Gentec-EO Beamage-M2 User Manual
WARRANTY
The Gentec-EO Beamage-M2 module carries a one-year warranty (from date of shipment) against material and/or
workmanship defects, when used under normal operating conditions. The warranty does not cover damages
related to battery leakage or misuse.
© Gentec Electro-Optics, Inc. 2014.
Beamage-M2 User Manual Revision 2.0 2
Gentec-EO Inc. will repair or replace, at Gentec-EO Inc.’s option, any Beamage-M2 that proves to be defective
during the warranty period, except in the case of product misuse.
Any attempt by an unauthorized person to alter or repair the product voids the warranty.
The manufacturer is not liable for consequential damages of any kind.
In case of malfunction, contact your local Gentec-EO distributor or nearest Gentec-EO Inc. office to obtain a
return authorization number. The material should be returned to:
Gentec Electro-Optics, Inc.
445, St-Jean-Baptiste, Suite 160
Quebec, QC
Canada, G2E 5N7
Tel: (418) 651-8003
Fax: (418) 651-1174
e-mail: service@gentec-eo.com
Website: www.gentec-eo.com
CLAIMS
To obtain warranty service, contact your nearest Gentec-EO agent or send the product, with a description of the
problem, and prepaid transportation and insurance, to the nearest Gentec-EO agent. Gentec-EO Inc. assumes no
risk for damage during transit. Gentec-EO Inc. will, at its option, repair or replace the defective product free of
charge or refund your purchase price. However, if Gentec-EO Inc. determines that the failure is caused by
misuse, alterations, accident or abnormal conditions of operation or handling, it would therefore not be covered by
the warranty.
Beamage-M2 User Manual Revision 2.0 3
Refer to the manual for specific Warning or Caution information to avoid any
damage to the product.
DC, Direct Current
SAFETY INFORMATION
Do not use the Beamage-3.0 or Beamage-M2 module if the device or the detector looks damaged, or if you
suspect that the Beamage-3.0 is not operating properly.
Note: This equipment has been tested and found to comply with the limits for a Class B digital device,
pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable
protection against harmful interference in a residential installation. This equipment generates,
uses, and can radiate radio frequency energy. If not installed and used in accordance with the
instructions, it may cause harmful interference to radio communications. However, there is no
guarantee that interference will not occur in a particular installation. If this equipment does
cause harmful interference to radio or television reception, which can be determined by turning
the equipment off and on, try to correct the interference by taking one or more of the following
steps:
• Reorient or relocate the receiving antenna.
• Increase the distance between the equipment and receiver.
• Connect the equipment to an outlet that is on a different circuit than the receiver.
• Consult the dealer or an experienced radio/TV technician for help.
Caution: Changes or modifications not expressly approved in writing by Gentec-EO Inc. may void the
user’s authority to operate this equipment.
SYMBOLS
The following international symbols are used in this manual:
Beamage-M2 User Manual Revision 2.0 4
TABLE OF CONTENTS
WARRANTY ......................................................................................................................................................................... 1
SAFETY INFORMATION ........................................................................................................................................................ 3
1. BEAMAGE-M2 ............................................................................................................................................................. 8
1.1. INTRODUCTION ............................................................................................................................................................... 8
1.2. SPECIFICATIONS .............................................................................................................................................................. 9
1.3. BEAMAGE- M2 TECHNICAL DRAWINGS ............................................................................................................................... 9
2. THEORY ..................................................................................................................................................................... 10
2.1. UNDERSTANDING THE M
2.1.1. Propagation Parameters ................................................................................................................................. 10
2.1.2. Practical Measurement ................................................................................................................................... 12
2.2. THE FABRY-PEROT INTERFEROMETER ................................................................................................................................ 12
3. HOW TO USE IT ......................................................................................................................................................... 13
2
FACTOR ................................................................................................................................... 10
3.1. “MOVING STAGE” CALIBRATION MODE MECHANICAL SETUP ................................................................................................ 13
3.1.1. Standalone Laser ............................................................................................................................................. 13
3.1.2. Final Adjustments ............................................................................................................................................ 14
3.1.3. Calibration ....................................................................................................................................................... 15
3.2. “CALIBRATION AT LENS” CALIBRATION MODE .................................................................................................................... 17
