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UK OPTICAL DESIGN MEETING

Thursday 19^th September 2019

Imperial College
South Kensington, London
 

Poster Abstracts 360o infrared imager with scalable architecture Laura Cowan1, James Babington1, Guillem Carles1, Andy Wood2, Andy Harvey1 Affiliation: 1 - University of Glasgow                                      2 - Qioptiq Ltd, Denbighshire, Wales Providing situational awareness in three dimensions using thermal imaging is of great practical importance for civilian and military applications, but there are currently no solutions available at acceptable cost. The emergence of low-cost computer power and thermal-imaging systems now provides an alternative solution, where the use of arrays of low-cost cameras enables imaging using quasi-curved detection planes to enable aberration-free imaging of extreme fields of view with an extremely high-pixel count. This presentation will discuss the design and practical demonstration of solutions based around the use of multi-camera imaging using low-cost thermal imaging cameras to provide 360° panoramic imaging. Through using compact low-pixel count detectors paired with inexpensive silicon lenses, we have created a compact scalable architecture with a high angular resolution. This parallelized camera system produces video-rate long-wave infrared panoramic snapshots and offers the multifunctionality of multiple-camera integral imaging such as 3D imaging, ranging and imaging through obscurants. Novel wavefront phase sensor as objective glass quality inspector M. Velasco-Ocaña, S. Bonaque, J. Trujillo, J.M. Rodriguez Ramos Wooptix S.L., Avenida Trinidad 61, S.C. de La Laguna Tenerife, 38204, España                    In this work we present a new method for optical characterization of glass samples. It is based on a new wavefront sensor method developed by the image processing specialist company Wooptix. With this novel wavefront phase sensor and a simple optical arrangement we have performed an objective optical characterization of glass specimens, accounting not only for striae and bubbles but also subtle changes in the homogeneity of the glass. The main advantage of wavefront phase based inspections over classical shadowgraphy are its robustness and quantitative behaviour. We show that interpreting the wavefront phase data, the quality metrics obtained provides more information than the obtained by shadowgraphy. Keywords: wavefront, striae, shadowgraphy, homogeneity Nanoplasmonic Stopped Light Fibres Yongqiang Wen Blackett Laboratory, Department of Physics, Imperial College London London, SW7 2AZ, UK                    Nanoplasmonics provides a way of manipulating light on the nanoscale. This project introduced the geometrical stopped light that the speed of light can be tuned by the geometry of plasmonic materials. Fibres are a good example of geometrical stopped light that require fewer layers than the planar structures to achieve stopped light. Single interface stopped light is observed. Multimode stopped light in the fibres is observed. Adding a gain medium can compensate the losses, and even lead to amplification of photons and plasmons. The capture of light spatially is beneficial for enhanced light-matter interactions. It enables future photonics and quantum devices. Photon emission and collection from single molecular dipole emitters Zhiheng Li, Ming Fu, Monica Mota, Rupert Oulton Blackett Laboratory, Department of Physics, Imperial College London London, SW7 2AZ, UK                    Single molecular dipole emitters have important applications in quantum computation, quantum communication, spectroscopy and imaging, but collecting light emissions from one single molecule can be very difficult and inefficient. The emergence of metalens and waveguide provides alternative ways to collect light emissions from single emitters. In this presentation, we will demonstrate the engineering of dipole emission by placing the dipole at dielectric interface (interfacial dipole). As for photon collection, we will present the design of metalens and waveguide to collect light emissions from interfacial dipole.   Long Range Optical Levitation and Particle Tracking for High Power Laser Experiments Adrian Grande and Roland A. Smith Blackett Laboratory, Department of Physics, Photonics Group Imperial College London, London, SW7 2AZ, UK                    The interaction of high intensity multi terawatt laser pulses with a small target of order of the laser wavelength gives rise to interesting phenomena such as non-uniform electric field “hot spots” on target’s surface that enhance laser absorption leading to the production of a bright source of x-rays, multi MeV ions and electrons. In order to irradiate the microtarget, optical levitation traps are designed to load, confine and trap the target in a small localised region of the order of a few microns by counterbalancing gravity with photon momentum transfer from a “low power” continuous laser beam allowing high accuracy pulse delivery. We will present a Zemax simulation, construction and characterisation of optical levitation traps designed for use in vacuum conditions and at large trapping distances of several cm. The traps were loaded with silicon-based oil microdroplets of different sizes and a particle tracking system based on a 1-D PSD sensor used to monitor and control the particle dynamics through active feedback control. Generation of an Optical Vortex using a Shear Plate Interferometer Jean-Benoit Jaillot, W. Kerridge-Johns, J.W.T Geberbauer, and M. J. Damzen Blackett Laboratory, Department of Physics, Photonics Group Imperial College London, London, SW7 2AZ, UK                    A shear plate is used to convert a Gaussian laser beam into an optical vortex with excellent quality and complete control of handedness of vorticity. A full mathematical formulation is made of the displacement and angular tilt transformation provided by the shear plate and shows excellent agreement with experiment. This study shows that a shear plate provides a simple, robust and inexpensive way to produce very high quality vortices with wavelength versatility and would considerably reduce cost and add simplicity for vortex generation in applications (e.g. STED super-resolution microscopy where expensive and complex spatial light modulators are commonly used). Ultra-compact freeform array projection for pattern generation with extended light sources Christoph Bösel1, Johannes Hartung2, Herbert Gross1,2, Affiliation:   1 - Friedrich Schiller University Jena, Institute of Applied Physics (IAP), Max Wien Platz 1, 07743 Jena, Germany                   2 - Fraunhofer Institute for Applied Optics and Precision Engineering, Albert-Einstein-Str. 7, 07745 Jena, Germany Compact, energy efficient projection systems are interesting for applications like structured-light 3D scanning. One possibility to realize such projection systems are freeform surfaces. The utilization of extended light sources like LEDs or VCSELs thereby causes the typical freeform illumination pattern blurring, which complicates the design of compact freeform projectors for structured illumination. We present the design of a highly compact freeform projection system that minimizes the pattern blurring and consists of a collimator, an array of double freeform surfaces and a projection lens array. Analogous to an object slide projector the arrangement in a channel array leads to the minimization of the longitudinal extension of the projection system as well as to an invariance of the projection system to the intensity distribution and the shape of the emission area of the light source. To avoid channel cross talk, the divergent input light requires the separation of the freeform channels. This causes energy losses but allows a constant continuation of the array channels and potentially enables a manufacturing process of every freeform channel on a single substrate. To demonstrate the capabilities of the concept it is applied to several illumination patterns and a real VCSEL light source, which is modelled by a ray file.

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