Use of tough material could unlock for next generation - Laser technique

Researchers, in 2004 discovered a super thin material which is best known conductor of heat and electricity and is at least a 100 times stronger than steel. Graphene, could bring faster electronics than is possible today with silicon. This switching creates strings of 0s and 1s that a computer uses for processing information like what silicon does in the form of billions of transistors on a computer chip. But to truly be useful, graphene would need to carry an electric current that switches on and off Band gap would need to be at least the previous record of 0.5 electronvolts to function as a semiconductor such as silicon, Purdue researchers created and widened the band gap in graphene to a record 2.1 electronvolts.. But graphene doesn't naturally have a band gap.Electrons need to jump across this gap in order to become conduction electrons, which makes them capable of carrying electric current This structure is a so-called "band gap" . In collaboration with the University of Michigan and the Huazhong University of Science and Technology, The Purdue University researchers, show how a laser technique could permanently stress graphene. Gary Cheng, professor of industrial engineering at Purdue, whose lab has investigated various ways to make graphene more useful for commercial applications.“An effort has achieved for the first time that without affecting graphene itself how high band gaps, such as through chemical doping. We have purely strained the material," Giving scientists and manufacturers the option to just use certain properties of graphene depending on what they want the material to do.Cheng and his collaborators not only kept the band gap open in graphene, also made it to where the gap width could be tuned from zero to 2.1 electronvolts. Researchers in the past opened the band gap by simply stretching graphene, but stretching alone doesn't widen the band gap very much. Cheng said You need to permanently change the shape of graphene to keep the band gap open. Along with scientists at Harvard University, the Madrid Institute for Advanced Studies and the University of California, San Diego researchers made the band gap structure permanent in graphene using a technique called laser shock imprinting, which developed in 2014 by Cheng . Researchers for this study used a laser to create shockwave impulses that penetrated an underlying sheet of graphene. Their work appears in an issue of Advanced Materials. Surpassing 0.5 electronvolts unlocks even more potential for graphene in next-generation electronic devices, the researchers say. Depending on whether their electrons are pushed across the band gap or not the presence of a band gap allows semiconductor materials to switch between insulating or conducting an electric current,. The technique grants more flexibility in taking advantage of the material's optical, magnetic and thermal properties, While still far from putting graphene into semiconducting devices, Cheng said. Dual-color picosecond laser rapidly tunable Our patented tuning mechanism requires no mechanical delay and allows comfortable fiber-delivery of synchronized dual-color pulses. All-fiber optical parametric oscillator in an wavelength conversion, pumped by a stable fiber laser provides an unmatched combination of tuning speed and tuning range. It require to minimize requirements on maintenance and environmental conditions by polarization-maintaining fiber technology. Patented prototype Preliminary technical specifications tuning range 750-970 nm 1020 - 1055 nm tuning speed <5 ms <1 ms average power 200 mW 500 mW covered wavenumber 865-3550 cm-1 pulse duration 7 ps spectral bandwidth <12 cm -1 repetition rate 40,5 MHz The Role of GreenLight High-Performance System Laser and Next Generation in Laser Treatments . The Characteristic and physics of the laser light, such as power densities and wavelength, influence efficiency of treatment and safety profiles of various laser techniques and systems. Over the past decade Lasers have evolved, with technical refinements that have resulted in a procedure that can achieve transurethral-like results in a safe and efficacious manner. Currently commercially available 80-W potassium-titanyl-phosphate laser used for photoselective vaporization of the prostate gland in men with lower urinary tract symptoms and benign prostatic hyperplasia has been shown to be effective and safe the rapeutic alternative for a wide spectrum of prostate sizes and configurations. Refinements based on clinical experience as well as progress in available technologies have produced an advanced system with improvements in beam quality and an increase in power to provide an increase in vaporization efficiency and flexibility in technique. The refinements require adjustments to current technique and the advanced technological developments enhance the utility of this laser for application in benign prostatic hyperplasia and urology.