Articles 2018-03-21T00:53:58+00:00

Articles

Burning Coal with Femtosecond Laser Pulses

Since before the industrial age, graphite materials have played an essential role in daily life: their properties are seen in everything from burning embers to the first electric bulbs. Even as technologies advance, graphite materials continue to pique interest in the human mind.  One example is graphene, a two-dimensional material with remarkable optical and electronic properties, which has sparked a renewed interest in the field of semiconductor research, particularly in studies of solar energy conversion. Prof. Hrvoje Petek and his research group at the University of Pittsburgh are [...]

By | Sep 21, 2017|

Progress of Industrial Femtosecond Machining – A Rich 20-year History

Micromachining with femtosecond lasers (also known as ultrafast or ultra-short pulse lasers) is gaining popularity due to several advantageous properties, including the nearly athermal, or "cold," ablation process. For industries demanding smaller and more precise parts, this technology offers several benefits, including higher yields, tighter tolerances, little to no collateral damage, and no post processing. While femtosecond lasers have begun gaining significant attention in recent years, they were originally showcased 20 years ago at the Laser World of Photonics in Munich, Germany by Clark-MXR, a company founded in [...]

By | Jun 21, 2017|

Catching Molecules in the Act

Chemical reactions are characterized by the motion of atoms; transformation of chemical compounds, reactants, and raw materials is therefore governed by molecular vibrations. While the motion of the atoms is easily seen at the beginning and end of a chemical reaction, the molecular changes occur too rapidly in the middle of the process, making them impossible for humans to observe. With novel techniques that employ the use of ultrafast lasers, however, we can essentially freeze the chemical reaction. This allows us to thoroughly observe the intermediate steps of [...]

By | May 31, 2017|

Synchronization of a 25 MHz Magellan Yb-doped Fiber Oscillator with a Streak Camera from Optronis

Clark-MXR, Inc. is pleased to announce the first demonstration of a Yb-doped femtosecond fiber oscillator running at 25 MHz successfully synchronized with a Streak camera. This is a result from a collaboration with the companies Optronis GmbH (Dr. Patrick Summ, summ@optronis.com) and Horiba Scientific GmbH (Dr. Hans-Erik Swoboda hans-erik.swoboda@horiba.com) from Europe. The Magellan is a telecom-qualified single emitter diode-pumped Yb-doped femtosecond fiber oscillator. A Streak camera from Optronis, Optoscope SC10, with Synchroscan sweep unit was triggered by the Magellan oscillator and different triggering set-ups were tested for best [...]

By | Jan 16, 2017|

Observation of Rapid Exciton–Exciton Annihilation in Monolayer Molybdenum Disulfide

A  publication from Prof. Tony Heinz group with Model IMPULSE from Clark-MXR. Dezheng Sun, Yi Rao, Georg A. Reider, Gugang Chen, Yumeng You, Louis Brézin, Avetik R. Harutyunyan, and Tony F. Heinz Monolayer MoS2 is a direct-gap two-dimensional semiconductor that exhibits strong electron–hole interactions, leading to the formation of stable excitons and trions. Here we report the existence of efficient exciton–exciton annihilation, a four-body interaction, in this material. Exciton–exciton annihilation was identified experimentally in ultrafast transient absorption measurements through the emergence of a decay channel varying quadratically with [...]

By | Sep 9, 2016|

Mapping Carrier Dynamics on Material Surfaces in Space and Time using Scanning Ultrafast Electron Microscopy

Re-published from The Journal of Physical Chemistry Letters Jingya Sun, Aniruddha Adhikari, Basamat S. Shaheen, Haoze Yang, and Omar F. Mohammed* Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia ABSTRACT: Selectively capturing the ultrafast dynamics of charge carriers on materials surfaces and at interfaces is crucial to the design of solar cells and optoelectronic devices. Despite extensive research efforts over the past few decades, information and understanding about surface-dynamical processes, including [...]

By | Mar 18, 2016|

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