Wavelength calibration of dispersive near-infrared spectrometer using relative k-space distribution with low coherence interferometer

Lensless fiber-deployed low-coherence interferometer for in-situ measurements in nonideal environments

“…(2) Or use of a software-based method, acquiring the signal nonlinearly in k and resampling it during postprocessing through the use of a λ to k-mapping function. 15,[22][23][24][25][26][27][28][29] However, literature shows that for software-based methods, the interpolation is not as good for reflectors close to the maximum achievable depth (Nyquist limit) due to high-frequency fringes in the interferogram that are poorly sampled. Methods of circumventing remapping captured spectra through various computational techniques have also been investigated in literature.…”

“…Methods of circumventing remapping captured spectra through various computational techniques have also been investigated in literature. [31][32][33] The approach taken in this work is similar to that presented for automatic calibration 15 and interferometric methods, [23][24][25] relying on the knowledge that for a singular reflector, and while operating in a common-path configuration negating the requirement for dispersion compensation, the interference fringes will be evenly spaced in k-space. By using zero-crossing detection, fringe spacing as a function of pixel number is obtained from which a mapping relationship between linear in λ and linear in k-space can be created, this allows interpolation of the data using a B-spline interpolation to create an evenly sampled dataset in k-space before performing an FFT.…”

Spectrometer calibration for spectroscopic Fourier domain optical coherence tomography

“…Comparison of spectra registered by a calibrated spectrum analyzer and by the spectrometer to be calibrated has been shown by Ding et al [31]. Recently, additional light sources with narrow spectral lines from argon lamp have been used to assign wavenumbers to pixels in SOCT spectrometers by Kim et al [32,33]. In these two steps approaches zero-crossing detection is applied to single component spectral fringe signal to extract the distribution of spectrometer points equidistant in wavenumber space.…”

“…In these two steps approaches zero-crossing detection is applied to single component spectral fringe signal to extract the distribution of spectrometer points equidistant in wavenumber space. This step is followed by calculation of absolute wavenumbers for all points of the detector using information provided either by calibration lamp with multiple spectral lines [33] or by recalculation of spectral range of the spectrometer from imaging range of the SOCT device [32]. Another interesting approach was presented by Faber et al [21] where the Doppler frequency was introduced in data acquired during motion of a mirror used as a sample.…”

Fotónica de microondas aplicada a la interferometría de baja coherencia

“…En este sentido, como se ha comentado anteriormente, una de las mayores debilidades de las técnicas basadas en SB-LCI es la no linealidad del espectrómetro dispersivo empleado. Por ello, algunos autores están centrando su atención en mejorar la linealidad de este dispositivo o de proponer métodos alternativos para abaratar el coste [72,73,74]. Sin embargo, la mayor parte de las publicaciones más actuales se basan en la técnica SS-LCI, dadas sus ventajas sobre SB-LCI.…”