User guide

Here you will find in-depth guides on how to use Finesse in both a legacy style (for those familiar with previous versions of Finesse) and more advanced usage via the new script syntax and Python API.

• Building and interacting with models
  • KatScript
    • Quick reference
    • A quick example
    • Language fundamentals
    • Components and detectors
    • Commands and analyses
    • Ports and nodes
    • Paths
    • Expressions and references
    • Arrays
    • Generating KatScript from a model
    • Registering custom KatScript directives
  • Python Interface
    • Models and Components
    • Adding components to a model
    • Connecting components
    • Visualizing the model
    • Component freezing and unfreezing
    • Examining components
    • Saving and loading models
    • Parallel processing
    • Displaying tabulated data
    • Tracebacks in Jupyter notebooks
  • Symbolics
    • Referencing parameters
    • Variables vs ParameterRef
    • Substitution
    • Making a function from an expression
    • Preserving intent
    • two-arg vs N-arg operators
    • Basic simplification
• Model elements
  • Components and detectors
    • Optics
    • Sources
    • Connectors
    • Detectors
    • Readouts
    • Control and filtering
    • Mechanical Elements
  • Other elements
    • Variables
    • Gaussian beams
• The port and node system
  • Basic usage of ports and nodes
    • Accessing ports
    • What does a port contain?
    • Accessing nodes — via a component
    • Accessing nodes — via the model
• Commands
• Actions, Analyses, and Solutions
  • Introduction
    • The ‘xaxis’ and ‘noxaxis’ action
    • Python API
    • Solutions
    • Analysis with multiple actions - ‘series’
    • Actions and model state changes
    • Analysis with multiple actions - ‘parallel’
    • Extracting model states from an analysis
    • Action events
  • Groups
  • Axes
  • Physics
  • Utilities
• Symbolics
  • Referencing parameters
  • Variables vs ParameterRef
  • Substitution
  • Making a function from an expression
  • Preserving intent
  • two-arg vs N-arg operators
  • Basic simplification
• Modelling with higher-order modes
  • Selecting the modes to model
    • Maximum TEM order
    • Selection method
    • Assigning to modes property
    • Including additional modes
    • A note on specifying mode indices explicitly
  • Defining the modal basis
    • Using cavity objects
    • Defining manual beam parameters
    • Remove a manual beam parameter or cavity
    • Defining manual beam parameters with the Python API
  • Creating and detecting mode mismatches
    • Defining a figure of merit
    • Creating a custom mismatch
    • Detecting mode mismatches
    • Trace priority
  • Capturing beam images with camera objects
    • Detecting a single pixel
    • Capturing a full beam image
    • Producing animated beam images
  • Beam propagation
    • The ‘propagate_beam’ function
    • Symbolic beam propagation
    • Reverse beam propagation
  • Computing arbitrary scattering matrices
    • Calculating coupling matrices via the Bayer-Helms formalism
  • Adding spatial defects with maps
    • The map object
    • Optical path depths
    • Quadratic lensing with maps (What not to do)
    • Mirror surface maps
• Linear time invariant system modelling
  • Modelling transfer functions
    • Operating points: Carrier and signals — DC and AC
    • Computing transfer functions - manual method
  • Readouts for frequency domain analysis
  • Calculating general transfer functions
    • Setting up the model
    • Calculating the transfer functions
    • Frequency response of the fundamental mode
    • Frequency response between HOMs
  • Closing control loops
    • DC control loops - ‘lock’
    • AC control loops
  • Using degrees of freedom
• Viewing logs
  • Making log messages visible
    • Option 1: use ‘logging.basicConfig()’
    • Option 2: use command line interface option
    • Option 3: wrap your code in a ‘logs’ context
• Command line interface
  • Quick start
  • Getting help
  • Running KatScript files
  • Looking up KatScript syntax
  • Controlling verbosity
    • Showing or hiding log messages
    • Showing tracebacks
    • Fancy error messages
  • Keeping multiple plots open using job control
    • Bourne-compatible shells (e.g. ‘bash’)
    • Windows command prompt
  • Command reference
    • Shared options
    • kat3
    • kat3 info
    • kat3 syntax
    • kat3 convert
• Numerical precision
  • In elements
  • In simulations
• Bespoke GW Models
  • Importing finesse-ligo
  • Choosing what to model
  • Initialising the locks
  • Modelling the Interferometer
• Physics of Finesse
  • Plane-wave optics
    • Mirror and beamsplitter phase relationships
    • Tuning
    • Phase jumps in the untuned case
    • Phase jumps in the tuned case
    • Reflection
    • Modulation of light fields
    • Input fields or the ‘right hand side’ vector
    • Cavities
  • Higher-order spatial modes
    • Phase configuration settings
    • Transformation of the beam parameter
    • Cavity eigenmodes
    • Tracing the beam
    • Coupling of higher-order-modes
    • Accumulated Gouy phase
    • General optical cavity round trip Gouy phase
    • Parity transformations on reflection
    • ABCD definitions in Finesse: extra minus sign
    • Segmented photodiodes
    • Simulating off-axis beams: calculating the shift
    • Simulating off-axis beams: convergence and scaling
    • Laguerre higher order modes
  • Radiation Pressure
    • Radiation Pressure at a Mirror
  • Thermal effects
    • Thermal lensing and deformations using Hello-Vinet
    • Thermal lensing and deformations from ring heaters