Refractive index database

nk database   |   n2 database   |   about




Optical constants of NH4H2PO4 (Ammonium dihydrogen phosphate, ADP)
Zernike et al. 1964: n(e) 0.214–1.53 µm

Wavelength: µm

Complex refractive index (n+ik)[ i ]

n   k   LogX   LogY   eV

Derived optical constants

Dispersion formula [ i ]



24.8 °C. Extraordinary ray (e).


F. Zernike, Jr. Refractive Indices of Ammonium Dihydrogen Phosphate and Potassium Dihydrogen Phosphate between 2000 Å and 1.5 µ, J. Opt. Soc. Am. 54, 1215-1219 (1964). Cited in Handbook of Optics, 3rd edition, Vol. 4. McGraw-Hill 2009.


[Expressions for n]   [CSV - comma separated]   [TXT - tab separated]   [Full database record]


Ammonium dihydrogen phosphate, NH4H2PO4 (ADP)

Ammonium dihydrogen phosphate (NH4H2PO4), commonly known as ADP, is a white, crystalline solid that readily dissolves in water. In the realm of optics, ADP crystals have been employed for various applications due to their nonlinear optical properties. These crystals are particularly valuable for frequency doubling of laser light, especially in the ultraviolet range. ADP crystals exhibit birefringence, which makes them suitable for modulating light and serving as Pockels cells. Additionally, these crystals are used in optical parametric oscillators. Beyond optics, ADP is used as a fertilizer, given its high phosphate content. It also serves as a component in some fire extinguishers and is involved in various biological processes as a source of phosphorus and nitrogen.

Other names

  • Monoammonium phosphate (MAP)
  • Ammonium phosphate

External links