A CO2 laser at 10.6 micrometres cannot use glass optics, so the cutting head's focusing lens is zinc selenide — the same documented material line as this manufacturer's ZnSe windows. The documented focus lens listing is specific: a hot-sale CO2 laser focus lens, 20 mm diameter with a 50.8 mm focal length — the two-inch focus. Diameter and focal length are the two parameters the listing records for this product class, and it states both plainly.
ZnSe focus lenses are consumables: they degrade under contamination and thermal stress. That is why the practical enquiry states the machine or head type, the lens diameter and the focal length — and why the surrounding beam-delivery set matters. The same catalogue supplies the silicon gold-coated mirrors that deliver the beam to the head and the ZnSe protection windows that sit in the path; each mirror and window is confirmed against the head it has to fit, item by item, in the enquiry.
Documented CO2 Focus Lens
| Item | Documented detail |
|---|---|
| Product | CO2 laser focus lens (ZnSe) |
| Diameter | 20 mm |
| Focal length | 50.8 mm |
| Documented MOQ | 10 pieces |
| Related CO2 optics | ZnSe windows (AR coated), silicon gold-coated mirrors, galvo mirrors |
Choosing the Focal Length
Shorter focal lengths focus to a smaller spot with a shorter depth of focus — the engraving and thin-material choice. Longer focal lengths give a larger spot, a longer working depth and better tolerance of material thickness variation — the cutting choice. The documented 50.8 mm lens sits in the middle of that trade. If your machine uses a different focal length or a meniscus form, state it in the enquiry; whether a matching ZnSe lens can be supplied in that focal length or form is confirmed before the quotation is issued.
Frequently Asked Questions
What focal length is documented?
50.8 mm — two inches — on a 20 mm diameter ZnSe focus lens.
Is the lens a consumable I should stock?
Yes. ZnSe focus lenses degrade in service, so they are worth holding as spares; the 10-piece listed minimum suits maintenance stocking.
Can I order the mirrors and windows with the lens?
Silicon gold-coated CO2 mirrors and AR-coated ZnSe windows are documented listings in the same catalogue; whether they are quoted together with a given lens is confirmed item by item in the enquiry.
Lens Forms and Head Compatibility
Two lens forms serve CO2 focusing and the distinction is worth one paragraph. The plano-convex form has one flat face and one convex face. Meniscus ZnSe lenses bend both surfaces in the same direction and correct the spherical aberration of the focusing geometry better, giving a tighter, more consistent spot. The documented CO2 listing in this catalogue — ZnSe, 20 mm diameter, 50.8 mm — records no lens form, so neither form should be assumed for it. The forms are not drop-in interchangeable in every head — the lens seat, the focal position and the nozzle relationship are designed around one form — so the enquiry should name the head or machine and the form it currently uses, and the form to be supplied is confirmed before the quotation is issued. That single fact prevents a costly CO2 lens ordering error: a correct focal length in the wrong mechanical form. Everything else about the order is the standard ZnSe discipline: handle by the edges, keep spares, and replace on degradation rather than on failure.
Request a Quotation
Tell us the component, material, dimensions and coating you need. Pricing and lead time for your specification are confirmed in the written quotation.