Feasibility of 3D-Printed Locking Compression Plates with Polyether Ether Ketone (PEEK) in Tibial Comminuted Diaphyseal Fractures.

The applicability of a polyether ether ketone locking compression plate (PEEK LCP) fabricated using FDM (fused deposition modeling)-based 3D printing to treat actual patients was studied. Three different tests-bending, axial compression, and axial torsion-were conducted on tibial non-osteoporotic comminuted diaphyseal fracture samples fixed with the commercial titanium alloy LCP and 3D-printed PEEK LCP. Comparing the outcomes of these tests revealed that the commercial titanium alloy LCP underwent plastic deformation in the bending and axial torsion tests, though the LCP did not fail even when an external force greater than the maximum allowable load of the tibia fixture of the LCP was applied.

Enhanced lateral resolution in continuous wave stimulated emission depletion microscopy using tightly focused annular radially polarized excitation beam.

The lateral resolution of continuous wave (CW) stimulated emission depletion (STED) microscopy is enhanced about 12% by applying annular-shaped amplitude modulation to the radially polarized excitation beam. A focused annularly filtered radially polarized excitation beam provides a more condensed point spread function (PSF), which contributes to enhance effective STED resolution of CW STED microscopy. Theoretical analysis shows that the FWHM of the effective PSF on the detection plane is smaller than for conventional CW STED.

Investigation on improvement of lateral resolution of continuous wave STED microscopy by standing wave illumination.

In this paper, we report the enhancement of resolution of continuous wave (CW) stimulated emission depletion (STED) microscopy by a novel method of structured illumination of an excitation beam. Illumination by multiple excitation beams through the specific pupil apertures with high in-plane wave vectors leads to interference of diffracted light flux near the focal plane, resulting in the contraction of the point spread function (PSF) of the excitation. Light spot reduction by the suggested standing wave (SW) illumination method contributes to make up much lower depletion efficiency of the CW STED microscopy than that of the pulsed STED method.

Investigation on achieving super-resolution by solid immersion lens based STED microscopy.

The feasibility of stimulated emission depletion (STED) microscopy using a solid immersion lens was investigated. First, the theoretical feasibility of the considered system is discussed based on a vectorial field algorithm that uses a stratified medium composed of a SIL air-gap and test sample. Using the simulation, we verified that evanescent waves with much higher spatial frequencies corresponding to the high numerical aperture in the air-gap can be utilized to achieve a higher resolution than a confocal fluorescent image without a depletion beam.

A study on the realization of high resolution solid immersion lens-based near-field imaging optics by use of an annular aperture.

We report on the realization of solid immersion lens (SIL)-based near-field (NF) optics with an annular aperture, which is targeted to achieve high optical resolution. A numerical aperture (NA) = 1.84 hemisphere SIL-optics with an annular aperture achieves higher optical resolution than the conventional NA = 2.

Cover-layer-protected solid immersion lens-based near-field recording with an annular aperture.

Currently, data recording density in cover-layer-protected near-field-recording (NFR) and multiple-recording layered NFR optical data storage technology is limited by the difficulty in obtaining high-refractive-index cover layer materials. In addition, with the exception of improved resolution, the higher the numerical aperture (NA), the poorer the optical characteristics. However, in this study, we present novel cover-layer-protected solid immersion lens (SIL)-based NFR optics that provide superior optical performance with higher recording density, greatly enhanced focal depth, and less sensitivity to near-field air-gap-distance variation by modulating the amplitude and phase in the entrance pupil using annular pupil zones.

Effects of motion of an imaging system and optical image stabilizer on the modulation transfer function.

This paper analyzes the effects due to the angular motion of a small-sized imaging system equipped with an optical image stabilizer (OIS) on image quality. Accurate lens moving distances for the OIS required to compensate the ray distortion induced by the angular motion are determined. To calculate the associated modulation transfer function, the integrated and the compensated point spread functions are defined.

Effects of fabrication errors in the diffractive optical element on the modulation transfer function of a hybrid lens.

Diffractive optical elements (DOEs) are often used to improve the performance of optical systems. However, when a blazed DOE is machined, shape errors can be generated in the discontinuity region of the DOE due to the finite radius of the processing tool. We simulated the effects of this shape error on the optical path and modulation transfer function (MTF) in a hybrid lens for a compact camera module.

Design and fabrication of diffractive optical elements by use of gray-scale photolithography.

Diffractive optical elements (DOEs) are key components in the miniaturization of optical systems because of their planarity and extreme thinness. We demonstrate the fabrication of DOEs by use of gray-scale photolithography with a high-energy-beam sensitive glass photomask. We obtained DOE lenses with continuous phase profiles as small as 800 microm in diameter and 5.