumber Spectrometer With a 1800 Lines/mm Grating for 4.8 mm Imaging Depth in SD-OCT
AU - Cao, Liangqi
AU - Zhong, Haozhe
AU - Zhao, Duohao
AU - Zhang, Wenxin
AU - Huang, Jianfeng
AU - Zhang, Jiacheng
AU - Zhang, Xiao
N1 - Publisher Copyright:
© 1995-2012 IEEE.
PY - 2026
Y1 - 2026
N2 - In SD-OCT, linear-in-wavenumber spectrometers play a key role in direct k-domain sampling, which eliminates interpolation artifacts and reduces computational load. However, prevalent designs in the 850 nm band using 1200 lines/mm gratings face a fundamental trade-off between imaging depth, system size and cost: achieving a large imaging depth necessitates large-volume, costly optics with long focal lengths and large apertures. To overcome this limitation, we present the design and experimental validation of a linear-in-wavenumber spectrometer employing a 1800 lines/mm grating. The high dispersion of this grating enables a compact system that achieves an imaging depth of ∼4.8 mm with a 76 nm spectral detection range, compatible with single-SLD sources. Compared to the conventional 1200 lines/mm design, our spectrometer reduces the total optical length from ∼325 mm to ∼190 mm and the entrance pupil diameter from 11 mm to 7.2 mm, allowing for smaller and more cost-effective components. Furthermore, our optimization method incorporates wavenumber nonlinearity introduced by the focusing group, overcoming the limitations of traditional approaches that neglect lens aberrations. Experimental results demonstrate a considerable wavenumber linearity (R2 = 0.9999995) and a system sensitivity of 103.4 dB. High-quality in vivo imaging of human skin and nailfold, revealing microvasculature and layered structures, validates the practical utility. This work provides a high-linearity, compact, and cost-effective spectrometer solution, particularly suited for SD-OCT applications requiring large imaging depths.
AB - In SD-OCT, linear-in-wavenumber spectrometers play a key role in direct k-domain sampling, which eliminates interpolation artifacts and reduces computational load. However, prevalent designs in the 850 nm band using 1200 lines/mm gratings face a fundamental trade-off between imaging depth, system size and cost: achieving a large imaging depth necessitates large-volume, costly optics with long focal lengths and large apertures. To overcome this limitation, we present the design and experimental validation of a linear-in-wavenumber spectrometer employing a 1800 lines/mm grating. The high dispersion of this grating enables a compact system that achieves an imaging depth of ∼4.8 mm with a 76 nm spectral detection range, compatible with single-SLD sources. Compared to the conventional 1200 lines/mm design, our spectrometer reduces the total optical length from ∼325 mm to ∼190 mm and the entrance pupil diameter from 11 mm to 7.2 mm, allowing for smaller and more cost-effective components. Furthermore, our optimization method incorporates wavenumber nonlinearity introduced by the focusing group, overcoming the limitations of traditional approaches that neglect lens aberrations. Experimental results demonstrate a considerable wavenumber linearity (R2 = 0.9999995) and a system sensitivity of 103.4 dB. High-quality in vivo imaging of human skin and nailfold, revealing microvasculature and layered structures, validates the practical utility. This work provides a high-linearity, compact, and cost-effective spectrometer solution, particularly suited for SD-OCT applications requiring large imaging depths.
KW - isosceles prism
KW - linear-in-wavenumber spectrometer
KW - Spectral-domain optical coherence tomography
KW - volume phase holographic grating
UR - https://www.scopus.com/pages/publications/105028156183
U2 - 10.1109/JSTQE.2025.3649911
DO - 10.1109/JSTQE.2025.3649911
M3 - Article
AN - SCOPUS:105028156183
SN - 1077-260X
VL - 32
JO - IEEE Journal of Selected Topics in Quantum Electronics
JF - IEEE Journal of Selected Topics in Quantum Electronics
IS - 4
M1 - 7100508
ER -