基于和频效应和环形光的超分辨红外显微成像方法  

Super-resolution infrared microscopy based on VSFG and donut-beam illumination

作　　者：陈丹妮[1] 李亚晖 刘伟[1] 刘正一 Chen Danni;Li Yahui;Liu Wei;Liu Zhengyi(Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province,College of Opto-Electronic Engineering,Shenzhen University,Shenzhen 518060,China;State Key Laboratory of Transient Optics and Photonics,Xi＇an Institute of Optics and Precision Mechanics of CAS,Xi＇an 710119,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]深圳大学光电工程学院光电子器件与系统(教育部/广东省)重点实验室,广东深圳518060 [2]中国科学院西安光学精密机械研究所瞬态光学技术国家重点实验室,陕西西安710119 [3]中国科学院大学,北京100049

出　　处：《红外与激光工程》2018年第8期179-185,共7页Infrared and Laser Engineering

基　　金：国家自然科学基金(61335001;11774242;61235012;61705144);国家重点基础研究发展计划(2012CB825802;2015CB352005);国家重大科学仪器设备开发专项(2012YQ15009203);深圳市科技计划(JCYJ20160308104404452;JCYJ20170818142804605)

摘　　要：提出了一种结合和频效应和环形光照明的远场超分辨红外显微成像方法。红外光、不同频率的环形和高斯可见光同时共轴激发样品,当红外光频率等于样品分子某一共振频率时,样品分子吸收红外光到达振动激发态,环形和高斯可见光与共振分子作用分别产生无效和有效的和频信号。利用三束光的矢量光场表达式和模型能级系统的速率方程进行数值模拟发现,当总可见光足够强时,可使总和频信号饱和,环形和高斯可见光与共振分子的作用出现竞争,通过提高环形可见光光子流密度超过饱和光子流密度,并降低高斯可见光光子流密度,可有效地抑制环形区域有效和频信号的产生,从而达到压缩PSF的目的,在物镜数值孔径0.6的情况下,通过数值模拟得到有效和频信号PSF半高宽为56 nm。A method of far-field super-resolution infrared microscopy was presented by using vibrational sum-frequency generation（VSFG） and donut-beam illumination. To achieve this, one Gaussian-shaped visible beam and one donut-shaped visible beam with different wavelengths were combined with an infrared beam coaxially to excite the sample. When the frequency of the infrared light was as the same as the resonant frequency of the molecules, the molecules absorbed the energy of the infrared photon and were excited to the vibrational excited state. The photons in the donut-shaped and the Gaussian-shaped visible beams both interacted with the excited molecules, and generated useful and useless SFG signal respectively. Simulations based on the vectorial field of the three beams and rate equations demonstrated that, when the visible intensity was improved to a certain level, the SFG signal tended to be saturated, then the donut-shaped visible photons and the Gaussian-shaped photons competed with each other. By increasing the photon flux density of the donut-shaped visible light to be larger than the saturated value, and reducing the photon flux density of the Gaussian-shaped visible light, the useful SFG signal in the donut-shaped area was surpressed effectively, which means the effective PSF was shrinked. With an objective which has a small numerical aperture （NA） 0.6, a simulated resolution as high as 56 nm was obtained.

关 键 词：红外吸收 超分辨显微成像 衍射极限 高分辨 

分 类 号：O439[机械工程—光学工程]