Injectable Plasmonic Nanolasers—From Miniaturization to Single-Cell Barcoding Applications

Nanolasers have recently gained attention as multiplexed imaging agents in biomedicine, driven by the need to systematically understand large-scale, complex biological systems. The further miniaturization of lasers from their current size of a few hundred nanometers to sub-100 nm, and their development as stand-alone particles, holds great promise not only as novel optical probes but also for labeling biomolecular structures in a broader range of colors than fluorescent proteins or quantum dots.
In this talk, I will present our recent efforts on laser miniaturization and the development of injectable plasmonic laser particles for biomedical imaging applications. First, I will briefly discuss high-Purcell quasi-1D plasmonic hinge mode lasing on 3D metal-coated CsPbBr₃ perovskite particles near the dispersion asymptote. These particles, which can lase at sizes as small as 680 nm, feature optically thin gold coatings created via solution-based chemistry. This coating acts as a barrier to water diffusion, significantly improving the lifetime of water-soluble perovskites and enabling successful intracellular lasing.
Next, I will highlight our achievements with room-temperature half-wave plasmonic dipole lasers made of InGaAsP, as small as 170 nm—equivalent to half the free-space wavelength divided by the semiconductor’s refractive index. These particles are fabricated using optical lithography and wet etching, producing size-tunable, narrowband, spatially coherent, and bright linearly polarized laser emissions. The experimental observations are well-aligned with the 'waterfall semiconductor model,' which describes the interplay between plasmonic dipole modes and electrons in the semiconductor. I will also demonstrate the use of injectable, one-sided metal-coated semiconductor nanoparticles for biologically compatible intracellular plasmonic lasing with energy requirements as low as a few picojoules, applied to the optical barcoding of cancer HeLa cells.