Other Equipment

Measuring position and dimension of the focus

The LaserQualityMonitor (LQM) is a perfect measurement system for the charaterization and qualification of the beam propagation of lasers in the range of UV to NIR.

• Laser development
• Quality assurance in production of laser sources
• Service and maintenance

Application

The LaserQualityMonitor (LQM) is a perfect measurement system for the charaterization and qualification of the beam propagation of lasers in the range of UV to NIR.

Furthermore, errors in the optical assembly of resonators and beam guiding systems are easily analyzed.

Typical areas of application are:

• Laser development
• Quality assurance in production of laser sourcesn
• Service and maintenance

all cw and pulsed laser sources in the wave length area of 248 nm to 1100 nm with medium power from ca. 1 mW up to multi-kilowatt ranges with an M²- ranging from 1 to ca. 50. The beam diameter at the aperture of the measuring system can vary in the range of 1nm to 15mm.

Technical description

The LaserQualityMonitor measures the laser power density directly in contrast to many other devices on the market. The advantage of the measuring system is direct visualization by diffraction patterns, misalignment, asymmetry and other effects. A focussing lens is integrated.

In short time, the LaserQualityMonitor chacaraterizes the beam parameters of a beam source automatically in accordance with ISO 11146. Results are:

• Beam waist diameter
• Focus position
• Far field divergence
• Rayleigh -length
• · Beam propagation factor K and M² value

The LaserQualityMonitor is a compact measuring system, easily adjustable. It is positioned directly in front of the laser and is aligned to the laser beam. You will find that characterizing your raw beam is a piece of cake!

In essence, the LaserQualityMonitor consists of a basic system. Within this system, all optical components and measuring functions are completely integrated. It is possible to expand this basic system by an attenuator (with integrated beam splitter, absorber and alignment unit ) to extend the power range into the kW area.

If required, fiber optic holders, neutral density filter elements as well as additional measuring lenses are available.

On request, fully integrated laser class 1 gaging stations are available, as well.

Technical data

Measurable beams

• Beam diameter: 1 mm to 15 mm
• Spectral range: 248 nm to 1100 nm
  Max. power: 1 W bis 10 kW (depending on configuration) 
  Max. energie densitiy: damage threshold of the measuring optics 3 J/cm ² at 10 ns pulse length
  Max. power densitiy: 100 kW/cm²) in cw-operation
• Pulsed laser: 
  - max. 25 kHz single-pulse in trigger-operation
  - from 100 Hz in continuous mode

Features of the measuring system

• CCD-chip acquires a two-dimensional power density distribution of the laser beam in xy- plane.
• Applicable optical attenuators 0-100 dB
• Measuring range: x-, y- direction: size range of the measuring window depends on sensor and objective: 0,03 mm to 4,0 mm
• Window size adapted in a increment of 1,4
  z-axis length: 280 mm
• Lateral resolution: in x- direction (numbers of measuring 
  points per trace) 32, 64, 128, 256
  in y-direction (numbers of lines per image)
  32, 64, 128 256 up to 0,5 ìm per pixel diffraction limited by the objective
• Stages of the system in x, y, z- axes: Motor with encoder and ball screw drive
  Digitalization of the measured data: 12 Bit A/D- converter
• Measuring time: Standard window with 64 x 64 pixels: 100 ms 
  Repetition rate of repetitive measurements app.: 5-10 Hz in video mode
• Conversion of the beam data of the focus into beam parameter of the raw beam

Electrical Supply

• Voltage: 24 V DC ± 5%
• Power input: maximum 1,8 A in standby: 0,4 A
• Electrical pins: 1 PRIMES- RS485 bus (D-sub-min) and 1 Ethernet

Communication

• Ethernet or serial communication For communication with the PC by serial communication the data is converted from RS485 to RS232. The Software uses a graphical user interface executable under Windows 95/ 98/ 2000/NT/ XP

Mechanical Dimensions

• Dimensions: (width x height x depth) 285 mm x 150 mm 
  x 130 mm (plus plug) Weight: 5 kg

Software LDS

• Measurement categories:
  Beam radius (86% and 2nd moments), beam position, power density, beam propagation ratio M²
• Measurement functions: 
  Single measurement, automatic caustic measurement, average, monitoring
• Presentation:
  Isometry, false miscolors, contour lines, caustic, overview, symmetry check
• Data format:
  Saving in PRIMES-format (binary) or MDF file format (ASCII)

