Mid-IR Crystals

IPG Photonics offers Cr2+, Co2+ and Fe2+ diffusion-doped ZnSe/ZnS

polycrystalline ceramic gain materials and saturable absorbers. IPG’s

proprietary fabrication process allows low cost mass production of

a large variety of iron and chromium doped ZnSe/ZnS crystals

with low losses, uniform distribution of transition metal dopant,

excellent reproducibility and reliability. The optical and

spectroscopic characteristics of these crystals make them

the gain materials of choice for compact and efficient

laser sources operating in 1.8 to 6 microns range.

Chromium and iron doped ZnSe/S lasers are promising

for spectroscopy, sensing, medical and defense

applications, as well as for seeding or pumping

middle-infrared optical parametric oscillators.

Cr2+:ZnSe and Cr2+:ZnS Laser Active Materials

The unique combination of available pump sources (Er-fiber, Tm fiber, telecom or InP diodes, Er:YAG/YLF; Tm: YAG/YLF), technological (low cost ceramic material), optical and spectroscopic characteristics (ultrbroadband gain bandwidth, high st product and high absorption coefficients) make them the gain materials of choice when one needs a compact system with continuous tunability at 300 K over 1.8-3.4 mm, output powers up to 30 W and high (up to 70%) conversion efficiency.

Cr2+:ZnSe/S lasers are promising for spectroscopy, sensing, medical and defense related applications, as well as for seeding or pumping middle-infrared optical parametric oscillators.

IPG’s fabrication process allows low cost mass production of a large variety of diffusion-doped Cr2+:ZnSe/ZnS crystals with low losses, uniform distribution of chromium, good reproducibility and reliability.

 

uniformly doped chromium ZnSe/S

Uniformly-doped 5 x 5 x 20 mm Cr:ZnSe Crystals

Output Characteristics of Cr:ZnSe/S Lasers Based on IPG's Gain Materials

Laser Characteristics

Output Parameter
CW Output Power, W  30
CW Tuning Range, nm  1800 - 3400
CW Efficiency, %  70
Free-running Energy, J 1.05 @7 ms
Gain-switched Energy, mJ 20 @ 15 ns
Mode-locked Pulse Duration, fs 50 @ 2 W

Fe2+:ZnSe Laser Active Materials

Fe²+:ZnSe crystals are ideal gain materials for room temperature gain-switched lasers tunable over 3.4-5.2 µm spectral range.

These lasers are promising for spectroscopic, sensing, medical and defense related applications, as well as for seeding or pumping middle-infrared optical parametric oscillators.

IPG’s fabrication process allows low cost mass production of a large variety of diffusion-doped Fe²+:ZnSe/ZnS crystals with low losses, uniform distribution of iron, good reproducibility and reliability.

 

Mid IR Crystals

 

TM:ZnSe/S Crystals

State-of-the-art of Fe:ZnSe Laser Characteristics

Laser Characteristics

Output Parameter
CW Output Power, W 2
Tuning Range, nm 3400 - 5200
Efficiency, % 30
Free-running Energy, J 0.42 @ 250 μs @ 5 Hz
Free-running Average Power, W 35 @ 150 μs @ 100 Hz
Gain-switched Energy, mJ 5 @ 15 ns

 

Please contact IPG Photonics for more information.

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Co2+:ZnS, Cr2+:ZnS and Cr2+:ZnSe Passive Q-Switches

Co2+:ZnS, Cr2+:ZnS and Cr2+:ZnSe saturable absorbers (SA) are ideal materials for passive Q-switches of eye-safe fiber and solid-state lasers operating in the spectral range of 1.5-2.1 µm.

 These lasers are used in numerous applications such as free-space communication systems, target designation, time-of-flight range finding, surgery, reflectometry and laser lidars.

 IPG offers a large variety of diffusion-doped Co2+:ZnS, Co2+:ZnSe, Cr2+:ZnS and Cr2+:ZnSe polycrystals appropriate for Q-switching of the lasers operating in the 1.5-2.1 µm spectral range.

 

 

 

Co Cr Zn Se S

Samples of Cr2+:ZnS, Cr2+:ZnSe and 
Co2+:Zns Saturable Absorbers

 

Material Properties 

Crystallographic   ZnS  ZnSe
Syngony  Cubic  Cubic
Symmetry Class  ...  43 m
Mechanical    
Density, g/cm3

4.09

 5.27
Young Modulus, Pa 7.45×1010  7.03×1010
Poisson Ratio  0.28 0.28 
Thermal    
Thermal Expansion, deg C-1  6.5×10-6  7.6×10-6
Thermal Conductivity, W/(m deg C)  27.2 16 
Specific Heat, J/(kg deg C)  0.515×103 0.339×103 
Optical    
Refractive Index at 1.0 µm 2.29  2.49
dn/dt, deg C-1  5.4×10-5 6.1×10-5 
Transmission Range, µm  0.37 - 14 0.55 - 20 

 

Q-Switching Cr:ZnS Cr:ZnSe Co:ZnS Co:ZnSe
σGSA (at 1.54 µm)  1.6×10-18  1.3×10-18 0.7×10-18 0.76×10-18
σESA (at 1.54 µm)  0  0.02×10-18  0.1×10-18  0.1×10-18
τGSA (at 1.54 µm)   5 µs  8 µs  200 µs 290 µs 
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 Fe2+:ZnSe, Fe2+:ZnS Passive Q-Switches

Fe2+:ZnSe and Fe2+:ZnS saturable absorbers (SA) are ideal materials for passive Q-switches of solid-state lasers operating in the spectral range of 2.5-4.0 µm.

These lasers (e.g. 3.0 µm Er:YAG/YSGG/YLF are used for pumping middle-infrared Optical Parametric Oscillators and for numerous medical and dental applications.

IPG’s fabrication process allows low cost mass production of a very large variety of diffusion-doped Fe2+:ZnSe/Zns crystals with low losses, uniform distribution of iron, good reproducibility and reliability.

 

Fe Q sw

Samples of Fe2+:ZnSe Single and Polycrystalline Saturable Absorbers

 

Crystal Peak Coefficient Absorption, cm-1 Upper Level Lifetime 
at 300 K, µs
σGSA at 
2.8 µm, 10-20 cm2
σgsaesa σgsa/σYSGG
Fe:ZnSe 1-20 0.37 90 0 30
Fe:ZnS 1-20 <0.3 130 0 43

According to the criterion for saturable absorber Q-Switching

the criterion for saturable absorber Q-Switching

 

(where sQgsa and AQ are absorption cross section and area of the cavity mode at passive Q-switcher; sYSGG and AYSGG are emission cross section and area of the cavity mode at the gain element) Fe2+:ZnSe/S can be used as a saturable absorber Q-Switch for the Cr:Er:YSGG laser without intracavity focusing.

Output energies of 15 and 85 mJ were achieved in single and multipulse modes of operation, respectively.  The combination of a high values of saturation cross-sectio, small saturation energy with good opto-mechanical (damage threshold - 2 J/cm2) and physical characteristics of ZnSe and ZnS hosts make Fe2+:ZnSe/S crystals an ideal material for passive Q-Switching of mid-infrared laser cavities.


Please contact IPG Photonics for more information

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TM:ZnSe_S Series Datasheet

Passive Q-switch Co_ZnS Cr_ZnS and Cr_ZnSe Datasheet

Passive Q-switch Fe_ZnS and Fe_ZnSe Datasheet

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