Fabry-Pérot Interferometer and Rings

wavelength (nm)

400

450

500

550

600

650

700

reflectance %

50

60

70

80

90

air thickness (mm)

0.1

0.15

0.2

0.25

0.3

focal length (cm)

30

40

50

The Fabry–Pérot interferometer is composed of two highly reflective plane mirrors separated by an air layer. The multiple waves interference pattern (rings) is located at infinity and can be observed in the focal plane of a converging lens.

You can vary four parameters: the wavelength of the light source, the reflectance, the air thickness, and the focal length of the converging lens.