Raw Beam Measurement

Measuring device for the characteristics of the unfocused laser beam

The CameraMonitor 10.6 is a camera-based measuring system analyzing IR laser radiation at 10,6 µm wavelength.

  • Determinatoin of beam width and beam position based on the measured power density distribution
  • Intuitive grahical user interface
  • High dynamic due to a 14 bit A/D
  • Quartz-stabilized motor drive of the rotational axis
  • Power range 100 W - 20 KW
  • power density range 100 W/cm2 - 10 kW/cm2 >20kW
  • Different apertures matched to the applications between 40 mm and 100 mm

Application

The laser beam is scanned with a rotating mirror So a small part of the beam is faded-out and directed to the detector.During the motion of the mirror the incoming signal is digitized and transmitted to acomputer. The position of the scanning track is changed by a linear motion in y- direction. The 12 bit A/D- converters and a resolution of 128x256 pixel enables an exact analysis of even small pertubations. operation laser-induced variations of the beam parameters cause a decrease of processing quality and velocity. The exact analysis of the true reason is ordinarily rather complicated, since other phenomena like variation of the focal position or the nozzle's adjustment have similar errors. At this point a detailed analysis of the'raw' laser beam between outcoupler and focussing optics is a reliable method to detect variations of the beam diameter, bad mode-structure or wrong beam position.

With the BeamMonitor from PRIMES the customer gains the opportunity of quick and reliable diagnostics of the beam parameters. The BeamMonitor is a device to determine the spatial power density distribution of high power CO2- und Nd:YAG - Lasers.

The beam diameter and position are calculated from these data.

Technical description

The laser beam is scanned with a rotating mirror So a small part of the beam is faded-out and directed to the detector. During the motion of the mirror the incoming signal is digitized and transmitted to acomputer. The position of the scanning track is changed by a linear motion in y- direction. The 14 bit A/D- converters and a resolution of 128x256 pixel enables an exact analysis of even small pertubations.The device is designed for operation in rough industrial environments.

Technical data

BeamMonitor 40 mm


Beam Data to be acquired

  • Maximum power density (cw): dependent on scanning mirror design up to 10 kW/cm2
  • Clear aperture: 40 mm
  • Maximum beam radius (86 % = 1/e2): approx. 12.5 mm

Measurement System

  • Function: Two - dimensional scanner to determine power density distribution of the laser beam in x- and y plane by scanning a partial beam due to a rotating mirror. The complete beam transversed the device and needs to be trapped during the measurement cycle.
  • Dimension of the scalable measurement window: Range from 3.3 x 3.4 to 40.0 x 40.0 mm with a scaling factor of approx. 1.4
  • Spatial resolution: towards x (# of measured dots per track) 32, 64, 128, 256; towards y (# of tracks per image) 32, 64, 128
  • Mirror driver for x - axis: maintanance - free brushless DC - driver with quartz - stabilized speed - control.
  • Mirror driver for y - axis: Driver with absolute encoder and ball screw spindle
  • Measurement data digitizing: 14 - bit AD - converter
  • Measurement cycle: Standard measurement window with resolution of 64 x 64 (4096 dots): 2.5 s ; repetition rate approx. 0.2 Hz

Power supply and communication bus

  • Electrical power supply: 24 V DC ± 5 %
  • Current consumption: max. 1.8 A; standby consumption 0.4 mA
  • Electrical connectors: 2 x PRIMES - RS485 - bus D - sub - min
  • Communication: The incoming RS 485 bus - signal will be converted for the serial PC COM port. The PRIMES software with graphical - user - interface operates under Windows operating systems, like WIN 95/98, NT, WIN 2000, XP

Mechanical Dimensions

  • Dimensions (LxWxH): 243 mm x 146 mm x 76 mm ( plus connector)
  • Weight: 2,6 kg

Software

  • measuring results: beam radius (86 % and 2. moment), beam position, power density distribution, beam propagation factor M2
  • Modes: Single plane measurement, averaging, monitoring
  • Presentation: Isometry, false color, graphical cut, data table.
  • Formats: storage of PRIMES *.foc files or ASCII

BeamMonitor Options

  • Measuring at a fix y-position


Control and presentation

Control is realized by different user specific solutions such as: graphical user interfaces in Microsoft WINDOWSTM availiable as well as a direct connection to a SPC.For interface to a PC or SPC, the built in RS485- interface is used.The software has the following features:

  • Measurement parameters: beam radius (based on 86 % and 2nd moment calculation), beam position and power density calculated from a given power value in peak and 86 % - radius.
  • Measuring modes: single and serial measurement, temporal development
  • Presentation: Isometry, false color, contour lines and check of symmetry.

