Dear Sasa,
We have had a number of enquiries similar to yours. There are a few parameters we need to know before a Dual-focus lens can be specified:
1) Beam diameter & mode (the patterns shown on the form are to represent what your laser gives out, i.e. select one which most closely matches your laser beam. If your beam is actually 20mm dia, your lens should be at least 50% bigger.
2) Lens diameter you currently use (20mm)
3) Material thickness (8 – 10mm)
4) Lens edge thickness – in case there is significant gas pressure, which I guess there is not in your case.
The cost is more expensive than conventional lens due to the extra diamond-turning process.
Based on other enquires which have required a 20mm or 19mm dia lens with a 2mm edge thickness:
1 off price 490.0 Euro
2 off price 450.0 Euro each
5 off price 369.0 Euro each
Shipping costs to Croatia are about 50 Euro.
Lenses of this size would have to be made from the very start (cannot be made from standard metal cutting lenses), and would be 8 weeks.