게시판 최근논문

[Editor's Pick] Current Optics and Photonics Vol. 7 no. 1 (2023 February)

사무국 hit 1861 date 2023-02-27

Partial Spectrum Detection and Super-Gaussian Window Function for Ultrahigh-resolution Spectral-domain Optical Coherence Tomography with a Linear-k Spectrometere

Hyun-Ji Lee1,2 and Sang-Won Lee1,2 *

 

Current Optics and Photonics  Vol. 7 No. 1 (2023 February) pp. 73-82
DOI: https://doi.org/10.3807/COPP.2023.7.1.73

 

  Fig. 1  Schematic of the SD-OCT based on a linear k-domain spectrometer. (a) The sample arm to measure the system performance and obtain the skin tissue’s image. (b) The sample arm to get the image of the retina. SD-OCT, spectral domain optical coherence tomography; PC, polarization controller; CL, collimation lens; OL, objective lens; DCB, dispersion compensation block; RM, reference mirror; RC, reflective collimator; G, grating; DP, dispersive prism; PM, prism mirror; L1 to L4, lenses.

 

Keywords: Spectral domain, Super-Gaussian window, Ultrahigh resolution optical coherence tomography
OCIS codes: (110.4500) Optical coherence tomography; (170.3880) Medical and biological imaging;(170.4500) Optical coherence tomography


Abstract
In this study, we demonstrate ultrahigh-resolution spectral-domain optical coherence tomography with a 200-kHz line rate using a superluminescent diode with a −3-dB bandwidth of 100 nm at 849 nm. To increase the line rate, a subset of the total number of camera pixels is used. In addition, a partialspectrum detection method is used to obtain OCT images within an imaging depth of 2.1 mm while maintaining ultrahigh axial resolution. The partially detected spectrum has a flat-topped intensity profile, and side lobes occur after fast Fourier transformation. Consequently, we propose and apply the super-Gaussian window function as a new window function, to reduce the side lobes and obtain a result that is close to that of the axial-resolution condition with no window function applied. Upon application of the super-Gaussian window function, the result is close to the ultrahigh axial resolution of 4.2 μm in air, corresponding to 3.1 μm in tissue (n = 1.35).