The fluorescence of optical glasses is a property that needs to be taken into account in optical designs for life science applications. Many optical glasses from SCHOTT show a very low intrinsic or auto-fluorescence. The fluorescence depends mainly on the applied excitation wavelength and the optical glass type. The fluorescence of optical glasses is usually defined as the quotient of the integral of the emission spectrum with the integral of the emission spectrum of a reference glass. This definition does not give any information about the actual quantum efficiency of the fluorescence. In this presentation recent data on the integral fluorescence of SCHOTT optical glasses are presented. Additionally, first measurements of the quantum efficiency of SCHOTT optical glasses are presented and compared to the standard method.
Modern pulsed laser applications cover a broad range of wavelength, power and pulse widths. Beam guiding optics in laser systems do not only have specific requirements on the imaging quality but also have to withstand high laser power. The laser damage threshold of an optical component depends on the surface (polishing, coating ...) and also on the bulk material properties. Actual values of bulk laser damage thresholds, particularly at pulse lengths less than 1 nanosecond (1 ns), of optical glasses are rarely found in literature, except for fused silica, which is known as a key optical material for components in high power laser. However, fused silica is rather expensive and limited in optical properties. That is the reason why customers often ask for laser damage threshold data of optical glasses. Therefore, SCHOTT has started a project for the characterization of the bulk laser damage threshold of optical glasses at the wavelengths 532 nm and 1064 nm with pulse lengths in the nano- and pico-second range. Bulk and surface laser damage testing has been performed by the Laser Zentrum Hannover in Germany according to the S-on-1 test of DIN EN ISO 11254-2 / DIN EN ISO 21254.
The new generation of survey telescopes and future giant observatories such as E-ELT or TMT do not only require very
fast or very large mirrors, but also high sophisticated instruments with the need of large optical materials in outstanding
The huge variety of modern optical materials from SCHOTT covers almost all areas of specification needs of optical
designers. Even if many interesting optical materials are restricted in size and/or quality, there is a variety of optical
materials that can be produced in large sizes, with excellent optical homogeneity, and a low level of stress birefringence.
Some actual examples are high homogeneous N-BK7 blanks with a diameter of up to 1000 mm, CaF2 blanks as large as
300 mm which are useable for IR applications, Fused Silica (LITHOSIL<sup>®</sup>) with dimensions up to 700 mm which are
used for visible applications, and other optical glasses like FK5, LLF1 and F2 in large formats.
In this presentation the latest inspection results of large optical materials will be presented, showing the advances in
production and measurement technology.