Fabrication of multi-level graded photonic super-crystals
Direct pixel-by-pixel phase engineering in a SLM is an effective method for the holographic fabrication of graded photonic super-quasi-crystals with desired disorder and graded photonic super-crystals with rectangular unit-cells. Multiple levels of filling fractions of dielectric in the crystal have been created in the graded regions. Fabrication of these graded photonic super-crystals and super-quasi-crystals with small feature size is possible, using a laser projection system consisting of integrated spatial light modulator and reflective optical element.
1. A system for fabricating multi-level graded photonic super-crystals, comprising:
a laser for generation of an incoming laser beam;
a spatial light modulator (SLM) comprising a phase pattern for diffraction of the incoming laser beam along an optical axis;
a first lens having a first focal length located adjacent to the spatial light modulator (SLM);
a second lens having a second focal length;
a Fourier filter located between the first lens and the second lens, wherein the first lens, the second lens, and the Fourier filter are each positioned substantially parallel to each other, and wherein the first lens, the second lens, and the Fourier filter are each perpendicular to and centered around the optical axis;
a reflective optical element (ROE) located adjacent to the second lens, wherein the reflective optical element (ROE) comprises reflective surfaces positioned at a tilt angle relative to the optical axis; and
a sample located adjacent to the reflective optical element (ROE), wherein the incoming laser beam is diffracted by the spatial light modulator (SLM) into a series of diffracted laser beams, wherein all or a portion of the diffracted laser beams pass through the first lens, the second lens and the Fourier filter along the optical axis, wherein all or a portion of the diffracted laser beams reflect off of the reflective surfaces of the reflective optical element (ROE) to produce beam overlapping, and wherein the spatial light modulator (SLM), the first lens, the second lens, the Fourier filter, and the reflective surfaces of the reflective optical element (ROE) generate an interference laser pattern out of the incoming laser beam that contacts the sample and creates a multi-level graded photonic super-crystal.
2. The system of claim 1 , further comprising a motion stage for holding and moving the sample.
3. The system of claim 1 , wherein the multi-level graded photonic super-crystal comprises periodic structures.
4. The system of claim 1 , wherein the multi-level graded photonic super-crystal comprises a rectangular unit super-cell.
5. A method for fabricating multi-level graded photonic super-crystals, comprising:
directing an incoming laser beam at a spatial light modulator (SLM) to produce diffracted laser beams, wherein the diffracted laser beams are centered around an optical axis;
generating an interference laser pattern by passing all or a portion of the diffracted laser beams through a combination of:
a first lens having a first focal length,
a Fourier filter,
a second lens having a second focal length, wherein the first lens, the Fourier filter, and the second lens are each positioned substantially parallel to each other, and wherein the first lens, the Fourier filter, and the second lens are each perpendicular to and centered around the optical axis, and
a reflective optical element (ROE), wherein the reflective optical element (ROE) comprises reflective surfaces positioned at a tilt angle relative to the optical axis, and wherein the reflective surfaces reflect the diffracted laser beams; and
contacting a sample with the interference laser pattern to create a multi-level graded photonic super-crystal.
6. The method of claim 5 , wherein the multi-level graded photonic super-crystal comprises periodic structures.
7. The method of claim 5 , wherein the multi-level graded photonic super-crystal comprises a rectangular unit super-cell.
8. The multi-level graded photonic super-crystal fabricated by the method of claim 1 .