Deep Subwavelength Scale Plasmonic Nanolasers under Electrical Injection (Research Area 42 Optoelectronics)

Abstract The proposed efforts aim to explore the limit of the size reduction of plasmonic nanolasers and emitters by performing systematic design, simulation, fabrication, and experimental characterization. Our goal is to develop plasmonic nanolasers under electrical injection that are significantly smaller than what has been achieved so far with a total volume on the order of one hundredth of a cubic of wavelength in vacuum using a semiconductor-metal core-cladding structure. Semiconductor lasers have profoundly changed many aspects of our daily life and provided revolutionary capabilities to the national defense. Miniaturization has been an everlasting theme in the development of semiconductor lasers. During the last 50 years of semiconductor laser development, every paradigm shift in the design and fabrication has led to the reduced size and improved performance. All these in turn have led to the improved quality of life and increased capabilities for our military. During the last five years, a new paradigm shift has occurred with the adoption of metallic cavities or plasmonic structures as the key element of light confinement. This paradigm shift has resulted in dramatic reduction of laser size. The overall size of a nanolaser has been reduced below the cubic of the wavelength in vacuum. Electrical injection and room temperature operation of these lasers have been demonstrated. While these lasers represent remarkable progress beyond what was thought possible a few years ago, many remaining issues remain to be resolved to push the limit of laser size even further and to understand the fundamental limitation on such nanolasers both in terms of design and device physics and in terms of nanoscale fabrication. This proposal focus on developing a semiconductor membrane based nanolaser with metallic film sandwiched on both sides. Our proposed approach attempts to achieve the best tradeoff among several key factors: fabricability, electrical injection, smallest size possible using semiconductor-metal composite structures, plasmonic resonances, metal loss and semiconductor optical gain. The better understanding of the interplay of these factors would eventually lead to better and smaller nanolasers. The significance of proposed efforts is multifold: First, the exploration of the smallest possible size of a nanolaser would help us understand the limitation and potential of plasmonic based nanophotonic systems. Such plasmonic nanolasers will in turn allow us to design the future ultrascale integrated nanophotonics circuits that would enable the integration of electronic and photonic functionalities for on-chip computing, communication, and sensing. These ultrascale optoelectronic nanochips would significantly enhance the capabilities of our military by enabling autonomous systems with on-board sensing, communication and information processing capabilities. The same technology would also be expected to play an important role in future information technology.