A broadband non-dispersive thin-film polarizer for ultrafast applications is presented. The polarizer has a controllable flat-phase and a high extinction ratio of 23:1 in the working bandwidth from 680 nm to 900 nm. This bandwidth allows supporting laser pulses down to 12 fs. The unavoidable mechanical stress of the interference coating is completely compensated by a specially designed antirefl...

Modifying stress-strain curves is one of the important topics in mechanical engineering and materials science. Real stress-strain curves should be modified after necking point as stress becomes three-dimensional after creation of throat, and consequently, equivalent stress should be used instead of axial one. Also, distribution of triple stresses across throat section is not uniform anymore, an...

Recent advances in atomic force microscopy, biomembrane force probe experiments, and optical tweezers allow one to measure the response of single molecules to mechanical stress with high precision. Such experiments, due to limited spatial resolution, typically access only one single force value in a continuous force profile that characterizes the molecular response along a reaction coordinate. ...

We construct a statistical framework for static assemblies of deformable grains which parallels that of equilibrium statistical mechanics but with a conservation principle based on the mechanical stress tensor. We define a state function that has all the attributes of entropy. In particular, maximizing this function leads to a well-defined granular temperature and the equivalent of the Boltzman...

Macromolecular crowding, a common phenomenon in the cellular environments, can significantly affect the thermodynamic and kinetic properties of proteins. A single-molecule method based on atomic force microscopy (AFM) was used to investigate the effects of macromolecular crowding on the forces required to unfold individual protein molecules. It was found that the mechanical stability of ubiquit...

Many species of macroalgae have flat, strap-like blades in habitats exposed to rapidly flowing water, but have wide, ruffled "undulate" blades at protected sites. We used the giant bull kelp, Nereocystis luetkeana, to investigate how these ecomorphological differences are produced. The undulate blades of N. luetkeana from sites with low flow remain spread out and flutter erratically in moving w...

Rodents use their whiskers to locate nearby objects with an extreme precision. To perform such tasks, they need to detect whisker/object contacts with a high temporal accuracy. This contact detection is conveyed by classes of mechanoreceptors whose neural activity is sensitive to either slow or fast time varying mechanical stresses acting at the base of the whiskers. We developed a biomimetic a...