Right angle and roof
Right-angle prisms turn a beam 90 degrees or retroreflect it through two reflections. Roof prisms fold the same path while inverting the image along one axis in a more compact envelope.
ProductsPrisms
Precision Optical Prisms.
IRD manufactures custom optical prisms for OEM applications in laser systems, imaging technologies, aerospace instrumentation, medical devices, sensing systems, and advanced photonics. Working from customer drawings, IRD fabricates prisms for beam steering, image rotation, light displacement, alignment correction, and optical path control.
What we manufacture
IRD prisms are used in laser beam steering systems, imaging platforms, aerospace instrumentation, medical devices, spectroscopy systems, semiconductor equipment, and advanced sensing technologies where precision optical control is critical. When optical systems require precise beam manipulation, dimensional stability, and repeatable performance, IRD delivers optical prisms manufactured to the customer drawing.
Penta and dove
Penta prisms hold a fixed 90-degree deviation without inverting the image, even under small mounting movement. Dove prisms rotate or invert an image as the prism turns about its long axis.
Coated pentas are also used as beamsplitters
Wedges and rhomboids
Wedges deviate a beam at a controlled shallow angle, and two together steer it. Rhomboids displace a beam laterally without changing its direction or inverting the image.
NIST-traceable wedge certification accurate to within 5 arc seconds
Custom and compound geometry
Challenging variations, custom prism geometries and optical assemblies, and entirely new prism forms developed for applications that no standard geometry covers.
Process capability
Manufacturing limits by process
These are IRD's published capability limits across materials and geometries, not a grade every part ships to. Open the process that controls your critical surface and quote against that one.
Precision grinding and polishing for high optical clarity, with UV, visible, and IR wavelength optimization, from prototype through production manufacturing. Specify each attribute to what the assembly needs.
| Attribute | Typical | Best case |
|---|---|---|
| Angle toleranceBeam steering and interferometric alignment | 5 arc min | 3 arc sec |
| Surface flatnessWavefront-critical faces | 1 wave | < 1/20 wave |
| Surface roughnessPolished prism faces | Ra < 1 µin | Ra < 2 Å |
| ParallelismRhomboids, wedges, and reference faces | 30 arc sec | < 2 arc sec |
| Dimensional toleranceMounting features and interfaces | ±.005″ | ±.0001″ |
Angle and surface controls
An arc second is roughly a millimeter seen from two hundred meters away. Nothing about that survives a process that was designed for dimensions and then asked to hold angles. These are the controls IRD holds across a production run.
Angle is verified by autocollimation, not by the fixture
IRD's inspection floor runs a Nikon autocollimator alongside toolmaker's scopes and interferometers. Blocking sets the angle; autocollimation is what proves it held after polishing, and it is where a drifting fixture shows up before the batch finishes.
Surface quality is scored against a written standard
IRD inspects to MIL-PRF-13830B and ISO 10110. The dig number is measurable, the diameter of the largest surface dig in hundredths of a millimeter, but the scratch number is a visual brightness comparison and varies with the inspector. Naming the standard on the print is what makes the acceptance repeatable.
Over-specifying scratch-dig raises cost without changing function on most faces
Wedge references are traceable
IRD certifies custom optical wedges, from precision NIST-certifiable references through custom lighting wedges, accurate to within 5 arc seconds for the optical angle or angle of deviation.
Coating is specified per face, including the circumference
Coatings are applied to prism faces and to the circumference, and IRD works in solder-compatible as well as dielectric and metallic stacks. Deciding that before polishing is what determines masking, fixture contact, and edge handling.
Capabilities
Capabilities, materials, and coatings
IRD optical prisms are available in a wide range of advanced optical materials, including fused silica, BK-7, sapphire, infrared transmitting materials, and specialty optical substrates engineered to application requirements.
