Photons exist across the entire electromagnetic spectrum, not just in visible light. Photons are elementary particles that are the basic units of light and all other forms of electromagnetic radiation. They carry energy and momentum and exhibit both wave-like and particle-like properties, known as wave-particle duality.
The electromagnetic spectrum encompasses a wide range of frequencies or wavelengths, including radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays. Each of these regions corresponds to a different frequency range and has photons associated with it.
The only difference between photons in visible light and other regions of the spectrum lies in their respective frequencies. Visible light photons have frequencies that are within the range that can be detected by the human eye, hence allowing us to perceive them as different colors. However, photons with higher frequencies, such as X-rays and gamma rays, have energies that are much higher than visible light, while photons with lower frequencies, such as radio waves, have energies lower than visible light.
So, photons are not limited to visible light but exist throughout the entire electromagnetic spectrum, with different energies and frequencies corresponding to different regions of the spectrum.