BEZ30 Zoom Beam Expander
Model BEZ30 zoom beamexpander is a high specification unit with a low beam compression ratio,
designed for use with CO2 lasers having up to 30mm full beam diameter and 3000W CW power.
Some important features of model BEZ30 are:
* Excellent beam pointing accuracy.
* Output beam focus control.
* Forced gas cooling.
The focus control, combined with variable magnification, allows the user of model BEZ30 to
achieve ideal downstream laser beam conditions from a variety of input beam parameters.
BEZ30 was originally designed to give user-control of process parameters when using Dual-Focus optics.
Dimensions : see figure (24.281)
Weight : 3.5 kg
Cooling : Forced-gas cooling.
Focus range : +4M, through ‘infinity’ to -4M
Zoom range (magn.) : x0.50 to x1.40, continuously variable
Output clear aperture : 50mm diameter
Input clear aperture : 38mm, (35.7mm usable at M= x1.4)
Beam compression ratio : 2:1 max (-ve / +ve / -ve design)
Fitting (2 ends) : 4 off M5 tapped on 65.0 pcd
Beam wander : <30 arcseconds
The BEZ30 has a 3-element design using ZnSe lenses in black-anodised aluminium housings.
BEZ30 has a ‘negative/positive/negative’ design, minimizing beam compression and thermallensing
effects. 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.The lenses are mounted in sub-cells, each
centred to accuracies of a few arcseconds. Each main lens cell contains linear bearings running on
precision-ground steel rods which run the whole length of the unit. 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 <30 arcseconds (about 0.1 milliradian) is specified for an incident beam aligned
to the optical axis of the BEZ30. With a misaligned input beam, the beam wander will be 1.3x the
misalignment error (taken over the full zoom magnification range).
* Allows some commonality of beam properties to be obtained from a variety of different laser
* Establishment of ideal processing parameters for cutting, welding and profiling at medium laser
* Special test equipment.
* Use with dual-focus lenses to optimize optical conditions in the focal region.
Model BEZ30 is not directly compatible with other Umicore Laser Optics equipment. Accessory adaptors
BEZ30/I01 plus BEZ30/O01 allow compatibility with ‘LPG’ piping (coupling rings with 70.0 dia x
1.5 pitch threads).