optics{ global_illumination{ } }

• usage: $\mathrm{optional}$

• items: maximum 1

This group is defining a spectrum of radiation illuminating modelled device.

Note

Lorentzian, Gaussian and Planck illumination spectra are fully additive, i.e. several of each can be added as needed in order to synthesize more complex illumination spectra.

Hint

Spectral data can be defined in the database (see also Optical groups in database{ } for list of predefined illumination spectra), in the database section of the input file, or imported from external files.

Important

The following general conditions must be satisfied when defining optics{ global_illumination{ } }

• Maximum one of the following can be defined: database_spectrum{ }, import_spectrum{ }, constant_spectrum{ } within this group.

• Exactly one of the following must be defined: direction_x, direction_y, direction_z within this group.

• If global{ simulate1D{ } } is specified in the input file, then direction_y and direction_z are not allowed.

• If global{ simulate2D{ } } is specified in the input file, then direction_z is not allowed.

---

---

Maintained Keywords

The keywords below are available in at least one of currently published releases and are planned to be included also in the next release.

---

direction_x

• usage: $\mathrm{optional}$

• type: integer

• values: $z=-1$ or $z=+1$

• unit: $-$

Sets ascending $+1$ or descending $-1$ direction of illuminating radiation along the $x$-axis of simulation.

---

direction_y

• usage: $\mathrm{optional}$

• type: integer

• values: $z=-1$ or $z=+1$

• unit: $-$

Sets ascending $+1$ or descending $-1$ direction of illuminating radiation along the $y$-axis of simulation.

---

direction_z

• usage: $\mathrm{optional}$

• type: integer

• values: $z=-1$ or $z=+1$

• unit: $-$

Sets ascending $+1$ or descending $-1$ direction of illuminating radiation along the $z$-axis of simulation.

---

database_spectrum{ }

• usage: $\mathrm{optional}$

• items: maximum 1

Importing one of several spectra (solar spectra, CIE illuminants, coefficient, reflectivity, …), which can be found in the database file Optical groups in database{ }. Relative intensities (e.g. CIE illuminants) are normalized to 1.0 ${\mathrm{W}/\mathrm{m}}^2$

---

database_spectrum{ name }

• usage: $\mathrm{required}$

• type: character string

Name of the illumination spectrum contained in the database to be used.

---

database_spectrum{ concentration }

• usage: $\mathrm{optional}$

• type: real number

• values: [0.0, ...)

• default: $r=1.0$

• unit: $-$

Scaling factor multiplying the values of the spectrum.

---

import_spectrum{ }

• usage: $\mathrm{optional}$

• items: maximum 1

Importing spectrum from a file

Important

The following general conditions must be satisfied when defining import_spectrum{ }

• The import{ } must be specified in the input file.

---

import_spectrum{ import_from }

• usage: $\mathrm{required}$

• type: character string

Reference name used in the import{ } group to label the imported spectrum.

---

import_spectrum{ cutoff }

• usage: $\mathrm{required}$

• type: choice

• values: yes or no

If set to yes, then the values of the spectrum which are outside the definition interval are set to zero. Otherwise, the spectrum is extrapolated as a constant with the value on the boundary of the imported data.

---

import_spectrum{ energy_spectrum }

• usage: $\mathrm{optional}$

• type: choice

• values: yes or no

• default: no

If set to yes, then the imported spectrum is assumed to be given as a function of energy. Otherwise, the spectrum is assumed to be given as a function of wavelength.

---

import_spectrum{ absolute_intensities }

• usage: $\mathrm{required}$

• type: choice

• values: yes or no

• default: yes

If set to yes, then the values are directly imported without normalization. Otherwise, the values of the imported spectrum are normalized to the total intensity of the spectrum.

---

import_spectrum{ concentration }

• usage: $\mathrm{optional}$

• type: real number

• values: [0.0, ...)

• unit: $-$

• default: $r=1.0$

Scaling factor multiplying the values of the spectrum.

---

constant_spectrum{ }

• usage: $\mathrm{optional}$

• items: maximum 1

Define illumination source with a constant radiation spectrum of the form

$$I(E)=\frac{I_0}{E_{\max }-E_{\min }}$$

---

constant_spectrum{ irradiance }

• usage: $\mathrm{required}$

• type: real number

• values: [0.0, ...)

• unit: $\mathrm{W}/{\mathrm{m}}^2$

Total intensity :math:` I_0 = int I(E)dE` of the spectrum, integrated from $E_{\min }$ to $E_{\max }$.

---

planck_spectrum{ }

• usage: $\mathrm{optional}$

• items: no constraints

Define illumination source with a black-body radiation spectrum

$$I(E,T)=\frac{I_0}{\sigma T^4}\frac{2\pi E^3}{c^2{h}^3}\frac{1}{\exp \left(\frac{E}{k_{B}T}\right)-1},$$

where $\sigma$ is the Stefan–Boltzmann constant.

---

planck_spectrum{ irradiance }

• usage: $\mathrm{required}$

• type: real number

• values: [0.0, ...)

• unit: $\mathrm{W}/{\mathrm{m}}^2$

Total intensity :math:` I_0 = int I(E)dE` of the spectrum

---

planck_spectrum{ temperature }

• usage: $\mathrm{required}$

• type: real number

• values: [1e-6, ...)

