Optical Materials beyond Glass

Specialty optical glass is the major lens material for imaging optics in consumer, industrial as well as military optical systems. Due to its high compositional flexibility a huge variety of glass based lens materials can be realized at low costs in huge sizes tailored individually to a specific optical design. However, increasing requirements from both high-end industrial as well as consumer optics system side have continuously asked for sophisticated optical materials with extraordinary property combinations. For instance refractive indices significantly higher than nd = 2.0 combined with outstanding specialty dispersion characterisistics and/or expanded transmission windows for example towards the UV- regime are of interest. Here optical glass tend to its intrinsic limits considering the processability of property determining extreme chemical compositions. Simple chemistry crystalline optical materials are considered to be potential solutions for the challenges of designing of future optical imaging systems. In more detail the talk will discuss both benefits and drawbacks of using transparent polycrystalline ceramics in optical lens systems. Furthermore recent progress on the growth of high performing ultra pure single crystals for deep-UV applications like microlithography will be presented.