What are the drawbacks of flash lamps?
• The lifetime of lamps is very limited – normally up to a few thousand hours. • Flash lamps have a broad emission spectra (see adjoining figure) whereas the absorption spectra of lasing media have more or less discreet absorption peeks. As a result, most of the optical energy being emitted by the flash lamp goes waste. • The wall plug efficiency of the laser (electrical to optical efficiency) is low – typically ~ few percent. This results in a higher heat load, making necessary a more powerful cooling system, and the strong thermal lensing and hence a poor beam quality. • Electric power supplies for lamp-pumped lasers involve high electrical voltages, which raise additional safety issues. • The low pump brightness (compared with that achievable with diode lasers) and the broad emission wavelength range exclude many solid-state gain media.
