chirpWavePulse

chirpWavePulse

Works with VSimBase, VSimEM, VSimPD, VSimPA, and VSimVE licenses.

Produces a plane wave modulated by a pulse envelope, where the envelope is a half-sine function along the direction of motion, and it is Gaussian transverse.

chirpWavePulse Parameters

vg (float)

Group velocity by which the origin of the envelope is moved.

amplitude (float)

Amplitude of the pulse.

phase (float)

Additional phase of the sinusoid.

keepon (option)

If true, pulse is on after rises to max value.

origin (float vector)

Origin of the envelope.

widths (float vector)

Widths of the pulse.

• widths[0] (float)

  Width along the direction of motion. This is half the width of the non-zero extent of the half-sine, or the FWHM of the square of the half-sine.

• widths[1] (float)

  Width along the direction of perpendicular to \({\bf k}\) and the third (index 2) axis, unless \({\bf k}\) is along the third (index 2) axis, in which case this is the width along the first (index 0) axis. The width for transverse directions is the full width at the \(\frac{1}{\sqrt{e}}\) points.

• widths[2] (float)

  Width along the direction of perpendicular to \({\bf k}\) and the direction for widths[1].

chirp (float)

The chirp of the pulse is equal to the change in frequency during the full width at half power max; a positive chirp indicates rising frequency along the pulse.

skewness (float)

Skewness in the pulse; positive skewness.

waistDisplacement (float)

Displacement of the waist along the direction of propagation.

Example chirpWavePulse Block

<STFunc component0>
  kind = chirpWavePulse
  chirp = -0.9
  amplitude = 5.0e+12
  phase = 1.57
  k = [125.6 0. 0.]
  vg = LIGHTSPEED
  widths = [1.e-1  2.e-1 2.e-1]
  origin = [-1.e-1 0.e-5 0.e-5]
</STFunc>