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Beam Splitter Calculator

Calculate R/T power splitting, Fresnel reflectance, and plate beam displacement.

Beam splitters appear in three distinct engineering contexts addressed by this tool's three modes. R/T Power Splitter distributes an input power into reflected and transmitted fractions for standard coating ratios (50/50, 70/30, 90/10, 95/5, 99/1, or custom), accounting for surface absorption loss. Fresnel Reflectance computes s- and p-polarization reflectance and transmittance at an interface between two refractive indices via the Fresnel equations, reporting the refraction angle and Brewster's angle — useful for uncoated glass substrates and optical windows. Plate Displacement calculates the lateral beam offset introduced when a flat optical plate is placed in a beam at angle, along with front-surface and back-surface contributions — relevant for any diagnostic or sampling plate inserted at oblique incidence.

R/T Power Splitter
Power Distribution
Reflected Power
50.000mW
Transmitted Power
50.000mW
Absorbed Power
0mW
Total Throughput
100.0%
Abridged Optics — Beam Splitter Calculator v1.0Fresnel calculations assume a single uncoated interface. Real beam splitters use multi-layer coatings that modify R/T beyond Fresnel predictions. See the Beam Splitters Comprehensive Guide for coating design details.

All information, equations, and calculations have been compiled and verified to the best of our ability. For mission-critical applications, we recommend independent verification of all values. If you find an error, please let us know.