Further resolution enhancement of high-sensitivity laser scanning photothermal microscopy applied to mouse endogenous

Photothermalmicroscopy has intrinsically super resolution capability due to the bilinear dependence of signal intensity of pump and probe. In the present paper, we have made further resolution improvement of high-sensitivity laser scanningphotothermalmicroscopy by applying non-linear detection. By this, the new method has the following advantages: (1) super resolution with 61% and 42% enhancement from the diffraction limit values of the probe and pump wavelengths, respectively, by a second-order non-linear scheme, (2) compact light source using inexpensive conventionaldiode lasers, (3) wide applicability to nonfluorescent materials such asgold nanoparticles (GNPs) and hematoxylin-eosin stained biological samples, (4) relative robustness to optical damage, and (5) a high-frame rate using a Galvanomirror. The maximum resolution is determined to be 160  nm in the second-order non-linear detection mode and 270 nm in the linear detection mode by the PT signal of GNPs. The pixel rate and frame rate for 300 × 300 pixelimage are 50  μs and 4.5 s, respectively. The pixel and frame rate are shorter than the rates, which are 1 ms and 100 s, respectively, using the piezo-driven stagesystem.
Source: Journal of Applied Physics - Category: Physics Authors: Source Type: research