New F Theta lens with large scan field

18. April 2018

A hundred years ago the idea of cutting material without touching it seemed to be science fiction. 

However, Albert Einstein lay the foundation for laser material processing when he described the stimulated emission for the first time in 1916 – 1917. Fifty years later scientists presented the first laser which became a tool soon.

Today laser material processing is an established and often used technique for cutting, drilling and welding materials. The typical setup consists of four different elements – the laser itself, the scanner, focusing lens and beam expander and the working surface where the final cutting process takes place.

The development of lasers has not stopped until today, which results in more powerful devices. That requires a high qualitative beam expander and F‑Theta lens. The scanner enables a two dimensional beam displacement and with that a fast and precise machining. Therefore no movement of the heavy laser part or of the working plane is necessary. The higher the beam displacement the larger is the scan field and with that the maximum size of the building element. The scan field depends on the F‑Theta lens and is typically limited by the size of the last lens.

Sill Optics offers fused silica lenses with high scan fields. The S4LFT3250/328 which has a scan field of 160 x 160 mm² is a new innovation. A maximum input beam diameter of 15 mm is compatible to the lens, as well as a maximum beam diameter of 20 mm. The 20 mm diameter and the suitable scanner system reduce the scan field to 115 x 115 mm². Because of the ghost free design it even works in combination with ultrashort pulsed IR lasers. There are also lenses for other wavelengths in the Sill Optics catalogue with similar scan fields. Custom designs are the specialty of Sill Optics because of their high flexibility and high vertical range of manufacture.