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Polarimeter Systems with High Dynamic Range![]()
Accessories for Fiber-Coupled Optical Input Included PAX1000IR1 Application Idea The orientation of a WPH05M-532 half-wave plate mounted in a CRM1P 30 mm cage rotation mount is adjusted with the aid of a PAX1000VIS polarimeter. Related Items ![]() Please Wait Example Configurations (from Left to Right):
![]() Click to Enlarge Software GUI for the PAX1000 Series Polarimeter Showing Equally-Sized Polarization Ellipse and Poincaré Sphere Measurement Windows Features
Applications
Thorlabs' PAX1000 Series of Polarimeters measure the state of polarization (SOP) of collimated input light using the rotating-wave-plate method. Three models cover the visible to near-infrared wavelength range. Optical input must be monochromatic coherent light (i.e. laser light), and the light terminates inside the module. These polarimeters have a high 70 dB dynamic range, and they provide azimuth and ellipticity accuracies of ±0.25° on the Poincaré sphere. When electrical power is supplied via the USB 2.0 port, measurements can be at rates between 50 and 100 samples/s. When the polarimeters are powered using the included DS15 power supply, they can achieve measurement rates between 50 and 400 samples/s. Software, available for download on the Software tab, enables measurements from up to five measurement heads to be simultaneously acquired. For more information, please see the Operation tab. The measurement head accepts a free-space collimated beam up to Ø3.0 mm. Input from an FC/PC-terminated optical fiber can be coupled to the module using the included wavelength-appropriate F240FC Series Fiber Collimator, SM1M10 Lens Tube with SM1 (1.035"-40) internal threads, and KAD12F SM1 threaded adapter. Free-space and fiber-coupled configurations are shown at the left and second left, respectively, in the above image. If you would rather receive a fiber collimator that accepts FC/APC connectors, please contact Tech Support. The F240APC series collimators for FC/APC connectors are also available separately. Accessories from Thorlabs' selection of 30 mm Cage System components can be attached using the four 4-40 threaded holes located on the front panel. Software Measurements from up to five different sources, which include physical polarimeters, virtual devices, and saved data loaded from files, can be displayed simultaneously. The software provides control over sample rates and data averaging preferences. Long-term measurements are also supported. These measurements save a range of time-stamped data to a file according to the settings specified during the measurement setup. Long-term measurements can be acquired while using the software to acquire and manipulate measurements from other devices. Recalibration Service Specifications
Note: All technical specifications are valid at 23 ± 5 °C and 45 ± 15% non-condensing relative humidity. Front Panel Features![]() Click to Enlarge PAX1000IR1 Polarimeter Configured for Free-Space Optical Input
Back Panel Features![]() Click to Enlarge Back Panel of PAX1000IR1 Polarimeter
Operating Principle![]() Click to Enlarge Figure 1: Rotating Wave Plate Technique The PAX1000 series polarimeters are based on the rotating quarter-wave plate technique. The input light must be monochromatic and coherent (i.e. laser emission) with a known wavelength. As shown in Figure 1, the input light is collimated and normally incident on a rotating true zero-order quarter-wave plate. After the wave plate, the light passes through a fixed linear polarizer and then terminates on a photodiode. The polarization state of the light output by the quarter-wave plate changes as the wave plate rotates. The polarizer transmits only the component of light polarized along its transmission axis. As the rotating wave plate results in a continuously changing polarization state incident on the polarizer, the amplitude of the light transmitted by the polarizer, and incident on the photodiode, is modulated. The photodiode converts the modulated optical intensity to a modulated photocurrent. This setup produces photocurrent that has a DC term, a term proportional to twice the rotation frequency of the wave plate, and a phase-shifted term proportional to four times the rotation frequency of the waveplate. Fourier analysis is used to find the amplitude coefficients of each of these frequency-dependent terms, and then the Stokes parameters are calculated from those coefficients. True Zero-Order Quarter-Wave Plate Thorlabs uses true zero-order quarter-wave plates in the PAX1000 series polarimeters, as the highly accurate measurements of these