  Cavities play a fundamental role in optical physics by providing
spatio-temporal confinement of energy that facilitates light-matter
interactions. They are routinely utilized in a variety of settings, ranging
from lasers to spectral filters, to nonlinear wave mixers, and modulators.
While their resonant properties make them suitable for sensing, in many
applications, like in lasers, it is desired to alleviate their sensitivity in
order to make a device more resilient to perturbations. Along these lines there
have been several recent reports of using concepts from topological physics in
order to design laser arrays that are inherently more robust. Here, we present
a new class of topological cavities based on Majorana bound states that provide
unique scaling features as well as non-degenerate single-mode behaviors. These
cavities may lead to a new family of lasers and laser arrays that are robust to
defects, fabrication imperfections, and external perturbations.
