Barr Associates Rare High-Reflectivity Broadband Visible/NIR Mirror Witness Sample

This pristine fused silica witness sample features Barr Associates’ advanced secondary protective dielectric coating—optimized for broadband visible to near-IR applications (~400–1000 nm, peak in 400–700 nm visible spectrum).

Key Specifications

• Manufacturer/Coater: Barr Associates, Inc. (thin-film experts, now Materion Precision Optics)

• Description: Secondary protective dielectric-coated mirror witness sample for WFOV Telescope Assembly

• Excellent durability and environmental resistance (defense-grade for ground-based telescope optics)

• Substrate: High-purity fused silica (SiO₂) – low thermal expansion, ideal for precision visible/NIR

• Coating: Advanced secondary dielectric overcoat (SiO₂-based for protection and enhanced reflectivity) – high reflectivity >92–98% in visible broadband, optimized for silicon CCD detection

• Size: 38 mm diameter, 1.5 mm thick
• Condition: Excellent surplus – clean, highly reflective surface with classic dielectric mirror appearance (white/opaque under diffuse light), preserved in original packaging

  Why This Mirror Is Special This witness directly supported the Space Surveillance Telescope (SST)— 3.5-meter wide-field system for detecting faint space debris and satellites. Barr’s dielectric coatings ensure maximum light efficiency, minimal scatter, and long-term stability in demanding environments.

  Versatile Applications

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