Multi Plane Scanning System BeamMap

Description

Multiplane Scanningsystem BeamMap / BeamMap-Classic for focussed beams and real-time M2-Measurement

Beam diameters between 0.5µm and 3mm can be measured directly with the compact rotatable scanhead.

Measurement principle

There are single or XY-slits mounted in 4 or 5 planes on a rotating disk (puck) with different distances from the entrance aperture. The rotation axis is in the direction of the beam. By measuring the beam diameter and the centroid position as a function of the beam position in propagation direction, the divergence and the beam direction with respect to the z-axis is detected during one rotation in real time. The required distance between the different planes depends on the laser parameters and can be calculated with an Excel-program. The plane spacing is fixed and can not be changed from the user.

The 2D/3D representation of the beam is calculated from the scanned XY profiles in each plane. In order to determine the astigmatism or the M2 in other axis, the scan head can be rotated around the optical axis. An integrated encoder shows the effective angle in the software.

In order to calculate the M2 value of collimated lasers a lens with short focal length is requiered in order to focus the beam into the scan head. As an alternative it is also possible to use the BeamCollimate, which is especially designed for collimated beams.
For small distances to the sensor, please use a Lansplate (DAT-BMR-LP)

Configuration
There are different configurations of the scanhead with respect to plane number and plane spacing available, so that for nearly all types of lasers a suitable configuration can be found easily. We are happy to support you to select the right setup.
 

• BeamMap-Classic - 5 planes in equal distance: The measurement head contains 8 slits mounted on 5 planes in equal distance. During each rotation the profiles on each of the 5 points are measured in one direction (see screen shot). Around the central plane we have two additional slits with +/- 45° orientation with respect to the middle slit. These two profiles are used to simulate the 2D/3D representation of the beam. There is an additional broader slit in the central plane to enable knife-edge measurement of the profile in the focus.

• BeamMap-XY - 4 planes: The measurement head contains four XY slit pairs located on 4 different planes along the optical axis. During each rotation the XY profiles on each of the 4 points are measured. It is possible to display the XY profiles of each plane separately together with the resulting 2D/3D simulation or to display all four X or Y profiles at the same time.

The BeamMap is offered with Silicon-, InGaAs or InAs-detectors in the scanhead. Therefore it can be used from 190 nm - 3500 nm in total.

All our slits of the scanning systems are of true 2D design and are made using a lithographic process. They are suitable for highest power densities. The advantage of this design is to avoid any reflection or tunnel effect (multiple reflections within the propagation direction of the light, when measuring highly divergent sources).

Parameter:	Specification
Beam diameter:	Ø 0,5 µm to > Ø 3 mm (Ø 2 mm @ InAs)
Detector:	Wavelength range
- Si: (nm)	190 - 1150
- InGaAs: (nm)	700 - 1750
- extended InGaAs: (nm)	1000 - 2400
- InAs: (µm)	1 - 3.5
Diameter:	1/e2 / custom specific / Knife-Edge / 2.Moments (ISO 11146) / Gaussian fit
Resolution XY-Profiles & centroid:	0.1 µm or 0.05% of diameter
Accuracy:	± <2% or ± 0.5 µm
Focal position XYZ:	± 2 µm over 1 mm range in Z
Divergence:	± 1 mrad over ± 100 mrad range
M2 Measurement:	1 to > 20, ± 5%
Update rate: (Hz)	3.6
Max. power: (W)	1
Max. power density:	1 mW/µm^2 (lower at UV)
Opt. Dynamic range:	45 dB, automatic / man. Gain
Display:	XY Profiles / Centroid XY / M2 / Focal position / Divergence / Beam pointing
Analys. functions:	Pass-Fail / Averaging / Min-Max / Standard deviation
Control board:	USB
ADC: (Bit)	12