Herasil® 102

Herasil® 102 is an optical quartzglass grade manufactured by flame fusion of cultured quartz crystals. It combines excellent physical properties with outstanding optical characteristics in the UV and the visible wavelength range. The index homogeneity is controlled and specified in one direction (the direction of use or functional direction).

Herasil® 102 meets the requirements for bubble class 0 and is practically free of inclusions.

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

HERASIL® 102 is homogeneous in the primary functional direction. Weak striations, if any, are parallel to the major faces and do not affect the optical performance.

HERASIL® 102 is the preferred material for demanding optics in one directional use such as lenses, UV-laser windows, optical flats, etc.

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 (as per DIN 58927 2/70)
Bubble class 0 - i.e. total bubble cross section within the volume is ≤ 0.03 mm²/100 cm³

Bubbles according to DIN ISO 10100
1/ 1*0,16 for pieces <6 kg
1/1*0,2 for pieces 6-30 kg

Inclusions:
None

Spots:
None

Refractive Index
n_C = 1.4564 at 656.3 nm

n_d = 1.4585 at 587.6 nm

n_F = 1.4632 at 486.1 nm

n_g = 1.4668 at 435.8 nm

At 20°C, 1 bar atmospheric pressure

Accuracy: ± 1 x 10^-4

Dispersion
n_F - n_C = 0,00678
v_d = 67,6 ± 0,5

Granular Structure:
None

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

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

In primary functional direction guaranteed total ∆n≤ 4 x 10^-6;

with power subtracted ∆n (p.s.) ≤ 2 x 10^-6;

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

(No special limits on size and weight).

∆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.

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

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 150 ppm (weight).

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

Good, visible transmittance is not degraded significantly by ionizing radiation.