Dielectric waveguide lasers, microfluidic protein sensing, and raman spectroscopy
The work will be carried out within the ERC Advanced Grant “Optical Ultra-Sensor” (OPUS). This project will exploit the ultra-narrow linewidths, ultra-high quality factors (Q-factors), and ultra-high internal photon densities achievable in dual-wavelength, distributed-feedback (DFB), dielectric-waveguide lasers to perform on-chip-integrated, intra-laser-cavity optical sensing with unprecedented sensitivity. For our rare-earth-ion-activated Al2O3 lasers on silicon microchips, we will develop novel channel-waveguide and Bragg-grating geometries to decrease propagation losses, increase passive-cavity Q-factors, and enhance evanescent-field overlap with the measurands. Together with frequency stabilization, these advances will improve the current few-kHz laser linewidths (Q-factors of ~1011) to few-Hz linewidths (Q-factors of ~1014), thereby achieving intra-cavity laser powers of hundreds of Watts and light-measurand interaction lengths exceeding the circumference of the earth. Simple electrical read-out of the change in laser frequency and linewidth induced by the measurand is realized by photo-detection of the GHz beat-frequency signal produced between the perturbed and reference resonance of the dual-wavelength laser. Besides Al2O3:Yb3+ lasers emitting at 1-µm wavelength, we will develop Al2O3:Tm3+ and Al2O3:Ti3+ lasers on silicon chips operating at 2 µm and 700-1000 nm, respectively, thereby addressing new sensing applications. We will combine single and multiple dual-wavelength DFB lasers with microfluidic channels and arrayed-waveguide gratings in Al2O3, and place protein-antibody layers on top of the gratings or differently rare-earth-ion-doped nm-thin layers inside the active waveguide. This will enable intra-laser-cavity evanescent-field trapping and sensing of nano-sized bio-particles in optofluidic chips, first-ever demonstrations of on-chip intra-laser-cavity trace-gas detection and Raman spectroscopy, as well as intra-laser-cavity rare-earth-ion and energy-transfer spectroscopy approaching the single-ion level.
Applicants are expected to have a first-class or 2:1 degree or equivalent in physics, electrical engineering, optics, photonics, or anotechnology; a solid background in lasers, rare-earth spectroscopy, integrated optics, or biomedical optics is an additional advantage.
You should have an aptitude and suitable background for conducting research in the field of waveguide lasers, integrated optics, and optical sensing.
You are expected to have a very good understanding of optics in general, with particular emphasis on either lasers or optical sensing. Practical research expertise in an optical lab and/or a clean-room environment is desirable.
How to apply
Formal applications can be made through our Phd Advanced Technology Institute course page. In your application you must mention this studentship in order to be considered.
The application should include:
- A cover letter
- A curriculum vitae (including a list of publications)
- Contact details of two academic referees
- Copies of academic transcripts and qualification certificates.
For a full award applicants must must be from the UK, EU or the EEA (European Economic Area) as well as meeting all the requirements in this advert to be considered.