polarimeters cannot be achieved with other types of quarter-wave plates. True zero-order wave plates possess the minimum thickness necessary to produce a phase difference of exactly 90°. Key characteristics of true zero order wave plates include high retardance accuracies, low temperature dependence, low wavelength dependence, and lower sensitivity to angle of incidence than other wave plates. Wave plates with greater thicknesses, but which are constructed to share some performance characteristics with true zero order wave plates, are more common. Examples are pseudo-zero-order and achromatic wave plates, which are constructed by cementing two different wave plates into a single assembly. The fabrication process of the pseudo-zero order and achromatic plates results in a small misalignment error between the component plates' fast and slow axes, which causes unacceptably large errors in the polarization measurements made using the rotating wave plate technique. The wavelength dependency of the true zero-order wave plates used in the PAX1000 series polarimeters determines the operating range of each model. Pulsed vs. CW Input Light Using the Included Accessories to Enable Fiber-Coupled Input Polarization Measurements using the Software GUISoftware with an intuitive and graphical user interface (GUI) with multiple user-configurable attributes is available for the PAX1000 Series of polarimeters. Please note that this software is not backwards compatible with previous generations of Thorlabs' polarimeters. State of Polarization Sample Rates The software provides the option of selecting whether polarization measurements are calculated using data acquired during one half, one full, or two full rotations of the quarter-wave plate. As the quarter-wave plate is driven at revolution rates between 25 Hz and 200 Hz by a low-vibration DC motor, the associated Sample Rates are:
Please see the Chapter 5 of the manual for detailed information describing the sampling rate settings. ![]() Click to Enlarge Figure 3: Optimized Alignment Alignment Tool To assist with the alignment process, Thorlabs has developed an alignment tool. The alignment tool can be opened through the TOOLS tab on the toolbar, which is described in the following section. As shown in Figure 2, the tool consists of a scale with red and green regions. The indicator needle on the scale, and the numerical value readout to the left of the scale, shows the fraction of desired components in the photocurrent. In Figure 2, the indicator needle is in the red region, which corresponds to an unacceptably poor alignment. Improving alignment reduces contributions from scattered light, which increases the fraction of desired components in the photocurrent. The size of the green range is set using the Acceptable Alignment control to the left of the scale. As a rule, good alignment is achieved when the alignment is better than 98%. However, the alignment should be optimized as much as possible, as it is in Figure 3. ![]() Click to Enlarge Figure 5: Measurements from up to five sources, including physical and virtual devices as well as data saved to a file, can be plotted to this view. ![]() Click to Enlarge Figure 4: Main Screen of the GUI with the Poincaré Sphere and Polarization Ellipse Views Active and Equally Sized Key Features of the Display Data are displayed in the large area below the toolbar section. Measurement display windows of interest can be added to this region using the VIEW tab in the toolbar. These different views can then be organized, and their sizes and other appearance attributes modified, by the user. The example in Figure 4 shows the Polarization Ellipse and the Poincaré Sphere Views active and sized equally. The views that may be enabled are:
A Status Bar, located at the bottom of the page, indicates error events and communicates information about long term measurement progress, including an actively-updated progress bar. Multiple Active Devices Polarization Ellipse View Poincaré Sphere View ![]() Click to Enlarge Figure 7: Four different graphs can be selected in Scope Mode. To activate a graph of interest, click the corresponding circled arrow located at the very left of the row. Scope Mode View
