Fluid Jet Polishing
Fluid jet polishing is turning the world of optical fabrication upside down. LightMachinery can routinely create near perfect optical components using this cost effective, computer controlled technique.
Fluid jet polishing is an enabling technology that enables LightMachinery to tackle some very complex and difficult optical fabrication tasks with confidence. The ability to adjust the shape and flatness of components with very thin aspect ratios has allowed LightMachinery to fabricate very uniform thin etalons and wafers. The ability to measure the final performance of complex assemblies such as Michelson Interferometers and then to make arbitrary surface corrections to these components is opening up a new era of astronomical device manufacture. Contact us to discuss your requirements
Fluid Jet Technology
LightMachinery's patented fluid jet polishing system uses a fine stream of slurry to accurately remove nanometers of material. Fluid jet polishing is a type of computer controlled polishing that has been refined by LightMachinery. The process is simple;
Step 1 Measure the current surface profile, this is usually done using an interferometer
Step 2 Compare the current surface to the target surface profile
Step 3 Compute the required removal patern
3 Simple Steps to Perfect Surfaces


The resulting surfaces can be polished to within a few nanometers of the target shape. The following section on applications shows the wide variety of applications for fluid jet polishing; corrected flat surfaces, making aspheric lenses, ultra-uniform thickness substrates and etalons, unusual shapes and corrected accumulated errors in large optical assemblies.
Applications and Capability
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A conventionally polished 2" x 2" fused silica substrate (before fluid jet polishing)
Measured with tunable laser mapping system in transmission there is a peak to valley slope of about 115nm |
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This same substrate after FJP
Measured again with tunable laser mapping system in transmission there is a peak to valley error of about 3nm. Shown here in the same scale as above |
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Another 2" x 2" fused silica square
This substrate was measured in reflection using a Zygo interferometer, the error is very large, about 1.8um of concave shape |
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After FJP
Shown here at the same scale as the picture above the error is 10nm peak to valley |
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A Very Flat 4" Silicon Mirror
Measured with a Zygo GPI after fluid jet polishing this silicon mirror has a surface variation matched to the zygo test flat to 1/100 wave peak to valley over a 95% clear aperture |
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Note the rms surface figure of lambda/1000!
This is important for creating high finesse etalons |
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This before and after fluid jet polishing
interferogram clearly demonstrates the FJP's ability to correct transmitted wavefront errors. This process was completed in a single pass, processing on only one side, based on transmitted wavefront data from a Zygo interferometer. |
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Target surface
A simple .jpg, 256 x 256 of ISO (we are still very pleased about our ISO 9001 certification). The depth was set to 250nm for the text. |
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Starting Surface
This was already a pretty good surface, polished my our opticians to about 1/8 wave over the 2" x 2" square |
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After Fluid Jet Polishing
This beautiful pattern was made using the fluid jet polishing machine in the usual raster mode. |
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After Fluid Jet Polishing
The ISO image is polished (backwards) into the square optical component that has then been optically contacted to the lower 3" diameter holder. The visible fringes are from the air space between the surfaces. |
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Fluid Jet Polished
And then Adhesive Free Bonded (optically contacted) |
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Target surface
Another simple .jpg, 256 x 256. A constant change in color value between each segment. |
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After Fluid Jet Polishing
A stepped depth that gives rise to a phase mask matrix |
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Air Spaced Etalon Matrix
This piece was then optically contacted to a flat piece of fused silica creating an array of air spaced etalons. Each one is has a gap that is 100nm wider than its neighbor |
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Conventional Flatness λ/10
Shown here a conventionally polished fused silica substrate. The wedge in the part is very good, about 50nm, less than lambda/10 |
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An Early FJP result - Flatness of λ/100
After processing half of the part with fluid jet polishing. The surface flatness is reduced about 6nm peak to valley or lambda/100
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Atomic force microscope analysis of a conventionaly polished fused silica surface. The size of the area is 1.5 x 2.5 microns. Surface roughness is 1nm Rms |
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Atomic force microscope analysis of a fluid jet polished fused silica surface. The size of the area is 1.5 x 2.5 microns. Surface roughness is 1nm Rms |
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Micro-channels and complex patterns can also be created by combining fluid jet polishing with masking. These shallow microchannels are about 20nm deep and more than 1000nm wide (the vertical axis is greatly expanded). Applications include microfluidics and optical phase masks. |
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More strange surfaces
A fluid jet polished an image of a Canadian Penny in a 2" square of fused silica. The fused silica was then optically contacted to another piece of fused silica and the air space in between creates visisble finges that look a lot like an actual penny.
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A depth map of the penny image |
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More strange surfaces
Another optical element that would be impossible to make using conventional polishing, crossed cylindrical lenses |
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A top view of the crossed cylinders |
Fluid Jet Polishing Technology
Perhaps your application is outside the world of conventional optical polishing. We are still here to help. Fluid jet polishing is capable of adjusting a very wide range of materials from metals to Silicon Carbide. Please contact us to discuss you application and we will be glad to work with you on finding a solution.
If your application requires truly flat smooth surfaces, uniform thickness or surfaces with arbitrary shapes then contact our staff to discuss your needs.
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