The missing link between standing- and traveling-wave resonators

Optical resonators are structures that utilize wave interference and feedback to confine light in all three dimensions. Depending on the mechanism, can support either standing- or traveling-wave modes. Over years, distinction between these two different types of modes has become so prevalent nowadays it is one main characteristics for classifying optical resonators. Here, we show an intermediate link rather groups exists. In particular, introduce a new class photonic supports hybrid mode, i.e. at location along resonator electromagnetic fields associated with mode feature purely standing-wave pattern, while location, same represent pure traveling wave. The proposed concept general be implemented using chip-scale photonics as well free-space optics. Moreover, extended other phenomena such microwaves acoustics.