Varifocal Metalens for Optical Sectioning Fluorescence Microscopy

Fluorescence microscopy with optical sectioning capabilities is extensively utilized in biological research to obtain three-dimensional structural images of volumetric samples. Tunable lenses have been applied in microscopy for axial scanning to acquire multiplane images. However, images acquired by conventional tunable lenses suffer from spherical aberration and distortions. Here, we design, fabricate, and implement a dielectric Moiré metalens for fluorescence imaging. The Moiré metalens consists of two complementary phase metasurfaces, with variable focal length, ranging from ∼10 to ∼125 mm at 532 nm by tuning mutual angles. In addition, a telecentric configuration using the Moiré metalens is designed for high-contrast multiplane fluorescence imaging. The performance of our system is evaluated by optically sectioned images obtained from HiLo illumination of fluorescently labeled beads, as well as ex vivo mice intestine tissue samples. The compact design of the varifocal metalens may find important applications in fluorescence microscopy and endoscopy for clinical purposes.

Conventional volume holography for unconventional Airy beam shapes

Utilizing multiplexed volume holography, a single optical element, enabling to shape structural variants of non-diffracting Airy wavefronts, from one-dimensional Airy mode to unconventional Airy modes such as vortex Airy and quad Airy modes, has been experimentally realized. Here, beam shaped angularly multiplexed volume holographic gratings (AMVHGs) are recorded in PQ: PMMA photopolymer, where five different spatial wavefronts of Airy beams have been sequentially recorded, for simultaneous reconstruction of different Airy modes, by a conventional Gaussian beam. Spatial and spectral mode selective properties of AMVHGs are demonstrated by narrow-band as well as by broadband light source. In addition, through wavelength degeneracy property, the maximum sensitivity wavelength of blue (488 nm) is used for recording in PQ: PMMA, but the AMVHGs are operated at a broad wavelength band of interest, all the way to longer wavelength in near infrared (850 nm). The K-sphere representation is used to explain the spectral properties of AMVHGs.

Neoadjuvant endocrine therapy in primary breast cancer: indications and use as a research tool

Neoadjuvant endocrine therapy has been increasingly employed in clinical practice to improve surgical options for postmenopausal women with bulky hormone receptor-positive breast cancer. Recent studies indicate that tumour response in this setting may predict long-term outcome of patients on adjuvant endocrine therapy, which argues for its broader application in treating hormone receptor-positive disease. From the research perspective, neoadjuvant endocrine therapy provides a unique opportunity for studies of endocrine responsiveness and the development of novel therapeutic agents.

Aorta wall motion monitoring by 1-d MRI of perpendicular diameters

A method for monitoring the cross-sectional size of blood vessels rapidly is introduced. The method creates a one-dimensional (1-D) profile of a strip along the diameter of a vessel using magnetic resonance imaging (MRI). The strips can be much wider than pixels in a typical two-dimensional (2-D) image to increase the signal-to-noise ratio. A second strip perpendicular to the first is also imaged sequentially to allow the detection, estimation, and correction of errors in diameter measurements resulting from the strip inadvertently covering a chord, rather than a diameter. Diameter measurements derived from 1-D profiles agree with measurements derived from 2-D images. This method is nearly an order of magnitude faster than 2-D MRI and has the potential for real-time implementation. J. Magn. Reson. Imaging 1999;10:833-840.