Doubling the far-field resolution in mid-infrared microscopy

作者：Kumbham Mahendar; Daly Susan; O'Dwyer Kevin; Mouras Rabah; Liu Ning; Mani Aladin; Peremans Andre; Tofail Syed M; Silien Christophe^*

来源：Optics Express, 2016, 24(21): 24377-24389.

DOI：10.1364/OE.24.024377

The spatial resolution in far-field mid-infrared (lambda > 2.5 mu m) microscopy and micro-spectroscopy remains limited with the full-width at half maximum of the point-spread function ca. lambda/1.3; a value that is very poor in comparison to that commonly accessible with visible and near-infrared optics. Hereafter, it is demonstrated however that polymer beads that are centre-to-centre spaced by lambda/2.6 can be resolved in the mid-infrared. The more than 2-fold improvement in resolution in the far-field is achieved by exploiting a newly constructed scanning microscope built around a mid-infrared optical parametric oscillator and a central solid-immersion lens, and by enforcing the linear polarization unidirectional resolution enhancement with a novel and robust specimen error minimization based on a particle swarm optimization. The method is demonstrated with specimens immersed in air and in water, and its robustness shown by the analysis of dense and complex self-assembled bead islands.

• 出版日期2016-10-17