Alignment Screens

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Made from anodized aluminum, the TPSM1(/M) and TPSM2(/M) Alignment Screens have been laser engraved with a target grid to assist in the alignment and height measurement of a beam. Each alignment screen features magnets in its base for quick placement and removal. For more permanent mounting to magnetic or nonmagnetic surfaces, each screen also has a mounting slot for a 1/4"-20 or M6 cap screw.

The BHM3 and BHM4 Magnetic Beam Height Rulers feature holes at 25 mm and 1" intervals to allow a laser beam to pass through. The rulers are laser engraved with both imperial and metric scales and are held onto any magnetic surface by either one or two neodymium magnets. The BHM3 has one of these magnets, while the BHM4 has a pair. Two beam height rulers can be attached at a 90° angle using the BHMA1 Mounting Bracket, allowing for horizontal alignment of a laser beam in addition to measuring its height off the table.

Posted Comments:

williamg (posted 2016-02-12 15:49:47.28)

I have an improvement suggestion for the family of vertical rulers like BHM1 etc. It would be nice if both sides had the scales, but the back side had the metric and imperial scales switched. In other words, when you look on one face, it's imperial scale on the left, but when you look on the other face, it's metric scale on the left. This would be very useful in crowded optical setups, when it's inconvenient or impossible to set up the ruler to use the desired scale. It would also be nice to have an option to buy a vertical ruler (like BHM1) that has both magnetic feet on the same side (like TPSM1 does). I often need to take height measurements inside a laser, where floor space is very limited, and feet on opposite sides make it very difficult sometimes. Such ruler, with both scales on both sides, like described in the first paragraph, would be very nice to have, indeed.

cevered (posted 2016-02-16 10:25:44.0)

Thank you very much for your valuable product feedback. I have begun a discussion within our internal ideas forum and we will inform you of any new releases or suggestions that may arise from your feedback.

christoph.testud (posted 2015-05-20 15:52:27.753)

Dear Sir or Madam, we are using the alignment screens in our laser lab and would suggest that the magnet in the base do not need to be so strong. If you is not careful the screen can easily snap onto the optical table. Best regards, Christoph Testud Christoph Testud University of Hamburg Center for Free Electron Laser Science (CFEL) Geb. 99, office 02-129 Luruper Chaussee 149 22761 Hamburg Tel.: +49 (0)40 8998 6287 christoph.testud@uni-hamburg.de

msoulby (posted 2015-05-26 06:50:44.0)

Response from Mike at Thorlabs: The laser safety screens are designed to be used on steel optical tables, we used magnets rather than screw slots in order to give the customer greater flexibility when placing the screen. The magnets are strong in order to help prevent the safety screen from being knocked and moving easily, which could be a potential hazard if you are using the screen to block a beam.

Magnetic Laser Safety Screens

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TPSM1 in a Beam Stabilization Setup

Aluminum Laser Safety Screen with Laser-Engraved Target Grid
Available in Two Sizes:
- TPSM1(/M): 7.87" x 2.95" (200.0 mm x 75.0 mm), Footprint: 2.95" x 1.38" (75.0 mm x 35.0 mm)
- TPSM2(/M): 11.81" x 2.95" (300.0 mm x 75.0 mm), Footprint: 2.95" x 1.38" (75.0 mm x 35.0 mm)
Two Magnets on Underside Provide Holding Force
Slotted Mounting Hole for Non-Magnetic Surfaces
Homogeneously Diffusive Anodized Coating
Damage Threshold: >350 J/cm² (1064 nm, 20 ns, 20 Hz, Ø1.14 mm)

Our Magnetic Laser Safety Screens are laser engraved on one side with a 1/2" (10 mm for metric versions) target grid for rough laser alignment, while the other side is blank to provide a complete beam blocking option. The base of the screen is fitted with a pair of magnets that hold the screen to magnetic work surfaces and provide flexibility of movement. A through hole is also provided to allow the screen to be tightened down using a cap screw for more permanent placement or for use in non-magnetic applications. The compact size of the screen allows it to fit into small gaps between your accessories, enabling easy integration into a laser setup. This screen is constructed from bead-blasted aluminum to remove any sharp edges, which is then anodized to create a homogeneously diffusive surface.

Please note: Due to the presence of strong magnets, these laser screens should not be used in the vicinity of pacemakers, credit cards, or other devices affected by magnetic fields.

Magnetic Beam Height Rulers

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Each ruler has holes next to the major ticks of the metric and imperial scales to allow a laser beam to pass through.

