BEZ10 Zoom Beam Expander

IntroductionBEZ10 Zoom Beam Expander
The BEZ10 zoom beamexpander has both zoom and focus controls. It is designed for use with CO2
lasers having up to 12mm beam diameter and 1000W CW power. Notable features of model BEZ10
* Good beam pointing accuracy.
* Output beam focus control to 500mm focus.
* Low beam compression ratio (see Tech. Data section 24.00).
The focus control, combined with variable magnification, allows the user of model BEZ10 to
achieve ideal downstream laser beam conditions from a variety of input beam parameters.
BEZ10 is designed for use with lasers such as the Coherent ‘Diamond’ series, as an aid to finding
optimum processing conditions.
Technical specifications
Dimensions : See Figure 24.221.
Weight : 1.2 kg (approx).
Cooling : Air cooled.
Focus range : +0.5m, through ‘infinity’ to -5m.
Zoom range : x1.0 to x2.0, continuously variable.
Output clear aperture : 25mm diameter.
Input clear aperture : 22mm, (12.5mm usable at M= x2.0).
Beam compression ratio : 1:1.
Fitting (input end) : 52mm dia. x 1.5mm pitch F/M thread.
Beam wander : <2 arc minutes.

BEZ10 Zoom Beam Expander drawing

The BEZ10 has a 3-element design using ZnSe lenses in black-anodised aluminium housings. A
‘negative-positive-negative’ lens design gives a better-than-unity beam compression ratio.
The two input lenses provide the zoom magnification and are contolled by means of an external zoom
control ring.
Lens (3) is moved axially to provide beam focus control, and this motion is effected by means of an
external focus ring.
All lenses are centred within their mounting cell to accuracies of a few arcseconds. Each cell is driven
within a precision bore.
During zoom or focusing action, there is no rotation of any lens, and so the assembly has a very high
level of inherent centration accuracy, minimizing beam wander.
The beam-wander of <2 arc minutes (about 0.6 milliradian) is specified for an incident beam aligned
to the optical axis of the BEZ10.
(1) Establishment of ideal beam conditions for processing in medium power CO2 laser systems.
(2) Production of variable beam waist diameters at 500mm+ distances for low intensity processing.
(3) Special test equipment.
(4) Drilling variable hole diameters.
Associated equipment
Model BEZ10 attatches directly to ‘OPG’ optical piping (section 61.1). Lateral adjustment modules
LAU25, or LAM25, may be used to aid centration of the zoom beamexpander to the input beam
(sections 72.1, 72.2).
The input beam alignment is critical. A fine-tilt adjustment unit, TAU25, is available as an accessory.
(See section 72.8).