Beam Analysis System for CO2-Laser and -Systems

The CameraMonitor 10.6 is a camera-based measuring system analyzing IR laser radiation at 10,6 µm wavelength.

Application

The PRIMES CameraMonitor 10.6 forwards the benefits of camera-based beam diagnostics like real time measurements with high resolution at or near by the wavelength of the typical CO2-laser.

Due to its high resolution and sensitivity, the CameraMonitor 10.6 can be adapted by various attenuator- and optical imaging systems to a lot of different applications. For instance the following set-ups are possible:

  • Real-time monitoring of the beam shape at the rear mirror of a laser. 
  • Raw beam analysis within a laser machine. This can be done by using a beam splitter (diffractive or partial-reflective) within the beam path to monitor the beam shape in real-time.
  • Measurement of the  power density distribution and laser power at the raw beam, for example for use in field service
  • Spatial resolved investigation of the polarization of linear,- circular, radial or azimuthal polarized CO2 laser radiation
  • Determination of the beam  propagation parameter from the raw beam according ISO 11146. This is done by focussing the beam and characterizing the caustic. The propagation parameter of the raw beam can finally be recalculated.
  • Diagnostics of the focussed beam for diameter even below 100 µm and power density of more than 50MW/cm². This indeed requires a very sophisticated imaging and attenuation.  Due to the wide range of different focus geometries and the limited resolution of the IR- cameras this will need a special adaption of the set-up on each special application.

Technical description

The IR camera module includes the sensor core unit of the Camera-Monitor 10.6 provides up-to date technology of infrared-camera modules. It converts the laser radiation directly into an electronic signal using a 14 bit resolution.

The compact camera housing includes shutter and attenuator, control electronic and interface as well.

The CM-10.6 system can be connected via Ethernet to any PC or network. Data aquisition as well the presentation and analysis of results is done by the well established PRIMES LaserDiagnostics-Software. Available are various camera modules with spatial resolution from 80x60 to 320x240 pixel working with a repetition rate of 25 Hz.

Technical data

Relative Resolution 80 x 60 Pixel to 320 x 240 Pixel (different camera modules)
Pixel spacing 38 µm
Wavelength 10.6 µm, optional other wavelengths
Repetition frequency in video mode up to 25 Hz

Due to matched attenuation and beam imaging the following beam parameters will be visualized: 

 

Power range 1 mW to 10 kW
Beam dimensions 50 µm up to ca. 50 mm

Control and presentation

The control and representation take place with the proven PRIMES LaserBeamDiagnostic software

Compact Laser Profiler

The CameraMonitor 10.6 is a camera-based measuring system analyzing IR laser radiation at 10,6 µm wavelength.

  • fast and convenient
  • easy handling
  • practical design

Application

The new reference system for raw beam diagnostics of CO2 -Lasers is available now.

The BeamMonitor HQ terminates the era of “mode” burns in acrylic glass.
The new beam profiler enables fast high performance measurement with high accuracy. This is ensured by a high dynamics detector system.

Technical description

Measured Beam Parameter

•    Beam position
•    Beam dimensions
•    Beam symmetry

Modes of Operation

  • Service operation


The system is operated by a PC. In this case, it is possible to visualize the complete power density distribution.
The repetition rate of the measurement is limited mainly by the data transmission. With Ethernet-based communication a maximum repetition rate of 0.5 Hz is possible.

  • Remote operation


The BeamMonitor HQ is designed to run via different interfaces by the SPC of the laser machine. All the calculated beam parameters are available. This enables a direct monitoring of all beam parameters.

Technical data

Mechanics

50 mm aperture:
H x B x D:  183 mm x 138.5 mm x 63 mm (without connectors)

Weight:    1.5 kg

Interfaces

•    Ethernet (TCP/IP) DHCP
•    RS 485 / RS 232 - optional

Power supply

•    24 V and maximum 1 A

Maximum acceleration
(device not in operation):  4 g.
During operation no external force should be applied to the device.

The option LineScan enables the operation of the BeamMonitor HQ at a fix y-position. Then, single traces can be measured with a repetition rate up to 30 Hz.

Control and presentation

The BeamMonitor HQ is the perfect tool for the characterization of your laser beam. Its applications reach from monitoring during production to beam profiling during the adjustment of a laser resonator.

The mechanically-scanning system measures the spatial power density of collimated CO2-laser beams at full power.
Due to its compact design and low weight, the BeamMonitor HQ is optimized for service and machine integration.