Method for fabricating nanostructured optical elements
AssigneeUniversity of Southampton
InventorsPeter Kazansky, Masaaki Sakakura, Lei Wang
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Abstract
A method of fabricating an optical element comprises: providing a substrate of a transparent material; applying a plurality of circularly polarised focused femtosecond laser pulses to a volume within the substrate to create substantially spherical nanopores in the volume; and applying at least one and not more than ten non-circularly polarised focused femtosecond laser pulses to the volume to transform the spherical nanopores into oblate spheroidal nanopores.
Claims19
A method of fabricating an optical element, wherein the method is a two-stage method comprising a seeding stage and a writing stage, comprising:
- providing a substrate of a transparent material;
- carrying out a seeding stage comprising applying 40 or more circularly polarised focussed femtosecond laser pulses, being seeding pulses, to a volume within the substrate to create a non-birefringent structure of spherical nanopores in the volume and create an intermediate stage in the substrate;
- and
- following the seeding stage, carrying out a writing stage comprising applying at least one and not more than ten non-circularly polarised focussed femtosecond laser pulses, being writing pulses, to the volume to transform the spherical nanopores into a birefringent structure of randomly distributed oblate spheroidal nanopores.
A method of processing an optical substrate comprising:
- providing a substrate of a transparent material;
- and
- carrying out a seeding stage comprising applying to each of a plurality of volumes within the substrate 40 or more circularly polarised focussed femtosecond laser pulses, being seeding pulses, to create a non-birefringent structure of spherical nanopores in each volume and create an intermediate stage in the substrate for transformation into a birefringent structure of randomly distributed oblate spheroidal nanopores.
A method of storing data in a multi-dimensional optical memory comprising:
- providing an optical substrate of transparent material comprising a non-birefringent structure of spherical nanopores in each of a plurality of volumes within the substrate, wherein the substrate is in an intermediate stage;
- and
- applying to each of at least some of the volumes at least one and not more than ten non-circularly polarised focussed femtosecond laser pulses, being writing pulses, to transform the spherical nanopores into a birefringent structure of randomly distributed oblate spheroidal nanopores, wherein for each volume the orientation of the non-circular polarisation and/or the ellipticity of the non-circular polarisation is selected in order to achieve a desired birefringence slow axis orientation and/or birefringence retardance value for the oblate spheroidal nanopores in order to encode data.
Dependencies are inferred from the claim text.