Yb: YLF

Yb: YLF Crystal has a high absorption characteristic near the wavelength of 960nm and is suitable for laser with 960nm wavelength. Since the Yb ion has only two energy levels associated with absorption and emission, this special electron configuration makes its heat load small. The high purity material with high external quantum efficiency determines its position in the laser cooling industry. Recently, it has been proved that the temperature accuracy of Yb: YLF Crystal measured by DLT method at 78-300k is ± 1k, which makes Yb: YLF Crystal widely used in the temperature detection direction in the low temperature range. It not only has high thermal conductivity and higher average power, but also as the gain medium of high-power laser does not need temperature control device. So Yb: YLF Crystal is a particularly promising laser material.

Yb: YLF Crystal is a very advantageous Crystal in laser cooling industry

If you want to complete the cooling work, high purity materials with high external quantum efficiency are essential. Because optical refrigeration is based on the principle of anti-stokes fluorescence. After absorbing the energy, the valence electron jumps from the lower energy level to the higher energy level and then spontaneously returns to the lower energy level, emitting fluorescence at a wavelength smaller than that of the excitation radiation from the light source. they also bring heat out when they effectively escape, acting as laser cooling.

Parameter

Physical and Chemical Properties

Crystal structure	Tetragonal
Point group	I41/a
Lattice parameters	а = 5,164 Å, c = 10,741 Å
Thermal expansion	4×10-6 / ºC
Thermal conductivity	4,36 W/mK
Density	3,95 g/cm³
Mohs’ hardness	5
	825 ºC
dno/dT	-2,0×10-6 / ºK
dne/dT	-4,1×10-6 / ºK

Optical and Spectral Properties

Transmission range	0.2-5 μm
Refractive indices (λ=1.06 μm）	no = 1,448, ne = 1,470
Fluorescence lifetime	2.1 ms
Emission bandwidth	60 nm
Absorption peak wavelength	960 nm
Absorption cross-section at peak	10.5×10-21 cm2
Absorption bandwidth at peak wavelength	~10 nm
Laser wavelength	1017 nm
Emission cross-section @1053 nm	4.1×10-21 cm2
Refractive index @1040nm	~1.4

Material and Specifications

Typical doping level	5-20 at.%
Orientation	a-cut
Clear aperture	>90%
Face dimensions tolerance	+0/-0,1 mm
Length tolerance	±0,1 mm
Parallelism error	<10 arcsec
Perpendicularity error	<10 arcmin
Protective chamfers	<0,1 mm at 45˚
Surface quality	10-5 S-D
Surface flatness	<λ/10@632,8 nm
Coatings	AR(R<0,5%)@960 nm + AR(R<0,15%) @1000-1060 nm on both faces
Laser induced damage threshold	>10 J/cm2@1030 nm, 10 ns
Mount	Unmounted