The giant circular photo‐galvanic effect is realized in chiral metals when illuminated by circularly polarized light. However, the structure itself is not switchable nor is the crystal chirality in the adjacent chiral domains. Here spindle‐shaped liquid crystalline elastomer microparticles that can switch from prolate to spherical to oblate reversibly upon heating above the nematic to isotropic transition temperature are synthesized. When arranged in a honeycomb lattice, the continuous shape change of the microparticles leads to lattice reconfiguration, from a right‐handed chiral state to an achiral one, then to a left‐handed chiral state, without breaking the translational symmetry. Accordingly, the sign of rotation of the polarized light passing through the lattices changes as measured by time‐domain terahertz spectroscopy. Further, it can locally alter the chirality in the adjacent domains using near‐infrared light illumination. The reconfigurable chiral microarrays will allow us to explore non‐trivial symmetry‐protected transport modes of topological lattices at the light–matter interface. Specifically, the ability to controllably create chiral states at the boundary of the achiral/chiral domains will lead to rich structures emerging from the interplay of symmetry and topology.
In this paper, we present the development and testing of a balanced Zeeman spectroscopy method utilizing wavelength modulation for selective detection of paramagnetic molecules. We perform balanced detection via differential transmission measurement of right-handed circularly polarized and left-handed circularly polarized light and compare the performance of our system to the Faraday rotation spectroscopy technique. The method is tested using oxygen detection at 762 nm and can provide real-time oxygen or other paramagnetic species detection for a variety of applications.
more » « less- NSF-PAR ID:
- 10396838
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optics Express
- Volume:
- 31
- Issue:
- 5
- ISSN:
- 1094-4087; OPEXFF
- Page Range / eLocation ID:
- Article No. 7226
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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