The past 55 years has witnessed unprecedented progress in humanity's ability to compute, enabling applications that were previously unimaginable. This has been achieved with the advent of the electronic integrated circuit, where electrical elements are built together on a single chip. Increasing computing power is accomplished through size "scaling", namely shrinking the size of each computing element to accommodate more elements on a single chip, enabling more complex functions to be performed in a given time. Humanity's ability to exchange information is undergoing a similar paradigm shift, due to the recent commercialization of the photonic integrated circuit, an analog of the electronic integrated circuit that encodes information on light, rather than electricity. The light carrying this information can then be transmitted over great distances using fiber optics. In these photonic integrated circuits, numerous components that produce and process light are integrated together in much the same way as their electronic integrated circuit counterparts; however, the fundamental minimum size of components is limited by the rather large length scale of light. As a result, many fewer components may be combined on a single chip because the size of each optical component is necessarily much larger than their electrical counterparts, limiting the capabilities of photonic integrated circuits. The approach here to surmount this challenge is to employ crystalline metals to confine light within components to much smaller dimensions than the wavelength of light. This would enable much smaller optical components and, hence, significantly more powerful photonic integrated circuits. The focus here will be on building extremely small lasers, which are the components that generate light in photonic integrated circuits. This work will provide cutting-edge research opportunities for two Ph.D. students, increase research opportunities for undergraduates from historically underrepresented groups, and help engage countless pre-K-12 students with the exciting world of nanoscience.
Based upon current projections, subwavelength optical components will be required in the next ~10 years to continue the Moore's Law of InP-based photonic circuits progress. Current efforts that could address this challenge are focused mainly on heterogeneous integration of crystalline semiconductors with amorphous/polycrystalline metals, limiting their performance and/or the prospects for application to photonic integrated circuits. An orthogonal approach to this critical challenge is to employ monolithic integration of III-V active media with epitaxial silver to greatly reduce the optical losses that plague the broad field of metal-based nanophotonic devices. Recent progress in the growth of epitaxial silver has revealed that optical losses can be greatly reduced and plasmon propagation lengths significantly enhanced, enabling a solution to this fundamental limitation. While this effort concentrates on addressing the need for efficient subwavelength nanolaser sources, the approach is broadly applicable to the other active and passive devices required in photonic integrated circuits. This multifaceted investigation will couple the growth and device fabrication of epitaxial III-V/silver heterostructures to (1) realize high-performance, electrically-injected nanolasers that operate at room temperature and (2) illuminate and quantify novel methods to integrate silver and III-V active structures that dramatically enhance light-matter interactions at the nanoscale.
