双光栅快速扫描光学延迟线的色散补偿

光学相干层析成像(OCT)系统的纵向分辨力不仅与光源的带宽有关,而且与系统中两干涉臂间的色散匹配有关。如果色散没有得到精确匹配,将使光学相干层析成像系统的纵向分辨力达不到所预期的理论值。色散问题在超高分辨光学相干层析成像系统中尤为突出。提出了一种基于双光栅快速扫描光学延迟线(RSOD),用于光学相干层析成像系统的色散补偿。该方法中新增的光栅引入了光栅间距这一独立变量,其与常规单光栅快速扫描光学延迟线机构中的光栅离焦量一起,可使光学相干层析成像系统中的群速度色散(GVD)和三阶色散(TOD)同时得到补偿。分析了双光栅快速扫描光学延迟线的色散特性和色散调节原则,并提供了一个典型光学相干层析成像系统中的色散补偿实例。

Double-Grating Rapid Scanning Optical Delay Line for Dispersion Compensation

The axial resolution of optical coherence tomography (OCT) depends on not only the bandwidth of the light source but also the dispersion balance between the sample arm and reference arm.If the dispersion between two arms is not matched accurately,the axial resolution of optical coherence tomography system will degrade.Dispersion problem is very important especially in ultrahigh resolution optical coherence tomography system.A method for dispersion compensation in optical coherence tomography by a double-grating based rapid scanning optical delay line (RSOD) is put forward.The independent variable of the distance between gratings in the added gratings,along with the adjustable distance between grating and Fourier transform lens in a conventional rapid scanning optical delay line can be used to compensate the group velocity dispersion (GVD) and third order dispersion (TOD) of optical coherence tomography system simultaneously.The dispersion characteristics as well as the dispersion management scheme are discussed.Example of dispersion compensation in a typical optical coherence tomography system is provided.