Optical Materials Database

Comprehensive reference of refractive indices for optical materials. Use these values in the lens maker formula calculator.

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About Refractive Index Values

All values are measured at the sodium D-line (589 nm) unless otherwise noted. Refractive index varies with wavelength (dispersion) and temperature. For precise optical design, consult manufacturer specifications.

Materialn
Vacuum

By definition

1.000
Air (STP)

At standard temperature and pressure

1.000
Carbon Dioxide

At STP

1.000
Water (20°C)

Varies with temperature

1.333
Ethanol
1.361
Fused Silica@589nm

Very low dispersion

1.458
Glycerin
1.473
Borosilicate Glass
1.474
PMMA (Acrylic)

Lightweight, shatterproof

1.492
CR-39

Most common eyeglass material

1.498
Immersion Oil

Matches typical glass

1.515
Crown Glass (BK7)@589nm

Most common optical glass

1.517
Soda-lime Glass
1.520
Trivex

Lightest lens material

1.530
Quartz (Crystalline)

Birefringent

1.544
Polycarbonate

Impact resistant

1.585
Polystyrene
1.590
Flint Glass (F2)@589nm

Higher dispersion

1.620
Carbon Disulfide
1.628
Calcite

Strong birefringence

1.658
High-Index Plastic (1.67)

For strong prescriptions

1.670
High-Index Plastic (1.74)

Highest index plastic

1.740
Sapphire

Very hard, scratch-resistant

1.770
Ruby

Same as sapphire (Al₂O₃)

1.770
Dense Flint (SF11)@589nm
1.785
Lanthanum Glass

Low dispersion, high index

1.800
Diamond

Highest natural refractive index

2.42
Zinc Selenide (ZnSe)@10.6μm

For infrared applications

2.67
Silicon@10.6μm

Opaque in visible

3.50
Germanium@10.6μm

Only for IR wavelengths

4.00

Common Refractive Index Ranges

Low Index (n < 1.5)

Air, water, some plastics. Common in everyday optics.

Medium Index (1.5-1.7)

Most optical glasses, standard eyewear. Best balance of properties.

High Index (n > 1.7)

Specialty glasses, crystals. For thin lenses and special applications.

Use These Values in Calculations

Select a material and use its refractive index in the lens maker formula.