Topologically enhanced nanowire photonic crystal lasers for information technologies

University Of Cincinnati Main Campus, Cincinnati OH

Investigators

Abstract

Non-technical abstract: The steady increase of internet traffic and energy consumption in information technology has raised the demand for high performance and low power integrated circuits. The next evolution in information technology is to replace metal wire connected integrated circuits (ICs) with optically connected ICs on computer chips. These novel photonic integrated circuits (PICs) would be faster and less energy consuming. Ultra-compact photonic crystal surface emitting lasers which are composed of semiconductor nanowires with diameters less than one thousand of the human hair have the potential to fulfil the demands of a few micrometer-size on-chip laser light source. To enhance the performance of these novel lasers we propose in this project to design, fabricate, and characterize electrically pumped photonic lasers with a special symmetry arrangement of the nanowires. The special arrangement of nanowires within the photonic crystal makes the micro-lasers more defect robust due to a so-called topological protection. This research will open new prospects for designing photonic integrated circuits with unique physical properties and significant impact in the areas of information technology including avenues for quantum information. The project fully integrates education and training of graduate and undergraduate students with an emphasis on recruitment from underrepresented groups. The training prepares the students for a wide range of careers. Outreach to the public includes contributions to local STEM programs. Technical abstract: Ever-increasing data transfer rates and the emergent higher energy consumption of information technology have raised the demand for high performance and low power consuming integrated circuits. Replacing the metallic chip-to-chip interconnects by micrometer sized photonic devices will offer a significantly enhanced bandwidth at reduced power. Two-dimensional topologically enhanced photonic crystal (PhC) lasers have the potential to fulfil the demands of an on-chip coherent light source in these photonic integrated circuits (PICs). In this project, we propose to design, fabricate, and characterize electrically pumped topological nanowire (NW) PhC surface emitting lasers (TCSELs) and defect robust topological insulator lasers (TILs) which are compatible with existing silicon-based technologies and integrable into PICs. The device designs will be guided by finite-difference time-domain (FDTD) simulations and by modelling topologically induced photon correlation effects. The NW PhCs will be grown with selective area epitaxy. We will investigate the dynamics of photogenerated carriers in the PhC arrays ranging from sub-100 femtosecond to nanosecond resolution. Paired with these analytical measurements, we will characterize the lasing of electrically pumped NW PhC lasers at telecommunication wavelengths. This research will open new prospects for designing PICs with unique physical properties and significant impact in the areas of information technology. It also provides new opportunities in topological photonics including avenues for quantum information. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.