Angular-momentum nanometrology in an ultrathin plasmonic topological insulator film

Abstract

Complementary metal–oxide–semiconductor (CMOS) technology has provided a highly sensitive detection platform for high-resolution optical imaging, sensing and metrology. Although the detection of optical beams carrying angular momentum have been explored with nanophotonic methods, the metrology of optical angular momentum has been limited to bulk optics. We demonstrate angular-momentum nanometrology through the spatial displacement engineering of plasmonic angular momentum modes in a CMOS-compatible plasmonic topological insulator material. The generation and propagation of surface plasmon polaritons on the surface of an ultrathin topological insulator Sb2Te3 film with a thickness of 100 nm is confirmed, exhibiting plasmonic figures of merit superior to noble metal plasmonics in the ultraviolet-visible frequency range. Angular-momentum nanometrology with a low crosstalk of less than −20 dB is achieved. This compact high-precision angular-momentum nanometrology opens an unprecedented opportunity for on-chip manipulation of optical angular momentum for high-capacity information processing, ultrasensitive molecular sensing, and ultracompact multi-functional optoelectronic devices.

Modulation of Crystal and Electronic Structures in Topological Insulators by Rare-Earth Doping

“…[8][9][10] These excellent electronic and optical properties enable topological insulator materials to be suitable for designing various advanced electronic and optoelectronic devices. [11][12][13] Magnetic doping can open up an energy gap at the Dirac point in topological insulators due to the breaking of time reversal symmetry by magnetic impurities. 14 A variety of exotic topological effects, including the quantum anomalous Hall effect (QAHE), topological magnetoelectric effects, image magnetic monopoles, and Majorana fermions, can be generated through magnetic doping.…”

Quantum Topological Photonics

“…Therefore, the topological detectors are helpful in detecting the change of a system, for example, the topological quantum phase transition, avoiding the impact of environmental disturbance on detection accuracy. [ 196–199 ] We know that the high Q ‐factor of optical cavity can improve the sensitivity of the detectors, and topological optical cavities can have high Q ‐factor and they have robustness with small Q ‐factor fluctuation, they can work in harsh environments. Furthermore, trivial devices have defect of high dark current noise, and the quantum channels generated by topological devices can reduce it.…”

Topological-Insulator-Based Gap-Surface Plasmon Metasurfaces

“…When shifting to higher energies, which enable strong interband transitions, the bulk acts as if it were "optically metallic," meaning that the real part of the complex dielectric function is negative while the imaginary part is sufficiently small [20,21]. There have been multiple reports on plasmonic resonances with bulk TIs in the visible regime for applications ranging from nanometrology to holography [22][23][24][25][26]. Due to low losses at small wavelengths close to and in the UV, TIs exhibit superior plasmonic properties that outperform conventional noble metals, including gold and silver [23,27].…”