- Mach-Zehnder interferometer
Derived from the Twyman-Green interferometer, the Mach Zehnder is an amplitude splitting interferometer that consists of two beamsplitters and two fully reflecting mirrors. Light from an extended source passes through the first beamsplitter resulting in two lightwaves traversing equal and separate optical paths. The two paths are later recombined with a set of mirrors at a second beamsplitter in which the resultant beam is then passed to an observation plane where interference fringes are recorded. The effectiveness of the Mach Zehnder interferometer is solely based off the equal optical path lengths that the two light paths travel before being recombined. Any difference between the two optical paths can be introduced by a slight tilt of any of the beam splitters.An object placed in either of the individual beam paths will also introduce a variation in optical path length thereby making the Mach Zehnder interferometer a common device for observing the density variations in gas flow patterns amongst a myriad of other applications in which fringe patterns are useful in characterizing the quality of transparent objects and optical parts.