3.2.1. Optical setup and calibration .......................................................................................................................... 17
3.3. “REAL TIME” CALIBRATION MODE ................................................................................................................................... 21
3.3.1. Optical setup .................................................................................................................................................... 21
3.3.2. Final Adjustments ............................................................................................................................................ 22
3.3.3. Calibration ....................................................................................................................................................... 25
3.4. THE “M
3.5. THE M
3.6. THE M
3.7. M
3.8. M
3.9. OPENING SAVED M
2
MEASURES” TAB ............................................................................................................................................. 27
2
DISPLAY ........................................................................................................................................................... 30
2
CURVES DISPLAY ................................................................................................................................................ 32
2
BEAMS TAB ............................................................................................................................................................ 33
2
PRINT REPORT ......................................................................................................................................................... 37
2
MEASUREMENTS .............................................................................................................................. 39
3.10. LOAD/SAVE CALIBRATION SETTINGS ................................................................................................................................. 40
4. TROUBLESHOOTING .................................................................................................................................................. 41
4.1. READ THIS SECTION BEFORE ANY OTHER ............................................................................................................................. 41
4.1.1. Verify your alignment ...................................................................................................................................... 41
4.1.2. Verify that you are moving back your camera (Moving Stage Calibration Mode) .......................................... 41
4.2. M
2
RESULTS ARE NOT STABLE BETWEEN EACH CALIBRATION ................................................................................................... 41
4.3. BEAMS ARE NOT ALIGNED HORIZONTALLY ........................................................................................................................... 41
4.4. THERE ARE LESS THAN 10 VISIBLE BEAMS ........................................................................................................................... 42
4.5. THERE IS A CURVE IN THE ALIGNMENT OF THE BEAMS ............................................................................................................ 43
4.6. A BIGGER SPOT APPEARS IN THE ARRAY OF BEAMS ................................................................................................................ 44
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4.7. OVERLAPPING BEAMS .................................................................................................................................................... 45
4.8. BEAMS ARE TOO SMALL (LESS THAN 55 ΜM OR 10 PIXELS) .................................................................................................... 45
4.9. THE MINIMUM BEAM WAIST IS TOO FAR TO THE LEFT ............................................................................................................ 45
4.10. BEAMS AT THE EXTREMITIES DO NOT HAVE ENOUGH INTENSITY ............................................................................................... 46
4.11. BEAMS AT THE EXTREMITIES HAVE SMALLER DIAMETERS ........................................................................................................ 46
4.12. INFINITE VALUES (-1.#IO, -1.#IND00) IN THE MEASURES TAB ............................................................................................. 46
4.12.1. With “Moving stage calibration” mode ........................................................................................................... 46
4.12.2. With “Calibration at lens” and “Real time calibration” modes........................................................................ 47
4.13. RESULT FOR THE VALUE OF M
2
SMALLER THAN 1 ................................................................................................................. 47
4.14. THE THREE TIMES RAYLEIGH LENGTH ARE NOT ACHIEVED ON EITHER SIDE OF THE MINIMUM WAIST POSITION ................................... 48
4.15. LASER DIODE DOUGHNUT NOISE AT THE EXTREMITIES ............................................................................................................ 49
4.16. ASTIGMATISM APPEARS WHERE IT IS NOT EXPECTED ............................................................................................................. 49
4.17. THE SOFTWARE CRASHES OR REBOOTS AUTOMATICALLY ........................................................................................................ 49
4.17.1. Known software issue for the Real Time Calibration Mode ............................................................................. 49
4.17.2. The camera is not recognized when starting the software.............................................................................. 49
4.18. NO SOLUTION COULD RESOLVE MY PROBLEM ...................................................................................................................... 49
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TABLE OF ILLUSTRATIONS
