λ/20 fused silica optical flat 50mm

Product Description

Premium Precision Optical Flat – λ/20 Surface Accuracy, 50mm Fused Silica – Lab Surplus with Provenance Markings

A laboratory-grade optical reference flat with exceptional λ/20 surface flatness—engineered for nanometer-level interferometric testing and precision metrology. Manufactured from premium UV-grade fused silica and polished to λ/20 peak-to-valley accuracy, this flat delivers the high-contrast fringe patterns essential for verifying surface figure in critical optical and mechanical systems.

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🔍 Key Specifications:

• Diameter: 50 mm (2 inches)

• Thickness: 9 mm (robust, minimizes flexure)

• Material: UV-grade fused silica – low thermal expansion, deep UV to near-IR transmission

• Surface Flatness: λ/20 P-V at 633 nm (≤ 31.6 nm maximum deviation)

• Surface Quality: Double-side precision polished, optically parallel

• Coating: Uncoated – ideal ~4% reflectivity for sharp interference fringes

• Edge Finish: Fine-ground bevel with professional lab markings

• Condition: Excellent – Pristine optical surfaces, light edge markings only

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✅ Lab Provenance & Markings:

This flat bears clear evidence of professional laboratory use—not defects, but valuable documentation etched into the bevel:

• “1/20” – Confirmed λ/20 flatness specification

• “C/R →” – Contact/Reference side orientation arrow for correct setup

These markings are common on high-end lab flats and help users orient the piece instantly for interferometric testing. New commercial units often lack such practical guides unless specially ordered.

Optical surfaces are completely pristine – no scratches, digs, or coating wear. Markings are confined to the beveled edge only, with zero impact on performance.

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⚙️ Why This Flat is Exceptional:

🔬 λ/20 Precision:
Surface accuracy of λ/20 peak-to-valley at 633 nm represents serious metrology capability—suitable for certifying precision optics, gauge blocks, and semiconductor components. This is not a workshop-grade tool; it is a laboratory reference standard.

💎 UV-Grade Fused Silica:
Unlike BK7 or standard glass, UV-grade fused silica offers:

• Near-zero thermal expansion – stable across temperature variations

• Deep UV transmission – usable down to 200 nm

• Superior homogeneity – no striae or bubbles

📐 Uncoated for Interferometry:
The uncoated, 4% natural reflectivity is ideal for generating high-contrast Newton’s ring fringes under monochromatic illumination (sodium, HeNe, LED). No coating means no durability concerns, no cleaning restrictions, and full broadband flexibility.

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🛠️ Applications:

🔬 Interferometric Flatness Testing:

• Verify surface figure of mirrors, prisms, lenses, and wafers

• Generate Newton’s ring fringe patterns under monochromatic light

• Quantitative fringe analysis for peak-to-valley deviation

📏 Precision Metrology & Calibration:

• Calibrate gauge blocks, surface plates, and machine tool tables

• QA/QC in precision optics manufacturing

• Semiconductor substrate flatness certification

🔭 R&D & Laboratory Use:

• Reference standard in optical testing labs

• Educational demonstrations of interference and optical contacting

• Aerospace and defense optics validation

🏭 Industrial Quality Assurance:

• Incoming inspection of precision components

• Process control for optical fabrication