Multi-element lens systems minimize the imaging errors of single lenses and provide precision focusing for non-scanning applications. You have to distinguish between monochromatic and achromatic systems.
Monochromatic systems are only corrected for a specific wavelength. So they are most suitable for laser applications. Especially fused silica lenses in air-spaced design are preferably chosen for collimation or focusing of high power laser. We offer mounted air spaced multi element systems in fused silica andoptical glass.
Achromatic systems have to consist of lenses with different glass types and dispersions. Only a matched combination allows the correction of the chromatic error especially in the visible range. Usually components are cemented. That leads to a reduced damage threshold of the achromatic system, which limits the use of laser with average powers of less than 200 watt.