ALKOR Technologies - your CRYSTAL optics supplier.   ALKOR Technologies - your CRYSTAL optics supplier.
ALKOR Technologies - your CRYSTAL optics supplier.
Materials>>KBr

Potassium Bromide (KBr). KBr windows and beamsplitters

Manufacturer of KBr optical components: KBr windows (drilled and undrilled), KBr wedges and KBr beamsplitters according to customer's specifications. Moisture protective coating (Parylene analog) can be applied on all KBr windows.

The largest diameter of KBr optics is 100mm. Please contact Sales Team for more information.

Please visit our KBr windows catalog.

Drilled KBr windows

KBr transmission. Sample thickness 10mm

KBr transmittance. Sample thickness 10mm.

Potassium Bromide is used for windows, lenses and prisms when transmission through the range 0.25µm to 26µm is desired. Potassium Bromide (KBr) is a material commonly used in FTIR spectroscopy (drilled KBR windows). Potassium Bromide is water soluble and KBr windows must be protected against moisture degradation of polished surfaces.

Alkor provides special anti-moisture polymer coating - Parylene analog to protect KBr optics. KBr windows cleaves readily, and can be used at temperatures up to 300C. Irradiation of Potassium Bromide produces color centers.

Packing: All KBr optics carefully packaged into plastic boxes with silicagel and sealed with special moisture protective film.

KBr properties

Chemical Formula KBr
Molecular Weight 119.01
Crystal Class Cubic
Lattice Constant, Å 6.60
Density, g/cm3 at 300 K 2.75
Absorption Coefficient, 1/cm
at 2.7 µm
at 3.8 µm

1.2 x 10-4
1.6 x 10-4
Reflection Loss for two surfaces at 10 µm, % 8.4
Dielectric Constant
for 102-1010 Hz at 298 K
for 102-1010 Hz at 360 K

4.9
4.97
Melting Temperature, K 1000
Thermal Conductivity, W/(m K) at 319 K 4.8
Thermal Expansion, 1/K at 300 K 38.5 x 10-6
Specific Heat, cal/(g K) at 273 K 0.104
Debye Temperature, K 174
Bandgap, eV 7.6
KBr Solubility, g/100 g H2O at 273 K 53.48
Knoop Hardness, kg/mm2 7.0 [100]
Young's Modulus, GPa 26.87
Rupture Modulus, GPa 0.0039
Shear Modulus, GPa 5.08
Bulk Modulus, GPa 15.02

KBr - Refractive Index

µm No µm No µm No
0.405 1.5898 0.436 1.5815 0.486 1.5718
0.508 1.5684 0.546 1.5639 0.587 1.5600
0.643 1.5559 0.707 1.5524 1.014 1.5441
2.440 1.5373 3.419 1.5361 4.258 1.5352
6.238 1.5329 8.662 1.5290 9.724 1.5270
11.04 1.5240 14.29 1.5150 17.40 1.5039
19.91 1.4929 23.86 1.4714 25.14 1.4632
28.00 1.4423 30.00 1.4253