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CGH Positioners

Why Frames and Positioners?

Aspheric metrology using CGH nulls requires precise multi-axis alignment of the CGH, either within the interferometer itself or within its test beam. Pre-alignment of CGHs in interchangeable frames speeds this alignment process and improves its accuracy.

Our versatile CGH frames and positioners provide 6-axis positioning while allowing easy and rapid interchangeability of CGHs with virtually no degradation of alignment. They are easily integrated with other optical fixturing and instrumentation already in your lab.

Three Frame Sizes

We offer three sizes of CGH frame. Our Model 6025 which accepts a full 6"×6"×0.25" photomask substrate. For applications where a smaller aperture will suffice, our Model 50R accepts a CGH substrate measuring Ø50.8 mm and 0.25" thick. Finally, the Model 50 is identical in overall dimensions to the 50R but accepts square substrates measuring 38 x 38 mm.

CGH Frames
Model Clear Aperture Glass Size Drawing Image
6025 127×127 mm 6"×6"×0.25" (photomask) 6025.dxf M6025_dwg.jpg
50R Ø48 mm Ø50.8x4 mm 50R.dxf 50R.2D.gif
50 35x35 mm 38x38x2.3 mm N/A N/A

Kinematic Mounting

Each CGH frame includes four precision hardened steel balls, any three of which register against six carbide rod bearing surfaces of the CGH positioner to provide exactly six mechanical constraints. A CGH frame can be repeatedly removed and reattached to its positioner with virtually no change in alignment.

Magnetic Coupling

CGH frames are held against a positioner’s carbide bearing surfaces by magnetic coupling. The coupling force is sufficient to hold the CGH securely, but not so great as to degrade system alignment when the CGH frame is pulled free.

Multiple Orientations

Each framed CGH can be attached in any of eight discrete orientations. Decentration on switching mounting orientations is typically less than 20 µm.

Prealigned CGHs

Our CGHs are permanently aligned and bonded to their frames. Tilt, tip and focus are controlled by locating the CGH optical surface to within about 10 µm of its design position relative to the plane of the four precision balls. Using fiducial marks incorporated into the CGH and a proprietary alignment tool, centering and rotation are controlled to a few µm.

Because our alignment technique does not depend on the CGH substrate thickness or its optical transmission properties, we can prealign transmission, reflection, visible and infrared CGHs.

Alignment Verification

Verification of CGH alignment and kinematic mounting can be performed by the user with standard metrology techniques. We will be glad to show you how.

CGH Positioners
Model Type Aperture Axis Height Drawing Image Price
M6025 5 or 6-axis Ø158 mm 125±3 mm Inquire M6025_dwg.jpg Pricing
M506 6-axis Ø48 mm 51±3 mm M506.dxf M506.2D.gif Pricing
1206R Adapter Ø55 mm N/A M1206R.dxf M1206R.2D.gif Pricing

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Page updated: 24 September 2015

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