Calcite (CaCO3) Crystals
Calcite is well known material for polarization optics. Due to structural anisotropy it has two refractive indices. So it divides an entering beam of monochromatic light into two beam having opposite polarization. This phenomenon is used to build polarization components. As the difference in the two refractive indices is very large calcite has become the most popular crystal in polarization applications.
ELAN uses natural Calcite minded from a few locations in Siberia, Russia. We differ calcite into 3 basic grade.
Grade “Unique”
Calcite that meets this grade exhibits no striae and scatter when examined by He - Ne laser. This is the highest quality material that should be used to fabricate high power laser optics only. |
Grade “Extra”
Material exhibits only light scatter and no striae when examined by He - Ne. Ligth scatter means one can see a few single centers of scatter or very weak laser beam track inside material. It is high quality material for fabrication of medium and high power laser optics. |
Grade “First”
Exhibits scatter and only light striae when examined by He - Ne laser. This good quality material is widely used to fabricate calcite optics. Majority of ELAN's products in this brochure are manufactured from this grade. We also use it to fabricate low and medium power laser optics.
Also calcite is classified to material of UV, VIS and IR quality depending on useful spectral range. |
UV material
Colorless material characterized by high transmission in UV range and widest useful spectral range (0.22 - 2.3
mkm). |
VIS material
Colorless or may have light yellow tint, transmits some amount of light in UV, for use at
0.35 - 2.3 mkm. |
IR material
It normally has yellow color and therefore reduced transmission at visible wavelengths shorter than 550 nm. We recommend to use it for range 0.55 - 2.3
mkm. |
Note: to specify material one should indicate one of the basic grades and transmission grade.
Examples: UV Extra, IR First.
Material propeties
| Chemical Formula |
CaCO3 |
| Crystal Structure |
Rhombohedral |
| Density, g/cm3 |
2.7 - 2.9 |
| Melting point, °C |
1612 |
| Mohs Hardness |
3.0 |
| Heat Capacity, cal/gK, at 20°C |
0.20 |
| Thermal Expansion Coefficient, 10-6 K-1 |
a^= 24.5
a|| = 5.7 |
| Thermal conductivity, cal / cm S K |
æ^= 0.0090
æ|| = 0.0083 |
| Transmission Range, microns |
0.24 - 1.90 |
Refraction indices
| Wavelength |
ne
|
no |
0,1318
0,1355
0,1411
0,1447
0,1467
0,1478
0,1487
0,1495
0,1513
0,1518
0,1536
0,1544
0,1558
0,1581
0,1596
0,1608
0,162
0,1633
0,1662
0,17
0,18
0,19
0,198
0,2
0,204
0,208
0,211
0,214
0,219
0,226
0,231
0,242
0,257
0,263
0,267
0,274
0,291
0,303
0,312
0,33
0,34
0,346
0,361
0,394
0,41
0,434
0,441
0,508
0,533
0,56
0,589
0,643
0,656
0,67
0,706
0,768
0,795
0,801
0,833
0,867
0,905
0,946
0,991
1,042
1,097
1,159
1,229
1,273
1,307
1,32
1,396
1,396
1,422
1,497
1,497
1,541
1,609
1,615
1,682
1,749
1,761
1,849
1,909
1,946
2,053
2,1
2,172
3,324 |
1,8
1,84
1,82
1,8
1,75
1,75
1,75
1,75
1,75
1,74
1,74
1,74
1,74
1,73
1,72
1,7
1,65
1,65
1,64
1,63
1,61
1,59
1,57796
1,57649
1,57081
1,5664
1,56327
1,55976
1,55496
1,54921
1,54541
1,53782
1,53005
1,52736
1,52547
1,52261
1,51705
1,51365
1,5114
1,50746
1,50562
1,5045
1,50224
1,4981
1,4964
1,4943
1,49373
1,48956
1,48841
1,48736
1,4864
1,4849
1,48459
1,48426
1,48353
1,48259
1,48215
1,48216
1,48176
1,48137
1,48098
1,4806
1,48022
1,47985
1,47948
1,4791
1,4787
-
1,47831
-
1,47789
-
-
1,47744
-
-
-
1,47695
-
1,47638
-
-
1,47573
-
-
1,47492
-
1,47392 |
1,56
1,48
1,4
1,48
1,51
1,54
1,58
1,62
1,68
1,72
1,8
1,87
1,92
2,02
2,14
2,2
2,1
2
2
1,94
1,7
1,72
-
1,90284
1,88242
1,86733
1,85692
1,84558
1,83075
1,81309
1,80233
1,78111
1,76038
1,75343
1,74864
1,74139
1,72774
1,71959
1,71425
1,70515
1,70078
1,69833
1,69316
1,68374
1,68014
1,67552
1,67423
1,66527
1,66277
1,66046
1,65835
1,65504
1,65437
1,65367
1,65207
1,64974
1,64886
1,64869
1,64772
1,64676
1,64578
1,6448
1,6438
1,64276
1,64167
1,64051
1,63926
1,63849
1,63789
1,63767
1,63681
1,63637
1,6359
1,6349
1,63457
1,63381
1,63261
-
1,63127
-
1,62974
1,628
-
1,62602
1,62372
-
1,62099
- |
|
