MIST Blog

The main new feature is the possibility to compute quantum noise.

New features

• Quantum noise computation. It is now possible to specify where quantum
  vacuum fluctuations enter in the system and compute the quantum noise
  limited sensitivity of all detectors. Squeezed vacuum is also supported.
• When tracing the Gaussian beam parameters, MIST issues a warning if there
  is a large mismatch at some node. Often, when this happens, the simulation
  needs a large number of higher order modes to return meaningful results
• When the user sets the maximum order of gaussian modes to zero, a plane
  wave approximation is used: therefore all surface curvatures, tilts and
  maps are simply ignored, as well as the beam shape change in propagation
• Added a new optical circulator object (command ‘circulator’)... read more

The main feature of this version is an upgraded equation solver. For complex optical systems such a dual recycled GW interferometer with RF sidebands, the time needed to compile the configuration file is reduced by at least 7 times...

Some minor bug fixes:

• solved a bug that prevented a correct recompilation at simulation time when drivers were present
• fixed a bug in the solver that however never caused any problems in all the tests performed so far
• fixed a bug in beam splitter radiation pressure equation dependencies

This version fixes a minor bug in the way the demodulation phase is taken into account: now static signals behave in the same way as transfer functions

Minor bug fixes and updates, mainly addressing a bug in the way demodulation phases were implemented.

• added an example about the use of 3F signals.
• beam_nocurv() function not working properly
• user specified window dimension for numerical computation was not considered
• fixed but in beam() function
• demodulation phases were not treated consistently in different functions
• documentation fixes

This version introduces a large number of new features, including: maps on beam splitters and radiation pressure on beam splitters.

New features

• MAPS:
  • The way maps are handled has been changed in this version. Now mirror objects can have a surface map (measured in meters of displacement with respect to the reference sphere, positive when the surface is displaced toward the first node). This surface map is taken into account for both the reflected field and the transmitted field, the latter only in the case where the mirror separates two spaces with different index of refraction.
  • Mirrors now can have a reflectivity map, which allows the user to simulate non uniform reflectivity in the surface. The map is a measure of the relative deviation with respect to the nominal uniform power reflectivity R0: R(x,y) = R0 * (1 + rmap(x,y))
  • Spaces can have transmission maps, to simulate the effect of substrate
    inhomogeneities. The map is measured in radians of additional delay in propagation
    and are applied to the beam at the first node of the space element.
  • Beam splitter also can have surface and reflectivity maps, with the same
    definition of the mirror case... read more

This version implements some minor bug fixes:

• fixed a bug that gave an error when changing a space length. It has been introduced in version 1.4.0 due to functions renaming for APIs

• fixed a bug that prevented a proper update of modulator frequencies at run time

This version introduces few new features that have been requested by the users:

• TransferFunction() method introduces a single function call to compute multiple transfer functions and frequency-dependent optical matrices.
• Sweep() method introduces a new way to compute the value of many signals while linearly sweeping some of the simulation parameters
• A new set of API functions have been added. They allow the user to create a MIST configuration directly from MATLAB, without having to write a separate configuration file. Please refer to the toolbox documentation for a list of these functions and for two examples.

This version addresses some bug fixes related to modulation.

In this version the filter object has the capability of implementing a low pass filter for the sidebands, thus providing a simple inexpensive way to build an ideal output mode cleaner.

This version contains some important bug fixes:

• solved a problem that prevented update of the simulation when changing the driving motion shape
• solved a bug in the modulator code, sometimes sidebands were not properly generated
• solved a bug that prevented MIST to run radiation pressure simulation in some specific configurations (like two FP cavities without recycling)
• solved a bug that prevented good results with dual recycled interferometer... read more

This version contains some bug fixes that prevented MIST to run with some particular configurations involving beam splitters, transfer functions and radiation pressure.

• Changes and new features:

  • compilation time is now largely reduced
  • added a "filter" object that can be used to filter out higher order modes selectively

• Fixed bugs:

  • error when using multiple cavity commands
  • wrong accounting of dependencies in laser and modulator equations

• there was an issue in mirror and beam splitter parameters definition, solved
• there was a problem when using subtrates with refractive index different from one, solved
• there was a problem when setting mirror diameters and refractive indexes

The latest version of MIST, released today, now finally includes radiation pressure effects. Have a look at the examples provided with the package, to see how you can simulate longitudinal and angular opto-mechanical couplings, as well as parametric instabilities in resonant cavities.

Version 1.3.0 (2013-09-09)

• New features:
  • mirror objects can be driven by RADIATION PRESSURE effects. Now MIST is completely able to simulate opto-mechanical effects.
  • new engine for compling the configuration file, much faster than before
  • added the possibility to define the diameter of a mirror
  • added the possibility of forcing the Gouy phase of a space... read more

Now MIST can compute transfer functions!

New features:

• it is possible to use more than one laser source. All sources are considered coherent. The input field and the input power of each source can be set using properties of the laser objects.

• now MIST can compute TRANSFER FUNCTIONS, i.e. the optical response of fields and probes to motions or modulations of mirrors, beam splitters, lasers and spaces NOTE: The documentation is not yet fully updated on this topic. See the example in the documentation for a primer... read more

Minor bug fixes

• when changing a mirror map on the fly during simulation, the mode coupling matrix was erroneously saved to disk, overwriting the reference one.

Implemented a new engine which provides faster results with low number of modes

This version introduces two critical bug fixes:

• error in equation solver that generated unsolved recursive call of field computation
• error in code creator that prevented using MIST with complex system (with more than 9 inversions)

This version fixes the following bugs:

• error related to equation solver and nodes with beam propagating in only one direction.

It also introduces new features:

• added command to retrace Gaussian beam parameters at simulation time;

• by default now MIST uses the same Gaussian beam parameter for both directions of propagations. This behavior can be changed using the "bidirectional command";

Modal Interferometer Simulation Tool (MIST) is a MATLAB toolbox that can simulate arbitrary resonant optical systems in the paraxial beam approximation. It allows the user to define any optical setup (composed typically of laser sources, mirrors, lenses, electro-optical modulators and detectors) and to compute the static laser field at any point. It uses a Hermite-Gauss modal decomposition to simulate diffraction limited optics.
This tool is being developed mainly for simulation of large scale interferometers with resonant cavities used for the detection of gravitational waves.... read more