Figure 1-1 Beamage-M2 Front and Side Views ..........................................................................................................9
Figure 2-1 Beam Propagation Diagram ................................................................................................................... 10
Figure 2-2 Schematic of the Fabry-Perot Optics...................................................................................................... 12
Figure 2-3 Time Delayed Spatial Slices (ROIs) ......................................................................................................... 13
Figure 3-1 Moving stage calibration camera setup with a Standalone Laser ......................................................... 13
Figure 3-2 Internal Adjustment Screws of the Beamage-M2 Module .................................................................... 15
Figure 3-3 Spots Seen With a Correctly Aligned Setup............................................................................................ 15
Figure 3-4 Moving Stage Calibration Mode Selection ............................................................................................. 16
Figure 3-5 M2 Moving Stage Calibration Mode ....................................................................................................... 16
Figure 3-6 Optical Setup for Step 1 of the Calibration At Lens Mode ..................................................................... 17
Figure 3-7 Save Beam Diameter for The Calibration at lens Mode ......................................................................... 18
Figure 3-8 Beam Diameter Saved Confirmation ...................................................................................................... 18
Figure 3-9 Optical Setup for Step 2 of The Calibration at lens Mode ...................................................................... 18
Figure 3-10 Calibration At Lens Mode Selection ..................................................................................................... 19
Figure 3-11 M2 Calibration Tab for the Calibration At Lens Mode .......................................................................... 20
Figure 3-12 Real Time Camera Mode setup with a Standalone Laser ..................................................................... 21
Figure 3-13 X-ADJ Screw alignment to rotate the beam around the first spot ....................................................... 22
Figure 3-14 Y-ADJ Screw alignment to change the distance between the spots .................................................... 23
Figure 3-15 Z-ADJ Screw alignment to change the distance between mirrors and then the optical path region .. 23
Figure 3-16 Internal Adjustment Screws of the Beamage-M2 Module .................................................................. 24
Figure 3-17 Spots Seen with a Correctly Aligned Setup .......................................................................................... 24
Figure 3-18 Send Diameter to M2 Real Time Calibration Mode .............................................................................. 25
Figure 3-19 Real Time Calibration Mode Selection ................................................................................................. 26
Figure 3-20 M2 Calibration Tab for the Real Time Calibration Mode ...................................................................... 26
Figure 3-21 M2 Measures Tab ................................................................................................................................. 27
Figure 3-22 Data Acquisition Tab ............................................................................................................................ 29
Figure 3-23 Start Data Acquisition Ribbon button .................................................................................................. 29
Figure 3-24 Acquisition File Example ....................................................................................................................... 29
Figure 3-25 2D M2 Display ....................................................................................................................................... 30
Figure 3-26 M2 Curves Display ................................................................................................................................. 32
Figure 3-27 M2 Beams with different intensities ..................................................................................................... 33
Figure 3-28 M2 Beams with peak exposure time .................................................................................................... 33
Figure 3-29 M2 Beams with multiple exposure time ............................................................................................... 34
Figure 3-30 Fixed exposure time ............................................................................................................................. 35
Figure 3-31 Multiple automatic exposure time detection and selection to see the first beam exposure time into
the displays .............................................................................................................................................................. 35
Figure 3-32 Multiple automatic exposure time detection and selection to see the tenth beam exposure time into
the displays .............................................................................................................................................................. 35
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Figure 3-33 M2 Beams configurations : Multiple automatic exposure time detection, multiple manual active
areas and selection to see the fifteenth beam exposure time into the displays .................................................... 36
Figure 3-34 M2 Beams configurations : Multiple automatic exposure time detection, multiple manual active
areas and removing of the sixth and sixteenth beams into the displays ................................................................ 36
Figure 3-35 M2 without beams 15 and 16 ............................................................................................................... 36
