All-fibre wavefront sensor

We report on a tapered three-core optical fibre that can be used as a tip-tilt wavefront sensor. In this device, a coupled region of a few millimetres at the sensing tip of the fibre converts fragile phase information from an incoming wavefront into robust intensity information within each of the cores. The intensity information can be easily converted to linear wavefront error over small ranges, making it ideal for closed loop systems. The sensor uses minimal information to infer tip-tilt and is compatible with remote detector arrays. We explore its application within adaptive optics and present a validation case to show its applicability to astronomy.Comment: 7 pages, 6 figure

Observation of rapid adiabatic passage in optical four-wave mixing

We observe clear evidence of adiabatic passage between photon populations via a four-wave mixing process, implemented through a dispersion sweep arranged by a core diameter taper of an optical fiber. Photonic rapid adiabatic passage through the cubic electric susceptibility thus opens precise control of frequency translation between broadband light fields to all common optical media. Areas of potential impact include optical fiber and on-chip waveguide platforms for quantum information, ultrafast spectroscopy and metrology, and extreme light-matter interaction science.Air Force Office of Scientific Research (FA9550-15-1-0356); United States-Israel Binational Science Foundation (BSF) (2014360); Office of Naval Research (N00014-19-1-2592); Dept. of Defense National Defense Science Engineering Graduate Fellowship (NDSEG) Progra

Controlled core-to-core photo-polymerisation – fabrication of an optical fibre-based pH sensor

The fabrication of fluorescence-based pH sensors, embedded into etched pits of an optical fibre via highly controllable and spatially selective photo-polymerisation is described and the sensors validated.</p

High fidelity fibre-based physiological sensing deep in tissue

Physiological sensing deep in tissue, remains a clinical challenge. Here a flexible miniaturised sensing optrode providing a platform to perform minimally invasive in vivo in situ measurements is reported. Silica microspheres covalently coupled with a high density of ratiometrically configured fluorophores were deposited into etched pits on the distal end of a 150 micron diameter multicore optical fibre. With this platform, multiplexed photonic measurements of pH and oxygen concentration with high precision in the distal alveolar space of the lung is reported. We demonstrated the phenomenon that high-density deposition of carboxyfluorescein covalently coupled to silica microspheres shows an inverse shift in fluorescence in response to varying pH. This platform delivered fast and accurate measurements, near instantaneous response time, no photobleaching, immunity to power fluctuations and a flexible architecture for addition of multiple sensors

Dataset for "An endlessly adiabatic fibre with a logarithmic refractive index distribution"

This dataset contains the data underlying the results reported in K. Harrington et al., "An endlessly adiabatic fibre with a logarithmic refractive index distribution". The data includes the results of calculations and measurements of a fibre with a novel refractive index distribution. This includes calculated mode field diameters for various outer diameters of the fibre. Also included are optical micrographs and near-field images recorded by digital sensors and stress distributions for fibres made with different drawing conditions.The methodology used to obtain the data is described in the paper K. Harrington et al., "An endlessly adiabatic fibre with a logarithmic refractive index distribution".The tabular data files (*.txt) are presented as tab-separated values