Varax95 Series (Variable Ring-Focus Lenses)

IntroductionVariable Ring Focus lens
The VARAX95 series of lenses produce a CO2 laser focus in the form of a ring of concentrated laser
power. The outer control allows the diameter of the ring focus to be varied from a maximum selected
value (depending on lens model) down to about 42% of the maximum diameter.
The standard range contains designs for maximum ring diameters of 1.0mm up to 5.0mm.
Varax95 lenses contain a standard ZnSe meniscus lens type 11ZLF95, (hence the ‘95’ designation).
Special zoom-axicon systems can be designed to suit specific customer requirements.
Technical specifications, optical / mechanical
Dimensions : See Figure 25.11
Construction : Aluminium alloy, black. ZnSe optics, AR/AR coated for 10.6μm,
Copper nozzle tip.
Clear aperture : 25.0 mm diameter.
Cooling : Air cooled, or use WMA mount.
Fittings : 1.5″ x 12TPI UNF (as for M11 cell).
Max CW power : 2000W CW, assumes use of WMA mount.
Calibration : Scale engraved at 5% intervals, (ie 100%, 95%, 90%… of maximum
ring diameter).
Method of operation : Actuation of the control ring moves an axicon component axially,
changing the diameter of the ring focus. An actuated linear slide
method eliminates lateral focus movement during operation.
Assist gas : Via 6/4 fitting.
Gas nozzle : Built-in. Nozzle tip diameter is 1mm larger than max. ring size.
Standoff : User adjustable 0 to 5mm.
Focus control : None, needs external z-axis control.

Applications notes
Variable axicon systems find their main use in drilling of materials, especially plastics of various
types. The ‘zoom’ control of ring diameter is useful when the laser operator needs to have finecontrol
over the diameter of the drilled hole.
An alternative application area occurs in the surface processing of relatively wide strips of material.
There are applications where thin-films of material must be evaporated away from a surface in even,
wide (eg: 1.0mm) strips. A normal ‘Gaussian’ energy distribution at the focus can damage the
underlying material and have less control over width-of-process. Variable axicon lenses can help to
avoid the need for expensive mini-integrator components in this type of process.
Associated equipment
VARAX95 models fit direct to any system which will accept an M11 lens cell (the standard mount
for 1.1″ ZnSe lenses). Compatible Umicore Laser Optics equipment includes:
WMA mount ….. section 20.3.
FF25 fine-focus unit ….. section 63.1.
CFF25 coarse/fine focus unit ….. section 63.2.
LAU25 lateral adjustment unit ….. section 72.1.
LAM25 lateral adjustment unit ….. section 72.2.