The CCD camera of the BC100 Series features a windowless sensor, which allows measurements without any intermediate optics. To access the sensor, the ND filter can be unscrewed.

Beam Profiler Features

• High Resolution: 1,360 x 1,024 pixels
• Low Noise: S/N > 62 dB
• 12 Bit CCD Camera
• Large Windowless Sensor Area (8.8 mm x 6.6 mm) for Best Uniformity and Linearity
• Full 2D Analysis of Complex Beam Profiles
• User Calibratable Power Readout
• Auto-Exposure from 20 µs to 1 s and Gain Control from 1x to 16x
• Black Level and Ambient Light Compensation
• For CW, Pulsed* Laser Beam, and Single Pulse Analysis
• External Shutter Trigger Input
• Optional M² Extension Kit for Automated M² Analysis

Software Features

• Versatile Graphical Interface with Easy-to-Adjust Sub-Windows
• Cross-Sectional X and Y Profiles at Adjustable Locations
• 2D Power Density Diagram with Elliptical Beam Fit, Flexible 3D Graph
• Total Beam Power Over Time Plots
• Analysis of Centroid Position Drifts
• Image and Text File Output with Sequential Saving Option (New)
• Pass/Fail Analysis
• Module for Automated M² Beam Quality Measurements
• Hot Pixel and Ambient Light Corrections for Higher Accuracy (New)
• Configurable Profile Colors (New)

The BC106 Series of camera-based beam profilers offers more details and true 2D analysis of the beam's power density distribution when compared to scanning slit profilers. This allows complex mode patterns (like flat top and donut) to be identified while optimizing the laser systems. The BC106-VIS is designed for use in the 350 - 1100 nm spectral range while the BC106-UV is meant for use with UV beams outputting between 190 and 350 nm. When used together with the BC1M2 Series M² Extension Set, an automated M² beam quality analysis system can be built. The BC106 ships with a versatile software and driver package. For screenshots and details see the User Interface tab or the Software tab.

BC106 Series are suited for use with either continuous wave or pulsed* sources of any frequency. Several trigger modes allow flexible capturing of single pulses. A TTL input is provided for triggered single pulse detection up to a repetition rate of 50 kHz.

The BC100 Series of beam profilers incorporate a high-quality 12-bit CCD camera with a large windowless sensor chip (active sensor size: 8.8 mm x 6.6 mm) having a resolution of 1.4 Megapixel (1360 x 1024 px). Compared to lower priced CMOS profilers, the features of the CCD camera chip of this profiler offer the following advantages:

• Excellent sensitivity and low noise
• An enhanced global shutter efficiency for improved exposure accuracy and uniformity
• Automatic dark level calibration for very stable dark currents independent of the device settings. This avoids recalibration of the dark level for each user setting.

An integrated filter wheel with 4 different high-quality ND filters allows the profiler to be adapted for use with beam intensities from µW to W. The BP106-VIS includes 10, 20, 30, and 40 dB filters and the BP106-UV includes 20 and 40 dB (Visible); 20 and 40 dB (UV). The internal SM1 (1.035"-40) thread of the additionally included adapter SM1BC allows direct connection to Thorlabs' lens tube system and mounting of optical components such as additional attenuation filters. The mounting adapter shields ambient light from the Beam Profiler Aperture which is advantageous in low power applications.

The integrated power meter can be user calibrated and is perfectly suited for simultaneous power and beam shape optimization without the need for an external power meter. A previously measured mean value of the ambient light intensity is subtracted from the measured value so as to compensate for ambient light. The Automatic Exposure and Gain Control feature adapts the camera settings to the actual beam intensity. The hi-speed USB 2.0 interface allows up to 10 full frames per second at full resolution. Measurements at higher frame rates can be achieved and transferred with reduced frame sizes, i.e. Region Of Interest (ROI).

*Damage threshold data is currently not available for our beam profilers. For use with pulsed lasers, we recommend the following procedure as a guideline for determining a safe upper limit: Set the beam profiler to the maximum integration time (i.e., set the exposure to 1 s). Slowly increase the power until your signal fills approximately 50% of the sensor's dynamic range. Multiply this power by a factor of 10. This is the safe upper pulsed power limit for the beam profiler.

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Note: The BC106-UV sensitivity is given throughout 1100 nm but shows increased non-uniformity and noise compared to BC106-VIS at longer wavelengths, outside of the 190 - 250 nm operating wavelerngth range.

Software Features of the BC106 Series Beam Profiler

Thorlabs Beam Software - Graphical User Interface

GUI Overview

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The GUI consists of a toolbar and specific windows for the different analysis options. These arrangement of these windows can be changed. They can be resized, opened, and closed as needed.

