I used fenicsx to create stress simulations of a silicon test mass which could then be converted to birefringence. The model used was based on the silicon test masses created for use in the Gingin 7m 2um cavity project. These have a diameter of 10cm and a thickness of 3cm. All the values used in […]
We would like to make a MICH scan of the microscopic length for a generic interferometer. This was the Finesse 2 code func rev = (-1)*$x1 xaxis NI phi lin -10 10 500put NIAR phi $x1put WI phi $revput WIAR phi $rev noplot rev We tried with dof MICH NITM.phi -1 NETM.phi -1 WITM.phi +1 […]
All the central parts of the simulation are written in Cython for faster execution. When investigating bugs in this code it is useful to have a debugger. Luckily Cython comes with a built-in debugger, cygdb, but setting up the environment for it to work is non-trivial. The Cython documentation itself does not explain much and […]
Hi! We are observing an excess of frequency noise on the sidebands, which is apparently due to laser noise being shifted by the modulation through an EOM We would like to try to simulate this, adding some frequency noise on the laser and modulating it. In particular, we would like to add some noise around […]
Here’s an example on how to create composite objects in Finesse 3. Below we create a thick mirror that better defines the AR, substrate, and HR surface. Internally this thick mirror is made from two thin mirrors plus a space. These are added to the model when the `_on_add` method is called just after the […]
Finesse3 provides multiple Actions to interact with a model. But maybe you want to do something no one else has thought of. In this case you can add your own Action to finesse. That way it can be easily used in any model, shared with other users and maybe even added to finesse itself. All […]
At the time of writing this entry, the way to do balanced homodyne detection is not yet fully implemented in Finesse3 as the example shows it here. The issue is the -3dB limitation of the squeezing level which comes from the fact that the beamsplitter is 50/50, so half of squeezing is lost before reaching […]
This is a simple snippet of code showing how to change the Schnupp asymmetry in the finesse3 virgo model. The process is quite straightforward and is based on simply changing the length of the space between the beamsplitter and one of the compensation plates. An important step to follow the Schnupp asymmetry change is to […]
Thanks to discussion with Virgo-ISC team, there are a few updates that need to be implemented to better match the current control scheme for the interferometer. (note that the tolerances are chosen arbitrarily by me; they could probably be fine-tuned) The updated katscript file to parse for the readouts in order to create the Virgo […]
We found an issue in the function DARM_RF_to_DC(dc_offset = XX), The DC offset given as an input to the function was wrongly dived by two, within the function . This has been fixed by Riccardo.