Laser Systems

As described in the Operation Principle section, APLI utilizes pulsed UV laser light with photon energies around 5 eV, which corresponds to a wavelength of about 250 nm. A typical laser system for routine APLI would provide repetition rates between 50 and 300 Hz, pulse widths of about 5 ns, pulse energies around 5-10 mJ and a beam diameter of approximately 5-10 mm.

Although there are several laser types, which reach the outlined specifications, for practical reasons APLI is primarily performed with two types of lasers: KrF Excimer gas lasers with 248 nm and quadrupled NdYAG solid state lasers with 266 nm wavelength. 

Both types are commercially available as “benchtop” systems with a relatively small physical footprint, and they both allow routine operation with high repetition rates, good robustness and  long maintenance intervals. 

For particular applications, which can tolerate lower pulse energies in the 200 μJ range and smaller beam diameters, like GC-API-MS with APLI, a highly miniaturized, diode pumped, quadrupled NdYAG (DPSS-NdYAG) Laser provides a compact, robust and very easy to integrate light source.