Multilanguage GUI

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For German and Chinese operating systems, localized language versions are built in and automatically used.

Measurement over Time

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This screen analyzes the drift of the centroid X and Y coordinates as a function of time to visualize drift patterns of a laser source. An ideal source shows horizontal lines for the X and Y coordinate. Additionally, "Power," "Gaussian Fit," and "Ellipse Orientation" can be plotted as a function of time.

Beam Stability Measurement

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This screen shows the path of the centroid position drift in X and Y coordinates to visualize beam pointing instabilities of a laser source. An ideal source shows a single point.

Distance Measurements

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In the 2D projection screen, distances can be measured by drawing a line between two points of interest.

Pass/Fail Analysis

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A selected set of calculation results is evaluated according to user-defined minimum and maximum limits. This Pass/Fail analysis is especially useful for high-volume production tests.

Sequential Saving

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Aside from the option to save single measurement results, diagrams, and device data, the software can sequentially save these automatically.

Color Schemes

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The color scheme of the 3D power distributions can be choosen from a set of predefined schemes with linear, logarithmic, or quadratic scalings. Custom schemes allow the user to optimize the display.

M² Measurements

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The beam diameter and location of the beam waist are shown after an M² analysis has been performed.
Note: This functionality is only enabled when either the M2SET series analysis set or the BP1M2 series extension set is connected to the PC.

Divergence Measurements

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The divergence of the beam is shown after an M² analysis has been performed.
Note: This functionality is only enabled with either the M2SET series analysis set or the BP1M2 series extension set is connected to the PC.

Software Packages for Thorlabs' Beam Profilers:

There are two complete software packages available for download below.

Software

Version 5.0

Standard full version of software package for 32 bit and 64 bit Windows with driver and graphical user interface for operating the device in standard applications.

OR

Advanced Beta Version*

Version 5.0.561.1304 (April 2, 2013)

Full software version software application with latest bug fixes:

• Calculation cluster in the Thorlabs Beam Library Wrapper adopted to the latest calculation result structure.

*This release candidate software version, which incorporates new features and/or bug fixes as outlined in the change log file on the download page, has been through several rounds of testing and there are currently no significant bugs. Once full testing and documentation is available, this version will become the standard software package. In the interim, Thorlabs is making this complete software file available for those customers whose research endeavors would benefit from the updated features.

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The optional BC1M2 Series M² Analysis Extension Set allows automated, motorized, computer-controlled M² analysis with our BC100 Series Camera Beam Profiler (sold separately). The Extension Set includes the motorized translation stage, plus mounting accessories to mount a BC100 Beam Profiler onto the stage. The set is available with two different travel lengths: 150, and 300 mm. The translation stage is controlled by the M² software module of the BC100 Series Camera Beam Profiler via RS232. A USB port can be used optionally with the included adapter. No additional driver is required. To build a complete system consisting of a BC106 Series Beam Profiler, a BC1M2 extension set, and accessories for beam alignment, please see the M² Set Config and the M2 Accessories tabs or consult the manual.

To truly characterize a laser beam, more than a single profile has to be measured along the propagation axis of the focused beam under test. According to the ISO11146 standard, 10 different z positions shall be taken. Approximately half of the measurements shall be distributed within one Rayleigh length on either side of the beam waist, and approximately half of them shall be distributed beyond two Rayleigh lengths from the beam waist. The BC1M2 Set can easily make all the required measurements.
During operation, the profiler is automatically moved, step-wise, along the beam path and analyses the beam at various positions. The beam quality is determined via curve fitting of the beam diameter versus profiler position. To perform the tests, the laser beam under test has to be aligned with the translation path of the stage and focused within a certain divergence angle. The divergence angle of unfocussed nearly parallel beams can be accurately determined by a Divergence Measurement, which is based on a linear curve fit.

The BC100 Series Beam Profiler and any other necessary components for beam alignment and adjustment have to be ordered separately. A power supply and serial cable are included with the extension set. Each BC100 Series Profiler includes a software package* with an easy to operate Graphical User Interface (GUI). Version v5.0 or newer fully supports automated M² measurements as well as basic beam profiling measurements and can be downloaded for free.

*The M² software included in the BC106 software package is v5.0 or newer. Please download an update if your software is older.

How To Configurate an M² Analysis System

A BC100-based M² Analysis system is made up of a BC100 Series Camera Beam Profiler, a BC1M2 series M² extension set, and optical components to align and focus the beam onto the camera profiler. The following guidelines aid in selecting the optimal focal length of the focusing lens and the optimal length for the translation stage of the BC1M2 Series Beam Analysis Extension Kit. The M2 Accessories tab provides a list of accessories (e.g., lens holders and some beam alignment mirrors) that we suggest for a typical M² analysis system.

