We don’t know what dark matter is, that’s why it’s called dark, not because it reflects special light but because we don’t even know if it exists. Dark matter has yet to be proven. The “dark” in dark matter means “unknown” not something devoid of light emission.

Dark matter is a theory of a weekly interacting particle (WIP) that adds gravity to the galaxy. It is doubtful that searching for energetic waves will reveal dark matter. For that we need some other detection process.

Here’s some images of the milky way seen in different wavelengths outside what you might call the “light spectrum.”

On the upper right of each image you can see what wavelength we looked at including visible light, gamma rays, infrared rays, x-rays and so on. This does show that we look outside the normal spectrum of light all the time and still dark matter is not visible. We need some other way to detect that stuff, if indeed it exists at all.