Full Definition
Peak wavelength is the wavelength where an LED emits its strongest optical output. It is measured in nanometers (nm) and is usually listed as a target number such as 660nm, 850nm, or 1060nm.
Why It Matters in Photobiomodulation
PBM depends on biological absorption, so a device's peak wavelength matters more than generic color language. A panel advertised as "red and infrared" is incomplete unless it lists the exact peaks and ideally the bandwidth around those peaks. Two red LEDs may look similar to the eye while delivering different optical spectra to tissue.
Peak wavelength also affects tissue targeting. Red peaks around 630-670nm are commonly used for superficial skin and wound-related goals, while near-infrared peaks such as 810, 830, 850, and 1060nm are used when deeper tissue penetration is the priority. That said, wavelength does not work alone; irradiance, treatment area, distance, and fluence determine the final dose.
For users comparing devices, peak wavelength is a quick credibility filter. A listing that says only "red light" or "infrared" without exact nanometers leaves too much unknown. Hale content should teach readers to look for named peaks, realistic measurement distance, and enough panel coverage for the tissue target they care about.
PubMed Reference
PBM mechanism literature emphasizes that biological effects depend on wavelength, dose, and cellular targets [de Freitas 2016, PMID:28070154]. Tissue penetration reviews show why wavelength choice changes delivered light at depth [Salehpour 2019, PMID:31553265].
How This Matters at Hale
Hale lists eight peak wavelengths across its RLPRO platform: 630, 650, 660, 670, 810, 830, 850, and 1060nm. That specificity helps buyers compare real PBM devices against vague listings. The RLPRO 1200 and RLPRO 2000 pair those wavelengths with at least 197 mW/cm² irradiance.
Related Terms
See wavelength, optical window, and tissue penetration depth.