Metallic subwavelength-cavity semiconductor nanolasers

Miniaturization has been an everlasting theme in the development of semiconductor lasers. One important breakthrough in this process in recent years is the use of metal-dielectric composite structures that made truly subwavelength lasers possible. Many different designs of metallic cavity semiconductor nanolasers have been proposed and demonstrated. In this article, we will review some of the most exciting progresses in this newly emerging field. In particular, we will focus on metallic-cavity nanolasers with volume smaller than wavelength cubed under electrical injection with emphasis on high-temperature operation. Such devices will serve as an important component in the future integrated nanophotonic systems due to its ultra-small size. Lasers: Rise of the nanolaser Semiconductor nanolasers based on subwavelength-scale metal cavities could become important light sources for integrated optical circuitry on silicon. In this paper, Kang Ding and Cun-Zheng Ning from Arizona State University in the USA review progress in this exciting and rapidly evolving field. They cover the achievement of milestones such as the reduction of cavity sizes to below the scale of one wavelength, operation at room temperature, continuous-wave emission and the use of electrical injection. They describe the design and operating principles of nanolasers, as well as the challenges faced in terms of device fabrication, overcoming cavity loss, high-temperature operation and waveguide integration. Future improvements in fabrication technology to address issues such as surface passivation and material deposition will bring further advances in device performance.