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Danqing Wang1 Marc Bourgeois1 Won-Kyu Lee1 Ran Li1 Dhara Trivedi1 Michael Knudson1 Weijia Wang1 George Schatz1 Teri Odom1

1, Northwestern University, Evanston, Illinois, United States

Mechanically tunable lasers are critical components in responsive optical displays, ultra-sensitive strain sensors, and flexible photonic devices. Compared to laser architectures that rely on photonic cavities having microscale device footprints and limited strain sensitivity, plasmonic nanocavities can confine light to subwavelength scales. Nanolasing has been realized from coupled arrays of metal nanoparticles surrounded by gain media, with wavelengths tailorable by varying refractive index environment and lattice spacing. However, their use in stretchable lasing has been precluded because the mode quality of dipolar coupling cannot be preserved under applied strain.
Here we focus on an entirely new architecture to achieve stretchable nanolasing based on our ability to harness hybrid quadrupole plasmons for robust lasing feedback. Large metal nanoparticles in a lattice produced hybrid quadrupole lattice plasmons with sharp resonances under different strains. We patterned Au nanoparticle arrays on elastomeric substrates to achieve mechanical control over the plasmonic nanocavity modes. Stretching the device along the polarization direction resulted in out-of-plane standing waves at the band edge that were tolerant to lateral changes in lattice spacing. We achieved reconfigurable, mechanical control of nanolasing with ultra-sensitive strain responses (31 nm for 0.03 strain) by stretching and releasing the substrate. Our semi-quantum modeling demonstrates that lasing build-up occurs at the hybrid quadrupole electromagnetic hot spots, which provides a route towards mechanical modulation of light-matter interactions on the nanoscale.

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