超高分辨光学相干层析成像技术与材料检测应用

Ultrahigh-resolution optical coherence tomography and its application in inspection of industrial materials

本文报道了一种超高分辨率谱域光学相干层析成像(SD-OCT)系统.该系统基于超连续谱激光光源并截取部分光谱作为宽带光源,其中心波长为665 nm,光谱半高全宽(FWHM)230 nm.系统轴向分辨率0.9μm,轴向扫描速率28600行/秒,横向分辨率3.9μm,横向视场1 mm,最大成像深度0.6 mm(空气中).利用研制的超高分辨率SD-OCT系统,对不同型号的工业砂纸精细结构进行了成像,并与普通SD-OCT的成像结果进行对比,充分展示了研制系统在材料无损检测中优势.

Since many industrial materials have micro or submicro structures on the surface or subsurface, utrahigh-resolution is required in the inspection of these materials. Ultrahigh-resolution optical coherence tomography uses broadband light sources to achieve axial image resolutions on the scale of a few microns. We have been investigating an ultrahigh-resolution spectral-domain optical coherence tomography （SD-OCT） system using supercontinuum sources （SC） in free space. The effective SC spectrum has a full width at half maximum of 230 nm centered around 665 nm, and the imaging setup has an ultrahigh axial resolution of 0.9 μm in air, and a lateral resolution of 3.9 μm, with the system measurement range being 0.6 mm in axial direction. At a 50 μm axial position, the sensitivity can be 63 dB with 28600 axial scans per second at 2048 pixels per axial scan. Images of polystyrene microspheres solution with an average diameter of 5 μm and different sizes of industrial abrasive papers are presented to illustrate the performance of the system.