Laser therapy is an FDA cleared modality that reduces inflammation and ultimately results in pain reduction, also called cold laser therapy—uses low-level light energy to treat a wide array of conditions, ranging from sprains, tendinitis, back pain, and arthritis to temporomandibular disorder (chronic jaw pain), carpal tunnel syndrome, diabetic neuropathy, fibromyalgia, and leg ulcers. The therapy is noninvasive and painless. The Science of Photobiomodulation Therapy All light is composed of photons. Photons are small packets of light energy in the form of waves with a defined wavelength and frequency.
Laser (acronym for Light Amplification by Stimulated Emission of Radiation) can be used as a therapeutic device which produces monochromatic (one specific wavelength), coherent (constant phase) and polarized (directional) light.
Photobiomodulation has been officially defined as a form of light therapy that utilizes non-ionizing forms of light sources, including lasers, LEDs, and broadband light, in the visible and infrared spectrum. It is a nonthermal process involving endogenous chromophores eliciting photophysical (i.e., linear and nonlinear) and photochemical events at various biological scales. This process results in beneficial therapeutic outcomes including but not limited to the alleviation of pain or inflammation, immunomodulation, and promotion of wound healing and tissue regeneration.
Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4390214