75mm N-BK7 plano-convex lens 1270mm focal length

Product Description

Precision US Surplus 75mm N-BK7 Plano-Convex Lens – ~1270mm Focal Length, Broadband AR Coated

A high-quality US-made plano-convex (PCX) lens in pristine new old stock (NOS) surplus condition. Featuring a 75mm clear aperture, extremely long ~1270mm focal length, and broadband anti-reflection (AR) coating on both surfaces, this lens is engineered for low-aberration performance in directed beam and precision optical applications. Includes a beam-direction orientation arrow for optimal alignment.

🔍 Key Specifications:

• Diameter: 75mm (clear aperture ~85%)

• Focal Length: ~1270mm (f/17 focal ratio)

• Material: N-BK7 optical glass – excellent transmission from visible to near-IR

• Surfaces: Plano (flat) on one side, gently convex on the other

• Coating: Broadband multi-layer AR – >99% transmission per surface, minimal ghosting

• Edge: Frosted/ground for secure mounting

• Thickness: ~11.5mm at edge

• Orientation: Arrow marking indicates recommended beam direction (convex side first)

• Condition: Excellent – New Old Stock (NOS)

⚙️ Applications:

• Laser Beam Control: Collimation or gentle expansion for HeNe, diode, or alignment lasers

• Beam Expanders & Telescopes: Output lens in Keplerian or Galilean expander systems

• Precision Alignment: Long working-distance focusing for interferometry, autocollimators, or sighting systems

• Optical Experimentation: Condenser or field lens in bench-top setups, spatial filters, or illumination

• Educational & DIY Projects: Ideal for advanced optics courses, prototyping, or amateur astronomy