Chromium, Thulium, Holmium: Yttrium Aluminum Garnet - CTH:YAG

Product catalog summary

Introduction to CTH:YAG
CTH:YAG is a novel crystal material that operates at a lasing wavelength of 2080 nm. It is utilized in various fields such as medical, military, and meteorological applications. The efficiency of CTH:YAG is attributed to the energy transfer processes between its co-dopants: Chromium (Cr), Thulium (Tm), and Holmium (Ho).

Energy Transfer Mechanism
Cr³⁺ ions absorb flashlamp energy, which is then transferred to Tm³⁺ ions with over 90% efficiency. A cross-relaxation process between Tm ions transfers energy to Ho ions, achieving a quantum efficiency close to 2.

Advantages of Cr,Tm,Ho:YAG

High-efficiency 2 µm laser source.
Operates effectively at room temperature.
Can be pumped using flashlamp or diode.
Diode pumping is possible via the strong 780 nm Tm³⁺ absorption line.
Chromium doping is not required for diode-pumped applications.
Wider pump line width compared to Nd:YAG.
Operates in an eye-safe wavelength range.

Properties of Cr,Tm,Ho:YAG

Lasing Properties: Transition from ⁵I₇ to ⁵I₈, with a fluorescence lifetime of 8.5 ms and a stimulated emission cross-section of 7x10^-21 cm².
Spectral Properties: Index of refraction is 1.80 at 2080 nm, with a diode pump band at 781 nm and absorption linewidth of 4 nm.

Material Specifications

Host material: Yttrium Aluminum Garnet (Y₃Al₅O₁₂).
Standard melt concentrations: Cr³⁺ at 0.85 at%, Tm³⁺ at 5.90 at%, Ho³⁺ at 0.36 at%.
Orientation: [111] crystallographic directions ± 5°.
Wavefront distortion: less than 1/2 wave per inch at 1064 nm.

Dimensional Tolerances

Diameter: +0.000” / -0.002”.
Length: +0.040” / -0.000”.
Barrel finish: 55 ± 5 micro-inch.
Chamfer: 0.005” ± 0.003” at 45° ± 5°.

End Configuration

Flatness: within λ / 10 wave at 633 nm wavelength.
Parallelism: within 30 seconds of arc.
Perpendicularity: less than 5 minutes of arc.
Surface quality: scratch-dig 10 - 5 per MIL-O-13830A.

Anti-Reflection End Coatings

Reflectivity: less than 0.25% at 2080 nm.
Adhesion and durability: meets MIL-C-48497A standards.
Pulsed damage threshold: greater than 10 J/cm².

Catalog excerpts

Chromium, Thulium, Holmium: Yttrium Aluminum Garnet - CTH:YAG-1

Chromium, Thulium, Holmium: Yttrium Aluminum Garnet - CTH: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 the Tm3+ with an efficiency of > 90%. A Tm:Tm cross relaxation then occurs and transfers this energy to the Ho with a quantum efficiency approaching 2. Advantages Of Cr,Tm,Ho:YAG Include: High-efficiency 2 µm source Operates well at room temperature(1) May be flashlamp or diode pumped Laser diode sources can pump the strong 780 nm Tm3+ ion absorption line Chromium doping not necessary for diode-pumped applications Pump line width of 4 nm; 4 times wider than the corresponding Nd:YAG diode-pump line width Operates in a relatively eye-safe wavelength range Applications in medical, military and scientific lasers Properties Cr, Tm, Ho;YAG Lasing Properties Lasing Transition: Lasing Wavelength Fluorescence Lifetime Stimulated Emission Cross-Section: Index of Refraction: Diode Pump Band: Absorption Linewidth: Major Pump Bands:

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Chromium, Thulium, Holmium: Yttrium Aluminum Garnet - CTH:YAG-2

Standard Specifications Material Parameters Host: Standard Melt Concentration: Yttrium Aluminum Garnet (Y3AI5O12) Chromium (Cr3+): 0.85 at % Thulium (Tm3+): 5.90 at % Holmium (Ho3+): 0.36 at % (Other Compositions Available) [111] crystallographic directions ± 5° less than 1/2 wave per inch of length @ 1064 nm Orientation: Wavefront Distortion: Diameter: Length: Barrel Finish: Chamfer: End Configuration within λ / 10 wave at 633 nm wavelength within 30 seconds of arc less than 5 minutes of arc scratch-dig 10 - 5 per MIL-O-13830A Flatness: Parallelism: Perpendicularity: Surface Quality: Anti-Reflection...

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