The new development comes from the Graphene Flagship, which is one of the European Unions’ biggest research initiatives boasting a budget of €1 billion. The possibilities of graphene are regularly featured on Digital Journal’s science pages. The new research was primarily undertaken at Cambridge University. Here researchers have demonstrated gate tunable third harmonic generation in graphene.
The research findings could help to enable the construction of on-chip broadband optical switches for data transport in optical systems. Considerable research is going into optics in terms of improving data storage and retrieval. For example there are optical storage devices that use a semiconductor laser less than a millimetre wide to scan the surface of the disc for data retrieval.
A further area of development is with Optical Transport Networking, which is becoming the next-generation, industry-standard protocol that provides an efficient way to multiplex different services onto optical light paths.
With the new research, optical harmonic generation involves the creation of new frequencies (as colors). This occurs when high intensity light interacts with a nonlinear material. Nonlinear optical effects can be exploited in a range of applications, such as laser technology, material processing and telecommunications.
One problem with developing such technology is that the efficiency of the process is small and it cannot be controlled externally. However, graphene has the potential to change this. Graphene has strong light matter interaction and a strong third order nonlinear response.
The researchers demonstrated how electrical control of the nonlinear optical response of a graphene can enables applications like gate-tuneable switches and frequency converters. Moreover, with graphene this can be controlled by an externally using an electric field.
The key outcome is that graphene optical switches have the potential to harness previously unused optical frequencies to transmit data along optical cables. This could increase the amount of data that can be transmitted and also to significantly increase data speeds.
The research has been published in the journal Nature Nanotechnology and the paper is titled “Broadband, electrically tunable third-harmonic generation in graphene.”
