Wideband Tuning and Deep-Tissue Spectral Detection of Indium Phosphide Nano-Laser Particles

Area of Science:

• Nanophotonics and optical engineering.
• Biomedical imaging and diagnostics.
• Materials science for optoelectronic devices.

Background:

• High-multiplex optical barcoding requires laser particles (LPs) with narrowband spectra across wide ranges.
• Indium phosphide (InP) nanostructures offer potential for miniaturized light sources.
• Whispering gallery modes (WGMs) in nanostructures enable tunable optical properties.

Purpose of the Study:

• To develop InP nanodisk laser particles for high-multiplex optical barcoding.
• To achieve ultrawide spectral coverage and narrow linewidths in the near-infrared.
• To demonstrate the efficacy of these LPs in scattering biological media.

Main Methods:

• Fabrication of size-tuned InP nanodisks to support low-order WGMs.
• Characterization of emission spectra, linewidths, and laser sizes.
• Testing spectral detection in highly scattering media like chicken breast tissue and live mouse blood vessels.

Main Results:

• Achieved LPs operating in the 740-970 nm near-infrared range.
• Demonstrated ultrawide color palette with 27% bandwidth utilization and nanometer-scale linewidth.
• Confirmed detection of laser peaks with high signal-to-background ratios in 1-cm chicken breast tissue and live mouse blood vessels.
• Minimum laser size of 430 nm in air and 560 nm within cytoplasm.

Conclusions:

• InP nanodisk LPs provide a promising platform for high-multiplex optical barcoding.
• The demonstrated spectral range and detection capabilities are suitable for in vivo and ex vivo biological applications.
• Miniaturized LPs enable robust optical barcoding in challenging scattering environments.