On-chip Phase and Polarization Engineering of GaN-based blue/UV VCSELs via Metasurfaces

Vertical cavity surface-emitting lasers (VCSELs) play a key role in the development of modern optoelectronic technologies, thanks to their unique characteristics such as low power consumption, high modulation speed, and large-scale two-dimensional array capability.

To further expand the spectral range of VCSELs from the red/near-infrared region down to the blue/UV region is attracting significant interest.

This will lead to versatile applications in for example retinal scanning displays, visible light communications, chemical sensing, and sterilization of viruses and bacteria.

However, blue/UV VCSELs are suffering from poor beam quality and unstable polarization property due to the lack of effective beam shaping solutions.

The recent advances in two-dimensional metamaterials, also known as metasurfaces, open new perspectives for the manipulation of light properties, including amplitude, phase, and polarization with exceptional subwavelength spatial resolution.

In particular, the ultra-thin, flat, and compact characteristics of metasurfaces greatly facilitate their integration with semiconductor laser for the development of a miniaturized laser system with a controllable optical wavefront.

Seizing on the timely opportunities provided by the latest metasurface technologies, this project aims to develop the very first solution for on-chip beam-shaping blue/UV VCSELs by exploiting metasurface optoelectronic integration, which will unlock the potential to tailor both the phase and polarization properties of blue/UV lasers at an ultra-compact wafer-level.

This will give rise to high beam quality lasers with small divergence angle and vector lasers in the blue/UV regime, paying their way toward real-world applications.