The lens is the final component that the laser beam will pass until it hits the surface of the workpiece. This lens has a focal length of 50.80mm or 2 inches. The diameter of the lens is 20mm. Make sure to get/make the correct nozzle that has a 20mm seat for the lens.
The material of the lens is CVD ZnSe (Chemical Vapor Deposited Zinc Selenide) which has a low absorption rate and high transmittance level.
Specifications:Design Wavelength: 10.6 umFocal Length Tolerance: ±1%Diameter Tolerance: +0.0 / -0.12 mmThickness Tolerance: ±0.2 mmSurface Accuracy: /2 per 1" Dia@632.8nmSurface Quality: 20-10 scratch and digCentration: <3' arc minutesClear aperture: >90%Beveling: <0.2 x 45°AR/AR Coating: R<0.5% per surface @10.6um