75mm 50/50 plate beamsplitter N-BK7

Product Description

75mm Diameter 50/50 Plate Beam Splitter – High-Precision Optic

This is a high-quality circular plate beam splitter, measuring 75mm in diameter and 11.5mm thick, ideal for visible wavelength applications. Crafted from N-BK7 borosilicate crown glass, it offers excellent optical homogeneity, high transmission in the 400–700nm range, and good thermal stability for demanding setups .

N-BK7 is the most common optical glass for precision optics, offering an excellent combination of optical performance, mechanical durability, and cost-effectiveness . Its high homogeneity ensures minimal wavefront distortion, critical for laser and imaging applications.

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Key Specifications

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Material Advantages – N-BK7

N-BK7 (borosilicate crown glass) is the industry standard for general-purpose precision optics :

N-BK7 provides excellent homogeneity, low bubble and inclusion content, and straightforward manufacturability, making it a top choice for transmissive optics .

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Coating Technology & Performance

Front Surface: Dielectric Multilayer 50/50 Beamsplitter Coating

• Designed for equal splitting of incident light (50% reflection / 50% transmission)

• Dielectric coatings offer superior durability and lower absorption compared to metallic coatings

• Optimized for visible wavelengths (400–700 nm)

Back Surface: Broadband Anti-Reflection (AR) Coating

• Reduces unwanted reflections to <1% per surface

• Minimizes ghosting and interference effects

• Improves overall system throughput

Polarization Effects (for reference at 45° incidence):

• S-polarized light: approximately 50/50 split

• P-polarized light: approximately 30/70 split

• Unpolarized light: approximately 40/60 average split

Surface Flatness: λ/10

• λ/10 flatness ensures minimal wavefront distortion for precision applications

• Comparable to precision-grade beamsplitters from major manufacturers

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Enhanced Rigidity – 11.5mm Thickness

This beamsplitter’s 11.5mm thickness is significantly thicker than standard plate beamsplitters (typically 1–5mm). This provides:

• Enhanced mechanical rigidity for robust assemblies

• Reduced beam offset at angled incidence (e.g., 45°)

• Minimal flexure under mounting stress

• Improved thermal stability in varying environments

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Applications

Laser Setups:

• Beam combining and power monitoring

• Beam sampling for feedback control

• Interferometry and holography

Interferometry and Metrology:

• λ/10 flatness minimizes measurement errors

• Ideal for precision optical testing

Microscopy and Imaging:

• Fluorescence microscopy (excitation/emission separation)

• Brightfield splitting for dual-channel imaging

• Beam routing in confocal systems

Photonics Research:

• Optical prototyping and experiment setups

• Educational laboratories

• DIY optics projects

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Edge Markings

The optic is marked with “λ/10” and “A/R” on the edge:

• A/R indicates the anti-reflection coated side

• This marking ensures proper orientation during installation

• Following the arrow direction (if present) helps identify the coated surfaces

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Condition

GOOD OPTICAL CONDITION
NO VISIBLE SCRATCHES OR CHIPS
SURFACES CLEAN, COATINGS INTACT
EDGES GROUND/POLISHED FOR SAFE HANDLING
READY FOR INTEGRATION

⚠ HANDLING NOTE: This is a precision optical component with delicate dielectric coatings. Handle only by edges with clean gloves. Never touch coated surfaces. Store in clean, dry environment when not in use.