激光损伤阈值测试.doc

激光损伤阈值测试
Laser Damage Threshold Testing
Laser Damage Threshold (LDT) is one of the most important
specifications to consider when integrating an ponent into
a laser system. Using a laser in an application offers a variety of
benefits to a standard light source, including monochromaticity,
directionality, and coherence. Laser beams often contain high energies,
though, and are capable of damaging sensitive ponents.
When integrating a laser into an optical system, it es crucial to
understand the effects of laser beams on optical surfaces and how laser
damage threshold is quantified for ponents.
The degree of damage induced to an ponent by a laser beam is highly dependent on the type of laser being used. Thermally-induced damage occurs under Continuous Wave (CW) laser operation. During exposure to the CW laser, the optical material may not have sufficient time to thermally relax, and failure can occur due to thermal damage to the bulk material or the optical coating. Alternatively, the damage caused by a short, intense laser pulse is due to ionization: the breakdown of the molecular bond. The electric field generated by the laser beam at the optical surface stimulates electrons at the outer energy band, causing ionization. However, it is important to keep in mind that lasers with long pulse widths (<10s) or high repetition rates
(>10MHz) may also cause