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标题: LBO的导热系数，比热 [打印本页]

作者: laserpad 时间: 2008-4-1 09:56
标题: LBO的导热系数，比热
有谁知道么，告诉一下啊，多谢啦

作者: watermoon 时间: 2008-4-1 10:02
表1 LBO晶体的物理和化学特性

晶体结构斜方晶系, 空间群Pna21, 点群mm2
晶格参数 a=8.4473A,b=7.3788A,c=5.1395A,Z=2
熔点约834℃
莫氏（Mohs）硬度 6
密度 2.47g/cm3
热膨胀系数 αx=10.8x10-5/K, αy=-8.8x10-5/K,αz=3.4x10-5/K
吸收系数＜0.1%/cm at 1064nm
热导率 3.5W/m/K
比热 1060 J/kg.K

[ 本帖最后由 watermoon 于 2008-4-1 10:10 编辑 ]

作者: laserpad 时间: 2008-4-1 10:39
多谢大胡子兄的帮助，
可是我有个疑问
LBO是各向异性晶体，
它的热导率按说在各个方向上不同
为什么上述只提供了就一个热导率？
那么这个热导率是哪个方向的？
那其他方向上的热导率又是多少？

PS：我看到很多关于非线性晶体的文献，都是提供了一个热导率
比如KTP的是13W/m/K
不懂了

作者: watermoon 时间: 2008-4-1 12:29

原帖由 laserpad 于 2008-4-1 10:39 发表
多谢大胡子兄的帮助，
可是我有个疑问
LBO是各向异性晶体，
它的热导率按说在各个方向上不同
为什么上述只提供了就一个热导率？
那么这个热导率是哪个方向的？
那其他方向上的热导率又是多少？

PS：我 ...

KTP Crystal
KTP crysta or Potassium Titanium Oxide Phosphate (KTiOPO4) is an efficient nonlinear optical crystal in the visible to infrared spectral region with relatively low cost. It has large nonlinear coefficient. The effective nonlinear optical coefficient of KTP deff at 1064nm is more than 1.5 times that of BBO. It's damage threshold is near 1 GW/cm2 for 1 Hz 10 ns pulses at 1064nm.

Features:

• Efficient frequency conversion(1064nm SHG conversion efficiency is about 80%)
• Large nonlinear optical coefficients(15 times that of KDP)
• Wide angular bandwidth and small walk-off angle
• Broad temperature and spectral bandwidth
• High thermal conductivity (2 times that of BNN crystal)
• Moisture free
• Minimum mismatch gradient
• Super-polished optical surface
• No decomposition below 900°C
• Mechanically stable
• Low cost compare with BBO and LBO



Applications:

• Frequency Doubling (SHG) of Nd-doped Lasers for Green/Red Output
• Frequency Mixing (SFM) of Nd Laser and Diode Laser for Blue Output
• Parametric Sources (OPG, OPA and OPO) for 0.6mm-4.5mm Tunable Output
• Electrical Optical(E-O) Modulators, Optical Switches, and Directional Couplers
• Optical Waveguides for Integrated NLO and E-O Devices

Additional applications for KTP include mixed frequency, electro-optical modulation, optical parametric generation and optical waveguide.

Physical Properties:

Crystal Structure Orthorhombic
Point Group mm2
Melting Point 1172°C incongruent
Lattice Parameters a=6.404Å b=10.615Å c=12.814Å Z=8
Temperature of Decomposition ~1150°C
Transition Temperature 936°C
Mohs Hardness ~5
Density  2.945 g/cm3
Color colorless
Hygroscopic Susceptibility no
Specific Heat 0.1737 cal/g.°C
Thermal Conductivity 0.13 W/cm/°C
Electrical Conductivity 3.5x10-8 s/cm (c-axis, 22°C, 1KHz)
Thermal Expansion Coefficients a1 = 11 x 10-6 °C-1
a2 = 9 x 10-6 °C-1
a3 = 0.6 x 10-6 °C-1

