https://www.selleckchem.com/ The accuracy of all the analytical results is verified by Monte Carlo simulation.Starting from a peculiar image observed below a bubble that is floating at a water-air interface, this paper analyzes several optical properties of these special types of refracting objects (termed bubble axicons). Using mainly geometrical optics, their relation to common axicons, the shadow-sausage effect, and elementary optical catastrophes (caustics) are discussed.While using digital halftoning to achieve multi-tones in a 1 bit electrophoretic display (EPD), e.g., a three-pigment chromatic EPD, the drive current is significantly increased because of frequently reversed pixel values. Aimed at this issue, this study first establishes a model that can accurately predict the drive current from image content. Next, based on the direct binary search method, a new halftoning method is proposed by constructing a combined merit function that incorporates both the perceptual image quality and the drive current. As a result, in experiments using a 13.5 in. three-pigment EPD and several test images, compared with the well-developed error-diffusion method, the proposed method produces little image quality degradation, whereas the drive current increase with respect to the minimum current of the EPD is reduced from 71.8 to 33.0 mA, for a significant reduction of 54.0%.A passively mode-locked thulium-doped fiber laser using a tungsten ditelluride saturable absorber ($\rm WTe_2\mbox-\rm SA$WTe2-SA) is demonstrated. High-power mode-locked pulses with an average output power of 108.1 mW were achieved by incorporating the $\rm WTe_2\mbox-\rm SA$WTe2-SA into a thulium-doped fiber oscillator. To the best of our knowledge, this is the highest average power obtained from a $\rm WTe_2\mbox-\rm SA$WTe2-SA-based fiber laser. We further amplified the output power to 5.60 W with an all-fiber thulium-doped double-cladding fiber amplifier. Our result indicates that $\rm WTe_2\mbox-\rm