II-VI designs a simple form lens to convert a Gaussian mode to a flat-top intensity profile.
Converting one beam mode to another type is always a difficult process. There are different products to address this problem, including diffractive lenses, special beam integrators, combinations of aspheric lenses, and phase plates. As with many design types, it™s desirable to use the simplest form. The II-VI aspheric form is one of the simplest types.
The method used to convert a Gaussian beam to a flat-top at focus is determined somewhat by the required focused beam size. A faceted beam integrator is necessary for large spot sizes (see above). However, when it™s necessary to focus a laser beam to a flat-top intensity with a spot size of 100µm, it™s also necessary to go to more sophisticated aspherics or diffractives. II-VI accomplishes this with a simple aspheric form. Depending on focal length, this lens is produced as a singlet or doublet.
- Focal lengths from 25 mm and up.
- Unit may consist of one or two lenses, depending on desired spot size.
- Requires Gaussian input beams with M2 values < 1.1 for best results.
- Applications for drilling and materials processing.
- Work best with laser beams having poor coherence.