Fused Silica is formed by chemical combination of silicon and oxygen. Fused Silica is perfect optical material due to its good UV and IR transmission, low coefficient of thermal expansion. It has high stability and resistance to thermal shock over large temperature excursions, wide temperature operating range and high laser damage threshold.
|
Properties
|
|
Density
|
2.20g/cm3
|
|
Abbe Constant
|
67.6
|
|
Refractive Index (nd) at 588nm
|
1.4586
|
Wavelength
(um)
|
Refractive
Index (n)
|
Wavelength
(um)
|
Refractive
Index (n)
|
|
0.2
|
1.55051
|
1
|
1.45042
|
|
0.22
|
1.52845
|
1.064
|
1.44962
|
|
0.25
|
1.50745
|
1.1
|
1.4492
|
|
0.3
|
1.48779
|
1.2
|
1.44805
|
|
0.32
|
1.48274
|
1.3
|
1.44692
|
|
0.36
|
1.47529
|
1.5
|
1.44462
|
|
0.4
|
1.47012
|
1.6
|
1.44342
|
|
0.45
|
1.46557
|
1.7
|
1.44217
|
|
0.488
|
1.46302
|
1.8
|
1.44087
|
|
0.5
|
1.46233
|
1.9
|
1.43951
|
|
0.55
|
1.46008
|
2
|
1.43809
|
|
0.588
|
1.4586
|
2.2
|
1.43501
|
|
0.6
|
1.45804
|
2.4
|
1.43163
|
|
0.633
|
1.45702
|
2.6
|
1.42789
|
|
0.65
|
1.45653
|
2.8
|
1.42377
|
|
0.7
|
1.45529
|
3
|
1.41925
|
|
0.75
|
1.45424
|
3.2
|
1.41427
|
|
0.8
|
1.45332
|
3.37
|
1.4099
|
|
0.85
|
1.4525
|
3.507
|
1.40566
|
|
0.9
|
1.45175
|
3.707
|
1.39936
|
There are different types Fused Silica according the different application. In China, there are mainly three types, i.e. JGS1, JGS2, JGS3.Below are the application and their equivalent to other Fused Silica supplier.
JGS1
UV grade Fused Silica: (JGS1) is synthetic amorphous silicon dioxide of extremely high purity. This non-crystalline, colorless silica glass combines a very low thermal expansion coefficient with good optical qualities, and excellent transmittance in thf orientation and temperature instability inherent in the crystalline form. Fused silica is used for both transmissive at ultraviolet. Transmission and homogeneity exceed those of crystalline quartz without the problems on reflective optics, especially where high laser damage threshold is required. JGS1 is transparent in the ultraviolet and visible regions, and has no absorption bands in the 170-250 nm wavelength intervals. It has an intensive OH absorption band in the interval of wavelength 2600-2800 nm.
JGS1 is used for optics operating in the deep UV and the visible wavelength range (Laser Lenses, Windows, Prisms, Mirrors, etc.). It is practically free of bubbles and inclusions.
JGS2
Optical Grade Fused Quartz (JGS2) provides good UV and visible transmission. It has almost the same physical and chemical properties with JGS1. However only in thin & small sheet pieces, JGS2 is virtually bubble-free. Elements built from larger pieces will most likely contain bubbles, so application should not be sensitive to these inclusions. But in cases where simple light gathering and strong mechanical properties are the primary goals, JGS2 grade provides excellent performance at a low price. Ideal Applications for JGS2:
● Condenser optics not concerned with scatter or distortion
● High temperature and pressure applications
● Optical flats, microscope slides and sight glasses
JGS3
JGS3:equivalent to Suprasil 300 (Heraeus). JGS3 is transparent in the ultraviolet, visible and infrared spectral regions, without considerable absorption bands in the 185-250 nm spectral region.
|
Hardness
|
5.5 - 6.5 Mohs Scale 570 KHN 100
|
|
Design Tensile Strength
|
4.8x107 Pa (N/mm2) (7000 psi)
|
|
Design Compressive Strength
|
Greater than 1.1x109 Pa (160,000 psi)
|
|
Bulk Modulus
|
3.7x1010 Pa (5.3x106 psi)
|
|
Rigidity Modulus
|
3.1x1010 Pa (4.5x106 psi)
|
|
Youngs Modulus
|
7.2x10-10 Pa (10.5x106 psi)
|
|
Poissons Ratio
|
0.17
|
|
Coefficient of Thermal Expansion
|
5.5x10-7cm/cm.°C (20°C-320°C)
|
|
Thermal Conductivity
|
1.4 W/m.°C
|
|
Specific Heat
|
670 J/kg.°C
|
|
Softening Point
|
1683°C
|
|
Annealing Point
|
1215°C
|
|
Strain Point
|
1120°C
|
|
Electrical Receptivity
|
7x107 ohm.cm (350°C)
|
|
Dielectric Properties (20°C and 1 MHz)
|
|
|
Constant
|
3.75
|
|
Strength
|
5x107 V/m
|
|
Loss Factor
|
Less than 4x10-4
|
|
Dissipation Factor
|
Less than 1x10-4
|
|
Velocity of Sound-Shear Wave
|
3.75x103 m/s
|
|
Velocity of Sound/Compression Wave
|
5.90x103 m/s
|
|
Sonic Attenuation
|
Less than 11 db/m MHz
|
|
Permeability Constants (cm3mm/cm2 sec cm of Hg)
|
(700°C)
|
|
Helium
|
210x10-10
|
|
Hydrogen
|
21x10-10
|
|
Deuterium
|
17x10-10
|
|
Neon
|
9.5x10-17
|
|
Chemical Stability (except hydrofluoric)
|
High resistance to water and acids
|
