Tm:YLF is the important middle infrared laser crystal. Because Tm:YLF is negative uniaxial crystal, whose thermal refractive index coefficient is negative, some thermal distortion may be counteracted and high-quality light can be output. Conveniently pumped at 792nm, 1.9μm linearly polarized beam is output in a axis, and non-linearly polarized beam is output in c axis.

Advantages of Tm:YLF Crystals

Linearly polarized output beam

Little heat effect while laser

Effective cross relaxing of Tm ions

Relatively high efficiency with LD pumping

Specifications

Dopant concentration

Tm: 0～5at%

Upon request of customer

Orientation

[100] or [001] within 5°

Wavefront distortion

≤0.25λ/25mm @632.8nm

Rod sizes

Diameter 3~9.5mm, Length 5~120mm
Upon request of customer (rod or slab)

Dimensional tolerances

Diameter:+0.00/-0.05mm，Length: ± 0.5mm

Barrel finish

Ground or polished

Parallelism

≤10"

Perpendicularity

≤5′

Flatness

≤ λ/10@632.8nm

Surface quality

10-5 (MIL-O-13830A)

Chamfer

0.15±0.05mm

AR coating reflectivity

≤0.25%

Optical and Spectral Properties

Laser transition

3F4→3H6

Laser wavelength

1.9μm

Index of refraction

no=1.443 ne=1.464 @633nm

no=1.448 ne=1.470 @1064nm

Physical and Chemical Properties

Crystal Structure

Tetragonal

Melting Point

825℃

Moh Hardness

4-5

Density

3.95g/cm3

Thermal Conductivity

0.06W/cm/K

Young's Modulus

7.5×1011dynes cm-2

Tensile Strength

3.3×108dynes cm-2

Thermal Expansion Coefficient

[100] Direction:13×10-6/K

[001] Direction:8×10-6/K