Using two photonic crystals to concentrate light on a chip, in a volume as small as the wavelength itself

https://phys.org/news/2025-04-mechanism-photonic-crystal-chip.html

"broader spectrum of wavelengths... 2 mirrored pattern crystals next to each other create waveguide at their boundary, where light movement confined... light conduction topologically protected: scattering/ reflection by crystal imperfection suppressed, ending waveguide with wall, eventually bouncing back through waveguide after delay... inherently works for multiple wavelengths, overcoming light focusing resonance limits... also, sound waves, electrons in specific crystals... quantum communication, sensors, lasers"