Holmarc's Model No: HO-ED-INT-06C is a compact Michelson Interferometer. The beam splitter is designed to reflect 50% of the incident light and transmit the other 50%. The incident beam therefore is split into two beams; one beam is reflected towards mirror M1, the other is transmitted towards mirror M2. Half the light is transmitted through the beam splitter to M1 and the other half is reflected by beam splitter to M2. The reflected beams from M1 and M2 superimpose at the beam splitter and interference pattern can be observed on the screen.
The light passes through a greater length of glass as the plate is rotated. The change in the path length of the light beam as the glass plate is rotated and relates the change in path length with the laser beam through air.
The refractive index of glass slide,
N = (2t - Nλ) (1 - cos θ) / 2t (1 - cos θ) - Nλ
Where t is the thickness of the glass slide, N is the number of fringes counted, λ is the wave length of light used and θ is the angle turned for N fringes.
The distance between the mirrors and beamsplitter is fixed
The components are mounted on a rigid platform
The instrument uses laser diode as light source
Precision kinematic mounts for optical components
The optics used in this device are of research quality