Product Description
Large Precision Fused Silica Plane Mirror – 125 mm Diameter × 24.5 mm Thick, Protected Aluminum First-Surface
This is an exceptional, large-diameter precision plane mirror crafted from high-purity fused silica, featuring a protected aluminum first-surface coating. With its substantial 24.5mm thickness, it delivers exceptional rigidity and wavefront stability, making it a professional-grade optic for demanding laser, metrology, and research applications—at a significant savings over new custom fabrication.
Key Specifications:
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Diameter: 125 mm (≈4.92 inches)
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Thickness: 24.5 mm (monolithic stability, minimizes distortion)
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Material: Fused Silica (UV-grade, low thermal expansion, high laser damage threshold)
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Surface Figure: Plano (λ/10 or better typical) – suitable as a reference flat
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Coating: Protected Aluminum (broadband ~95–98% reflectivity, visible to NIR)
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Clear Aperture: 117 mm (central area; holder marks outside this zone)
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Back & Edges: Finely ground for safety and mounting
Why This Mirror Is a Superior Value:
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Rare Size & Thickness: A 125mm diameter, 24.5mm thick fused silica mirror offers lab-grade stability rarely found on the surplus market.
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Reference-Grade Flatness: Suitable as a reference flat for interferometry, autocollimation, or testing other optics.
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High-Power Ready: Fused silica substrate and protected Al coating provide a high laser damage threshold for demanding beam steering applications.
Applications:
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Optical Metrology: Reference flat for interferometers, or for Foucault/knife-edge testing of telescope mirrors
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Laser Systems: Stable beam steering, folding, or periscope mirrors in UV-Vis-NIR setups
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Research & Instrumentation: Critical mirror in spectroscopy, imaging systems, or scientific instruments where thermal stability is paramount
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Advanced Hobbyist & Education: Perfect for serious amateur telescope makers, university optics labs, or laser enthusiasts



