Laser Hazard Analysis for Ultra-Fast Sub-Nanosecond, Mode-Locked Near Infrared Lasers Operated with Pulse Repetition Frequencies Above the Critical Frequency

摘要

Ultra fast, sub-nanosecond (picosecond to femtosecond) duration, laser pulses present unique challenges when performing laser safety analysis involving mode-locked lasers, which operate at pulse repetition frequencies above the critical frequency in the near infrared wavelength bands. Two specific cases are presented, one such case that agrees and one that disagrees with the general rule on critical frequency. The results show that in all cases the appropriate maximum permissible exposure is always the smallest of the values calculated from ANSI rule 1, 2 and 3.