Particle Velocity Measurement in Classically Forbidden Regions

For nearly a century, researchers have been fascinated by the intriguing features of quantum tunneling. In a previous study [1], we proposed a novel approach to explore evanescent phenomena at a step potential by examining particle motion within a system of coupled waveguides. In this system, the population transfer between the waveguides acts as a clock, enabling the determination of particle velocities. We implemented this approach for photons in a microcavity. By utilizing a novel nanostructuring method [2], we can guide these photons in an arbitrary potential landscape, specifically within a coupled waveguiding structure. By superimposing the coupled waveguides with a reflective step, we are able to measure the particle velocities in the classically forbidden region. We will present our latest results, shedding further light on the intriguing phenomenon of quantum tunneling.

[1] Klaers, J., Sharoglazova, V., & Toebes, C. (2023). Physical Review A, 107(5), 052201.
[2]Vretenar, M., Puplauskis, M., Klaers, J.. Adv. Optical Mater. 2023, 2202820.