One-dimensional photonic crystal enhancing spin-to-orbital angular momentum conversion for single-particle tracking

Area of Science:

• Optics and Photonics
• Biophysics
• Nanotechnology

Background:

• Single-particle tracking (SPT) is crucial for observing dynamic processes in life sciences and physics.
• Conventional microscopy techniques face limitations in precisely tracking particles in three dimensions over extended periods.
• Existing interferometric scattering (iSCAT) methods struggle with axial position estimation in 3D SPT due to contrast inversions.

Purpose of the Study:

• To enhance spin-to-orbital angular momentum conversion for improved three-dimensional single-particle tracking (3D SPT).
• To develop a novel all-dielectric one-dimensional photonic crystal (1D PC) substrate for optical microscopy.
• To integrate this 1D PC with iSCAT to create a double-helix point spread function (DH-PSF) for robust 3D SPT.

Main Methods:

• Fabrication of an all-dielectric one-dimensional photonic crystal (1D PC).
• Integration of the 1D PC with interferometric scattering (iSCAT) microscopy.
• Implementation of a double-helix point spread function (DH-PSF) for axial position encoding.

Main Results:

• The 1D PC effectively enhances spin-to-orbital angular momentum conversion.
• The resulting DH-PSF iSCAT provides uniform Fisher information for 3D position estimation, overcoming contrast inversion issues.
• Demonstrated 3D SPT of a microbead on a flagellum and 3D diffusion of 20 nm gold nanoparticles.

Conclusions:

• The DH-PSF iSCAT technique, enabled by a 1D PC, offers a promising solution for accurate 3D SPT.
• This advancement facilitates precise analysis of motor dynamics and nanoparticle diffusion.
• The technique holds significant potential for diverse applications across physical, biological, and chemical sciences.