Software controlling algorithms for the system performance optimization of confocal laser scanning microscope

Three-dimensional characterization of tightly focused fields for various polarization incident beams

Tightly focused vectorial optical beams have found extensive applications in variety of technical fields like single-molecule detection, optical tweezers, and super-resolution optical microscopy. Such applications require an accurate measurement and manipulation of focal optical fields. We have developed a compact instrument (with dimensions of 35 × 35 × 30 cm³) to rapidly measure the intensity distribution in three dimensions of the focused fields of vectorial beams and any other incident beams. This instrument employs a fluorescent nanoparticle as a probe to scan the focal region to obtain a high spatial resolution of intensity distribution. It integrates a liquid-crystal spatial light modulator to allow for tailoring the point spread function of the optical system, making it a useful tool for multi-purpose and flexible research. The robust applicability of the instrument is verified by measuring the 3D intensity distributions of focal fields of various polarization and wavefront modulated incident beams focused by a high NA (=1.25) objective lens. The minimal data acquisition time achievable in the experiment is about 8 s for a scanning region of 3.2 × 3.2 μm² (512 × 512 pixels). The measured results are in good agreement with those predicted by the vectorial diffraction theory.

CRAFT: Multimodality confocal skin imaging for early cancer diagnosis

Although histological analysis serves as a gold standard to cancer diagnosis, its application on skin cancer detection is largely prohibited due to its invasive nature. To obtain both the structural and pathological information in situ, a Confocal Reflectance/Auto-Fluorescence Tomography (CRAFT) system was established to examine the skin sites in vivo with both reflectance and autofluorescence modes simultaneously. Nude mice skin with cancerous sites and normal skin sites were imaged and compared with the system. The cellular density and reflective intensity in cancerous sites reflects the structural change of the tissue. With the decay coefficient analysis, the corresponding NAD(P)H decay index for cancerous sites is 1.65-fold that of normal sites, leading to a 97.8% of sensitivity and specificity for early cancer diagnosis. The results are verified by the followed histological analysis. Therefore, CRAFT may provide a novel method for the in vivo, non-invasive diagnosis of early cancer.