Bench Talk

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Over the years, many electronic devices have been miniaturized to a much smaller scale than their original predecessors. For many electronic devices, miniaturizing electronic components (batteries, circuits, etc.) to the micron and then the nano level has been enough to reduce the device's overall size while keeping its efficiency high.

However, devices that use optical components are inherently trickier to miniaturize and enhance because the materials used within them need to be very high quality, and the devices themselves need to be incredibly precise. Over the last decade or so, the use of nanomaterials in optic and photonic devices has significantly increased, and they are now present in everything from optical coatings on lenses to photodetectors, light polarizers, and many more.

Many different properties of nanomaterials enable them to absorb, reflect, and manipulate light to perform the desired effect. These have been exploited for a range of optical and photonic devices (as well as devices that use optical components).

The nanomaterials’ inherent small size enables the components and devices they are used in to be smaller than bulkier counterparts. In addition to the small size, the high active surface area of many nanomaterials can be exploited to manipulate and change the properties of light. As many optical components are used in electronic devices, those that perform both an optical and an electronic function, such as optoelectronic devices, also require highly conductive materials. Many nanomaterials have very high electrical conductivities that can be utilized. The abrasion resistance and toughness of many nanomaterials are also useful. This helps prevent delicate optical components from becoming damaged, which in turn changes the optical efficiency of the components.

One other significant aspect of nanomaterials in optic and photonic technologies is that they exhibit strong light-matter interactions, ensuring that the optical components efficiently interact with light. Many nanomaterials also exhibit a broad optical response and fast relaxation times, and some are efficient enough to be used in terahertz technologies. Even when the optical components remain nanosized—meaning they are used as stand-alone nano components instead of part of a bigger component—they can be easily integrated with other bulkier optical components.

Nanomaterials in optical components range from complete devices that rely on their optical properties to function to components that are used in non-optical devices and to optical coatings used to both protect and enhance the optical properties of the device.

Lenses are used within many electronic devices and large-scale technologies. Lenses are typically too large to be wholly made of nanomaterials. However, nanostructures of different materials can be incorporated into different lenses to improve the optical performance and toughness of the lens. One of the more common options for lenses is to use nanomaterial-based coatings (or specific thin films for higher-tech applications), which also improves the performance and abrasion resistance/toughness of the lens, without needing to directly incorporate the nanomaterial in the lens. This approach is less expensive, as standard lenses can be used that are of much lower cost (small amounts of coating are often not too costly). Moreover, the use of coatings can introduce specific effects to the lens, such as anti-reflective properties.

While basic lenses don’t usually require nanomaterials, the use of nanostructures within lenses—and coatings/thin films—can, aside from basic performance and optical clarity enhancements, drastically alter the properties of the lens. One of the more common ways is to turn a lens into a highly effective optical filter or optical polarizer, both of which are used in a range of technologies.

A few other specific applications of nanomaterials include optical cavities, saturable absorbers, and optical switches for ultrafast lasers, as well as in complementary metal-oxide-semiconductor (CMOS) sensors, optical biosensors for detecting various biomolecules, and wearable optic technologies.

Many of the areas of optics and photonics overlap because they both deal with light, although there are some specific areas where nanomaterials are only used in photonic applications (such as in the processing and sensing of light, rather than in the manipulation of light that concern many optical components).

Design engineers can incorporate photonic nanostructures into different lenses as well. Like many nanomaterial-enhanced optical lenses, photonic nanostructures improve the performance of microscopes. Another big area of nanophotonics is in photodetectors because the electromagnetic absorption properties of many nanomaterials lead to highly efficient photodetectors, which are used in many technologies, including computers. Moreover, because many nanomaterials have a broad absorption spectrum, these photodetectors can detect ultraviolet (UV), infrared (IR), and photons of visible light.

Nanomaterials have been used to create a range of components within fiber optic cables. These include optical filters and Bragg gratings, which are either used on their own within fiber optic cables or to build other components, such as fiber optic anemometers. Many nanomaterials are used to build different parts of fiber optic cables because they interact strongly with the propagating light. Other areas where nanomaterials are used to create photonics-based devices include fiber optic rectennas to convert electromagnetic waves into an electric current, more advanced magnetic recording devices, and ways of improving the light intensity in spectroscopy and solar cell technologies, to name a few.

Optical and photonic technologies have advanced recently, but the need for highly precise components makes their improvement more challenging than many other technologies. In recent years, however, a wide range of nanomaterials have been used due to their strong interaction with light and their ability to manipulate the properties of light. Thus, many more technologies are being developed that use high-tech nanomaterial optics and photonic components.