The PISA Prototype
The first two pictures show the actual interferometer (or the optical element) of the PISA prototype and the very first spectrum that was recorded with this prototype.
![](/phy/labore/photonik/images/forschung/PISA_prototype.png.scaled/b9d14e570d89e707e4862e1e28e55c38.png)
The POSA Breadboard
![](/phy/labore/photonik/images/forschung/breadboard01.gif.scaled/ccc542cf7d4fe56b1c0215d8ee9f6356.png)
The heart of the POSA is a unique double-beam high-resolution interferometer, consisting of basically a special prism-roof mirror (1), a double-dove prism (2), a beamsplitter (4) and two prism-roof end mirrors (3).
![](/phy/labore/photonik/images/forschung/breadboard02.jpg.scaled/3580fa559155ea3358d6a13999acbcf9.jpg)
The interferometer breadboard has been build in two versions, once with the special prism-roof mirror and in a second version with two hollow roof mirrors replacing the special prism-roof mirrors.
![](/phy/labore/photonik/images/forschung/breadboard03.jpg.scaled/276dd86a6b9cc69e36518c976c4f8f7c.jpg)
Because of the optical complexity, the breadboards are difficult to align. The alignment possibilities of the beam-splitter and the roof-prisms will thus be elaborated in the future. First interferogramms have been measured and the optimizations of the breadboards is under way.