Fraxicon for Optical Applications with Aperture ∼1 mm: Characterisation Study

Area of Science:

• Optics and Photonics
• Biomedical Engineering
• Materials Science

Background:

• Miniaturized light sources require matching micro-optical elements with sub-1 mm cross-sections and high optical quality.
• Spatially constrained biomedical applications like endoscopy and optogenetics demand reduced dimensionality in optical components.

Purpose of the Study:

• To adapt the Fresnel lens approach for conical lenses (axicons), creating planarized axicons (fraxicons).
• To fabricate and optically characterize positive and negative fraxicons using direct laser writing.
• To numerically model fraxicon performance under various illumination conditions.

Main Methods:

• Direct femtosecond laser writing (780 nm/100 fs) in SZ2080™ polymer.
• Fabrication of positive and negative fraxicons.
• Optical characterization and numerical modeling of fraxicon performance.

Main Results:

• Successful fabrication of planarized axicons (fraxicons) with sub-1 mm cross-sections.
• Optical characterization data for positive and negative fraxicons.
• Comparison of numerical modeling results under different illumination conditions (incoherent, extended, plane-wave).

Conclusions:

• The developed fraxicon fabrication method shows promise for demanding technological applications.
• The approach allows for rapid replication in soft polymers and resists.
• These micro-optical elements are suitable for miniaturized light source applications in biomedicine.