Refractive index of water

The refractive index, usually abbreviated as \(n\) varies with temperature and wavelength.

Usage

water_n(temperature = 20, w.length = 540, type = "freshwater")

Arguments

temperature

numeric Water temperature in degrees Celcius (C)

w.length

numeric Wavelength in nanometres (nm)

type

character One of "freshwater" or "seawater".

Details

Function `n.water()` implements the function proposed by Parrish for approximation of \(n\) for freshwater and seawater. The function is valid for wavelengths from 400 nm to 700 nm, and for temperatures from 0 C to 30 C. The function is vectorized.

References

Chris Parrish (2020) Index of Refraction of Seawater and Freshwater as a Function of Wavelength and Temperature. https://research.engr.oregonstate.edu/parrish/index-refraction-seawater-and-freshwater-function-wavelength-and-temperature

See also

For other materials see refractive_index.mspct and to compute reflectance from \(n\) see Rfr_from_n.

Examples

water_n(w.length = (40:70)*10)
#>  [1] 1.342809 1.342097 1.341405 1.340734 1.340084 1.339454 1.338845 1.338257
#>  [9] 1.337689 1.337142 1.336616 1.336110 1.335625 1.335160 1.334717 1.334293
#> [17] 1.333891 1.333509 1.333148 1.332807 1.332487 1.332188 1.331909 1.331651
#> [25] 1.331414 1.331197 1.331001 1.330825 1.330670 1.330536 1.330423
water_n(temperature = seq(0, 30, by = 5))
#> [1] 1.335679 1.335587 1.335396 1.335106 1.334717 1.334229 1.333642