F-theta distortion and field curvature are both field-dependent errors in a laser scan lens, but they fail in completely different ways. F-theta distortion is a position error: the focused spot lands somewhere other than where the scan angle says it should, while staying sharp. Field…
The relationship behind F theta lens focal length vs scan field is straightforward at first order: for an ideal F-theta mapping, the displacement of the focused spot is approximately proportional to effective focal length and optical scan angle. A longer focal length therefore produces a…
Choose zinc selenide (ZnSe) when the optic sits in a CO2 laser beam or has to transmit past about 14 µm. Choose zinc sulfide (ZnS) when the optic faces weather, sand, or rain, or when visible light and thermal infrared have to share one aperture.…
