Development Of Orthogonal Dispersive Fourier Domain Optical Coherence Tomography

In the thesis, the main part is around the theoretical and application study in Fourier domain optical coherence tomography (FDOCT), especially in its high resolution orthogonal dispersive spectrometer, with several application studies in analyzing the interference spectrum signal. The main works included in the thesis are:1. Theoretical study in FDOCT system based on high resolution orthogonal dispersive spectrometer:1.1. Two-dimensional dispersion generated by the combination of the VIPA and the grating in conjunction with a two-dimensional CCD leads to an improved performance of the spectrometer. Ultrahigh spectral resolution of0.002nm within a free spectrum range (FSR) of50nm is realized, providing the spectrometer with a spectral sampling rate up to～105. The developed FDOCT realizes an imaging depth over80mm, which is the longest depth range ever achieved by FDOCT. The increased spectral sampling rate also results in a high signal-to-noise ratio (SNR) of the SDOCT system.1.2. The spectrum calibration method based on a fixed optical thickness glass plate is raised. It can be used to solve the problem that large range spectrum has a non-linear distribution on the detector plane. Hence we can use this method to achieve one-dimensional spectrum signal from the two-dimensional orthogonal dispersed spectrum.1.3. Built the common path FDOCT system based on the high resolution orthogonal dispersive spectrometer, in order to eliminate phase turbulence due to environment variation. A sensitivity of optical delay measurement of3.0pm is achieved using an optical plate.2. Application study of FDOCT system:2.1Developed the Doppler method in FDOCT system, especially in its velocity measuring model, to capture the vessel area in the Doppler OCT image. The method is used in monitoring of drug and stimulation induced cerebral blood flow velocity changes in rat sensory cortex, and improvement of the design of microchip in detection of the circulating tumour cells.2.2Developed the Monte Carlo simulation method of photon transmission, with the improvement on adding the Doppler phase shift calculation and the multi-layer simulation. This method is used to improve the SNR of the Doppler signal and used in a portable Doppler laser flowmetry.2.3Raise the geometrical optics algorithms for numerical correction of the unavoidable image distortions in the raw OCT image due to the refraction and the mismatch. The mapping of the raw OCT images to the actual structures is obtained and experimentally verified. The corrected images of the glass tube and the human eye are coincident to the actual structures.2.4Improved application in three-dimensional OCT imaging, polarization sensitive OCT and spectral fluctuation analyzing of the OCT signal.