Phys org February 5, 2018
An international team of researchers (South Korea, USA – Columbia University, MIT, Cornell University, Stanford University, SLAC, University of Minnesota, Spain, Japan) encapsulated graphene in hexagonal boron nitride which allows the graphene to reach temperatures that are high enough to emit bright light in the visible and near infrared range, with good stability (estimated device lifetimes of at least 4 years), and fast cooling. As a result, the device generates ultrafast light pulses with a duration as short as 90 picoseconds and a modulation rate that is several orders of magnitude faster than conventional thermal emitters. They explain that the high speed likely occurs because there are two different types of phonons (optical and acoustic), and the electrons in graphene are strongly coupled to the optical phonons but weakly coupled to the acoustic phonons… read more. TECHNICAL ARTICLEÂ
Graphene-based devices that emit ultrafast light pulses with a duration of less than 100 picoseconds. Credit: Kim et al. ©2018 American Chemical Society