Abstract

We report on the new application, to the best of our knowledge, of a time-domain optical coherence tomography (TD-OCT) device used to measure the ordinary ${n_o}$ and extraordinary ${n_e}$ indices of calcite birefringence crystal at room temperature. A ${1.25}\;{\pm}\;{0.05}\;{\rm mm}$ thick slab of calcite crystal is cut, polished, and used as a sample in the OCT arm. While the calcite slab is axially scanned, the raw carrier ordinary signals that came from its front and rear facets are received and denoised with a set of digital filters. The extraordinary signals are generated by the change of beam polarization using a 90°-rotating polarizer plate. It is found that the wavelet transform is capable of reaching the highest signal-to-noise ratio (SNR) of about 24.50 and 23.91 for denoising the ordinary and extraordinary signals, respectively. Quantitative measurement of ${n_o}$ and ${n_e}$ is carried out by extracting a desired envelope from the denoised signals using standard methods. Average values of 1.660 and 1.444 are obtained for ${n_o}$ and ${n_e}$, respectively, using the wavelet-denoised signals. The weights of the results are finally searched with ones obtained from two sets of dispersion equations. We found a very good agreement between the wavelet-denoised OCT- and dispersion equation-based values with a very low relative differences of 0.04% and 2.8% for ${n_o}$ and ${n_e}$, respectively, when the Ghosh equation is used and averaged ones of 1.3% and 4.2% for ${n_o}$ and ${n_e}$, respectively, when the Zhao et al. equation is applied.

© 2024 Optica Publishing Group

Reducing noise in polarization-sensitive optical coherence tomography for high-quality local phase retardation imaging

Guoqiang Chen, Wen’ai Wang, and Yanqiu Li
Appl. Opt. 63(11) 2822-2830 (2024)

Mapping of birefringence and thermal damage in tissue by use of polarization-sensitive optical coherence tomography

Klaus Schoenenberger, Bill W. Colston, Duncan J. Maitland, Luiz B. Da Silva, and Matthew J. Everett
Appl. Opt. 37(25) 6026-6036 (1998)

Birefringence measurement of the retinal nerve fiber layer by swept source polarization sensitive optical coherence tomography

Badr Elmaanaoui, Bingqing Wang, Jordan C. Dwelle, Austin B. McElroy, Shuang S. Liu, Henry G. Rylander, and Thomas E. Milner
Opt. Express 19(11) 10252-10268 (2011)

Structural similarity assessment of an optical coherence tomographic image enhanced using the wavelet transform technique

Mohammad Dehshiri, Saeed Ghavami Sabouri, and Alireza Khorsandi
J. Opt. Soc. Am. A 38(1) 1-9 (2021)

In vivo depth-resolved birefringence measurements of the human retinal nerve fiber layer by polarization-sensitive optical coherence tomography

Barry Cense, Teresa C. Chen, B. Hyle Park, Mark C. Pierce, and Johannes F. de Boer
Opt. Lett. 27(18) 1610-1612 (2002)