Figure 3-36 M2 Selective Beams configuration ....................................................................................................... 37
Figure 3-37 M2 Print Report Example ...................................................................................................................... 38
Figure 3-38 Open/Save File Controls ....................................................................................................................... 39
Figure 3-39 M2 Measures Tab ................................................................................................................................. 39
Figure 3-40 Save/Load Calibration Settings............................................................................................................. 40
Figure 4-1 X-ADJ Screw Alignment to Rotate the Beams Around the First Spot ..................................................... 41
Figure 4-2 Full rotation around the first spot .......................................................................................................... 42
Figure 4-3 Adjust Setup to Place the First Spot on the Left-Hand Side of the Screen ............................................ 42
Figure 4-4 Y-ADJ Screw Alignment to Change the Distance Between the Beams ................................................... 42
Figure 4-5 Minimum Beam Waist Too Far on the Left ............................................................................................ 43
Figure 4-6 Overlap Problem .................................................................................................................................... 43
Figure 4-7 Curve in the Alignment of the Beams .................................................................................................... 43
Figure 4-8 Top View ................................................................................................................................................. 44
Figure 4-9 Side View ................................................................................................................................................ 44
Figure 4-10 Reflection Problem ............................................................................................................................... 44
Figure 4-11 Overlap Problem solved with Y-ADJ ..................................................................................................... 45
Figure 4-12 The Minimum Beam Waist is Too Far to the Left ................................................................................. 45
Figure 4-13 Beams at the extremities have smaller diameters ............................................................................... 46
Figure 4-14 Moving Stage Calibration Measures .................................................................................................... 47
Figure 4-15 Moving Stage Calibration Optical Setup............................................................................................... 47
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1. Beamage-M2
1.1. Introduction
The M2 factor can be considered as a quantitative indicator of laser beam quality. In terms of propagation, it is
an indicator of closeness to an ideal Gaussian beam at the same wavelength. Paired with a Beamage-3.0 beam
profiling camera, the Beamage-M2 module can provide Real-Time M2 measurement directly in the PC-Beamage-
3.0 software. The calculations are based on the second order spatial moments and therefore are fully compliant
to the ISO 11146 and 13694 standards.
Unlike other M2 measurement systems, the Beamage-M2 can measure the propagation parameters of a laser
beam without the need of any moving part, providing calculation of the M2 factor in less than a second. This
condition allows the possibility to do on-line monitoring. Its modular design allows users who only want to
measure the energy or intensity spatial profile of their beam to remove the Beamage-3.0 from the M2 module
and use it as a simple beam profiler.
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MEASUREMENT CHARACTERISTICS
M2 Measurement
Real-Time ISO Compliant measurement with no moving parts
Rayleigh Length
50 μm - 6 mm after the lens
Setup & Alignment
Easy setup and alignment
System can be calibrated and ready to go within minutes
SETUP
Wavelength Range
190 nm - 1100 nma
(covered by interchangeable sets of optics)
Maximum Input Power
1 W
Minimum Lens Focal Length
110 mm
Built-In Attenuation (Included)
Fabry-Perot Reflective Glasses: OD4
Additional Removable Attenuation
User choice
PHYSICAL CHARACTERISTICS
Dimensions (Module only)
(64.1H x 77.3W x 97.6D) mm
Dimensions (With a Beamage-3.0)
(64.1H x 81.1W x 113.6D) mm
Weight (Module only)
535 g
Weight (With a Beamage-3.0)
674 g
Operating Temperature Range
10 °C - 30 °C
Operating Relative Humidity Range
5% - 80%
C-Mount Thread
Entrance Port
a
1.2. Specifications
Table 1-1 List of Specifications
1.3. Beamage- M2 Technical Drawings
Figure 1-1 Beamage-M2 Front and Side Views
Limited by the spectral range of the CMOS sensor. Accessories can be used to upgrade wavelength capabilities.
Beamage-M2 User Manual Revision 2.0 10
2. Theory
2.1. Understanding the M
The M2 factor, which is unitless, can be considered as a quantitative indicator of laser beam quality. It indicates
the deviation of the measured beam from a theoretical Gaussian beam of the same wavelength. It can
mathematically be defined as the ratio between the Beam Parameter Product (beam waist radius w0 multiplied
by divergence half-angle θ) of the measured beam with the theoretical Gaussian beam. Thus, for a single mode
ideal TEM00 theoretical Gaussian beam, the M2 factor is exactly one. Since an ideal Gaussian beam diverges more
slowly than any other beam, the M2 value is always greater than one. An M2 value very close to 1 indicates an
excellent beam quality. This is associated with a low divergence and a good ability to focus. Multimode lasers
have higher M2 factors.
2.1.1. Propagation Parameters
In the following equations, ‘’th’’ refers to theoretical values and ‘’exp’’ to experimental or real values.
