Random lasing in micron-sized individual supraparticles.

Area of Science:

• Materials Science
• Photonics
• Nanoscience

Background:

• Self-assembled fluorescent particles are promising for random lasers.
• Micron-sized random lasers from fluorescent particles are challenging to produce.
• Supraparticles offer a theoretical route to micron-sized random lasers, but lasing generation is rarely reported.

Purpose of the Study:

• To develop a rapid and efficient method for producing supraparticles from fluorescent particles.
• To investigate the potential of these supraparticles as random laser structures.
• To analyze the lasing properties and wavelength dependence on supraparticle size.

Main Methods:

• Fabrication of supraparticles from fluorescent colloidal particles using a novel method.
• Characterization of supraparticle size, morphology, and internal structure.
• Optical excitation and spectral analysis of supraparticles to determine lasing thresholds and wavelengths.

Main Results:

• Successfully produced supraparticles with diameters from 50 to 150 µm.
• Demonstrated lasing emission from supraparticles larger than 80 µm with a threshold of ~77 μJ·mm⁻².
• Observed a redshift in lasing wavelength (~7.5 nm shift) with increasing supraparticle diameter from 80 to 150 µm.

Conclusions:

• The developed method provides an efficient route to micron-sized fluorescent supraparticles.
• Supraparticles are viable structures for generating random laser emission.
• The size-dependent wavelength shift offers a pathway for tuning random laser output.