Ultrasonic experiments 7: Mach-Zehnder-Interferometer

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### Ultrasonic experiments 7: Mach-Zehnder interferometer ### I have developed a series of experiments with ultrasound waves that can be done by students in upper-level physics lessons. These experiments include: 1: reflection and absorption of ultrasonic waves 2: standing waves 3: interference with two transmitters 4: the double-slits experiment 5: the effect of a semipermeable plate 6: the Michelson interferometer <b> 7: the Mach-Zehnder interferometer </b> 8: the distance measurement with an Arduino #### COMPONENTS #### <b> curcuit_board_mount: </b> For the curcuit i used a board of 5cm x 7cm, which is sufficent for the ultrasonic sound generator. I chose a standard curcuit for the generator with the NE555. The electrical circuit I have shown in a pdf file. The mount can be printed without a support. <b> mount for horn: </b> this print ist the mount for the transmitter horn and the reciever horn. Support is not necessary. <b> horn: </b> For this horn i choose an angle of approx. 20 degrees. Support is not necessary. <b> base: </b> For this part i used the excellent work of jandetlefsen and his thing http://www.thingiverse.com/thing:1412135. I could not find anything more suitable nor could I develop something better myself. Support is not necessary <b> nut M3: </b> a generic nut for M3 for the 20x20 aluminium profile system: For this experiment you will need five of them. <b> semipermeable plate </b>: This semi-permeable plate consists of squares with a side length of 7 mm (ie an area of ​​50mm²) with a square cutout with a side length of 5mm (ie an area of ​​25mm²). <b> connector: </b> ... to connect four 20x20 aluminium profiles. Support is not necessary. <b> mount for connector: </b> With a screw M3, this part can be movably mounted on the connector. Support is necessary. #### Things you need more #### <b> Aluminium profiles </b>: for this experiment i recommend two (or three) 40cm long profiles for the input arm and the output arm and four 25cm long profiles for the inner part of the interferometer. <b> Screws and nuts: </b> a lot of M3 screws for mounting on the profiles (M3 x 10mm, M3 x 16mm). Some M5 screws and nuts for the bases. <b> Aluminium plates: </b> i recommend two plates of 150mm x 150mm, with a thickness of 2mm. #### Results of the experiment #### In the MZ interferometer, the incident wave is divided by the first semi-permeable plate into two equal parts. One half of the wave runs in the upper arm, the other half of the wave in the lower arm. On the second semi-permeable plate both waves are superimposed again. If both arms are of equal length, the overlay (regardless of which side of the semi-permeable plate is measured) is always constructive. This can be demonstrated with this experiment very clearly. By changing the wave (for example with the gentle draft of a hair dryer) in only one arm of the interferometer, a change in the phase position (and thus a change in the output signal) can be achieved.