Heraeus Quarzglas Home of Quarz Solutions Fused Silica

Heraeus Quarzglas Home of Quarz Solutions Fused Silica for Infrared Applications Operation @946 nm @1064 nm @ 1319 nm Dr. Mark Altwein, Pisa, 21. 10. 2011

Fused Silica for Infrared Applications Overview Heraeus Group What influences absorption in the IR? § OH- Content § Metallic Purity Simulation: Absorption can lead to heating Material Synopsis Seite 2

The Group Who we are We are a globally active precious metals and technology Group with firm roots in Germany. The company has been family-owned for 160 years. We operate in global niche markets characterized by lasting growth and attractive returns. | Page 2

The Group Facts and Figures 2010 Heraeus Group Product revenue (in € million) 4, 079 Precious metals trading revenue (in € million) 17, 946 Employees at year-end 12, 931 Business Groups Product revenues (in € million) Human resources Precious metals 1, 447 2, 489 Materials and technologies 1, 501 2, 980 Sensors 375 3, 144 Dental products 306 1, 397 67 183 279 1, 419 99 689 Biomaterials and medical products Quartz glass Specialty light sources As of December 31, 2010 | Page 5

Heraeus Quarzglas: IR Material Grades Increasing demand for: Infrared Optics for high power laser applications Material inherent properties determine „behaviour“ under irradiation Seite 5

Heraeus Quarzglas: IR Material Grades - Attenuation 1319 nm 946 nm 1064 nm Source: O. Humbach et al. , J. Non Crystalline Solids, 203 (1996) OH – molecular vibrational or rotational excitation Blue: laser wavelengths Red: OH absorption @ 940 nm Low-OH material: Preferred choice! Bulk absorption can be calculated: x d. B/km => x * 2. 3 ppm /cm. Bulk Example: The attenuation @ 940 nm = 2 d. B/km => Absorption ~ 4. 6 ppm / cm Seite 6

Heraeus Quarzglas: IR Material Grades Absorption @ 946 nm: OH-Content dominating property Typical Absorption of different Heraeus Material Grades @ Wavelength = 946 nm 10000 Data by measurements from: Dr. Mühlig, Institut für Photonische Technologien (IPHT) , Jena OH 400 -1000 ppm OH ~250 ppm OH <8 ppm Absorptioncoefficient [ppm/cm] 1000 10 946. . . OH < 1 ppm 1 0. 01 Suprasil 3001 / 3002 / 300 Suprasil 311 / 312 Suprasil 1 / 2 Grade A Infrasil 301 / 302 / 303 Seite 7

Heraeus Quarzglas: IR Material Grades Absorption @ 1064 nm: Metallic purity dominating property Typical Absorption of different Heraeus Material Grades @ Wavelength = 1064 nm 10000 Absorptioncoefficient [ppm/cm] 1000 Data by measurements from: Dr. Kondilenko , Ginzton Lab, Stanford University, USA Dr. Pinard, Laboratoire des Matériaux Avancés, Lyon, France Dr. Mühlig, Institut für Photonische Technologien (IPHT) , Jena Priv. Communications OH <8 ppm 100 OH ~250 ppm 10 1 1064. . . OH 400 -1000 ppm OH < 1 ppm 0. 1 Suprasil 3001 / 3002 / 300 Suprasil 311 / 312 Suprasil 1 / 2 Grade A Infrasil 301 / 302 / 303 Seite 8

Heraeus Quarzglas: IR Material Grades Absorption @ 1319 nm: OH-Content dominating Typical Absorption of different Heraeus Material Grades @ Wavelength = 1319 nm 10000 Data by measurements from: Dr. Kondilenko, Ginzton Lab, Stanford University, USA OH ~250 ppm Absorptioncoefficient [ppm/cm] 1000 OH <8 ppm 100 10 1 1319. . . OH <= 1 ppm 0. 1 0. 01 Suprasil 3001 / 3002 / 300 Suprasil 311 / 312 Infrasil 301 / 302 / 303 Seite 9

Heraeus Quarzglas: IR Material Grades Simulation for 946 nm and 1064 nm excitation based on Steady-state diffusion equation with volume and surface heat sources Absorption can lead to heating Seite 10

Heraeus Quarzglas: IR Material Grades Excitation @ 946 nm: Suprasil 300 x series => neglible heating Beam La se r. B ea m Po we r Temperature Laser Radiu s Seite 11

Heraeus Quarzglas: IR Material Grades Excitation @ 946 nm: High OH content can lead to very strong heating! Seite 12

Heraeus Quarzglas: IR Material Grades Excitation @ ~1µ: metallic purity most important! Seite 13

Heraeus Quarzglas: IR Material Grades 2 main contributions: § OH-Content § Metallic impurity @ 1064 nm: Metallic impurites dominating! § Less metallic impurites => lower absorption § Same purity level: Lower OH content => lower absorption @ 946 nm: OH-Content dominating! § Lower OH content => lower absorption § Metallic impurites are only secondary! Seite 14

Heraeus Quarzglas: IR Material Grades Material Wavelength Remark Application Description Suprasil 3001 200 nm – 3500 nm Lowest absorption Highest Quality 3 D Optics High purity Synthetic Fused Silica, low OH Suprasil 3002 200 nm – 3500 nm Lowest absorption Highest Quality 2 D Optics High purity Synthetic Fused Silica, low OH Suprasil 300 200 nm – 3500 nm Lowest absorption Windows, lenses with medium need for homogeneity High purity Synthetic Fused Silica, low OH Suprasil 311 190 nm – 1100 nm Very low absorption @ 1064 nm 3 D applications, e. g. high grade prisms High purity Synthetic Fused Silica, medium OH Suprasil 312 190 nm – 1100 nm Very low absorption @ 1064 nm 2 D applications, e. g. lenses, windows High purity Synthetic Fused Silica, medium OH Infrasil 301 270 nm – 3500 nm Very good costefficency 3 D applications, e. g. high grade prisms Natural fused quartz Infrasil 302 270 nm – 3500 nm Very good costefficency 2 D Applications, e. g. lenses or windows Natural fused quartz Seite 15

Summary OH-absorption bands strongly influence performance. Low-OH synthetic fused silica grades show a better absorption. Absorption may lead to lens heating and changes the homogeneity. Suprasil 3001, 3002, 300 is the best choice for infrared applications, especially for excellent performance. Infrasil 301, 302 is a suitable alternative for normal IR applications. Seite 16

Heraeus Quarzglas: IR Material Grades Thank You For Your Attention! Seite 17