A moiré photonic crystal is an optical analog of twisted graphene. A 3D moiré photonic crystal is a new nano-/microstructure that is distinguished from bilayer twisted photonic crystals. Holographic fabrication of a 3D moiré photonic crystal is very difficult due to the coexistence of the bright and dark regions, where the exposure threshold is suitable for one region but not for the other. In this paper, we study the holographic fabrication of 3D moiré photonic crystals using an integrated system of a single reflective optical element (ROE) and a spatial light modulator (SLM) where nine beams (four inner beams + four outer beams + central beam) are overlapped. By modifying the phase and amplitude of the interfering beams, the interference patterns of 3D moiré photonic crystals are systemically simulated and compared with the holographic structures to gain a comprehensive understanding of SLM-based holographic fabrication. We report the holographic fabrication of phase and beam intensity ratio-dependent 3D moiré photonic crystals and their structural characterization. Superlattices modulated in the z-direction of 3D moiré photonic crystals have been discovered. This comprehensive study provides guidance for future pixel-by-pixel phase engineering in SLM for complex holographic structures.
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System design of a single-shot reconfigurable null test using a spatial light modulator for freeform metrology
We report the simulation of an adaptive interferometric
null test using a high-definition phase-only spatial light
modulator (SLM) to measure form and mid spatial frequencies
of a freeform mirror with a sag departure of 150 μm
from its base sphere. A state-of-the-art commercial SLM
is modeled as a reconfigurable phase computer generated
hologram (CGH) that generates a nulling phase function
with close to an order of magnitude higher amplitude than
deformable mirrors. The theoretical uncertainty in form
measurement arising from pixelation and phase quantization
of the SLM is 50.62 nm RMS. The calibration requirements
for hardware implementation are detailed. © 2019
Optical Society of America
https://doi.org/10.1364/OL.44.002000
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- NSF-PAR ID:
- 10161246
- Date Published:
- Journal Name:
- Optics letters
- Volume:
- 44
- Issue:
- 8
- ISSN:
- 0146-9592
- Page Range / eLocation ID:
- 2000-2003
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1364/OL.44.002000
