Laser began as an acronym: light amplification by stimulated emission of radiation. A laser gives off light in a very narrow range of wavelengths, with its waves moving in step, which is what makes it coherent. That is why its beam stays narrow and bright across a room.
Lasers were invented in 1960 (Heiskanen & Hamblin, 2018), the year T. H. Maiman reported stimulated optical radiation in ruby (Maiman, 1960). In 1967, Endre Mester at Semmelweis Medical University in Hungary shone a low-power ruby laser on mice and saw their shaved fur grow back faster, an effect he called laser biostimulation. Photobiomodulation research begins with that experiment (de Freitas & Hamblin, 2016).
Safety
The eye focuses light onto the retina, so a beam that seems faint at the front of the eye can be intense where it lands. When researchers measured two low-power red lasers used to slow myopia in children, three minutes of continuous viewing approached or exceeded the limit for retinal damage (Ostrin & Schill, 2024).
How we use it
Lasers draw the lines of light in our installations. Beams are aimed at sculpture and open air, kept away from where anyone sits or stands, and never directed at eyes.
References
de Freitas, L. F., & Hamblin, M. R. (2016). Proposed mechanisms of photobiomodulation or low-level light therapy. IEEE Journal of Selected Topics in Quantum Electronics, 22(3), 348–364. https://doi.org/10.1109/JSTQE.2016.2561201
Heiskanen, V., & Hamblin, M. R. (2018). Photobiomodulation: Lasers vs. light emitting diodes? Photochemical & Photobiological Sciences, 17(8), 1003–1017. https://doi.org/10.1039/c8pp00176f
Maiman, T. H. (1960). Stimulated optical radiation in ruby. Nature, 187(4736), 493–494. https://doi.org/10.1038/187493a0
Ostrin, L. A., & Schill, A. W. (2024). Red light instruments for myopia exceed safety limits. Ophthalmic and Physiological Optics, 44(2), 241–248. https://doi.org/10.1111/opo.13272