|Density:||5.81 g/ cm3|
|Young’s Modulus:||5×1011 dyne/cm2|
|Coef. of Thermal Expansion (500 K):
||α 1=6.26×10-6/K; α 3=4.28×10-6/K|
|Thermal conductivity (at 25 °C):
|Max. Transmittance (λ =2.5-15 μm):
||≥ 71 %|
|Absorption Coef. (λ =10.6 μm):
||≤ 0.0015 cm-1 (including 2 surfaces)|
|Refractive index (λ =10.6 μm):
|| no= 2.4258, ne=2.4437
|Max. single crystal diameter/length:||Ø50.8×40 mm|
|Max. IR optic blank diameter/length:||Ø50×50 mm or plate 60×60×6 mm|
|Surface quality:||As-cut, 60/40 scratch*dig per MIL-0-13830|
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Coherent sources in the mid-IR domain have potential applications in molecular spectroscopy, biomedicine, and remote sensing. Laser systems with CdSe crystal have obvious advantage – much broader tuning range [1-3]. In the difference-mixing of the output of parametric oscillator in CdSe to obtain the phase matched 9.4-24.3 µm tuning range . CdSe crystal has its band edge in the near infrared and shows transmission far into the infrared. The long wavelength limit determined by the onset of lattice absorption 1.5 cm-1 @ 24.3µm.
There is also a narrow impurity absorption centered at 18.5um which varies from one crystal to another. As a nonlinear optical material, CdSe crystal was explored for OPG, OPO and DFG in 1970’s [4,5]. First of all, picoseconds pulses tunable from 10 to 20 µm were produced . Furthermore, CdSe was also used to achieve megawatt peak power in the range of 8-13 and 7-12 µm, based on OPG and OPO respectively [7,8].