Prism types
- Right-angle prisms
- Rhomboid prisms
- Wedge prisms
- Penta prisms
- Dove prisms
- Roof prisms
- Custom prism geometries and optical assemblies
Capabilities
- Precision optical polishing and finishing
- Advanced thin-film optical coatings
- Surface roughness below 2 Å Ra at best on qualified materials and geometries
- Flatness better than 1/20 wave at best on qualified sizes and geometries
- Tight angular, dimensional, and parallelism tolerances
- Precision grinding and polishing for high optical clarity
- UV, visible, and IR wavelength optimization
- Prototype through production manufacturing
Materials
- Fused silica
- BK-7
- Sapphire
- Infrared transmitting materials
- Specialty optical substrates engineered to application requirements
Coatings
- Anti-reflective (AR) coatings
- High reflectivity (HR) coatings
- High laser damage threshold (HLDT) coatings
- Wavelength-specific thin-film coating solutions
- Optical coatings engineered for transmission efficiency and environmental durability
Applications
- Laser beam steering
- Imaging platforms
- Aerospace instrumentation
- Medical devices
- Spectroscopy
- Semiconductor equipment
- Advanced sensing
Measured on
- Zygo GPI interferometer
- Zygo NewView
- Zygo Verifire XPZ
- Nikon 6D interferometer
- Micro-Vu automated vision system
- TriOptics Triangle
- TriOptics PrismMaster
- Starrett MVR300
- Zeiss Spectrum
- Zeiss O-Inspect
- Tagarno digital microscope
FAQ
Frequently asked questions
The answers an applications engineer would give you on the first call.
Start a quoteCan every face hold 3 arc seconds?
3 arc seconds is IRD's published best-case polishing angle capability; typical is 5 arc minutes. Which faces earn the tighter number is a per-print decision, because each one costs process time. Name the angles that drive system performance and let the rest run at typical.
How should I specify surface quality?
Name the standard on the print. IRD inspects to MIL-PRF-13830B and ISO 10110, the dig number is measurable, but the scratch number is a visual brightness comparison that varies with the inspector, so the standard is what makes acceptance repeatable. Over-specifying scratch-dig raises cost without changing function on most faces.
What do you need in order to quote?
IRD's quoting checklist: application, product type, volume potential and schedule, material, dimensions, surface quality, coatings, assembly, cleaning, and packaging. Attach the drawing. For a new design the technical team runs a no-cost Design for Manufacturability review before quoting, then estimates prototype and production volumes separately.
Does IRD design the part?
No. IRD manufactures to your print or performance requirement and contributes material, process, and manufacturability input, the design stays with your team. When a print calls for tighter tolerances than the application requires, IRD will flag the potential over-specification, since it can add unnecessary cost. Final optical design decisions remain yours.
How large a part can you make?
Machining runs to 30″ × 16″ × 16″, polishing to 36″ diameter, grinding to 24″ diameter at 6″ height, lapping to 13.3″ diameter, waterjet to 40″ × 24″ × 2″, and dicing to 8″ diameter at .300″ thick. Larger geometry is quoted against whichever process controls the critical surface.
Which coatings are applied in-house?
IRD applies basic anti-reflective and metallic coatings in-house for quick turnaround. Other coating requirements are handled through select, vetted coating partners. Name the coating target in the RFQ and the team will confirm the route before quoting.
Can you take ITAR-controlled work?
IRD is registered with the Directorate of Defense Trade Controls, and controlled programs are manufactured and stored domestically across the Litchfield and Alexandria, Minnesota facilities. Both plants operate under quality systems certified to ISO 9001:2015 and ISO 13485:2016 for ultra-high-precision glass, optical, and ceramic components.
How is the finished part protected in transit?
Packaging is tailored to the part and can include multi-layer foam, custom corrugated packaging, gel packs for sensitive optics, and military-grade cases. Components are supported on edges or non-critical surfaces outside the clear aperture and held against shifting in transit.
Technical documents
Use these IRD references when reviewing precision optical prisms requirements.
Technical article
Surface Quality Specifications, Explained
How MIL-PRF-13830B scratch and dig numbers are assigned and counted, where ISO 10110 differs, and why over-specifying surface quality moves cost without moving function.
ArticleTechnical articleWhat Is Optics Metrology?
The instruments behind an acceptance number, optical profilers, the two classes of white-light interferometer, and what each one measures on a finished surface.
ArticleWebinarWriting an RFQ That Delivers the Right Product at the Right Price
IRD's applications team on the information that makes a quote accurate the first time, and the omissions that cause a requote.
Recording
Start with the print
Send us your precision optical prisms requirement.
Send the drawing with the deviation or image orientation the assembly needs, the controlling angles and their tolerances, surface figure and scratch-dig per face, coated faces including the circumference, material, annual volume, and the inspection standard you will accept against. For a new design, the technical team runs a no-cost Design for Manufacturability review before quoting.
Final capability is quoted to the drawing. Achievable tolerance depends on material, feature size, geometry, coating, and production volume. Or call 320.693.7217. If you need a NIST-traceable wedge certificate with the part, say so at the RFQ, it changes the inspection route.