Capability

Our capability is not just the equipment and tooling we have but it’s also what our engineers and operators can do with that equipment – coating, fabrication and metrology. At PFG we have extensive equipment that allows us to produce the variety of high precision optics our customers need. Our technicians use mills, grinders, spindle polishers, double sided polishers; CNC mills, polishers and edgers; MRF polishing, automated cleaning equipment, e-beam and IAD coaters, spectrophotometers and interferometers. While continually expanding and tightening the tolerances on our tooling, our engineers also focus on upgrading equipment and developing improvements to our existing processes. We attract, train and develop a workforce that strives to expand our capability and operate our equipment with increased proficiency.

Spherical

PFG delivers high precision lenses for a wide range of defense, medical, semiconductor and metrology applications. We specialize in high quality lenses featuring high index glasses, high included angles, tight centering and truncation. We have intensive experience with the production of tight tolerance achromats. We routinely supply inspection information including melt data, statement of findings and spectral scans for our lenses. The size range of our capability extends from 3mm to 250mm with radii from 3mm to 12 meters. The summation of specifications ultimately determines our ability to produce your parts as specified in the print. Below are what we presently consider to be our limits, but should you have requirements beyond these, we encourage you to contact us nonetheless. Our engineers and technicians seek challenges, ones outside our current comfort zone, but ones achievable with intensive effort.

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Tolerance Limits

Specification Limit
Diameter (mm) ±0.005
Center Thickness (mm) ± 0.020
Sag – Concave (mm) ± 0.010
Clear Aperture 100%
Radius (mm) ± 0.0025
Irregularity (ƛ) 1/20
Wedge Lens – ETD (mm) 0.003
Bevels – Face Width @ 45° (mm) ± 0.05
Scratch – Dig 10 – 5
Surface Roughness (Å, RMS) 3


Flat

We fabricate precision plano optics in a multitude of shapes, sizes and specifications. We are knowledgeable and have lengthy experience with a wide variety of materials including optical glasses (100+), fused silica, optical crystals (e.g., CaF2, MgF2, Ge, Si, ZnS and ZnSe) and optical ceramics (Zerodur).

Although we typically start with blanks, to shorten deliveries we have the capability for earlier stage processing by sawing, core drilling and shaping from slab to produce the optical blank. We have an extensive range of machining capabilities from mechanical and CNC mills to continuous and double-sided-polishers with pitch and synthetic laps. We carefully plan the entire process using the right combination of tooling, fixturing, equipment, materials and operator know-how to achieve planned results.

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Tolerance Limits

Specification Limit
Dimensions (mm) ± 0.125 to within ± 0.005
Surface Quality 10-5
Angles / Beam Deviation to within ± 1 arc second
Irregularity (λ) 1/20
Surface Flatness (λ) 1/20
Transmitted Wavefront (λ) 1/20
Sharp Roof Chips (mm) 0.005
Surface Roughness (Å, RMS) 2


Coating

With electron beam and automated ion-assisted coating process technologies, PFG is able to offer an extensive range of coatings – anti-reflective, broad-band AR, short and long wavepass filters, beamsplitters, polarizers and high reflectors, both dielectric and enhanced metallic coatings.

We use FilmStar design and characterization software to create customized coatings. Multiple optimization techniques ensure the coatings meet/exceed specifications. Custom programs allow us to analyze coating sensitivity, production yields, total coating thickness, the time required to produce the coating and to estimate the change in surface figure post-coat.

We clean and inspect our optics in a class 1000 clean room and under laminar airflow hoods with particle counts typically less that 10 (of ½ micron or larger) and use other techniques to produce absolute pristine surfaces. We understand the criticality of surface roughness, surface cosmetics, cleaning methods and materials, ambient conditions as well as process technology and execution to satisfy the spectral, mechanical, laser damage and environmental requirements of customer coatings.

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For spectral measurements from UV to NIR, we use Lambda 9, Lambda 900, and Lambda 1050 Perkin Elmer spectrophotometers. For IR spectral measurements, we use a Perkin Elmer 983.

We have in house capabilities to test our coatings for:

  • Abrasion
  • Adhesion
  • Humidity
  • Salt Spray
  • Temperature


Assembly

From the cementing of achromats to the alignment and mounting of optics in metal housings, we have the experience, process equipment and metrology to complete your sub-assembly. We are knowledgeable about and proficient with the most effective techniques for applying and curing optical cements, for contacting optics without using adhesives and we can proficiently build fixturing to facilitate ease and accuracy of the assembly.

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Some of our assemblies are:

  • Eyepieces
  • High-Resolution Objectives for Projection
  • High-Performance Scan Lens Assemblies
  • Illumination Systems
  • Laser Focusing Lens Assemblies for Excimer and YAG Lasers
  • Laser Beam Expanders
  • Sub-Assemblies for Lithography Inspection
  • F-theta Scan Lens Assemblies
  • Machine Vision Lens Assemblies
  • Multi-Element Custom Lenses
  • Night Vision Systems
  • Optical Rangefinders
  • Telecentric Objectives and Assemblies
  • Prism Assemblies
  • IR Objectives


Metrology

We believe that metrology equipment is equally as important as fabrication and coating equipment. Metrology is critical not only because it validates the finished specifications but it also aids in our fabrication and coating process. Every manufacturing cell has a Zygo interferometer, each with its own set of reference spheres or flats. For surface measurement we also have a very large inventory of test plates. We have several PE spectrophotometers for wavelength reflectance and transmission measurement.