Thermal Conductivity Coefficients k1 = 2.0 x 10-2 W/cm °C
k2 = 3.0 x 10-2 W/cm °C
k3 = 3.3 x 10-2 W/cm °C
Dielectric Constant eeff = 13

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Optical Properties:

Transmitting Range 350nm ~ 4500nm
Refractive Indices  nx ny nz
1064nm 1.7400 1.7469 1.8304
532nm 1.7787 1.7924 1.8873

Absorption Coefficients a < 1%/cm @1064nm and 532nm
Therm-Optic Coefficients dnx/dT=1.1x10-5/°C
dny/dT=1.3x10-5/°C
dnz/dT=1.6x10-5/°C
Electro-Optic Coefficients  Low frequency (pm/V) High frequency
(pm/V)
r13 9.5 8.8
r23 15.7 13.8
r33 36.3 35.0
r51 7.3 6.9
r42 9.3 8.8

Sellmeier Equations nx2=2.10468 + 0.89342λ2/(λ2-0.04438)-0.01036λ2
ny2=2.14559 + 0.87629λ2/(λ2-0.0485)-0.01173λ2
nz2=1.9446 + 1.3617λ2/(λ2-0.047)-0.01491λ2

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Nonlinear Optical Properties

Phase Matching Range 497nm - 3300 nm
Nonlinear Coefficients (@1064nm) d31=2.54pm/V, d31=4.35pm/V, d31=16.9pm/V
d24=3.64pm/V, d15=1.91pm/V at 1.064 mm

Effective Nonlinear Optical Coefficients deff (II) ≈ (d24 - d15)sin2θsin2φ - (d15sin2φ + d24cos2φ)sinθ

Type II SHG of 1064nm Laser

Phase Matching Angle θ=90° φ=23.2°
Effective Nonlinear Optical Coefficients deff  ≈8.3 x d36(KDP)
Angular Acceptance Δθ= 75 mrad Δφ= 18 mrad
Temperature Acceptance 25°C.cm
Spectral Acceptance 5.6 Åm
Walk-Off Angle 1 mrad
Optical Samage Threshold 1.5-2.0MW/cm2

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Main Specification:

Dimension 1x1x0.05mm - 30x30x40mm
Phase Matching Type Type II, θ=90° φ=phase-matching angle
a) S1&S2: AR @1064nm R<0.1%; AR @ 532nm, R<0.25%.
b) S1: HR @1064nm, R>99.8%; HT @808nm, T>5%, S2: AR @1064nm, R<0.1%; AR @532nm,    R<0.25%
Typical Coating Customized coating available upon customer request.

Angle Tolerance 6'
Dimension Tolerance Δθ< ±0.5°, Δφ< ±0.5°, ±0.02 - 0.1 mm
Flatness (W ±0.1mm) x (H ±0.1mm) x (L + 0.2mm/-0.1mm) for NKC series
λ/8 @ 633nm10/5 Scratch/dig per MIL-O-13830A
<10'
Scratch/Dig Code better than 10 arc seconds for NKC series
Parallelism 5'
Perpendicularity 5 arc minutes for NKC series
Wavefront Distortion less than λ/8 @ 633nm
Clear Aperture  90% central area
Working Temperature  25°C- 80°C
Homogeneity  dn ~10-6/cm

看了一下，各个厂家给出的标记方式都不同，有点乱，也有点看不懂，可能是材料方面的懂得太少了
比热KTP，上面的给了热导率，又弄个热导率系数，就不知道什么意思了
不过，我想，一般只给出一个值，是指的平均值，因为通常非线性晶体都不是沿轴切割的，这样，冷却边界也不与晶轴有直接的平行或垂直关系
所以都只给一个平均值。
如果你还是想知道LBO的各向异性热导率的话，如下：
2.7 || to x
3.1 || to z
4.5 || to y(=c)
（平均值正好差不多是3.5W/m/K）

作者: laserpad 时间: 2008-4-1 12:48
太漂亮了，多谢！

作者: wcq1224 时间: 2008-4-1 12:53
很不错啊～～～～～～～～～～～～～～～～～～

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