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Technology Transfer Time: the 2009-07-08   source: Xi'an Institute of Optics and Precision Mechanics of CAS   【big | medium | small】  【print

Magneto Optical Glass /Faraday Rotator Glass Family

 

Magneto Optical Glass /Faraday rotator glass materials Tb-10, Tb-12 and Tb-15 are designed for laser light flux output control in the magnetic field in visible and near-IR spectral range. It is used in manufacture of faraday rotating components based on Faraday rotation of the light polarization plane, such as optical isolators,circulators, magneto-optical modulators, fast optical switches, interleavers, laser gyroscopes, goniometric devices, magneto-optic storage and optical information process system, current measuring transducers for magnetic field measuring and high-voltage transmission line, new generation current sensors, wave guides, astrology, spaceflight control, satellite survey and other functional devices.
In high power laser systems, optical isolators are necessary to prevent the destruction of laser disks or other optical components caused by reflected laser from target. Faraday Isolators are passive unidirectional, non reciprocal devices that utilize the phenomenon of Magneto-Optic Rotation to isolate the source from reflections in an optical system. The isolator protects the laser oscillator from optical feedback making Faraday Isolators a key component in many of today's laser systems.
Large aperture Faraday rotator glass with high Verdet constant (defined as the rotation per unit path per unit field strength) is used as rotator material to obtain large rotation angle of linearly polarized laser form the given length of glass at low intensity of magnetic field. The amount of polarization rotation is

where:

 

= polarization rotation angle

= Verdet constant of optical element

= longitudinal component of magnetic intensity vector

= optical path length

Since glass material in high power laser system is damaged as a consequence of self-focusing, low non-linear refractive index as well as high Verdet constant is important factors for Magneto-Optical Glass.

Our advantages

Magneto Optical Glass /Faraday Rotator Glass offer the following advantages:

* High Verdet constant

* Excellent homogeneity

* High damage threshold

* Broad wavelength range

* Better transparency properties

* Lower nonlinear refractive index

* Lower absorption co-efficient

* Lower cost

* Available in very large plates / disks

 

Specifications  

Material

Tb-10

Tb-12

Tb-15

Verdet constant(min·Oe-1·cm-1)

 

λ = 632.8 nm

-0.26

-0.29

-0.33

λ = 1064 nm

-0.075

-0.090

-0.11

Transmission window

400nm-1600nm

Transparence rate T% (Uncoated)

89%

87%

85%

Density(g/cm3)

4.29

4.62

4.98

Refractive index(at 589.3 nm)

1.6989

1.7279

1.7551

Abbe number

53.1

53.7

53.4

Non-linear coefficient,n2(10-13esu)

2.65

2.51

2.55

Thermal expansion coefficient

50.6×10-7 -1

60.5×10-7 -1

63.2×10-7 -1

Transformation temperature Tg()

683

732

788

Sag temperature Ts()

724

776

824

Optical losses at 632.8nm and 1064 nm(cm-1)

0.001

0.001

0.001

Optical quality ,Δ n (cm-1)

< 2×10-6

< 2×10-6

< 2×10-6

Bulk laser damage threshold 3ns pulse width at 1064 nm(J/cm2)

>10

>10

>10

Chemical durability

Excellent

Excellent

Excellent

Elements maximum dimensions

Φ400×35 mm

Φ220×35mm

Φ100×30 mm

* Specifications and information are subject to change without prior notice.

State Key Laboratory of Transient Optics & Photonics, Xi'an Institute of Optics & Precision Mechanics, Chinese Academy of Sciences, Xi'an, 710068
 Tel: 862988887605 
Email:
yshwang@opt.ac.cn

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