Traditionally, 1 micron optics have been made from fused silica and, at times, other low cost materials. However, as high quality 1 micron lasers advance and more demanding applications develop, the demand for optics with better thermal properties, and optics that can be shaped for minimum aberration or specialty focusing properties, will increase.
II-VI Infrared manufactures 1 micron optics ideally suited to these more demanding applications. Made from optical materials including Zinc Sulfide MultiSpectral (ZnS MS), ZnSe, copper, and silicon, these optics offer good thermal conductivity, reduced thermal distortion, and (in transmissive materials) a relatively high index of refraction. ZnS MS is especially well-suited to 1 micron optics, as it (like ZnSe) can be diamond-turned. Via two-axis and free form diamond turning techniques, almost any type of surface can be machined onto a ZnS MS substrate. Faceted integrators, diffraction limited aspheric lenses, and axicon lenses are just some of the examples of diamond-turned ZnS MS lenses that find uses in high power 1 micron laser systems. Faceted integrators, like the lens in the photo (above), are frequently used to homogenize a laser beam into square or rectangular shapes used in surface treatment applications. Diamond turned aspheres with zero spherical aberration can lead to fewer lenses in the beam path. For example, a collimator doublet of FS and a focusing head doublet of FS can be replaced with one lens which can function to reimage the fiber end to the work piece. Alternatively the collimator doublet and the focusing doublet can be replaced with one aspheric ZnS MS lens each. Fewer lenses mean fewer maintenance problems and less thermal lensing, enabling increased uptime and increased beam quality.