Photon Avalanching Nanoparticles

Area of Science:

• Photonics and Nanotechnology
• Materials Science
• Optical Physics

Background:

• Photon avalanching (PA) was first observed in bulk crystals in 1979.
• PA at the nanoscale was achieved 41 years later in photon avalanching nanoparticles (ANPs).
• ANPs exhibit extreme nonlinearity, with emission scaling up to the 32nd power of pump intensity.

Purpose of the Study:

• To explore the novel optical and sensing properties of ANPs.
• To demonstrate the potential of ANPs in super-resolution imaging and optical computing.
• To investigate the application of ANPs in sensing external perturbations.

Main Methods:

• Utilized Tm³⁺-doped upconverting nanoparticles for extreme nonlinearity and super-resolution imaging.
• Employed scanning confocal microscopy to achieve 70 nm spatial resolution.
• Investigated NIR-controlled bidirectional photoswitching and intrinsic optical bistability (IOB) in ANPs.
• Assessed ANPs as force sensors across a wide dynamic range.

Main Results:

• Achieved a 5-fold improvement over the Abbe limit, reaching 70 nm resolution.
• Demonstrated over 1000 cycles of NIR-controlled bidirectional photoswitching with no photodegradation.
• Developed the INPALM super-resolution technique with sub-Ångstrom localization precision.
• Showcased Nd³⁺-based ANPs with intrinsic optical bistability for optical computing applications.
• Tm³⁺ ANPs detected forces from piconewtons to micronewtons.

Conclusions:

• ANPs offer significant advancements in optical imaging, nanoscale patterning, and optical computing.
• The extreme nonlinearity of ANPs enables unprecedented sensing capabilities for external perturbations.
• ANPs represent a novel platform for fundamental discoveries and technological innovation in photonics.