‌Research Areas

 

Strain-Engineered Ge-Based Lasers for Integrated Optical Computers


Optical computing is considered one of the most promising next-generation computing architectures. By using light to perform computation instead of using electrical signals in CPUs, one can expect unprecedented computing bandwidth with much lower power consumption. Until now, however, the realization of chip-scale optical computers has been hindered by the lack of an efficient group-IV laser that can be integrated into silicon-based CPU chips.
 
Over the past few years, our group has endeavored to develop practical group-IV on-chip lasers in the hope of completing the last missing link of electronic-photonics integrated circuits (EPICs). We have, for the first time, succeeded in observing lasing action in highly strained Ge nanowires. These days, we are pushing the boundaries of technology towards the realization of electrically-pumped room-temperature GeSn lasers.

‌Our grand aim is to integrate our Ge-based lasers and other key optoelectronic devices (e.g., detectors, modulators) into complementary metal-oxide-semiconductor (CMOS) chips to realize integrated optical computers.



 

Harnessing Giant Pseudo-Magnetic Fields for a New Class of Graphene Optoelectronics


Recently, graphene has been identified as one of the strongest candidates for the realization of electronic-photonics integrated circuits (EPICs) owing to its excellent electronic and optical properties. These superior properties of graphene have allowed overcoming the performance barriers set by Si-based photonic devices for optical modulation. Unfortunately, however, the creation of graphene lasers–a key ingredient of graphene-based EPICs–has been considered extremely challenging, if not impossible, because of the gapless nature of graphene. 

Our group recently made a theoretical prediction towards the possibility of achieving population inversion and stimulated emission in strained graphene under giant pseudo-magnetic fields. We also made the first experimental demonstration about how one can create large and controllable energy gaps in graphene over a very large area using the concept of strain-induced pseudo-magnetic fields.

‌Our ultimate goal is to achieve the world’s thinnest and strongest light bulbs and lasers using strained graphene. With this achievement, we will aspire to integrate graphene lasers and other graphene-based optoelectronic devices into CMOS architecture to realize various disruptive technologies such as graphene-based optical computing chips.