The beam waist is defined as the location along the beam propagation axis where the beam radius reaches its
minimum value (see Figure 2-1). For a theoretical Gaussian beam, the beam radius wth(z) at any position z along
the beam axis is given by the following equation:
2
Factor
Where λ is the laser wavelength and w
As depicted by Figure 2-1, the theoretical Rayleigh length Z
between the beam waist and the position where the beam radius is times larger than the beam waist
(doubled cross-section).
Mathematically, it is given by the following equation:
the theoretical beam waist radius.
0th
is the distance (along the propagation axis)
Rth
Figure 2-1 Beam Propagation Diagram
Beamage-M2 User Manual Revision 2.0 11
Far from the beam waist, the beam expansion becomes linear and the theoretical divergence half-angle θth (half
of the angle shown in figure 2-1) can be obtained by evaluating the limit of the beam radius’ first derivative as
the position tends towards infinity:
For a laser beam that passes through a focusing lens of focal length f, the theoretical radius of the beam w
the focal spot of the lens can be obtained by multiplying the beam divergence half-angle with the focal length f:
As mentioned, all of the equations above describe theoretical ideal Gaussian beams. However, they can describe
the propagation of real laser beams if we slightly modify them using the M2 factor, which can be mathematically
defined by the following equations:
fth
at
With the mathematics, it is easy to understand why small M2 values correspond to low experimental
divergences and small experimental beam waist radiuses.
The experimental beam waist radius w
beam radius at the focal spot of the lens w
(z), the experimental half-angle divergence θ
exp
are therefore given by the following equations:
fexp
and the experimental
exp
We can now easily understand why small M2 values correspond to low divergence beams with small focus spots.
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2.1.2. Practical Measurement
In order to measure the M2 factor, multiple slices of the beam within and beyond one Rayleigh length along the
propagation axis must be considered. For each one, the second order spatial moment beam radius w(z) is
measured. A hyperbola, which recalls the beam radius equation, is then fitted with the results. The M2 value is
derived from that fit.
Since the distance range within which the measures must be taken is too large (could be several meters), the
use of a focusing lens is mandatory. It is also mandatory to comply with ISO standard. It helps compressing the
slices of interest around the focal spot of the lens.
2.2. The Fabry-Perot Interferometer
Within the device, the rapid measurements are done with the use of a completely passive optical system. Inside
the device, a pair of Fabry-Perot etalons, which is in fact an interferometer made of a pair of partially reflective
glasses, is positioned in front of the CMOS sensor of the camera at a convenient angle for the light to oscillate
and, with each round trip of the focused laser beam, creating a time-delayed and spatial offset of the light.
Figure 2-2 Schematic of the Fabry-Perot Optics
The adjustable distance between the Fabry-Perot etalons allows the measurement of beam waists for a large
range of focal lengths. Measurement is possible for any system that uses a lens with a focal length equal to or
higher than 110 mm. For shorter focal lengths, a focusing adapter is required. It can be mounted onto the
entrance port of the system.
Multiple time-delayed slices of the beam will land on the CMOS sensor, each one being a spatial cross-section
along the waist which is evaluated as a region of interest (ROI). The software will then simultaneously image and
analyze them for unparalleled speed and accuracy of M2 value calculation. When used at its highest resolution,
the Beamage-M2 works at 11 frames per second divided by the number of beams measured. This results in a
measurement of the M2 factor in about 1000 milliseconds. Adjustments can be made for the exact beam waist
to be contained within the multiple regions of interest generated by the camera and software. In the software,
the smallest slice should be located midway in the series of slices. For all systems to be correctly optimized, the
separation between each region of interest is uniform and dynamically adjustable.
Beamage-M2 User Manual Revision 2.0 13
Figure 2-3 Time Delayed Spatial Slices (ROIs)
Three methods can be used to measure the M2 factor. The first two methods consist of using only one Beamage-
3.0 camera and one Beamage-M2 module. The third method uses two Beamage-3.0 cameras and one BeamageM2 module.