Control and presentation

The characterization of a freely propagating laser beam with a Rayleigh length of app. 10 m takes quite a lot of effort. The reasons for that are long measuring ranges of typically 3 to 6 Rayleigh lengths. Frequently, such a measurement is completely impossible for lack of space. Therefore, ISO 11146 recommends to measure a artifical generated caustic alternatively. Thus, it is possible to determine M². The problem of space can be solved by focussing the laser beam and subsequent characterization of the focussed laser beam. This way, the measuring ranges can be shortened from a few meters to a couple of millimeters. Therefore, the M² value can be determined easily assuming that the used optics do not create any aberration. For the back - calculation of the beam parameters, it is extremely important to know the exact properties of the focussing lens. A simple laboratory setup usually does not allow to determine these properties with the required precision. 
With the LaserQualityMonitor, PRIMES offers an integrated solution for fast and easy analyzis of the beam properties of a laser.
To do this, the laser beam is focussed by a multi-lens optics within the LQM. This focus is scanned by a measuring objective and a CCD-sensor which more along the beam propagation direction (z- axis).

To measure the polarization of high power laser

• Measuring tool for characterization of the degree and angle of polarization

Application

Polarization dependent effects during material processing with CO₂- lasers are well known. An example for this is shown in figure 1: the dependence of welding depth as function of the welding velocity. Two curves are shown for p- and s- polarization (plane of polarization parallel (p) and perpendicular (s) to the plane of incidence). As can be seen, especially for high welding velocities (> 3 m/min) there is a considerable difference between the welding depths for s- and p- polarization.

Also in laser cutting processing results and processing velocity depend on the degree and the angle of polarization.

These phenomena lead to processing results which are strongly dependent on the processing direction.

So it has become common to use phase retarders, to avoid any dependence of system's performance on processing direction during cutting and welding. These phase retarders transfrom linear polarized radiation into circular polarized radiation.

Theoretically every dependence of processing direction due to polarization should be eliminated. But in practical application it is very difficult to check the real polarization degree of the beam.

Technical description

Polarization is measured by the rotating four special coated mirrors. Depending on the orientation of the polarization the mirrors absorb 99 % of one polarization direction and reflects 99 % of the perpendicular direction. With this assembly a high contrast for analyzing the polarization is obtained.The laser beam is attenuated by two beam splitters. The angle between the two beam splitters is selected in such a way to avoid a change of the polarization state of the transmitted beam. The transmitted power is only 25 ppm of the incoming beam.The laser power which is reflected by the mirrors is focused by a lens on the detector. During the rotation of the mirrors the measured power and the angle of the mirrors are recorded.

Technical data

• Dimensions (Height, Length, Width): 420 mm x 150 mm x 150 mm
• Apertur : 55 mm
• Power range : up to 2 kW
• Maximum Power Density : 2 kW/cm²
• Degree of Polarization :
  ±1 % absolut for the range of 0 % - 20 % 
  ±2 % absolute for the range of 20 % - 40 %
  ±4 % absolute for the range of 40 % - 100%
  
  
• Direction of Polarization :
  ±2° for linear polarized beam
  
  
• Power supply : DC 24 V and 0,5 A
• Electrical connectors : 2 x PRIMES-RS485-bus (9-pin D-sub-min)

For industrial multi kilowatt applications

• air- or water-cooled systems
• Power: water-cooled systems: > 12 kW, air cooled systems: up 4 kW
• Power densities: plain absorber up to 1,2 kW/cm², inclined absorber up to 6 kW/cm²
• can be used directly beneath the processing area

Application

Somtetimes it is required in material processing to absorb the laserradiation bedind the focal point.

Laser sources working with mechanical a shutter need o beam dump.

Technical description

A highly absorting coating enables to dissipat laser power even in the multi kilo watt range.

The coating work also for Nd:YAG - laser radiation even with reduced efficency.

