Exploring the boundaries of high-power infrared lasers for skin damage thresholds

High-power infrared laser systems are essential in many fields, from medicine to manufacturing to military defense. Several have reached exceptionally high powers, where the possibility of skin damage is quite feasible. But for a given laser system emitting at a set wavelength, the energy dose for such damage depends on exposure duration and beam diameter, among other variables. Maximum permissible exposure limits defined by current safety standards are based on historic data trends and interpolations, often without solid experimental validation.

DeLisi et al. challenged these standards by parameterizing the responses for a wavelength of 1567 nm, and comparing them to limits associated with existing laser safety standards. Using a continuous wave erbium fiber laser, anesthetized mini-pigs, and a range of exposure durations, the team found that permissible exposure limits and damage thresholds may be overly restrictive.

“A high margin of safety exists, between a factor of 10 and 30,” said author Michael P. DeLisi. “This ensures the standards provide safety, but also suggests a case for relaxing exposure limits in this regime if there is an industry need.”

The researchers presented a comprehensive solution to laser skin damage studies, including in vivo porcine experiments with skin lesion assessments. They examined recorded surface thermography for each exposure; constructed and validated a computational model of laser skin interaction; and provided examples of histological progression of laser-induced lesions from minor to major.

“We also demonstrate that computational models of laser skin thermal response can produce reasonable agreement with experiments,” said DeLisi. “Maturation of these types of models will minimize further need for repeated animal experiments, and also allow industry to simulate responses for their own applications.”

Source: “Porcine skin damage thresholds and computational modeling of continuous-wave laser exposure at 1567 nm,” by Michael P. DeLisi, Emily M. Corbin, Andrea L. Smith, Amanda M. Peterson, Maria A. T. Hoffman, Alejandro Ramirez, Amanda J. Tijerina, and Semih S. Kumru, Journal of Laser Applications (2026). The article can be accessed at https://doi.org/10.2351/7.0002119 .