Development And Application Of High-resolution Spectral Domain OCT

Optical coherence tomography(OCT)is a new biological detection imaging technology born in the 1990s.So far,OCT in the biomedical field,especially in ophthalmology has been widely used,but in fact OCT can be applied to micro-structure measurement,defect detection and other industrial fields.Since many industrial materials have micron and submicron structures on the surface and subsurface,the detection of these materials requires ultra-high resolution.For the requirement of high resolution,a free-space ultra-high resolution spectral optical coherence tomography(SD-OCT)system based on Michelson interferometer is developed.The system uses a supercontinuum laser source with a central wavelength of 650 nm(650 nm is the center wavelength of the effective spectrum filtered out from the light source).The full width at half maximum is 260 nm,and the ultrahigh axial resolution of 0.9?m can be realized.The axial scan rate was 28600A-lines/s.The spectra of each A-line were received with a linear CCD of 2048 pixels.The lateral resolution was 3.9?m,the transverse field of view was 1mm and the imaging depth in the air was more than 0.6mm.A series of studies have been carried out,including the study of the elimination of dispersion algorithms,the detection of fine structure samples,and the measurement of nanoscale film thickness using the developed ultra-high resolution spectral domain OCT system.In addition,a stimulated emission spectral domain OCT system was developed on the basis of ultra-high resolution spectral domain OCT system.Conventional spectral domain OCT is through the organization of the backscattered light to obtain the interference signal,the molecular characteristics of the elements is essential to the early inspection of certain diseases,such as the skin melanin content is the diagnosis of melanoma evaluation.Standard OCT can only image the biological tissue structure,and the molecular characteristics of the element distribution information is not available.If the OCT system can achieve both micron-scale resolution imaging and molecular-specific information at the tissue surface,it is a huge step forward for the biomedical field.In this paper,stimulated emission,modulation and demodulation techniques are combined to develop a stimulated emission spectral domain OCT system,which can effectively detect the molecular information of fluorescent chromophore.This paper mainly includes two parts around the ultra-high resolution spectral domain OCT system:1.the development and application of ultra-high resolution spectral domain OCT system.2.the development of the stimulated emission spectrum domain OCT system on the basis of ultra-high resolution OCT and the grab of molecular contrast.