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Self-Phase Modulation

This branch is being updated to 1.0 via julia 0.7. Most of the work has been done, there's just a bunch of little deprecations to work through.

Code for simulation of SPM on laser pulses through hollow optical fibers from matlab -> julia

Done by Rigel Zifkin and Joseph McGowan as part of our undergraduate thesis.

julia -p <number of sims to run at once/cores to use> MultiThread.jl <Parameter File> <Number of times to save data>

Parameters

Parameters are input as either single numbers, or a triplet defining a range. In both cases, the parameter must be surrounded by square brackets '[]'. Ranges are given as [<min value>, <max value>, <step size>].

All parameters in the following list must be defined, and no others are available:

  • Energy - The total energy of the laser pulse in Joules.
  • Tfwhm - The full-width half-maximum pulse duration in seconds.
  • lambda - The central wavelength of the pulse in meters.
  • Pin - Pressure in bar at fiber entrance.
  • Pout - Pressure in bar at fiber exit; set equal to Pin for static pressure.
  • Chirp - Chirp value of pulse in femtoseconds^2.
  • fiberD - Diameter of optical fiber in meters.
  • dz - The spatial step of the simulation in seconds.
  • zmax - The simulation length (i.e. the length of the fiber) in meters.
  • Nt - Number of points in data grid.
  • tmax - The max time in seconds before/after the central peak of the pulse to simulate; defines max values for spatial and Fourier space. View params.yaml for an example.

Analysis

We've provided some Python code for analyzing the data sets produced from multiple simulations; these are locaded in the Analysis folder.

As is, the easiest way to import and use it all is to include the following in a script:

from plot import *

with a single directory containing one subfolder for each simulation run. The following loads the entire data set:

fibs = fs.load(<path/to/data>)

This will load in the data set, and for each one, load in or compute some useful metrics:

  • pwidth - Full-width half-maximum of pulse in femtoseconds.
  • bwidth - Full-width tenth-maximum of pulse spectrum in nm.
  • l_edge - Leftmost edge used to calculate bwidth in nm
  • r_edge - Rightmost edge used to calculate bwidth in nm
  • rho_max - Maximum plasma density during simulation in ions/cubic milimeter.
  • power - Ratio of final power to initial power.

The parameters will also be loaded in, and for ease of use, converted to typically used orders of magnitude.

Todo

  • Translate Main Loop
  • Translate "PPT.m"
  • Turn chunks of main loop into functions
  • Optimize (This will never be crossed out)
  • Test
  • Use plan fft/ifft to speed up all the transforms
  • Multi-Thread drifting
  • Fix analysis scripts

Citations

Original code adapted from simulation code used in:

P. Béjot, B. E. Schmidt, J. Kasparian, J.-P. Wolf, and F. Legaré, “Mechanism of hollow-core-fiber infrared-supercontinuum compression with bulk material,” Physical Review A, vol. 81, no. 6, Jun. 2010.

If you use our code, we ask that you cite:

Coming Soon