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Practically
all Rare Earths ions may be injected into YLF lattice. Maximal possible
concentration is different for different Rare Earths. For example, Y
may be 100% replaced with Yb or La, 50% - with Er, for Nd reachable
concentration is to 1.5%.
| Pattern wavelengths are: |
Nd:YLF |
1.047 µm, 1.053 µm, 1.313 µm, 1.324 µm and 1.370 µm |
|
Er:YLF |
0.85 µm and 2.81 µm |
|
Ho:YLF |
0.75 µm and 2.06 µm |
|
Tm:YLF |
0.435 µm,
1.89 µm and 2.30 µm |
Nd:YLF
(Nd:LiYF4) offers an alternative to the more common YAG
host for near IR operation. The combination of weak thermal lensing
(19 times lower than that of YAG), large fluorescence line width and
naturally polarized oscillation makes Nd:YLF an excellent material for
CW, modelocked operation. 1.053
µm output of Nd:YLF matches gain curves of Nd:Glass and performs
well as an oscillator and pre-amplifier for this host. YLF is
grown utilizing the modified Czochralsky technique. The as-grown crystals
are then processed into laser rods or slabs, coated in house, and inspected
per customer specifications. Long crystals for lamp pumping with concentration
to 1.1 atom % and short elements for diode pumping with concentration
to 1.5 atom % can be grown.
The Er:YLF, Ho:YLF and Tm:YLF single crystal rods are designed
to be applied in solid-state lasers which are widely used for industrial,
medical and scientific applications. Pure YLF crystals are transparent
within the spectrum band of 0.12 - 7.5 µm, photo-, thermo- and radiation-resistant.
The YLF crystals have low values of non-linear refraction index and
thermooptical constants. |
PROPERTIES
of Nd:YLF:
| Crystal
symmetry |
tetragonal |
| Nd
dopant concentration, at.% |
up to 1.6
|
| Density,
g/cm3 |
3.95 |
| Mohs
hardness |
4 - 5 |
| Lattice
constant, Å |
a = 5.26,
c = 10.94 |
| Refractive
index, at 1.053 µm |
no
= 1.448; ne = 1.47 |
| Transmission
band, µm |
0.1 - 7.5 |
| Thermal
conductivity, W x cm-1 x °K-1 |
0.06 |
| Thermal
expansion (a), 10-6 x deg
C-1 |
13 along
a, 8 along c |
| Thermooptical
factor (dn/dT), at 1.06 µm |
π =
4.3 x 10-6 x °K-1, σ = 2.0 x 10-6
x °K-1 |
| Non-linear
index n2, esu |
0.6 x 10-13 |
| Stimulated
emission cross-section, cm2 |
3.0 x 10-19 |
| Generated
wavelength, µm |
π =
1.047, σ = 1.053 |
| Lifetime,
µs |
540 |
| Optical
losses at 1.053 µm, cm-1 |
< 0.003 |
| Optical
quality |
< 0.3
x 10-5 |
STANDARD SPECIFICATIONS:
| Rod
dimensions, mm |
dia. (3 -
10) ± 0.1, length (25 - 140) ± 0.2 |
| Rod
end face flatness |
N = 0.5 interf.
band, ΔN = 0.5 interf. band |
| Parallelism
of rod end faces, arc.sec |
15 |
| End
faces perpendicularity, arc.min |
5 |
| Barrel
finish, µm |
1.5 |
| Surface
quality |
better than
10/5 Scratch/Dig per MIL-O-1380A |
| End
faces coating |
AR/AR coating |
We
supply rods and slabs with different cross-sections, dimensions and
coatings. Different dopants compositions with different concentrations
are available for specific customer requirements.
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