Lloyd's Single Mirror Experiment

Holmarc's Lloyd’s single mirror experiment apparatus (Model No: HO-ED-INT-20) is an instrument that demonstrates how Lloyd’s single mirror can be used to obtain fringes due to interference and to calculate the wavelength of monochromatic light. A virtual image of the light source is created at the mirror through the reflection of the laser light. Interference pattern is produced due to the superposition of the direct and the reflected light.

The apparatus consists of an optical rail on which components are mounted using posts, post holders and movable carriages. For setting up the experiment, the light source, Lloyd’s mirror, expanding lens and imaging lens are adjusted so as to obtain well defined interference pattern. Laser diode is used as the light source. All components are made out of anodized aluminum and stainless steel to avoid corrosion.

Lloyd’s Mirror is used to produce two-source interference patterns. Let S is a diverging source of light, strikes at front surface of a mirror at a low angle. Some of the beam reflects from the mirror to the screen, and some shines directly on the screen. The reflected beam coming from a virtual source S₂ , superpose with the direct beam coming from source S₁. As a result of this we get interference pattern at on the screen.

Experiment: