Pair of Rare High-Reflectivity Visible/NIR Mirror Witness Samples

his matched pair of ultra-thin fused silica mirror witness samples features Barr Associates’ high-reflectivity coatings—optimized for broadband visible to near-IR applications (~400–1000 nm, peak reflectivity >92–98% in 400–700 nm). Perfect for space surveillance telescopes, astronomy mirrors, laser systems, or high-resolution imaging. Excellent for visible/NIR lasers, CCD-based optics, or lab experiments.

Key Specifications

• Manufacturer/Coater: Barr Associates, Inc. (thin-film experts, now Materion Precision Optics)
• Description: Mirrors with high-reflectivity coatings witness samples
• Substrate: High-purity fused silica (SiO₂) – low thermal expansion, ideal for precision visible/NIR
• Coating: High-reflectivity metallic layer (likely protected aluminum/silver) with dielectric overcoat – optimized for silicon CCD detection
• Size: ~1 inch (25.4 mm) diameter each, 0.5 mm thick
• Condition: Excellent surplus – clean, highly reflective surfaces with classic mirror appearance, preserved in original packets, container, and bags with all labels

Why These Mirrors Are Special These witnesses directly supported the Space Surveillance Telescope (SST)—MIT LL’s innovative 3.5-meter wide-field system for detecting faint space debris and satellites. Barr’s coatings ensured maximum light efficiency and minimal scatter.

Versatile Applications

• Visible/NIR Laser Alignment & Experiments – Beam steering for HeNe (633 nm), diode lasers (780–980 nm), or visible systems in optics labs. Thin profile ideal for compact setups.
• Astronomy & Surveillance Optics Projects – Reference mirrors in DIY telescopes, wide-field demos, or educational models of space surveillance systems (direct tie to SST’s mission).
• Scientific Instruments – High-reflection elements in spectrometers, interferometers, or CCD cameras.
• Laser Communication / LIDAR Prototypes – Reflectors for visible/NIR free-space optics or ranging.
• Artistic & Display Uses – Stunning reflections create mirror-like effects under various lights.