Au nanoparticle concentration study in hybrid plasmonic microlasers

Area of Science:

• Materials Science
• Optics and Photonics
• Nanotechnology

Background:

• Microlasers offer tunable light emission for various applications.
• Gold nanoparticles can modify the optical properties of materials.
• Understanding nanoparticle concentration effects is crucial for optimizing device performance.

Purpose of the Study:

• To investigate the impact of gold nanoparticle concentration on the performance of dye-doped polymeric spherical microlasers.
• To determine the optimal gold nanoparticle ratio for improved laser characteristics.
• To evaluate the stability and emission properties of microlasers with varying gold nanoparticle concentrations.

Main Methods:

• Fabrication of spherical microlasers (∼293µm diameter) using a UV curable polymer (Norland Blocking Adhesive) doped with Rhodamine 6G.
• Incorporation of gold nanoparticles (∼5nm diameter) at four different ratios (1000, 2000, 3000, 4000).
• Characterization of laser emission using a spectrometer/CCD camera via optical fiber collection.

Main Results:

• The 3000 ratio demonstrated the lowest energy threshold and highest photonic emission slope.
• The 3000 ratio exhibited the most stable laser mode emission.
• The 4000 ratio showed minimal difference compared to microlasers without gold nanoparticles.
• TE and TM laser modes competed in the 2000 ratio case due to plasmonic emission overlap and thermal effects.

Conclusions:

• The optimal concentration of gold nanoparticles (3000 ratio) significantly enhances microlaser performance, including lower thresholds and improved emission stability.
• This study provides insights for selecting appropriate gold nanoparticle concentrations for mechanical and biomedical sensing applications.
• Quality factors remain consistent (∼10⁴) across different concentrations, indicating robust cavity properties.