Spatio-spectrally Tailored Multimode Metasurface Lasers in the Visible Range

Area of Science:

• Photonics
• Materials Science
• Nanotechnology

Background:

• Compact, spectrally engineered multifrequency nanolasers are crucial for integrated photonics, biosensing, and displays.
• Current challenges lie in achieving these functionalities within small-scale platforms.

Purpose of the Study:

• To demonstrate multimode lasing from a novel metasurface-dye platform.
• To engineer complementary feedback pathways for tunable, angle-selective emission.

Main Methods:

• Fabrication of symmetry-broken TiO2 metasurfaces integrated with an SU8 slab waveguide.
• Incorporation of rhodamine 6G dye as the gain medium.
• Coengineering of guided-mode resonances, surface lattice resonances, and quasi-bound states in the continuum.

Main Results:

• Achieved discrete lasing outputs across a ~100 nm bandwidth (548-648 nm).
• Demonstrated low lasing thresholds (~7 nJ) and up to four concurrent lasing peaks from a single device.
• Tailored emission directionality via Bragg diffraction and Rayleigh anomaly conditions for normal and oblique emission.

Conclusions:

• Established a metasurface-dye platform for multifrequency and angle-selective nanolasers.
• Opened new avenues for developing compact, multifunctional nanophotonic sources.