Unveiling a new quantum frontier: Frequency-domain entanglement

https://phys.org/news/2024-04-unveiling-quantum-frontier-frequency-domain.html

"frequency beam splitter alters individual photon's frequency with 50% success... 2-photon NOON state within single-mode fiber, double resolution of its single-photon counterpart... transform interference concept from occurring between 2 spatial paths to between 2 different frequencies, enabling channeling both color components through single-mode optical fiber, creating stable interferometer... quantum sensing, secure communication networks"