No abstract

We present a wide-field quantitative label-free imaging of mouse brain tissue slices with sub-micrometre resolution, employing holographic microscopy and an automated scanning platform. From the measured light field images, scattering coefficients and anisotropies are quantitatively retrieved by using the modified the scattering-phase theorem, which enables access to structural information about brain tissues. As a proof of principle, we demonstrate that these scattering parameters enable us to quantitatively address structural alteration in the brain tissues of mice with Alzheimer’s disease.

We demonstrate the cost-effective and facile method of fabricating close-packed microlens arrays using photoinduced two-dimensional (2-D) surface relief structures as original templates. 2-D surface relief structures are produced by successive inscription of two beams interference patterns with different grating vectors on azopolymer films. The employed exposure dose of 1st inscription stage and 2nd inscription stage are optimized to obtain symmetrical modulation heights. These photoinduced 2-D surface relief structures on azopolymer films are used directly to mold PDMS, and PDMS molds were then transferred onto photopolymer to imprint microlens arrays. Using this method, tetragonally and hexagonally close-packed microlens arrays are successfully fabricated in rapid and cost-effective way.

We report the spontaneous formation of unusual surface reliefs, in which two sets of sinusoidal gratings were hierarchically structured, merely by single-step holographic inscription on amorphous azopolymer films. By monitoring of growth behavior of surface reliefs during holographic inscription, we found that the formation of additional grating is caused by the creeping and resulting aggregation of dome structures. Our direct observation of creeping and aggregation behavior is expected to contribute to enhancing the understanding of unusual surface reliefs, and also in fabricating complex surface reliefs.