Abstract
High-precision three-dimensional ultrafast laser direct nanostructuring of silica glass resulting in multi-layered space-variant dielectric metasurfaces embedded in volume is demonstrated. Continuous phase profiles of nearly any optical component are achieved solely by the means of geometric phase. Complex designs of half-wave retarders with 90% transmission at 532 nm and >95% transmission at >1 μm, including polarization gratings with efficiency nearing 90% and computer generated holograms with a phase gradient of ∼0.8π rad/μm, were fabricated. A vortex half-wave retarder generating a single beam optical vortex with a tunable orbital angular momentum of up to ±100ℏ is shown. The high damage threshold of silica elements enables the simultaneous optical manipulation of a large number of micro-objects using high-power laser beams. Thus, the continuous control of torque without altering the intensity distribution was implemented in optical trapping demonstration with a total of 5 W average power, which is otherwise impossible with alternate beam shaping devices. In principle, the direct-write technique can be extended to any transparent material that supports laser assisted nanostructuring and can be effectively exploited for the integration of printed optics into multi-functional optoelectronic systems.
Highlights
Conventional optics manipulates the properties of light via an optical path difference by controlling the thickness or refractive index of the material
Various phase profiles of nearly any optical components ranging from lenses, gratings, and vortex-phase plates to elements capable of bending the light in unusual ways have been demonstrated using plasmonic metasurfaces[3,4] or dielectric gradient metasurfaces[5,6,7,8,9] referred to as geometric phase (Pancharatnam-Berry phase10–12) optical elements and realized by space-variant polarization manipulations.[13]
We propose a direct-write ultrafast laser nanostructuring of silica glass as an alternative method which is capable of fabricating geometric phase optics
Summary
Conventional optics manipulates the properties of light via an optical path difference by controlling the thickness or refractive index of the material. The recent advances in flat optics have challenged the limitations of conventional optics by implementing ultrathin planar elements that manipulate light waves via subwavelength-spaced phase shifters with spatially varying phase response.[1,2] Various phase profiles of nearly any optical components ranging from lenses, gratings, and vortex-phase plates to elements capable of bending the light in unusual ways have been demonstrated using plasmonic metasurfaces[3,4] or dielectric gradient metasurfaces[5,6,7,8,9] referred to as geometric phase (Pancharatnam-Berry phase10–12) optical elements and realized by space-variant polarization manipulations.[13]. We propose a direct-write ultrafast laser nanostructuring of silica glass as an alternative method which is capable of fabricating geometric phase optics. The key advantage of using femtosecond pulses for direct laser writing, as opposed to longer pulses, is
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