3. How to Use It
3.1. “Moving Stage” Calibration Mode Mechanical Setup
The first method consists of the simplest optical setup. The Beamage-M2 module must be moved by a known
distance to calibrate the measurement. This method, although simple, has the highest uncertainty.
3.1.1. Standalone Laser
Figure 3-1 Moving stage calibration camera setup with a Standalone Laser
This section will guide you through setting up the necessary components for the M2 factor measurement with a
single camera and a standalone laser. The use of an optical table or breadboard is recommended to align the
optical elements.
1- Fix the Beamage-M2 module on the optical breadboard using a stand. It is also recommended to use a
short millimetric moving stage to help you move the camera back and forth along the propagation axis.
In a subsequent section, this will help you to calibrate the device accurately.
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2- Fix a Beamage-3.0 camera on the back of the Beamage-M2 module via the C-mount adaptor. Once the
adaptor is screwed upon the camera, insert it in the Beamage-M2 module and use the small setscrew
located on the side of the module to fix the camera in place.
3- Determine how much attenuation you need on the module to avoid destruction and saturation of the
CMOS sensor. Please note that the Fabry-Perot reflective glasses offer an OD4 built-in attenuation.
Optional ND4, ND0.5 to ND5.0 attenuators are also offered. If a greater attenuation is needed to avoid
overheating of the optics, additional partially reflective glasses can be C-mounted onto the aperture of
the Beamage-M2 module.
4- Place a converging lens adapted for your laser in front of the Beamage-M2 module. The lens must be
chosen so that the beam has a Rayleigh length between 50 μm and 6 mm after passing through the lens.
The adjustable distance between the Fabry-Perot etalons allows the measurement of any system using a
lens with focal length equal to or higher than 110 mm. Ideally, the Bemage-M2 module should be
positioned such that the Beamage-3.0’s CMOS sensor is located slightly after the focal length of the lens.
5- Fix the lens in front of the laser. The lens must be at a distance greater than three times the Rayleigh
length from the laser to be in the linear portion of the propagation. If the lens is not positioned
accurately, it will not be possible to have the minimum diameter halfway through the series of spots
displayed in the software.
6- Make sure that the laser, the lens and the Beamage-M2 module are correctly aligned. The laser should
be aimed at the center of the lens and the aperture of the Beamage-M2 module.
Note: If you want to simultaneously monitor your laser system, you can place a beam splitter in the laser path in
order to have a pick off of the laser beam.
3.1.2. Final Adjustments
This section will guide you through the final adjustments on your setup. It is applicable to all kinds of lasers.
1- Connect your Beamage-3.0 camera to your computer, run the PC-Beamage-3.0 application, select your
camera and click Start Capture.
2- If your setup is correctly aligned, you should see some spots already in the software display. The camera
has a preliminary factory adjustment. If not, slightly move the optical components until you see spots.
3- For internal adjustments, use the three screws that are on the side of the module. Here are their
functions:
a. X-ADJ: mirror orientation to adjust the distance between the spots
b. Y-ADJ: mirror orientation to adjust the orientation of the spots (rotation around the first spot)
c. Z-ADJ: adjusts the distance between the Fabry-Perot etalons
Beamage-M2 User Manual Revision 2.0 15
Figure 3-2 Internal Adjustment Screws of the Beamage-M2 Module
4- The system is correctly adjusted once you see a profile similar to the figure shown below. A narrow and
tall spot should be surrounded by smaller and larger spots.
Figure 3-3 Spots Seen With a Correctly Aligned Setup
5- For ISO compliant calculations, at least 10 spots should be detected. Approximately half of the spots
should be distributed on one Rayleigh length around the beam waist and the other half should be
distributed three Rayleigh lengths around the beam waist.
3.1.3. Calibration
Now that your setup is ready, it is time to calibrate it and to make your first M2 measurement.
1- If it is not already done, run the PC-Beamage-3.0 software.
2- Before working in the M
2
mode, the steps listed below must be followed:
2.1- The active area should be at full resolution (2048 X 1088 pixels)
2.2- There should be no pixel addressing (set to ‘’none’’)
2.3- A background subtraction should be performed
3- Click the M2 mode button in top ribbon and choose Moving Stage Calibration Mode.
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