75mm N-BK7 plano-wedge prism

Product Description

Surplus Large 75mm N-BK7 Optical Plano-Wedge Prism – ~3.4° Wedge, Directional Markings

This is a high-quality, uncoated plano-wedge prism fabricated from N-BK7 optical glass. With a 75mm diameter and a wedge angle of approximately 3.4°, it provides a fixed, predictable beam deviation ideal for laser steering, alignment, and optical experimentation. Distinct directional markings suggest it originated from a precision surveying or alignment instrument, adding functional and historical interest.

Key Specifications:

• Diameter: 75 mm

• Thickness: 8 mm (thin edge) to 12.5 mm (thick edge)

• Wedge Angle: ~3.43°

• Beam Deviation (Visible Light): ~1.8° (beam deflects toward the thick side)

• Material: N-BK7 optical glass (high clarity, >90% transmission 350–2000 nm)

• Coating: Uncoated

• Clear Aperture: Central ~50 mm is pristine; outer edges have minor cosmetic chips that do not affect the usable area

• Markings: Includes a “v” arrow pointer (likely indicating thin edge or deviation direction)

Condition:

✅ EXCELLENT SURPLUS – CENTRAL OPTICS PRISTINE
📍 NOTE: Minor cosmetic edge chips outside the central 50mm clear aperture – no impact on performance

Why This Wedge Prism Is Versatile:

• Predictable Beam Steering: Provides a fixed ~1.8° deviation for visible light, useful for aligning or shifting laser beams in compact setups.

• Ghost Reflection Elimination: Can be used to eliminate undesired back-reflections in laser cavities or interferometers.

• Risley Pair Potential: Combine with a second wedge for adjustable beam steering.

• Historical Intrigue: Directional markings suggest origins in precision instrumentation, appealing to restorers and educators.

Applications:

• Laser Beam Steering: Fixed-angle deviation for alignment or path folding.

• Interferometry & Metrology: Component in shear plates, etalon suppression, or alignment autocollimators.

• Optical Experiments & Education: Ideal for teaching prism optics, beam deviation, and wedge applications.

• Vintage Instrument Restoration: Potential replacement part for classic surveying or optical tools.