Silien Christophe, Liu Ning, Hendaoui Nordine, Tofail Syed A M, Peremans André
Department of Physics and Energy, and Materials and Surface Science Institute, University of Limerick, Limerick, Ireland.
Opt Express. 2012 Dec 31;20(28):29694-704. doi: 10.1364/OE.20.029694.
A framework is proposed for infrared (IR) absorption microscopy in the far-field with a spatial resolution below the diffraction limit. The sub-diffraction resolution is achieved by pumping a transient contrast in the population of a selected vibrational mode with IR pulses that exhibit alternating central minima and maxima, and by probing the corresponding absorbance at the same wavelength with adequately delayed Gaussian pulses. Simulations have been carried out on the basis of empirical parameters emulating patterned thin films of octadecyltrichlorosilane and a resolution of 250 nm was found when probing the CH₂ stretches at 3.5 μm with pump energies less than ten times the vibrational saturation threshold.
提出了一种用于远场红外（IR）吸收显微镜的框架，其空间分辨率低于衍射极限。通过用具有交替中心极小值和极大值的红外脉冲泵浦选定振动模式的粒子数中的瞬态对比度，并通过用适当延迟的高斯脉冲在相同波长下探测相应的吸光度来实现亚衍射分辨率。已基于模拟十八烷基三氯硅烷图案化薄膜的经验参数进行了模拟，当用小于振动饱和阈值十倍的泵浦能量在3.5μm处探测CH₂伸缩振动时，发现分辨率为250nm。
