ADP (ammonium dihydrogen phosphate, NH4H2PO4)
Ammonium dideuterophosphate (ND4D2PO4)
Deuterated ammonium dihydrogen phosphate, crystal D ADP is an antiferroelectric synthetic crystal with a TCurie of 240 K, belongs to uniaxial negative single crystals.
It has a high electron-optical coefficient and is used in modulators of visible and near-IR radiation (based on the Pockels effect). The value of tg d allows it to be used up to frequencies of several hundred megahertz.
To obtain the maximum shift between the ordinary and extraordinary rays, DADP Z-medium plates are usually used (i.e., cut to the optical axis).
Spectral region 0.3 - 1.52 µm.
Trab \u003d 241 ... 353 K.
Disadvantage: low mechanical strength; high hygroscopicity;
- TCurie = 240 - 241 K;
- absorption index al [1/cm] in the area of the greatest transparency is 5·10-2;
- electro-optical coefficient r63 1010, cm/V at T = 293 K and for l = 0.5461 μm it is 10.63, and for l = 0.5893 μm it is 10.50;
- e = 30;
- tg d = 0.01;
- critical (half-wave) voltage Ucr, kV at T = 293 K is 8.5;
- optical strength (threshold of surface damage, P = 5 x 102 MW/cm2 when irradiated with a laser at n = 1.06 μm).