![]() Click to Enlarge Figure 9: ER Measurement Results ![]() Click to Enlarge Figure 8: The ER Measurement view. The minimized Polarization Ellipse and Poincaré Sphere views can be expanded by clicking on the gray tabs at the left of the screen. Extinction Ratio Measurement View The applied stress causes cross coupling of the light between the fast and slow axes of the PM fiber, and this changes the measured polarization state. During the application of a dynamic stress to the fiber, the measured polarization state continuously changes and a circle is traced on the Poincaré sphere, as shown in both Figure 8 and Figure 9. The circle should be centered near the equator of the sphere, as the light should be predominantly linearly polarized. Each measurement point represents an (azimuth, ellipticity) measurement pair. The calculation of ER requires the complete measurement set to trace at least one full circle on the Poincaré sphere. The diameter of the circle is a measure of the ER, and the smaller the circle, the higher the ER. Please note that ER measurements made by a polarimeter are not affected by the degree of polarization (DOP) of light. This is in contrast to measurements made by an ER meter, such as Thorlabs' ERM100. When the ER measurements made by the polarimeter are corrected for absolute ellipticity and degree of polarization, as described in Section 8.4 of the manual, the ER value measured by the polarimeter and the ER meter agree. The software for the PAX1000 series of polarimeters allows the user to correct the ER measurement result for absolute ellipticity, DOP, or both. This preference is specified in the ER Measurement setup screen shown in Figure 8. The results of a completed ER measurement are shown in Figure 9. Long-Term Measurement ![]() Click to Enlarge The PAX1000 Series Polarimeter GUI Interface GUI and Drivers for the Remote Control of PAX1000 Series PolarimetersThe download button below provides a link to the GUI and drivers that allow these polarimeters to be controlled via a PC with a Windows® operating system. The highly customizable GUI configuration of this software can be used to display measurements graphically on a polarization ellipse, a Poincaré sphere, and/or on an X-Y graph. An alignment tool is provided to optimize the beam path prior to measurement, long-term measurements are supported, and an extinction ratio (ER) tool facilitates ER measurements of polarization maintaining fibers. Measurements from up to five sources can be simultaneously displayed. These sources include physical and virtual devices displaying real-time data as well as measurements read from a file. A USB 2.0 connection is used to connect the controlling PC to the polarimeter. PAX1000VIS(/M)
*If you would like to instead receive a fiber collimator compatible with FC/APC connectors, please contact Tech Support. The F240APC series collimators for FC/APC connectors are also available separately. ![]() Click to Enlarge Components included with the PAX1000VIS(/M) polarimeters are shown above.
PAX1000IR1(/M)
![]() Click to Enlarge Components included with the PAX1000IR1(/M) and PAX1000IR2(/M) polarimeters are shown above. PAX1000IR2(/M)
*If you would like to instead receive a fiber collimator compatible with FC/APC connectors, please contact Tech Support. The F240APC series collimators for FC/APC connectors are also available separately.
![]() ![]() Click to Enlarge The DS15 power supply and mini-B USB ports are located on the back panel. The "READY" LED illuminates when power is connected.
Thorlabs' PAX1000 Series of Polarimeters measure the state of polarization (SOP) of collimated monochromatic light. Three models cover the visible to near-infrared wavelength range. Each polarimeter features one 1/4"-20 (M6) and two 8-32 (M4) tapped holes for post mounting. A power supply with a region-specific adapter is included with each polarimeter. Additional power supplies are available below. We also offer a recalibration service for our polarimeters, which can be purchased below. We recommend yearly calibration to ensure accurate measurements. ![]() ![]() Click to Enlarge Region-Specific Adapters for DS15 ![]()
The DS15 is a 15 V regulated power supply with a 1.53 m (60.24") long cable and a Mini-XLR connector. It is suitable for any Mini-XLR-compatible device that requires a 15 VDC output, and is directly compatible with our PAX1000 series polarimeters, sold above. A region-specific adapter plug is shipped with the DS15 power supply based on your location. ![]() Thorlabs offers recalibration services for our PAX1000 series polarimeters sold above. To ensure accurate measurements, we recommend recalibrating the polarimeters annually. Please enter the Part # and Serial # of the polarimeter that requires recalibration prior to selecting Add to Cart. Please Note: To ensure your polarimeter is routed appropriately once it arrives at our facility, please do not ship it prior to being provided an RMA Number and return instructions by a member of our team. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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