Suprasil® 311

Heraeus SUPRASIL® 311 is a high purity synthetic fused silica material manufactured by flame hydrolysis of SiCl4. It combines excellent physical properties with outstanding optical characteristics in the deep UV to the near IR. The most prominent property of Suprasil 311 is the high degree of index homogeneity which is controlled and specified in all three dimensions. In addition, the materials provide a high degree of radiation to damage and are therefore the preferred materials in high energy laser applications.

All synthetic fused silica SUPRASIL® grades are practically free from bubbles and inclusions.

The optical homogeneity is the main criterion for very low transmitted wavefront distortion!

SUPRASIL® 311 is an optically isotropic 3D-material. It is highly homogeneous and has no striations in all three dimensions. These properties are very important for multiple axis optics such as prisms, steep lenses, beam splitters or etalons.

SUPRASIL® 311 is the preferred material for UV-microlithography, interferometry, beam splitters, special laser, vacuum UV applications, high quality retroreflectors and prisms, etc. In the DUV, SUPRASIL® 311 and 312 show the highest transmission of all SUPRASIL® grades.

For general technical data please refer to our data sheet HQS-SO "Quartz Glass for Optics - Data and Properties" 06.2007/V1.0_D

(Bubbles and Inclusions ≤ 0.08 mm diameter are disregarded)

Bubble class :
better than 0 (as per DIN 58927 2/70)

Bubbles according to DIN ISO 10100
1/ 2*0,10 for pieces < 6 kg

Inclusions:
None

Spots:
None

Refractive Index
n_C = 1.45637 at 656.3 nm

n_d = 1.45846 at 587.6 nm

n_F = 1.46313 at 486.1 nm

n_g = 1.46669 at 435.8 nm

n = 1.50855 at 248 nm

At 20°C, 1 bar atmospheric pressure

Accuracy: ± 3 • 10^-5

Dispersion
n_F - n_C = 0.00676

^V_d = 67,8 ± 0,5

Granular Structure:
None

Striations
In all three dimensions free from striations, i.e. better than
grade A, MIL-G-174-B.

Index Homogeneity
Specified across 90% of diameter or sidelength for machined parts, respectively 80% for raw formed ingots.

In all three dimensions guaranteed total ∆n ≤ 3 • 10^-6;

with power subtracted ∆n (p.s.) ≤ 1 • 10^-6;

on special request total ∆n ≤ 1 • 10^-6.

(Maximum weight ca. 10 kg; larger pieces available on request).

∆n (p.s.) (power subtracted) is calculated by subtracting from a measured ∆n distribution the proportion that gives an exactly spherical aberration of an originally plane optical phasefront. This subtraction procedure is built into most modern interferometer software as an option.

≤ 5 nm/cm across 80% of diameter or side length

≤ 5...15 nm/cm in the rim area.

For typical transmission curves (including Fresnel reflection losses) please refer to our data sheet "Quartz Glass for Optics - Data and Properties" HQS-SO-DS-06.08

Decadic Extinction Coefficient at 200 nm
k₂₀₀ < 0.005 cm^-1 (typical)

k₂₀₀ < 0.01 cm^-1 (guaranteed)

Using the definition:

Transmittance T = 10^-kd

with d = thickness of sample

Infrared Absorption
OH absorption bands occur at wavelengths around 1.39 µm, 2.2 µm, and 2.72 µm according to an OH content of approximately 200 ppm (weight).

None

With 254 nm excitation (low pressure Hg lamp and Schott UG 5 filter) and visual inspection.

High degree of resistance to radiation.
High laser damage threshold.
No degradation of visible Transmittance after exposure to Co⁶⁰ γ-radiation (1.15 MeV) with 0.063 Mrad/h for 98 h.