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Light from a HeNe Laser Passing Through a Hole in a BHM3 Ruler

Imperial and Metric Laser Engraved Scales
- 1.0 mm Metric Graduations
- 1/16" Imperial Graduations
Facilitate Laser Beam Alignment Using Holes Spaced at 1" and 25 mm Intervals
Measure Beam Height on Magnetic Optical Tables or Breadboards
Neodymium Magnets Provide Holding Force
Homogeneously Diffusive Anodized Coating

Our BHM3 and BHM4 Magnetic Rulers measure beam heights up to 6" (155 mm) or 12" (305 mm), respectively. The front of the screen is laser engraved with 1.0 mm and 1/16" graduations for beam height measurement. A series of twelve or twenty four Ø2.0 mm (Ø0.08") holes (on the BHM3 and BHM4 respectively) are positioned next to the engraved numbers at 25.0 mm and 1.00" intervals to allow a laser beam to pass through the ruler.

The base of each ruler is fitted with either one or two neodymium magnets that hold the ruler to magnetic work surfaces and provide flexibility of movement when compared to an option that is bolted to the table. The BHM3 has one of these magnets, while the BHM4 has a pair. Both rulers are constructed from bead-blasted aluminum to remove any sharp edges and then anodized to create a homogeneously diffusive surface. The compact size allows the tool to fit into small gaps between components, enabling easy integration into a setup.

We also offer the BHMA1 bracket below for attaching two beam height rulers, allowing for the alignment of a laser beam horizontally in addition to measuring its height off the table.

Please note: Due to the presence of magnets, this ruler should not be used in the vicinity of pacemakers, credit cards, or other devices affected by magnetic fields.

Item #	Ruler Surface Dimensions (W x H)	Footprint (L x W)	Thickness	Numbered Graduations	Graduations	Hole Spacing	Hole Diameter	Damage Threshold
BHM3	30 mm x 160 mm (1.18" x 6.30")	20 mm x 30 mm (0.79" x 1.18")	2.0 mm (0.8")	Every 1" and 10 mm	1/16" and 1.0 mm	1.00" and 25.0 mm	2.0 mm (0.08")	>350 J/cm² (1064 nm, 20 ns, 20 Hz, Ø1.14 mm)
BHM4	40 mm x 310 mm (1.57" x 12.20")	20 mm x 40 mm (0.79" x 1.57")	2.0 mm (0.8")	Every 1" and 10 mm	1/16" and 1.0 mm	1.00" and 25.0 mm	2.0 mm (0.08")	>350 J/cm² (1064 nm, 20 ns, 20 Hz, Ø1.14 mm)

90° Mounting Bracket for Magnetic Beam Height Rulers

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BHM3 Ruler Mounted at 90° on a BHM4 Ruler Using the BHMA1 Bracket

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VRC4 IR Detector Card on a BHM3 Ruler

Mount Two Beam Height Rulers Perpendicularly
Ideal for Horizontal and Vertical Beam Measurements
Mount a Laser Viewing Card to a Beam Height Ruler
Built-In Spirit Level Simplifies Leveling of the Mounted Card or Ruler
Laser Engraved with 1.0 mm Graduations
Constructed From Black Delrin^®*

Thorlabs' BHMA1 Mounting Bracket allows two beam height rulers to be attached at a 90° angle. This capability allows for alignment of a laser beam horizontally in addition to measuring its height off the table. As shown in the image to the right, the bracket can also be used to attach Laser Viewing Cards to a ruler, allowing for the viewing of UV, NIR, or MIR beams.

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BHMA1 Mechanical Drawing

Constructed from durable black Delrin, this bracket contains a built-in spirit level (bubble level) for consistent leveling of the mounted part. When the bubble is centered between the two graduations the bracket is level. When the center of the bubble is under one of the graduations then the bracket is rotated by 31 arcminutes.

Laser engraved 1.0 mm spaced graduations are also included on three sides of the bracket. These markings can be used to indicate how far the mounted part has been translated horizontally or to repeatably add a ruler or viewing card into the setup.

A through slot in the top of the bracket, shown in the drawing to the left, is shaped to fit over the top of the BHM3 and BHM4 rulers. Once fitted the bracket is free to translate vertically across the ruler. From here a second ruler or a viewing card is placed in the space between the first ruler and the front of the bracket. Everything is held in place by applying pressure using the thumbscrew on the front of the bracket.

Please Note: These brackets are created from Delrin and are not rated for laser safety.

*Delrin^® is a registered trademark of DuPont Polymers, Inc.

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Alignment Screens

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90° Mounting Bracket for Magnetic Beam Height Rulers