Selecting the Focal Length

Figure 1 shows the minimum focal length as a function of wavelength for four beam diameters (500 μm, 1 mm, 2 mm, or 3 mm). Find your operating wavelength along the x axis, go up to the curve representing your initial (unfocussed) beam diameter, and read off the minimal required focal length. When between offered focal lengths for the collimating lens, round up to the next available focal length (100 mm, 150 mm, 200 mm, ...). Longer focal lengths generate waist diameters above 100 μm and relax the measurement requirements for the beam profiler. Be sure to order the appropriate AR coating.

Selecting the Length of the Translation Stage

It is advisable (but not necessary) that the translation stage length is at least as long as the focal length of the focusing lens. For a correct M² measurement, the translation range has to be at least 5 times the Rayleigh length of the focused beam to cover both the beam waist and the neighboring divergent beam propagation. The Rayleigh length depends strongly on the generated waist diameter and also linearly increases with M². Therefore, the translation range needs to be longer when measuring beams with poor beam quality (M² >> 1).

Figure 2 shows the minimum required stage length to achieve a measurement of M²=1 for four expected waist diameters (75 µm, 100 µm, 125 µm, and 150 µm). Find your operating wavelength along the x-axis, go up to the curve representing your expected waist diameter, and read off the minimal required translation range. Multiply this result with the highest expected M² value of your laser source, and round up to the next available translation stage length (150 or 300 mm). Please note this length is a minimum requirement for M² detection.

If using the shorter 150 mm stage, it may be necessary to reposition the beam profiler for different applications so that the profiler has sufficient stage length to move about the beam waist position. Therefore, the longer 300 mm stage is recommended for universal setups that require the use of various laser types, beam diameters, wavelengths, M² values, and focal lengths since the beam profiler itself can move significant distances without running out of translation range. In addition, the longer stage allows one to analyze the beam divergence on either side of the beam waist without needing to relocate the stage to a different position.

Theory Section

Focal Length
The generated beam waist diameter d₀ must not decrease below the minimum measurable beam diameter (30 µm for ellipse approximation) of the Beam Profiler. The beam waist diameter d₀ is given by:

To fulfill the minimum beam waist diameter for a given wavelength while providing the highest focusability (M²=1), the divergence angle θ must not exceed a maximum value θ_max:

Depending on initial beam size d_init, a minimal focal length f can be calculated:
(Please refer to Figure 1 for help selecting your collimating lens.)

Translation Stage Length
For optimal M² detection, the translation range should be at least 5 times the Rayleigh length of the focused beam to cover both the beam waist and the neighboring divergent beam propagation. Minimal translation stage length is:

L_min = Minimum Required Stage Length
z_R = Rayleigh Length
M² = Highest Expected M² Value
λ = Operating Wavelength
d₀ = Beam Waist Diameter

Figure 1: The photo above shows a typical M² analysis system built with a BC106 Series camera beam profiler and a BC1M2 Series M² analysis extension set. The shown optics, optomech components, and breadboard are not included and must be ordered separately.

Suggested Accessories for Building an M² Analysis System

Depending on existing lab equipment available, additional parts may be required to control the laser beam for the M² measurements. To focus parallel laser beams, you will need an appropriate focusing lens and holder. Additional beam alignment and redirection tools may be required to align your laser beam to the M² setup. See the typical setup of a complete M² analysis system including optional accessories on the right.

The following table suggests a typical setup for an M² measurement. Note that the listed Aluminum Breadboards (MB824 and MB824/M) are well suited for use with the shorter 150 mm stage but are too short for the 300 mm stage. For the 300 mm stage, we recommend an MB836 (imperial) or an MB2090/M (metric) breadboard.

Please note that the necessary focusing lens is not listed above because it will depend on the laser beam diameter. In addition washers and screws are needed to fix optical elements. Depending on the application, alternative components such as larger posts or different mirrors could be more useful than the suggested ones. If you have any questions, please contact us.

The following formula gives the shortest lens focal length lens that should be used to ensure a reliable measurement assuming that the beam diameter will not be less than 100 µm at the focal point:

Here d_beam is the beam diameter of the laser system and λ is the operating wavelength. Round the focal length up to the next available value if necessary. Longer focal lengths generate waist diameters greater than 100 µm and relax the measurement requirements for the beam profiler. In general, a focusing lens with a focal length between 100 mm to 150 mm is quite common; this focal length will work well with laser beam diameters between a few hundred microns and a few millimeters. Be sure to order a lens with the appropriate AR coating.