Laser processing methods for creation and engineering of crystal defects
The next generation of precision devices for sensing, communication, and the storage and processing of information will be derived from an ability to harness quantum effects. Optically active point defects in crystals, particularly diamond, can be used in the fabrication of devices effective for all of these applications.
However, whilst techniques for introducing point defects into crystals have been established, they are unable to introduce defects deep within a bulk crystal and also result in significant damage to the crystal lattice. Oxford researchers have developed a method for introducing defects into crystals accurately using laser processing for increased control. The Oxford method results in minimal damage to the crystal lattice and enables engineering of defects and the rapid creation of complex patterns.
Point defects in diamond have a range of potential applications in information technologies and devices. Examples include their use in sensors of magnetic fields, electric fields, and temperature, in quantum memory registers, and as sources of single photons in quantum communication. The most developed of these defects is the nitrogen-vacancy (NV) centre, however, several other defects have emerged as candidates for similar applications. Advantageous properties of diamond for these applications include:
- Environmentally robust
- Low thermal and magnetic noise
- Highly localised electron states in defects
The majority of point defects are associated with either single or multiple lattice vacancies. Currently, the creation of vacancies is carried out either by electron irradiation or the ion implantation process. These methods cause substantial lattice damage in addition to defect creation. Established methods are also not able to create isolated defects deep inside a crystal. Methods enabling controlled generation of lattice vacancies without causing residual lattice damage are, therefore, of significant value in the development of high-precision quantum devices.
Oxford researchers have developed a controlled method for the generation and engineering of crystal defects using laser processing techniques. The technique provides the ability to accurately position defect centres, which is vital for device functionality. Advantages of the Oxford method include:
- Accurate positioning of defects
- Creation of vacancies anywhere within a bulk crystal
- Insensitivity to surface quality, shape or impediment structures
- Rapid creation of complex patterns
- Minimal residual lattice damage
- Hallmarking of precious stones
This technology will find applications in creating quantum devices for a range of information technology applications, including sensing, telecommunications, and the storage and processing of information.
This technology is the subject of an international patent application. Substantial Proof of Concept work has been completed. Oxford University Innovation is seeking industrial partners that wish to use this method in the production of precision devices.
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