## Depth probe simulation

Depth probe simulation is an auxiliary simulation type, which helps to visualize the total intensity in dependence on the beam incidence angle and the position in the sample.

#### Compute intensity

To compute the total wave intensity as function of $\alpha_\text{i}$ and z, use

    import bornagain as ba
    scan = ...
    sample = ...
    z_axis = ba.EquiDivision("z (nm)", nz, z_min, z_max)
    simulation = ba.DepthprobeSimulation(scan, sample, z_axis)
    # ... set options
    result = simulation.simulate()

Supported scan types: grazing angle scan, wavelength scan, wavenumber qz scan.

For the constructor arguments, see sections scan, sample.

For optional settings, see simulation options.

For the return type of function `simulate()`, see Datafield.

#### Partial waves, modulus, phase

The constructor takes an optional `flags` argument

    simulation = ba.DepthprobeSimulation(scan, sample, z_axis, flags)

Flags may designate a partial beam

    ba.ZDirection_None        # = 0, may be ommitted: total field
    ba.ZDirection_Reflected   # = 1, reflected beam only
    ba.ZDirection_Transmitted # = 2, transmitted beam only

or/and a property of the simulated wave field

    ba.WaveProperty_Intensity # = 0, may be ommitted: intensity, |psi|^2
    ba.WaveProperty_Modulus   # = 4, modulus of wave amplitude, |psi|
    ba.WaveProperty_Phase     # = 8, phase of wave amplitude, arg(psi), in rad

To combine flags from each of these groups, combine them with the “or” operator:

    flags = ba.ZDirection_Reflected | ba.WaveProperty_Modulus

#### Examples

- Basic example: thin film on substrate
- Transmitted amplitude modulus
- Resonator

- Introduction
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- Literature
  - Babonneau2010
  - Babonneau2013
  - Croset2021
  - Lazzari2002
  - Lazzari2006
  - Pospelov2020
  - Renaud2009
  - Sears1992
  - Wuttke2021

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