Subfrequency search at a laser as a signal of dark matter sector particles

We introduce a new method to search for the dark matter sector particles using laser light. Some dark matter particles may have a small mixing or interaction with a photon. High-power lasers provide substantial test grounds for these hypothetical light particles of exploding interests in particle physics. We show that any light source can also emit a subfrequency light as a new physics signal. Searching for this subfrequency light at a laser can be a simple and effective way to investigate the new light particles, even in tabletop optics experiments.