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We demonstrate determination of the location of the distal-end of a fibre-optic device deep in tissue through the imaging of ballistic and snake photons using a time resolved single-photon detector array. The fibre was imaged with centimetre resolution, within clinically relevant settings and models. This technique can overcome the limitations imposed by tissue scattering in optically determining the in vivo location of fibre-optic medical instruments.

Previously unobtainable measurements of alveolar pH were obtained using an endoscope-deployable optrode. The pH sensing was achieved using functionalized gold nanoshell sensors and surface enhanced Raman spectroscopy (SERS). The optrode consisted of an asymmetric dual-core optical fiber designed for spatially separating the optical pump delivery and signal collection, in order to circumvent the unwanted Raman signal generated within the fiber. Using this approach, we demonstrate a ~100-fold increase in SERS signal-to-fiber background ratio, and demonstrate multiple site pH sensing with a measurement accuracy of ± 0.07 pH units in the respiratory acini of an ex vivo ovine lung model. We also demonstrate that alveolar pH changes in response to ventilation.

A continuous flow microfluidic cell separation platform has been designed and fabricated using femtosecond laser inscription. The device is a scalable and non-invasive cell separation mechanism aimed at separating human embryonic stem cells from differentiated cells based on the dissimilarities in their cytoskeletal elasticity. Successful demonstration of the device has been achieved using human leukemia cells the elasticity of which is similar to that of human embryonic stem cells.

Using ultrafast laser inscription, we report the fabrication of a prototype three-dimensional 121-waveguide fan-out device capable of reformatting the output of a 120-core multicore fiber (MCF) into a one-dimensional linear array. When used in conjunction with an actual MCF, we demonstrate that the reformatting function using this prototype would result in an overall through put loss of ≈7.0??dB. However, if perfect coupling from the MCF into the fan-out could be achieved, the reformatting function would result in an overall loss of only ≈1.7??dB. With adequate development, similar devices could efficiently reformat the output of so-called “photonic lanterns” fabricated using highly multicore fibers.

Laser slope efficiencies close to the quantum defect limit and in excess of 78% have been obtained from an ultrafast laser inscribed buried channel waveguide fabricated in a ytterbium-doped bismuthate glass. The simultaneous achievement of low propagation losses and preservation of the fluorescence properties of ytterbium ions is the basis of the outstanding laser performance.

A novel technique was used to control the spatial overlap of the orthogonal linearly polarized waveguide modes in ultrafast laser inscribed BiB_3O_6 waveguides. We report that the strain fields induced by the expansion of material in the laser focus can be considered independently in the design of “type II” waveguides guiding orthogonal linearly polarized light. The waveguide with the optimal mode overlap was used for type I birefringently phase-matched second-harmonic generation of a continuous wave laser source at 1047?nm.

We report optical guiding and laser action at around 1.9?μm in a Tm^3+-doped fluorogermanate glass waveguide fabricated using ultrafast laser inscription. A monolithic laser cavity was constructed by directly butt coupling dielectric mirrors to each facet of the 6.0?mm long Tm^3+-doped waveguide. When the waveguide was pumped by a Ti:sapphire laser tuned to 791?nm, laser oscillation was achieved at around 1.91?μm. This waveguide laser exhibited a maximum slope efficiency of 6% and a maximum output power of 32?mW when pumped with 620?mW of incident laser power.

We report the successful fabrication of a low-loss near-IR waveguide in polycrystalline ZnSe using ultrafast laser inscription. The waveguide, which was inscribed using the multiscan fabrication technique, supported a well-confined mode at 1.55μm. Propagation losses were characterized at 1.55μm using the Fabry–Perot technique and found to be 1.07dB·cm^−1±0.03dB·cm^−1.