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YAG Focal Spot Analyzer

YAG Focal Spot Analyzer
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3.2.2.1 YAG Focal Spot Analyzer ֺ ֺ ֺ ֺ ֺ ֺ ֺ ֺ ֺ ֺ ֺ ֺ ֺ ֺ ֺ ֺ ֺ ֺ ֺ ֺ Image focal spots down to 25µm in size For laser powers up to 400W (additional external ND filters required) Measure how focal distance shifts with power Can measure systems with focal length as short as 50mm Modular design allows flexibility in use C-mount, compact laser beam sampler/attenuator for camera based laser beam profiling systems High damage threshold optics for measuring energetic sources Produces undistorted sample of laser under test Adjustable attenuation maximizes system dynamic range Up to 1 x 10-10 attenuation available (without external filters) Measure the focal spot of a relatively high power laser, in particular a YAG laser. The average power can be from <1 to 400 Watts and the focal spot can be as small as 25µm. The FSA can also be used to measure how the focal spot shifts with power. The lasers focal length from the lens to the focal spot is usually on the order of 70 to 120mm. The YAG FSA assembly adds a negative lens to the LBS-300 beam splitter assembly to increase the focal path and at the same time enlarge the image. Several focal length lenses are available to accommodate different host system focal paths. The FSA includes; user selectable negative lens, 2 beam splitters, a removable beam block on the 2nd splitter, and user selectable attenuation filters prior to the beam entering the camera. An excel spreadsheet is downloadable from our website that calculates which lenses are available to use for your application, how far to mount the FSA from your focusing lens in order to see the focal spot and what the magnification of the image will be. 3.2.2.1 Beam Profile Operation: The FSA is mounted to the camera as shown. Then the assembly is placed below the final focusing lens of the laser at the recommended distance. The focal spot is found by moving the assembly closer and farther from the beam until the smallest spot size is seen. The exact magnification factor (usually 2-3 times) is calculated by moving the stage holding the FSA assembly a given lateral distance and seeing how far the centroid of the focal spot moves in the beam profiling software. This scaling factor is then entered into the software. In order to find focal spot shift with laser power, simply find focal spot at one power, change the power and measure how far the stage has to be moved up or down to get to the smallest beam size again. Incoming Beam Camera Negative lens LBS-300 2nd Output Beam; built-in beam block Focal Spot Assembly Looking from camera mounting position 1st Output Beam; either to power meter or to Beam Dump User selectable ND filters for attenuating input to the camera Focal Spot Assembly showing various beam paths 146 01.01.2012 For latest updates please visit our website: www.ophiropt.com/photonics

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Examples of Usage 65µm diameter focal spot Focal spot shape changing with laser power level Specifications YAG Focal Spot Analyzer Wavelength Wedge Material Wedge Coating Clear aperture Wedge ND value, each ND Filters ND Values, nominal Filter Slides Filter Damage (1) 1064nm BK7 AR ≤1% 17.5mm ND ≥2 Bulk ND 0.3, .7, 1.0, 2.0, 3.0, 4.0 (Red holders) 3 50 W/cm2 1J/cm2, 10ns pulse FSA-50Y -50mm YAG FSA-100Y -100mm YAG FSA-125Y -125mm YAG FSA-150Y -150mm YAG FSA-200Y -200mm YAG Negative Lens To add FSA capability Accessories Variable Wedge ND Filter kit Beam Dumps WVF-300 BD-040-A, 40 Watts Max...

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