Added optika.sensors.AbstractChemical.absorption() function. (#38)

optika/chemicals/_chemicals.py

@@ -160,6 +160,21 @@ def wavenumber(
  """
  return np.imag(self.n(wavelength))
 
+ def absorption(
+ self,
+ wavelength: u.Quantity | na.AbstractScalar,
+ ):
+ """
+ The absorption coefficient of this chemical for the given wavelength.
+
+ Parameters
+ ----------
+ wavelength
+ The wavelength of light in vacuum for which to compute the
+ absorption coefficient.
+ """
+ return 4 * np.pi * self.wavenumber(wavelength) / wavelength
+
 
 @dataclasses.dataclass(eq=False, repr=False)
 class Chemical(

optika/chemicals/_tests/test_chemicals.py

@@ -60,6 +60,16 @@ def test_wavenumber(
  assert isinstance(result, na.AbstractScalar)
  assert np.all(result >= 0)
 
+ @pytest.mark.parametrize("wavelength", _wavelength)
+ def test_absorption(
+ self,
+ a: optika.chemicals.AbstractChemical,
+ wavelength: u.Quantity | na.AbstractScalar,
+ ):
+ result = a.absorption(wavelength)
+ assert isinstance(result, na.AbstractScalar)
+ assert np.all(result >= 0)
+
 
 @pytest.mark.parametrize(
  argnames="a",

optika/sensors/_materials/_materials.py

@@ -420,9 +420,7 @@ def attenuation(
  self,
  rays: optika.rays.AbstractRayVectorArray,
  ) -> na.ScalarLike:
- result = self._chemical.wavenumber(rays.wavelength)
- result = 4 * np.pi * result / rays.wavelength
- return result
+ return self._chemical.absorption(rays.wavelength)
 
  @property
  def is_mirror(self) -> bool: