A two-dimensional optical coherence tomography using spectral domain interferometry

Recently, low coherence interferometry (LCI) and optical frequency domain reflectometry (OFDR) have become a very popular noninvasive sensing method to obtain a tomographic image with high resolution and high sensitivity. It is necessary to use mechanical or frequency scanning of the coherent light source to obtain a tomographic image. By use of a spectrometer and a photodiode array, absolute optical path difference (OPD) is obtainable from a spectral density function and its Fourier transform without any mechanical scanning. When one analyzes a spectrally resolved interference is detected by a CCD camera at a frequency plane, OPD information as well as its sign and also the spatial information, thus the two-dimensional information, are simultaneously obtainable without any mechanical scanning. We present a new method to obtain a two-dimensional tomographic image without any scanning. The proposed scheme is experimentally demonstrated for multilayered high reflectance objects.