Design and fabrication of dielectric meta-optical elements for light shaping

  • 23



Name of the Speaker: Jerin Geogy George (EE20D029)
Name of the Guide: Dr. Shanti Bhattacharya
Venue: ESB-244 (Seminar Hall)
Date/Time: 23rd November 2022, 11.00am

In the era of planar photonics, there has been much effort to redesign the conventional refractive optical elements into thin, flat optical elements. Meta-optics (phase gradient metasurfaces) have arguably emerged as an efficient flat optics solution to displace refractive optics. These optical elements are sub-wavelength scatterers arranged suitably in a region of space and can impart spatially varying phase delays in the incident light. The phase variations are achieved by changing the scatterer’s lateral dimension(s) while keeping the height fixed. Hence a single lithography step is sufficient to generate any arbitrary phase profile using meta-optics. The unique features of Bessel beams, like ‘propagation-invariance’ and ‘self-healing’ nature, were found to be helpful, especially in generating high-contrast images in light-sheet microscopy. But the high sidelobe energy in the Bessel beams, which sit concentrically to the main lobe, limits its optical sectioning ability. Currently, methods such as confocal line detection, selective illumination and multiphoton excitation are employed to fully exploit the potential of Bessel beams. A Bessel-like beam with reduced sidelobes will be advantageous in such an application.