Variable "time.pulse" in MATLAB version of WavePacket
Specifies the electric field(s) to be used to externally control a quantum system by interaction with a dipole moment and/or a polarizability. The time-dependence of the electric field is constructed as a sum of pulses each of which is given by the expression F(t) = A(t−τ) cos(ω(t−τ)⋅(t−τ)+φ0) with amplitude (pulse shape) vector A(t), delay τ, and phase φ0. The carrier frequency is given by ω(t)=ω0+αt+½βt², optionally with linear and/or quadratic chirp.
In the following, we give a complete list of the pulse shape classdef's along with their settable properties, see also the corresponding package folder.
| efi.generic (sourceforge.net) |
generic classdef from which all of the classdef's below inherit properties |
default |
| fwhm |
Full width at half maximum |
0 |
| ampli |
Maximum amplitude F0 of the pulse |
0 |
| delay |
Delay time τ of the center of the pulse |
0 |
| frequ |
Constant part of the (carrier) frequency ω0 of the pulse |
0 |
| phase |
Phase shift φ0 of the pulse |
0 |
| linear |
Linear part α of the chirp |
0 |
| quadratic |
Quadratic part β of the chirp |
0 |
| polar |
Polarization angle of each pulse. Angles 0 and π/2 stand for x and y, resp. |
0 |
| efi.gauss (sourceforge.net) |
Gaussian envelope g(t−τ) = exp(−(t−τ)²/(2σ²) |
| fwhm |
The full width at half maximum is related to the variance σ = FWHM / √(8 ln 2). |
| efi.recta (sourceforge.net) |
Rectangular pulse g(t−τ) = Θ(abs(t−τ)−w/2) |
| fwhm |
The length w of the pulse. |
| efi.sin^2 (sourceforge.net) |
Squared sine shape g(t−τ) = sin²(π(t−τ)/(2T)+π/2)= cos²(π(t−τ)/(2T)) |
| fwhm |
The half-width T of the pulse. |
Note: The shifted sin² pulse shape is actually rather a cos² but we keep this notation for reasons of backward-compatibility.
| efi.inter (sourceforge.net) |
interpolates the shape function g(t) from data points in an external file (see the manual for details on interpolation). Outside of the interval of given time values, the electric field is set to 0. |
| file |
Name of file from which to load the tabulated shape function. If complex fields are to be used, then the real and imaginary part should be in the second and third column, respectively. Time is always in the first column. |
| method |
The method to use for interpolation. Method 'spline' is recommended which is also the default. |
| t_conv |
Optional: Conversion factor to apply to the time values. The values in the file are given in units of ''t_conv'' atomic units. Default is 1. |
| f_conv |
Optional: Conversion factor to apply to the field values. The values in the file are given in units of ''f_conv'' atomic units. Default is 1. |
Trick: If not only the shape function but the whole pulse including the oscillations (i.e. electric field versus time) shall be interpolated from tabulated data, then all other variables have to be set to dummy values in order to suppress the oscillatory part.
time.pulse{1} = 'inter';
time.pulse{1}.ampli = 1;
time.pulse{1}.delay = 0;
time.pulse{1}.frequ = 0;
time.pulse{1}.phase = 0;
time.pulse{1}.polar = 0;
time.pulse{1}.file = 'field.dat';
time.pulse{1}.method = 'spline';
