Sensor technology impacts almost all major technologies and new and improved sensor systems will continue to be needed in the future. This project will develop a new paradigm for ultra-high-speed laser manufacturing of low-cost novel micro- and nano-sensor structures and smart 2-D sensory materials that could be even flexible and wearable. These could lead to diverse societal benefits ranging from personalised medicine to next generation consumer and industrial data and communication products.
Traditional laser manufacturing is limited to micron feature size by the laser wavelength and usually operates by selective removal of material by cutting and drilling. In this project we will develop a very different methodology for laser manufacturing using vortex laser beams. Using the central zero intensity “dark” core of an optical vortex laser beam we can make nanometre feature sizes that can be two orders of magnitude smaller than the wavelength of light. Remarkably, instead of selectively removing surface material, the laser processing in the central vortex core can grow tall and thin nanoneedles with nanometre radius tips. Using the orbital angular momentum of the vortex beam, these tall nanoneedles can be created with chirality (i.e. they have a spiral corkscrew structure) with a handedness that can be controlled by the vorticity direction of the light beam. Such chiral nanoneedles could have unique potential for nanoscale sensing and imaging. Since they can be grown in a single pulse, or further grown in a few pulses, a high pulse rate vortex laser can rapidly manufacture large areas of 2-D sensor arrays to form low-cost smart sensory materials (e.g. metal and silicon). As the processing is a surface modification it is possible to envision the exciting prospect of fabrication of thin flexible or wearable sensory materials.
To bring this potential forward, this project will address two critical aspects of high speed vortex sensor production: a) a high pulse rate vortex laser source technology; and b) high-speed vortex-based nanoneedle processing methodologies. This project will take a new vortex laser concept invented at Imperial College London and develop it towards the high power and high pulse rates (100kHz) required for high speed vortex manufacturing. This prototype vortex laser source will be trialled for processing of material surfaces to demonstrate and investigate methodologies for high speed manufacture of high aspect ratio nanoneedles and high density 2-D nanoneedle arrays over large surface areas.
Alongside the vortex laser and laser processing experimental trials, to aid the understanding and control of nanoneedle creation, theoretical modelling will be performed to reveal the underlying principles. The outcome of this project will be to opening up exciting possibilities for directly creating new sensor structures and smart materials with sensory capabilities at high speed and low cost and thereby enable societal benefits through breakthrough technological, consumer and medical applications.