Technical data

Air-cooled Plates absorbers

Water-cooled plates absorbers

• Maximun density: 1,0 kW/cm²
• Maximun power: 10 kW
• Aperture: 120 x 88 mm
• Specific features: small setup (Thickness 20 mm)

V-Absorber - Model V80S

• Maximum density: 6 kW/cm²
• Maximum power: 12 kW
• Aperture: 50 mm Diameter
• Specific features: Reflexion < 0,5 % at 0.8 - 1.1 µm

V-Absorber 40 - Modell V40M2B

• Maximum density: 6 kW/cm²
• Maximum power: 6 kW
• Aperture: 40 mm Diameter
• Specific features: Reflexion < 0,5 % at 0,8 µm - 1.1 µm

V-Absorber 40 - Modell V40M2

• Maximum density: 6 kW/cm²
• Maximum power: 8 kW
• Aperture: 40 mm Diameter
• Specific features: Reflexion < 0,5 % at 10.6 µm

Welding-Absorber

• Maximun Density: 6 kW/cm²
• Maximun power: 12 kW
• Aperture: 80 x 45 mm
• Specific features: Connection lead for exhauster

Diodes ingots-Absorbers

• Maximun density: 4 kW/cm²
• Maximun power: 12 kW
• Aperture: 250 x 50 mm
• Specific feature: particularly suitably for pump modules

Power-Absorber

• Maximun density: 15 kW/cm²
• Maximun power: 8 kW
• Aperture: 48 mm Diameter
• Specific features: Reflexion < 0,5 %

Blower absorber

• Maximun density: 1,5 kW/cm²
• Maximun power: < 3,5 kW
• Aperture: 100 x 100 mm
• Specific features: no water connection , temperature dependent trick number of regulation

for integration into laser system

The BeamControlSystem is designed for the measurement of the most significant beam parameters in the field of industrial produc-tion. Not only the laser power but also the focus spot geometry are determined by the system which is completely dustproof.

Application

This integrated system includes the functio-nality of  three PRIMES products:

• FocusMonitor
• CompactPowerMonitor
• Profibus-Interface

Therefore, it is ideal for the integration into a laser system.

The combination device is completely dust-proof. In the stand-by mode the beam entrance is sealed by a pneumatic shutter. This ensures a steady protection of the measuring devices from pollutions in rough industrial environments. 

Features of BeamControlSystem:

• Power measurement up to 10 kW
• Focus analysis from 0.2 mm to  3 mm
• Power density in the focus up to  10 MW/cm2 (@ 800 nm tos 1100 nm)
• Wavelength ranges: 800 to1100 nm, or 9 to 11 µm
• PLC Interface enabling  the communication with laser- or system-control
• Script-controlled, automatic measurements
• Observation of limit values for beam parameter
• Dust-proof housing
• Electro-pneumatic shutter

Technical description

Using script control, a feature of the PRIMES LaserDiagnosticSoftware, enables a fully automated analysis of the laser power as well as the focus geometry. 

The EVALUATION function enables a comparison of the measured data with prescribed limiting values. Corresponding alarm signals are then passed on to the laser - or system -control. Altogether, it allows a fully automated observation of the beam parameters. 

Controlled beam parameters:

• Laser power, typ. ± 3 %
• Focus position in z, app. 10 % zR
• Focus diameter, app. ± 5 %
• Rayleigh length, app. ± 5 %
• Beam parameter product, typ. ± 10 %
• M2, app. ± 10 %
• Ellipticity, typ. ± 10 %
• Astigmatism, typ. ± 10 %
• Beam pointing z, typ. ± 0,2°

Technical data

Automated Beam Control in Production with High Brightness Multikilowatt NIR-lasers

The HighPower-MSM-I is designed to work in rough industrial environment: automated beam monitoring in continious working manufacturing facilities.

Application

Beam power, focus position laterally and in depth, focus geometry in form of diameter, divergence and Rayleigh length, beam parameter product and M² as well as further derived parameters can be monitored. The measured values are compared to preset limit- and critical values. Hence, an alarm is generated.
Fully automated measuring programs are running using the communication between system control and laser source. The measuring results are given back to the system control with a corresponding evaluation. All measuring results and status parameter of the measuring decive can be saved with a special timestamp.

Besides an automated beam parameter measurement within a production environment, the device is also suitable for the qualification and verification of beam parameter of beam sources, laser machines and processes in development, production, maintenance and service.

Technical description

The device is provided with a comprehensive internal  sensoric for self controlling  and for identification of internal malfunction sources. Additionally, a further port for a secondary light conducting cable enables an automatic testing of all measuring functions and the status of the internal optics. A power measurement test can be done due to a  corresponding internal heat source.

Technical data