Localized surface plasmon resonance in the IR regime

Area of Science:

• Plasmonics
• Nanophotonics
• Quantum Dot Optics

Background:

• Arrays of gold nanoantennas exhibit localized surface plasmon resonance (LSPR) and Rayleigh anomalies.
• These phenomena occur in the near-infrared and telecom range (1000-1500 nm).
• The spectral position of grating resonances is sensitive to array period and nanoantenna size.

Purpose of the Study:

• To investigate the enhancement of photoluminescence (PL) from lead sulfide (PbS) quantum dots (QDs) using gold nanoantenna arrays.
• To explore the role of grating resonances and diffractive feedback in PL enhancement.
• To demonstrate wavelength tuning of emission based on nanoantenna geometry.

Main Methods:

• Fabrication of gold nanoantenna arrays with varying disk diameters on glass substrates.
• Characterization of optical properties, including LSPR and Rayleigh anomalies, in the 1000-1500 nm range.
• Embedding PbS QDs in PMMA to surround the nanoantennas and measuring photoluminescence enhancement.

Main Results:

• An up to fourfold enhancement in photoluminescence was observed at the grating resonance frequencies.
• The enhancement is attributed to constructive diffractive feedback among neighboring nanoantennas.
• A clear shift in emission towards shorter wavelengths was demonstrated with decreasing disk diameter, correlating with grating resonances.

Conclusions:

• Gold nanoantenna arrays can significantly enhance the photoluminescence of embedded PbS QDs.
• Diffractive coupling and grating resonances play a crucial role in achieving PL enhancement.
• The emission wavelength can be controlled by tailoring the nanoantenna dimensions, offering possibilities for tunable light sources.