Copyright: | AXTAL GmbH & Co. KG |
Einführung (in Englisch)
YCOB crystal was first found in 1990s. Because it has good nonlinear optical properties and high temperature piezoelectric properties and it is easy to grow large size crystal with high quality, it attracts attention new in recent years.
Compared with Lithium Tetraborate (LBO) crystals, which are commonly used in high power laser system, it has the following advantages:
- no deliquescence,
- larger effective NLO susceptibilities,
- larger Temperature Acceptance,
- similar laser induce damage threshold,
- less parametric luminescence (three orders less),
- smaller thermal expansion coefficient,
- less anisotropy,
- better processability,
- shorter growth period by Cz method and cheaper to make larger aperture element.
YCOB crystal is suitable for applications in high energy and high power laser fields,including
- Laser wavelength conversion: second-harmonic generation (SHG) and third-harmonic generation (THG),
- optical parametric oscillator (OPO),
- optical parametric amplification(OPA),
- optical parametric chirped-pulse amplification (OPCPA).
- Another application is in the field of piezoelectric devices at high temperature.
YCOB crystal has very high electric resistivity that can be fabricated as piezoelectric sensors working at the temperature as high as 1000ºC in aerospace engines.
Chemical and Structural Properties of YCOB Crystal
Crystal Structure | Monoclinic, Point group m |
Lattice Parameter | a = 8.0770 Å, b = 16.0194 Å , c = 3.5308 Å , β = 101.167º, Z = 2 |
Melting Point | About 1510 ℃ |
Mohs Hardness | 6 ~ 6.5 |
Density | 3.31 g/cm3 |
Thermal Conductivity | 2.6 W/m/K (║X), 2.33 W/m/K (║Y), 3.1 W/m/K (║Z) |
Thermal Expansion Coefficient | ax = 10.8•10-5/K, ay = -8.8•10-5/K, az = 3.4•10-5/K |
Optical and Nonlinear Optical Properties of YCOB compared with LBO
Properites | YCOB | LBO |
Transparency Range | 210 ~ 2600 nm | 160 ~ 2600 nm |
SHG Phase Matchable Range | 724 ~ 2600 nm (Type I) 1030 ~ 2150 nm (Type II) | 551 ~ 2600 nm (Type I) 790 ~ 2150 nm (Type II) |
Thermo-optic Coefficient (T in [°C], λ in [μm]) |
| dnx/dT=-9.3•10-6 |
Absorption Coefficient | <0.1% cm-1 at 1064nm | <0.1% cm-1 at 1064nm <0.3% cm-1 at 532nm |
Angle Acceptance | 0.062 º-cm (θ, Type I,1064 SHG) | 0.19 º-cm (φ, Type I,1064 SHG) |
Temperature Acceptance | 112°C-cm (Type I, 1064 SHG) | 4.7 °C-cm (Type I, 1064 SHG) |
Spectral Acceptance | 1.19 nm-cm (Type I, 1064 SHG) | 1.0 nm-cm (Type I, 1064 SHG) |
Walk-off Angle | 1.26° (Type I 1064 SHG) | 0.60° (Type I 1064 SHG) |
NLO Coefficients | deff(I)=d13sinΦ (Type I in XY plane) | deff(I)=d32cosΦ (Type I in XY plane) |
Non-vanished NLO susceptibilities | d12 = 0.24 pm/V; d13 = -0.73 pm/V d31 = 0.41 pm/V; d32 = 2.35 pm/V; d33 = -1.60 pm/V | d31 = 1.05 ± 0.09 pm/V |
Sellmeier Equations(λ in μm) | nx2 = 2.7697 0.02034 / (λ2 - 0.01779) - 0.00643λ2 ny2 = 2.8741 0.02213 / (λ2 - 0.01871) - 0.01078λ2 nz2 = 2.9107 0.02232 / (λ2 - 0.01887) - 0.01256λ2 | nx2 = 2.454140 0.011249 / (λ2- 0.011350) - |
Piezoelectric Properties of YCOB
Recommended literature (e.g.):
Yttrium Calcium Oxoborat (YCOB)
Anwendung | Größe [mm] | Theta | Phi | deff [pm/V] |
---|---|---|---|---|
2nd Harmonic Generation (SHG) | 30x30x15 | 30.8° | 180° | 1.14 |
3rd Harmonic Generation (THG) | 4x4x7 | 106° | 77.2° | NA |
Optical Parametric Amplifier (OPA) | 15x15x20 | 28° | 180° | 1.32 |
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