Dynamically Selective and Simultaneous Detection of Spin and Orbital Angular Momenta of Light with Thermoresponsive Self-Assembled Chiral Superstructures

Featuring a self-assembled helical nanostructure and external stimuli-responsive chiral photonic band gap, cholesteric liquid crystals (CLCs) create more opportunities in harnessing multiple degrees of freedom of light, especially the spin and orbital angular momenta (SAM/OAM). Here, we propose and demonstrate an innovative method for a dynamically selective and simultaneous detection of SAM and OAM of light via two cascaded CLC superstructures with thermal controllability and opposite chirality. By independently regulating their temperatures, on-demand selective detection for the intended wavelength and spin eigenstate is achieved with high efficiency and broadband tunability. The information of the desired angular momenta is vividly identified by the reflected diffraction patterns from cascaded chiral superstructures, while the nondetected components are preserved in the transmitted light. This indicates an in situ and nondestructive manner and may facilitate advanced optical manipulation, imaging, and information (de)multiplexing. This work brings important insights into the design, construction, and application of self-assembled chiral nanostructures, promoting multiple and active functionalities in diverse intelligent devices.

Automated summary

An innovative method for dynamically selective and simultaneous detection of the spin and orbital angular momenta of light is proposed and demonstrated using two cascaded cholesteric liquid crystal superstructures. This method allows for efficient and broadband tunable selective detection of the intended wavelength and spin eigenstate.