A Mach-Zehnder interferometer is an optical device used to measure the phase difference between two collimated beams of light. It is named after the physicists Ludwig Mach and Ludwig Zehnder, who independently proposed the design in the early 20th century.
The Mach-Zehnder interferometer consists of a beamsplitter, two mirrors, and two beam combiners.
Here is a basic description of its components and operation:
Beamsplitter: The incoming light beam is split into two beams by a semi-transparent mirror or beamsplitter.
Paths: The two split beams travel along separate paths. Each path typically includes a mirror that reflects the light back toward the beam splitter.
Phase modulation (optional): In some cases, one of the paths may include an adjustable phase modulator, which introduces a controllable phase shift to one of the beams.
Beam recombination: After reflecting off the mirrors, the two beams are recombined at a second beamsplitter. This beamsplitter is identical to the first one.
Interference pattern: The recombined beams interfere with each other. The interference pattern depends on the phase difference between the two beams.
Output: The interference pattern is observed at the output, where the combined beams either reinforce each other (constructive interference) or cancel each other out (destructive interference).
The interference pattern can be detected using a screen, camera, or other suitable detectors. By adjusting the path length or introducing a phase shift in one of the arms, the interference pattern can be manipulated, making the Mach-Zehnder interferometer a versatile tool for various applications such as measuring small displacements, testing optical components, and quantum information processing.
Mach-Zehnder interferometers are commonly used in optics and photonics laboratories for their ability to provide precise measurements of phase changes and interferometric effects.