Thorlabs' dual scanning slit Beam Profiler is easy to align and features fast simultaneous measurement of both the X and Y profiles with a large dynamic range of 72 dB. The beam diameter is measured in accordance with the ISO11146 standard. The diameter of the beam can be displayed using a number of industry standard clip levels such as 1/e² (13.5%) and 50% or an arbitrary clip level input. Please see the User Interface tab above for more details on the functionality of the software.

The system is available in 4 wavelength ranges: UV 200-1100 nm, VIS 400-1100 nm, IR 700-1800 nm, and IR 1000-2700 nm. Additionally, two slit and aperture sizes are offered: BP104 models have a physical aperture diameter of 4 mm and can accommodate beam diameters as small as 10 µm (1/e²), while BP109 models have a physical aperture diameter of 9 mm and accommodate beam diameters as small as 20 µm (1/e²). The operating principles are detailed on the tab provided above and labeled "Operation."

A variable scan rate of up to 20 Hz allows for real time optical system alignment. Both beam parameters and spatial power distribution can be monitored in dynamically changing systems. To obtain absolute optical power measurements, the user can perform a calibration using the integrated power meter and software and applying a calibration measurement at the wavelength of interest.

The Beam Profiler can work directly with a connected PC with no additional hardware or power supply required. For ease of use, Thorlabs utilizes a Hi-Speed USB2.0 interface to connect the measurement head with user supplied PC. Flexible data export options and the readout option via TCP/IP to standart data socket servers ease the integration into customized data processing environments.

Pulsed Laser Beams

The beam profile of pulsed laser sources with repetition rates of 10 Hz or higher and of any pulse widths can be measured. Several scans of the XY slit pairs are used to reconstruct the complete beam shape. Synchronization is done by manually adjusting the scanning speed to very close to an integer fraction of the laser’s repetition frequency. See Operations Manual for a detailed description. For M² measurements the minimum pulse repetition rate is >= 300 kHz.

Each Beamprofiler comes with the following parts:

• BP100 Series Profiler Head
• USB 2.0 Connection Cable, 2 m
• Beam Profiler Software CD ROM with GUI software package and LabVIEW™ and LabWINDOWS™ /CVI Driver Set
• Printed Operation Manual

* BP109-UV, -VIS, -IR: beam diameter error <10% at 9 mm beam diameter, BP109-IR2: beam diameter error <20% at 9 mm beam diameter for beam divergence <5°
** Using one of the M² Options

The upper limit on optical power with respect to the instruments' saturation level is related to the intensity (power per unit area). Therefore, the maximum power acceptable to the device is dependent on the width of the beam being measured. As depicted below, the measurable power range depends on both the model used (slit size and sensor type) as well as the width of the beam measured.

The graph shows the power ranges, indicated on the vertical axis of the graph that can be measured as a function of the specific model number (four colored lines), and the 1/e² beam width indicated on the horizontal axis of the graph.

Please note that the maximum average power needs to be limited to below 1W to prevent thermally damaging the measurement head. Levels up to 10W are acceptable for short term analysis only.

BP100 Series Operating Ranges

With the included GUI software, one can view the measurement results as either 3D, 2D, or single axis (X or Y) beam shapes. In addition, the beam profiler also extracts and displays: X & Y peak power and peak position, X & Y centroid position and beam width (at variable clip level), and total power and beam ellipticity. Each of the latter can be presented numerically or in a bar graph display.

BP100 Beam Profiler Series Graphical User Interface: Pseudo 3D Beam Profile

BP100 Beam Profiler Series Graphical User Interface: Separate X- and Y- Axis 2D-Profile with Gaussian Fit

Our BP100 Beam Profiler series is based on a scanning slit technology.

A narrow slit scans the beam at two defined orthogonal directions. This method allows a wide range of power and beam diameters to be analyzed without the need of attenuators or lenses.  

To determine the beam's quality and spatial characteristics, the passing light is sampled by the detector in two directions and the overall power distribution is calculated. From the resulting power distributions in the X and Y directions, appropriate beam characteristics are analyzed. These parameters include: beam diameter, ellipticity, centroid location, 3D profile and the beam power distribution. These parameters, as well as the 2D and 3 -plots, and a Gaussian fit of the scanned profiles are then displayed.

The direction of X and Y is manually set by a rotation mount. A variable average function provides adjustable noise reduction and increases the measurement accuracy. The maximum-hold function allows analysis of pulsed laser sources, while the automatic or manual gain control enables the user to adapt to different beam powers. The power meter readouts in mW or dBm can be calibrated by the user. The provided GUI shows all parameters as digital or bar graph readouts, and parameter drifts can be visualized by a trend indicator. All resulting data can be exported as text or spreadsheet files.

Rotation mount
The rotation mount is essential for measurement of the beam's ellipticity. For example, since the major and minor axis of an elliptical beam may have arbitrary position in space, the scan axes of the Beam Profiler needs to be oriented to these axes in order to measure the real ellipticity. Without scan axes alignment, the Beam Profiler will measure erroneous beam ellipticities. The BP104/BP109 Beam Profiler is an external optical beam measurement sensor and was designed for applications with an open beam.

The BP104/BP109 comes with a rotation mount, which enables you to rotate the scan axis X and Y up to +/- 60° manually. Simply take the plug on the top and move it to the left or right (while keeping the mount fixed); the Beam Profiler rotates within its mount. To get the desired angle, use the short markers set every 10° and the long markers set at 0° and 45° on the rotation mount in order to measure your beam profile at different directions easily.

The available software is organized into the following categories:

Use this link to download the below software packages:

1. Applications: Standard application software packages and graphical user interfaces. This is what most users need to operate the device for typical applications.
2. Drivers: Instrument drivers for the National Instruments™, LabWindows™/CVI and LabVIEW™ development environments. These are intended for developers who want to extend or adapt the functionality of the device to their special requirements.