CY2255 Thulium-Doped Yttrium Lithium Fluoride Crystal (Tm:YLF)

Catalog No. CY2255
Crystal Structure Tetragonal
Perpendicularity <5"
Protective Chamfer <0.1 mm at 45˚
Laser Wavelength π:1880 nm; σ:1908 nm

Stanford Advanced Materials (SAM) is a trusted supplier of laser crystals with rich experiences. In addition to standard products, we can meet your individual customization requirements. Contact us with your specific requirements or for availability and pricing.

Related Products: Titanium-doped Sapphire Crystal (Ti:Sapphire), Ho:Cr:Tm:YAG, Neodimium-doped Yttrium Aluminum Garnet (Nd:YAG).

Description of Thulium-Doped Yttrium Lithium Fluoride Crystal

Two-micron Tm3+ lasers are of interest for many applications in the scientific, defense, and medical fields. Thulium readily substitutes many crystal hosts that are suitable for high-average-power laser systems and it has an absorption band at ~0.8 μm allowing excitation with commercially available high power laser diodes. Thulium doped yttrium fluoride lithium crystals have a low nonlinear refractive index and thermal optic constant, which are very suitable for application in the fields of scientific research, production, education, and other optoelectronic fields. The crystal is a negative uniaxial crystal with a negative refractive index temperature coefficient, which can offset some thermal distortion and thus has high beam quality output. The pump wavelength is 792 nm, and the linear polarized laser with a wavelength of 1900nm outputs in the direction of an axis. outputting light from the c axis is non-linear polarized. High power laser output can be obtained by selecting the proper crystal size and doping concentration.

Advantages of Tm: YLF:

- Low nonlinear refractive index
- Low thermo-optical constant
- Low polarization loss
- Long upper energy level fluorescence lifetime
- Small up-conversion effect
- No absorption loss of sensitized ions


Specifications of Thulium-Doped Yttrium Lithium Fluoride Crystal

Material specifications

Concentration Tolerance (atm%)

2-4 at. %

Lattice Constants



a-cut, other orientations also available





Surface Quality

10-5 scratch & dig

Wavefront Distortion

λ/8 @ 633nm

Surface Flatness

λ/10 @ 633nm

Clear Aperture


Length Tolerance

±0.1 mm

Face Dimensions Tolerance

+0/-0,1 mm

Protective Chamfers

<0.1 mm at 45˚

Damage Threshold

over 15J/cm2 TEM00, 10ns, 10Hz

Optical and spectral properties

Laser Transition


Laser Wavelength

π:1880 nm; σ:1908 nm

Absorption Cross-section at Peak

0.55×10-20 cm2

Absorption Bandwidth at Peak Wavelength

16 nm

Absorption Peak Wavelength

792 nm

Lifetime of 3F4 Thulium Energy Level

16 ms

Quantum Efficiency


Non-linear Index n2

0.6 x 10-13

Optical Quality

< 0.3 x 10-5

Refractive Index @1064 nm

no=1.448, ne=1.470

Laser Induced Damage Threshold

>10 J/cm2@1900 nm, 10 ns


R<0,5% @792 nm + R<0,15% @1800-1960 nm on both sides; custom coatings also available


Applications of Thulium-Doped Yttrium Lithium Fluoride Crystal

- Medical diagnosis and treatment
- Laser radar
- Laser ranging
- Electro-optical countermeasure
- Laser remote sensing
- Laser imaging
- Optical signal processing
- Material processing



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