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Cr,Tm, Ho:Yttrium Aluminum Garnet¡ªCTH:YAG
 CTH:YAG is a new crystal material which lases at 2080 nm. It has applications in medical, military and meteorological fields.
The key to efficient operation lies in the energy transfer processes between co-dopants of Cr,Tm and Ho. Cr3+ acts to effectively absorb flashlamp energy, which is then transferred to theTm3+ with an efficiency of > 90%. A Tm:Tm cross relaxation then occurs and converts this energy into the IR with a quantum efficiency approaching 2, after which the Tm:Tm energy migration facilitates an efficient Tm:Ho energy transfer.
Advantages Of Cr,Tm,Ho:YAG Include:
High-efficiency 2¦Ìm source
- Cr-Tm transfer quantum efficiency approaching 2
- Operates well at room temperature
- May be flashlamp or diode pumped
Laser diode sources can pump the strong 780nm Tm3+ ion absorption line
- Chromium doping not necessary for diode-pumped applications
- Pump linewidth of 4 nm; 4 times wider than the corresponding Nd:YAG diode-pump linewidth
Operates in a relatively eye-safe wavelength range
- Should lead to military and scientific applications in coherent radar and range-finding
Standard Rod Specifications
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Common properties |
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PROPERTY |
VALUE |
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chemical formula |
Y3Al5O12:Cr3+, (Tm3+, Ho3+) |
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crystal structure |
10Oh |
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lattice constant, A |
12.00 |
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refractive index n |
1.82 (1.0 mm) |
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dielectric constant |
11.7 |
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dn/dT, K-1 |
7.3 x 10-6 |
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density, g/cm3 |
4.56 |
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melting point, ¡ãC |
1950 |
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specific heat, J/(kg K) |
590 |
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thermal conductivity, W/(cm K) |
0.13 |
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thermal expansion |
8.2 x 10-6 K-1 in [100]
7,7 x 10-6 K-1 in [111] |
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Knoop Hardness |
1215 | |
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Element specification |
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PROPERTY |
VALUE |
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orientation |
[100] within 1 degree |
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dopant level |
¡À 0.1 % |
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dimensions |
¡À 0.1 (diameter)
¡À 0.5 (length) |
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wavefront distortion |
¡Ü l/4 per inch |
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flatness |
l/10 |
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parallelism |
¡Ü 1minute of arc |
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perpendicularity |
¡Ü 10 minutes of arc |
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scratch-dig |
10-5 per MIL-O-13830A |
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barrel finish |
polished or grinded |
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end coatings (AR at 1,66 µm) |
¡Ü0.25 % | |
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