Harmonic light-generating metasurface
A harmonic light-generating metasurface includes a base substrate and a plurality of structures, that include nonlinear material, that are disposed in a pattern on a surface of the base substrate. Each structure of the plurality of structures individually supports a magnetic dipole mode. An electromagnetic field enhancement of the magnetic dipole mode induces generation of a harmonic signal by the plurality of structures. Alternatively, a harmonic light-generating metasurface, includes a base substrate, a supporting substrate that includes a nonlinear material, and a plurality of paired structures disposed in a pattern on a surface of the supporting substrate. Each paired structure, of the plurality of paired structures, collectively supports a toroidal dipole mode. An electromagnetic field enhancement of the toroidal dipole mode penetrates the supporting substrate to induce generation of a harmonic signal by the supporting substrate.
1. A harmonic light-generating metasurface, comprising:
a base substrate;
a supporting substrate comprising a nonlinear material; and
a plurality of paired structures disposed in a pattern on a surface of the supporting substrate, wherein
each paired structure, of the plurality of paired structures, collectively supports a toroidal dipole mode, and
an electromagnetic field enhancement of the toroidal dipole mode penetrates the supporting substrate to induce generation of a harmonic signal by the supporting substrate.
2. The harmonic light-generating metasurface of claim 1 , wherein the pattern controls an emission profile of the harmonic signal generated by the plurality of paired structures.
3. The harmonic light-generating metasurface of claim 1 , wherein the pattern is rectilinear.
4. The harmonic light-generating metasurface of claim 1 , wherein the pattern is polar and comprises polar coordinate axes.
5. The harmonic light-generating metasurface of claim 1 , wherein the nonlinear material is a wide-bandgap semiconductor.
6. The harmonic light-generating metasurface of claim 5 , wherein the wide-bandgap semiconductor is indium tin oxide (ITO).
7. The harmonic light-generating metasurface of claim 1 , wherein the plurality of paired structures comprise a plasmonic material.
8. The harmonic light-generating metasurface of claim 1 , wherein the plurality of paired structures are covered by an oxide film disposed on the surface of the supporting substrate.
9. The harmonic light-generating metasurface of claim 1 , wherein
the toroidal dipole mode interacts with a second mode of the structure to generate a higher-order multi-pole mode, and
the combined toroidal dipole mode electromagnetic fields and high-order multi-pole mode electromagnetic fields penetrate the supporting substrate to induce generation of the harmonic signal.
10. A harmonic light-generating optical system, comprising:
a pump laser; and
the harmonic light-generating metasurface of claim 1 .
11. The harmonic light-generating optical system according to claim 10 , wherein an ambient atmosphere of the system has access to a first optical path of the pump laser and a second optical path of a harmonic signal generated by the harmonic light-generating metasurface.
12. A method of manufacturing a harmonic light-generating metasurface, the method comprising:
disposing a supporting substrate comprising a nonlinear material on a base substrate; and
patterning a plurality of paired structures on a surface of the supporting substrate, wherein
each paired structure, of the plurality of paired structures, collectively supports a toroidal dipole mode, and
an electromagnetic field enhancement of the toroidal dipole mode penetrates the supporting substrate to induce generation of a harmonic signal by the supporting substrate.
13. The method according to claim 12 , wherein patterning the plurality of paired structures comprises:
disposing a resist film on the surface of the supporting substrate;
pattering the resist film using electron beam lithography;
developing the resist film into a mask with a developer;
disposing a plasmonic material into and onto the mask;
lifting-off the mask with a second developer to leave the pattern of a plurality of paired structures of the plasmonic material directly on the surface of the supporting substrate.
14. The method according to claim 12 , wherein patterning the film comprises stamping the plurality of paired structure onto the surface of the supporting substrate.
15. The method according to claim 12 , wherein the pattern of the plurality of paired structures controls an emission profile of the harmonic signal.
16. The method according to claim 12 , further comprising disposing an oxide film on the surface of the supporting substrate to cover the plurality of paired structures.
17. The method according to claim 12 , wherein
the toroidal dipole mode interacts with a second mode of the structure to generate a higher-order multi-pole resonance, and
the combined toroidal dipole mode electromagnetic fields and high-order multi-pole electromagnetic fields penetrate the supporting substrate to induce generation of the third harmonic signal by the supporting substrate.
18. The method according to claim 12 , wherein the nonlinear material is a wide-bandgap semiconductor.
19. The method according to claim 18 , wherein the wide-bandgap semiconductor is indium tin oxide (ITO).
20. The method according to claim 12 , wherein the plurality of paired structures comprise a plasmonic material.