Crazing is usually a precursor of the brittle fracture of glassy polymers. In this paper, an optical technique is presented to quantify the crazing dominated creep damage that occurs on a stressed transparent glassy polymeric sheet of polymethyl methacrylate (PMMA). The specimens, with various sections, are loaded for a predefined period of time under a constant load at room temperature, and th...

BACKGROUND Fiber fuse is a process of optical fiber destruction under the action of laser radiation, found 20 years ago. Once initiated, opical discharge runs along the fiber core region to the light source and leaves periodic voids whose shape looks like a bullet pointing the direction of laser beam. The relation between damage pattern and propagation mode of optical discharge is still unclear...

Robust preclinical test methods involving tribological simulations are required to investigate and understand the tribological function of osteochondral repair interventions in natural knee tissues. The aim of this study was to investigate the effects of osteochondral allograft implantation on the local tribology (friction, surface damage, wear and deformation) of the tissues in the natural kne...

We report on cell damage of single cells confined in continuous-wave (cw), near-infrared (NIR) multimode optical traps as a result of multiphoton absorption phenomena. Trapping beams at NIR wavelengths less than 800 nm are capable of damaging cells through a two-photon absorption process. Cell damage is more pronounced in multimode cw traps compared with single-frequency true cw NIR traps becau...

Molybdenum disulfide (MoS2), whose monolayer possesses a direct band gap, displays promising applications in optoelectronics, photonics, and lasers. Recent researches have demonstrated that MoS2 has not only a significant broadband saturable absorption performance, but also a higher optical nonlinear response than graphene. However, MoS2 shows much lower optical damage threshold owing to the po...

We propose ihe use of tapered-up structures such as the fiber-horn lens and the straight-tip fiberhorn lens to be integrated in single-mode fiber devices to raise the damage threshold for input power. The optical damage limit with the use of such structures in single mode fibers is studied in this work. It is observed that for these devices to be practical, special attention needs to be put in ...

Nonlinear optical phenomena in the optical spectral range followed by the invention of laser in early 1960’s directed the generation of optical pulses using Q switching and mode locking techniques. Ultrafast lasers with extremely short pulse duration (<100 fs) opened a new avenue towards fabrication of integrated photonic and signal processing devices in a variety of transparent materials. A ne...

The Dark Reader optical system (Clare Chemical Research, Denver, CO, USA) uses relatively low intensity broad-band visible blue light in combination with broad-band optical filters to detect fluorescence with a level of sensitivity that often surpasses that of UV transilluminators and can rival that of laser-based scanners. Applications of DR (Clare Chemical Research) devices include the detect...

We report experimental results of using an f/5 , cascaded-focus optical geometry for a high-dynamic-range optical limiter. The device consists of a 2-cm-thick CS(2) cell at the first focus and a reverse saturable-absorber dye in a thin cell (0.1 mm) at the second focus. The strong self-focusing in the CS(2) that is due to the ac Kerr effect and electrostriction keeps the energy at the second ce...

Optogenetics is a revolutionary technique that enables noninvasive activation of electrically excitable cells. In mammals, heart rate has traditionally been modulated with pharmacological agents or direct stimulation of cardiac tissue with electrodes. However, implanted wires have been known to cause physical damage and damage from electrical currents. Here, we describe a proof of concept to op...