基于受激辐射信号的谱域光学相干层析分子成像方法

Stimulated-emission based spectral domain optical coherence tomography for molecular contrast imaging

鉴于不同生理病理状态下组织复折射率实部的变化不大,传统光学相干层析(OCT)成像技术在分子特异性识别上存在先天不足.为此,本文提出了基于受激辐射信号的OCT成像方法,可在实现传统散射成像的同时,实现基于受激辐射信号的分子成像.在超高分辨率谱域OCT系统的基础上,通过增设光谱分光与调制抽运光支路,建立了基于单宽谱光源的抽运探测谱域OCT系统,详细推导了调制抽运下受激辐射信号的获取与成像公式.利用搭建的抽运探测谱域OCT系统,实现了瞬态受激辐射信号的相干探测.基于同时获取的受激辐射OCT信号和传统OCT信号,成功重构了氮化物粉末构建样品的基于受激辐射信号的分子对比OCT图像.

Due to unnoticeable changes in complex refractive index of tissue under varied pathological and physiological states, the traditional optical coherence tomography（OCT） is deficient in molecular characterization. In this paper,the stimulated-emission based optical coherence tomography is proposed, which provides both molecular contrast and scattering contrast OCT imaging simultaneously. Based on the established ultra-high resolution spectral domain OCT system, a pump-probe spectral domain OCT system with a single wide-bandwidth light source is developed through an added modulated pump beam via spectrum splitting. In addition, the theory about the stimulated-emission signal and the image formulation under the modulated pump beam is presented. The coherent detection of the transient stimulated emission is realized by the developed pump-probe spectral domain OCT system. With the stimulated-emission OCT signal and the traditional OCT signal obtained at the same time, molecular contrast OCT images of the samples consisting of nitride powder are reconstructed successfully.