Glass has been used since ages for optical components, but since plastic has come up they have made their way in modern optics. A plastic optical fiber or polymer optical fiber is an optical fiber made out of polymer. It is similar to glass optical fiber, in which POF transmits light through the bottom of the fiber. This key feature gives it the benefit over glass products. Moreover, it is very powerful when bending and stretching is concerned.
Within the wide range of plastic materials, there is a special category that comprises incredible optical fiber material properties. They have high-transmission and refractive index properties suitable for optimal purposes like lenses, optical fibers, gratings, etc.
List Of Plastic In Optical Applications
1) Acrylics:
The most widely used plastic is Acrylic glass or plexiglass. It is also called PMMA or Poly Methyl. It has amazing properties such as a refractive index of 1.49 at 589.3 nm and a 3 mm thick sheet that conveys 92% of light in the apparent spectrum. Moreover, it consumes UV light with wavelengths that are shorter than 400 nm, and IR wavelengths taller than 2800 nm. All this makes it an absolute substitute for glass in the optical world. They are used as glass alternatives and as Ophthalmology Optical Fibers.
2) Polycarbonate:
Polycarbonates (PC) are a type of thermoplastics that deliver impressive optical transmission in the visible range. It is known for being tough when compared to other optical plastics. PCs consume UV wavelengths shorter than 400 nm and in apparent range, they have 90% transmission. They have a refractive index of 1.59. Eyeglass lenses, Substrates for Filters, Reflectors, CDs/DVDs are some of the applications of polycarbonate, thanks to its toughness and optical clarity.
3) Polyethylene Terephthalate (PET):
It is commonly known as PET. It is used for the production of various products such as ubiquitous water bottles, polyester fabric to thin-film solar cells. It is the most adaptable and flexible plastic. PET substrates are highly translucent. In the apparent spectrum, it has a transmission of 90% and a refractive index of 1.57. Touch panels and solar cells are some widespread applications of PET.
4) Polyether Ether Ketone (PEEK):
In cases where high temperature and mechanical stability are required, PEEK is most widely demanded. They melt at around 340oC. Moreover, they consist of huge tensile stability and creep resistance. Furthermore, they don’t handily dissolve in water and are flame retardant which makes them best suited for industrial purposes. In optical fiber and automobile parts, they are required as buffer materials while they act as an aluminum replacement in the aerospace field. The application of PEEK is CR-39 (Allyl Diglycol Carbonate or ADC).
5) Polystyrene:
Polystyrene, specifically General Purpose Polystyrene (GPPS) is another optical plastic material that is apparent, though, and brittle. It has a refractive index of 1.59, which is identical to PCs but bigger than PMMA. PS has a high transmission of 90% In the visible spectrum PS has 90% transmission. Diffusers for Lighting Applications is the application of GPPS.
6) Silicones:
Optical silicones are not only flexible but transparent too. Unlike PMMA, Polystyrene, and Polycarbonates silicones are not rigid, instead, they are highly adaptable. However, poly dimethyl siloxane (PDMS) is widespread optical silicone as it has 90% optical transmission from 250-1000nm. This makes it suitable for lenses and flexible substrates. Additionally, PDMS is a viscoelastic polymer, which means by governing the cross-linking between polymer chains their viscosity and elasticity can be adjusted. Silicones are used for applications such as Intraocular Lenses.
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