Detection of back-reflected SHG from corneal histological sections

Abstract

The feasibility of using reflective surfaces to increase the detection of SHG signals from corneal histological sections in the backward direction was attempted. Three reflective surfaces were tested: aluminum foil, a silver mirror, and a dielectric mirror with specific high reflectivity around 400 nm. To compare the SHG signal detected with and without reflective surfaces, the translation caused by the bending of the sample due to the extra weight on top of the microscope slide was determined. All reflective surfaces resulted in an increase of the detection of SHG signals. Increases of 4%, 11%, and 16% were observed for aluminum foil, dielectric mirror and silver mirror, respectively. A method for increased detection of backward SHG signals when forward detection is not possible was herein demonstrated.

High-speed, multi-modal, label-free imaging of pathological slices with a Bessel beam

“…Meanwhile, the lateral resolution of the system is substantially consistent with the lateral resolution of the Gaussian beam. To efficiently collect signals from pathological slices, we add a closely-attached reflection mirror under the sample, and show its effectiveness in improving the 2PAF signals, SHG signals, and THG signals [23][24][25][26]. Considering that SHG signals are closely related to the polarization state of the excitation light [27][28][29], we employ circularly polarized beams for comprehensive information acquisition.…”