Lenses, prisms, and other optical elements are usually made of hard solid glass because this is a durable and stable ma terial. However, components made of glass also entail some drawbacks: their shape is predefined, which means that it is difficult to adapt them to external circumstances; further more, they are vulnerable to cracks and scratches, which may render them unusable forever. Kana M. Sureshan and his group at IISER Thiruvananthapuram have mol ded optical components out of organogels which are shatter-free, self-healing, and can be cut with a knife into any desired shape.
Sureshan et al developed two sugar based gelators that can congeal various oils to produce transparent gels. Employing the oil that has transmittance and refractive index similar to glass, one can make gels with glass-like optical properties. Interestingly, these gels are self healing; the fibers can rearrange themselves over time, healing small scratches/lesions on the surface of the gel. Furthermore, this self-healing property can be used to merge two or more blocks of gel into a single block, simply by juxtapo sing the two pieces and allowing them to heal. By exploiting these properties, Sureshan et al made several optical elements such lenses, prisms, gel plates etc. As gels are intrinsically soft unlike glass, these orga nogel-based optical components are shatter free as well.
Another appealing property of these organogels is their thermo-reversible nature, which offers the possibility of developing adaptive optics. Also Sureshan et al have shown that it is possible to add some UV absorbing dopants to the gels and change their optical properties in order to produce optical filters. Interestingly, such doping did not affect the transparency or gel strength to a considerable extent.
This report not only introduces the organogels to optics but also affirms that there are interesting uncharted areas for organogel based applications.
For the original paper, see: Angew. Chem. Int. Ed. 2011, 50, 8021-8024.
This paper has been highlighted in following journals: Nature 2011, 475, 427
Optics & Photonics Focus, 2011, 15, story 2
Angew. Chem. Int. Ed. 2012 DOI: 10.1002/anie.201107167