Description
Convert spectral density per frequency to per wavelength.
Spectral and radiation quantities depend on their denominator coordinates, reference levels and physical definitions. A density per wavelength changes by a Jacobian when expressed per frequency, and photon counts, radiant energy, exposure and absorbed dose remain different quantities.
Convert spectral density per frequency to per wavelength.
When to use this tool
Use Spectral Flux Frequency Wavelength Jacobian when checking the stated spectral, photon, attenuation or radiometric conversion.
How to use the tool and how it works
- Enter perFrequency, wavelength, lightSpeed. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read perWavelength. Use the output convention below.
Convert spectral density per frequency to per wavelength. Require wavelength/lightSpeed > 0; perWavelength = perFrequency*lightSpeed/wavelength².1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| perFrequency | Per Frequency | Required. Finite number. |
| wavelength | Positive wavelength; metres with SI lightSpeed produce density per metre. | Required. Finite number; strictly above 0. |
| lightSpeed | Light Speed | Required. Finite number; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| perWavelength | Per Wavelength | Required. Finite number. |
{
"input": {
"perFrequency": 4,
"wavelength": 2,
"lightSpeed": 299792458
},
"output": {
"perWavelength": 299792458
}
}Limitations and assumptions
- Use a consistent wavelength and speed unit, such as metres and m/s for per-metre output; this changes a density, not merely its coordinate label.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use a complete spectrum, measurement calibration and appropriate physical interaction model for integration, uncertainty or exposure interpretation.
References
Similar or alternative tools
- Spectral Irradiance Wavenumber Jacobian
Apply a wavelength-to-wavenumber density Jacobian.
- Spectral Angular Frequency Frequency Density
Convert density per angular frequency to density per hertz.