NFOV F2 protected gold mirror witness samples – set of 4

Product Description

US Defense Lab NFOV F2 Protected Gold IR Mirror Witness Samples – Set of 4, Pristine & Level 1 Certified

For sale is a rare set of four high-precision optical witness samples, originally produced by Barr Associates, Inc. (now Materion Barr Precision Optics) for a leading US Defense laboratory specializing in advanced space optics programs . These are NFOV F2 (Narrow Field of View Filter 2) witness samples with a durable protected gold coating optimized for infrared (IR) applications.

The coating ensures exceptional broadband reflectivity (>98% across near-IR to mid-IR wavelengths) with a dielectric overcoat for superior environmental resistance against humidity, abrasion, and handling. Industry-standard protected gold mirrors achieve >98% average reflectivity for 900 nm – IR , and >98% for 2 µm to 20 µm .

These samples are factory-sealed, pristine, with original Barr Associates labeling and Defense inventory tags. They carry a Level 1 certification for cleanliness and quality compliance, meeting rigorous aerospace and defense standards (similar to MIL-STD or NASA contamination controls).

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Key Specifications

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Materion Barr Precision Optics Heritage

Barr Associates (now Materion Barr Precision Optics) is a world leader in precision thin film coatings for defense, aerospace, space, astronomy, and scientific applications . Founded in 1971 by Edgar Barr, a pioneer in thin film filters, the company is known for advanced deposition technologies including IBS, IAD, and magnetron sputtering . Their upgraded facility supports coating of optics up to 1.4 meters for space and astronomy programs, and Materion provided beryllium mirrors for the James Webb Space Telescope . This witness sample heritage represents the same exacting standards applied to flight hardware .

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Protected Gold Coating Performance

Protected gold coatings offer the highest reflectance in the infrared spectrum :

Gold is the preferred metal coating for infrared use due to its >98% average reflectivity at IR wavelengths and superior durability when protected with a dielectric overcoat . The proprietary overcoat increases abrasion resistance with minimal impact on optical properties, allowing regular cleaning with standard organic solvents such as alcohol or acetone .

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Thickness Advantage – 14 mm Profile

The 14 mm thickness offers significant advantages over standard 3-6 mm witness samples :

Standard commercial witness samples are typically 1-3 mm thick . This 14 mm thickness represents a custom specification for defense applications requiring exceptional stability under thermal and mechanical loads.

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Surface Quality & Flatness

λ/20 Surface Flatness:
Peak-to-valley surface deviation of just 31.6 nm at 632.8 nm, enabling diffraction-limited performance and minimal wavefront error in high-resolution systems . Surface accuracy is expressed in units of λ, using the 632.8 nm wavelength of a HeNe laser . λ/20 flatness is among the highest precision grades available, exceeding λ/10 or λ/4 standards .

20-10 Scratch-Dig:
The 20-10 specification indicates exceptional surface quality, critical for low scatter and high laser damage threshold :

Precision laser applications typically require 20-10 scratch-dig, while intra-cavity optics may require 10-5 . This surface quality ensures low absorption and scatter, with no visible scratches, digs, or defects under inspection.

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Serial Identification & R&D Value

The etched serial numbers 1/2, 3/4, 5/6, and 7/8 represent normalized radial positions within the coating chamber during deposition. This provides exceptional R&D value for:

• Uniformity verification across the coating run

• Benchmarking deposition process repeatability

• Radial performance mapping at different positions

• Correlation of witness sample properties with flight optics

• Statistical analysis of coating thickness and uniformity

Having a set of four samples from known positions enables rigorous characterization of the coating process – a capability rarely available in surplus optics.

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Applications and Usefulness

These witness samples are invaluable for engineers, researchers, and optical system developers in fields such as defense, aerospace, and scientific instrumentation. They serve as calibration standards or test pieces to verify coating performance metrics like reflectivity, transmission, uniformity, and environmental durability without sacrificing production optics.

IR Sensing and Imaging:

• Narrow field-of-view systems for high-resolution satellite imagery

• Laser radar (LIDAR) and undersea communications

• Precision beam control applications

Laser Systems:

• High-power laser communications and reconnaissance sensors

• Directed energy applications leveraging protected gold’s IR efficiency

• Testing of laser damage thresholds (LIDT)

R&D and Prototyping:

• Academic or industrial labs testing thin-film coatings

• Environmental simulations (thermal cycling, humidity, abrasion)

• Optical alignments in spectrometers, interferometers, and vacuum chambers

Aerospace/Defense Prototypes:

• Simulating performance in electro-optical systems for intelligence, surveillance, and reconnaissance (ISR)

• Level 1 cert ensures compliance for sensitive projects

Educational and Collector Value:

• Perfect for collectors of scientific artifacts

• Educational demonstrations of thin-film optics

• Integration into custom optical setups

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Condition

PRISTINE – FACTORY-SEALED
UNUSED – NEVER DEPLOYED IN SERVICE
ORIGINAL BARR ASSOCIATES LABELING INTACT
DEFENSE INVENTORY TAGS PRESENT
LEVEL 1 CERTIFICATION MAINTAINED
STORED IN PROTECTIVE PACKAGING
READY FOR IMMEDIATE SHIPMENT

⚠ HANDLING NOTE: These are precision optical witness samples with delicate protected gold coatings. While the dielectric overcoat improves durability, always handle only by edges with clean gloves. Never touch coated surfaces. Clean only with approved optical methods if absolutely necessary. Store in clean, dry environment when not in use.