Optofluidic hollow-core photonic crystal fibre (HC-PCF) allows light to be guided at the centre of a microfluidic channel, maximizing its interaction with liquids and particles. This system offers unique opportunities to study photochemical reactions and in advanced optical trapping experiments.
Current work:
Optofluidic microreactors
The maximized overlap between light and sub-µL samples enables highly-efficient photochemistry at optical powers a million times less than in conventional systems [1]. The system also allows sensitive in-situ reaction monitoring, which is also of great importance in catalytically active fibre [2]. In a continuous flow arrangement, photoproducts can be analysed in parallel by mass-spectrometry, which is particularly important in the development of novel light-activatable anticancer drugs.
Fibre sensing in active batteries
Li ion battery degradation is a huge problem for their lifetime, but it is hard to discern the chemistry involved. By sealing a holey fibre into current battery packs, we are able to track how the lithium organic chemistries change, tracking their vibrational spectra while cycling them. This new tool can be used in a wide variety of battery and storage technologies. [3]
Optothermal trapping in air-filled holey fibre
Radiation pressure from the fundamental mode of a HC-PCF can keep a microparticle trapped at the centre of the core, while propelling it along the fibre. Our experiments in which light scattered by the particle creates a temperature gradient along the fibre, have led to the discovery of an opto-thermal trapping mechanism from competition between optical forces and viscous drag. [4]
Optical conveyor belt
Wavefront shaping techniques make it possible to selectively excite higher-order spatial modes of a holey fibre. We recently showed that microparticles can be moved over long distances and precisely positioned in a low-loss air-filled hollow-core photonic crystal fibre by exciting coherent superpositions of spatial modes. The beat pattern allows trapped microparticles to be moved and exquisitely positioned along the fibre by tuning the relative phase between the modes [5].
Key papers:
- Photonic crystal fibres for chemical sensing and photochemistry, Chem. Soc. Rev. 42, 8629 (2013). Highlighted on front cover.
- Chemical and (Photo)-Catalytical Transformations in Photonic Crystal Fibers, Chem. Cat. Chem. 5, 641 (2013). Highlighted on front cover.
- Hollow-core optical fibre sensors for operando Raman … Li-ion battery liquid electrolytes, Nature Comm (2022); DOI: 10.1038/s41467-022-29330-4
- Reconfigurable optothermal microparticle trap in air-filled hollow-core photonic crystal fiber, Phys. Rev. Lett. 109, 024502 (2012)
- Mode-based microparticle conveyor belt in air-filled hollow-core photonic crystal fiber, Opt. Express 21, 29383 (2013).
Current people involved:
Tijmen Euser, Ermanno Miele, Megan Groom