• unit: $\mathrm{K}$

Temperature $T$ entering the spectrum model

---

lorentzian_spectrum{ }

• usage: $\mathrm{optional}$

• items: no constraints

Define illumination source with a Lorentzian radiation spectrum

$$I(E)=\frac{I_0}{\pi }\frac{\mathrm{\Gamma }/2}{(E-E_0)+(\mathrm{\Gamma }/2{)}^2}$$

Important

The following general conditions must be satisfied when defining lorentzian_spectrum{ }

• Exactly one, lorentzian_spectrum{ wavelength } or lorentzian_spectrum{ energy } is specified within this group.

• Exactly one, lorentzian_spectrum{ width } or lorentzian_spectrum{ gamma } is specified within this group.

---

lorentzian_spectrum{ irradiance }

• usage: $\mathrm{required}$

• type: real number

• values: [0.0, ...)

• unit: $\mathrm{W}/{\mathrm{m}}^2$

Total intensity :math:` I_0 = int I(E)dE` of the spectrum

---

lorentzian_spectrum{ wavelength }

• usage: $\mathrm{optional}$

• type: real number

• values: [10.0, ...)

• unit: $\mathrm{nm}$

Central wavelength ${\lambda }_0$ of the spectrum

---

lorentzian_spectrum{ energy }

• usage: $\mathrm{optional}$

• type: real number

• values: [1e-6, ...)

• unit: $\mathrm{eV}$

Central energy $E_0$ of the spectrum

---

lorentzian_spectrum{ width }

• usage: $\mathrm{optional}$

• type: real number

• values: [1e-3, ...)

• unit: $\mathrm{nm}$

Define the width of the spectrum in nm

---

lorentzian_spectrum{ gamma }

• usage: $\mathrm{optional}$

• type: real number

• values: [1e-6, ...)

• unit: $\mathrm{eV}$

Define the width of the spectrum in eV

---

gaussian_spectrum{ }

Define illumination source with a Gaussian spectrum

• usage: $\mathrm{optional}$

• items: no constraints

$$I(E)=\frac{I_0}{\sqrt{2\pi }\sigma }\exp [-\frac{(E-E_0{)}^2}{2{\sigma }^2}]$$

Important

The following general conditions must be satisfied when defining gaussian_spectrum{ }

• Exactly one, gaussian_spectrum{ wavelength } or gaussian_spectrum{ energy } is specified within this group.

• Exactly one, gaussian_spectrum{ width } or gaussian_spectrum{ gamma } is specified within this group.

---

gaussian_spectrum{ irradiance }

• usage: $\mathrm{required}$

• type: real number

• values: [0.0, ...)

• unit: $\mathrm{W}/{\mathrm{m}}^2$

Total intensity :math:` I_0 = int I(E)dE` of the spectrum

---

gaussian_spectrum{ wavelength }

• usage: $\mathrm{optional}$

• type: real number

• values: [10.0, ...)

• unit: $\mathrm{nm}$

Central wavelength ${\lambda }_0$ of the spectrum

---

gaussian_spectrum{ energy }

• usage: $\mathrm{optional}$

• type: real number

• values: [1e-6, ...)

• unit: $\mathrm{eV}$

Central energy $E_0$ of the spectrum

---

gaussian_spectrum{ width }

• usage: $\mathrm{optional}$

• type: real number

• values: [1e-3, ...)

• unit: $\mathrm{nm}$

Define the width of the spectrum in nm

---

gaussian_spectrum{ gamma }

• usage: $\mathrm{optional}$

• type: real number

• values: [1e-6, ...)

• unit: $\mathrm{eV}$

Define the width of the spectrum in eV

---

Examples

constant_spectrum{
        irradiance = 10000.0  # in [W/m^2], integrated as min_energy...max_energy
}

planck_spectrum{
    irradiance = 10000.0  # in [W/m^2], for complete(!) Planck spectrum; real value >= 0.0
    temperature = 5000.0  # real value >= 1e-6
}

global_illumination{
    direction_x = 1

    database_spectrum{
        name = "Solar-ASTM-G173-global"
    # name = "CIE-D75"
        concentration = 300 # e.g. 300 suns
    }
}

global_illumination{
    direction_x = 1

    import_spectrum{
        import_from = "filename"
        cutoff = yes  # yes/no: If yes, set values outside definition interval to zero.
                    # (default=?)
        absolute_intensities = yes  # yes/no (default: yes)
                                    # If no, spectrum does not contain absolute values,
                                    # normalize intensity to 1 [W/cm^2 nm^-1] before concentration
        concentration = 300 # e.g. 300 suns
    }
}

lorentzian_spectrum{
        irradiance = 10000.0  # in [W/m^2], for complete(!) Lorentzian spectrum; real value >= 0.0

        # Specify either wavelength and width, or ...
        wavelength = 500.0   # real value >= 10.0 in |unit:nm|
        width = 100.0        # real value >= 1e-3 in |unit:nm|

        # ... specify energy and gamma.
        energy = 2.5         # real value >= 1e-6 in |unit:eV|
        gamma = 1.0          # real value >= 1e-6 in |unit:eV|
}

gaussian_spectrum{
    irradiance = 1000.0  # in [W/m^2], for complete(!) Gaussian spectrum; real value >= 0.0

    # Specify either wavelength and width, or ...
    wavelength = 500.0   # real value >= 10.0 in |unit:nm|
    width = 100.0        # real value >= 1e-3 in |unit:nm|

    # ... specify energy and gamma.
    energy = 2.5         # real value >= 1e-6 in |unit:eV|
    gamma = 1.0          # real value >= 1e-6 in |unit:eV|
}