We report the development of a monolithic, mechanically tunable waveguide platform based on the flexible polymer polydimethyl siloxane (PDMS). Such devices preserve single mode guiding across a wide range of linear geometric distortions. This enables the realization of directional couplers with tunable splitting ratios via elastic deformation of the host chip. We fabricated several devices of this type, and verified their operation over a range of wavelengths, with access to the full range of input/output ratios. The low cost and relative ease of fabrication of these devices via a modified imprint lithographic technique make them an attractive platform for investigation of large scale optical random walks and related optical phenomena.

We propose a robust photonic platform for encapsulation and addressing of optically active 2D-and nano-materials. Our implementation utilises a monolayer of MoS 2 transition metal dichalcogenide embedded in an elastomeric waveguide chip. The structure is manufactured from PDMS using soft-lithography and capable of sustaining a single mode of guided light. We prove that this setup facilitates addressing of the 2D material flake by pumping it with polarised laser light and gathering polarisation-resolved photoluminescence spectra with the extinction ratio of 31, which highlights the potential for selection-rule dependent measurements. Our results demonstrate improved handling of the material and experimental simplification compared to other techniques.

Fast, direct electron detectors have significantly improved the spatio-temporal resolution of electron microscopy movies. Preserving both spatial and temporal resolution in extended observations, however, requires storing prohibitively large amounts of data. Here, we describe an efficient and flexible data reduction and compression scheme (ReCoDe) that retains both spatial and temporal resolution by preserving individual electron events. Running ReCoDe on a workstation we demonstrate on-the-fly reduction and compression of raw data streaming off a detector at 3 GB/s, for hours of uninterrupted data collection. The output was 100-fold smaller than the raw data and saved directly onto network-attached storage drives over a 10 GbE connection. We discuss calibration techniques that support electron detection and counting (e.g., estimate electron backscattering rates, false positive rates, and data compressibility), and novel data analysis methods enabled by ReCoDe (e.g., recalibration of data post acquisition, and accurate estimation of coincidence loss).

We present a method to map the evolution of photonic random walks that is compatible with nonclassical input light. Our approach leverages a newly developed flexible waveguide platform to tune the jumping rate between spatial modes, allowing the observation of a range of evolution times in a chip of fixed length. In a proof-of-principle demonstration we reconstruct the evolution of photons through a uniform array of coupled waveguides by monitoring the end-face alone. This approach enables direct observation of mode occupancy at arbitrary resolution, extending the utility of photonic random walks for quantum simulations and related applications.Quantum walks have been studied extensively in the context of quantum computing and simulation [1][2][3][4]. Systems built around a quantum walk have been proposed as physical simulators for a wide variety of quantum [5] and classical [6] phenomena. When random walks are leveraged for physical simulation the dynamics and evolution of the random walker as it traverses the graph are often of primary interest.In the experimental domain, quantum walks have been demonstrated across a range of physical systems, employing trapped particles [7-9] and photons [10][11][12][13][14][15]. The field of photonic quantum walks is particularly developed, owing to the ease of access to long coherence times and the ability to perform high fidelity manipulation of single particles using relatively low cost devices. Within this class, devices comprising waveguide arrays have proved popular due to their favourable scaling properties [16].When simulating a physical system, the evolution of the quantum walker is commonly inferred by monitoring fluorescence in the host device [11,[17][18][19]. Unfortunately, this signal is able to capture only the intensity of the propagating optical modes, and so is unsuitable for following the evolution of more complicated inputs, for example multi-photon entangled states. Systems which leverage these inputs are only able to obtain a snapshot of the random walk at a fixed propagation length corresponding to the output plane [20]. Even where the evolution of the walker is not of primary interest, access to this information may be desired as a diagnostic or calibration tool.We have designed and implemented an optical circuit in which the evolution of a photonic quantum walk can be observed in a chip of constant length. In our system, a sequence of observations at the end face combined with appropriate tuning of the device parameters exposes the evolution of the input state in a manner that is compatible with single photon intensities, and extensible to multiphoton states. We demonstrate this technique by implementing the well-studied [12] one dimensional, continuous-time random walk on a uniform graph.A continuous-time, discrete-space quantum walk on a one-dimensional graph comprising a set of vertices connected with edges (as depicted in Fig 1, middle row) can be realized physically by injecting photons into an array of identical, continuously coupled waveguides....

To facilitate the implementation of large scale photonic quantum walks, we have developed a polymer waveguide platform capable of robust, polarization insensitive single mode guiding over a broad range of visible and nearinfrared wavelengths. These devices have considerable elasticity, which we exploit to enable tuning of optical behaviour by precise mechanical deformations. In this work, we investigate pairs of beamsplitters arranged as interferometers. These systems demonstrate stable operation over a wide range of phases and reflectivities. We discuss device performance, and present an outlook on flexible polymer chips supporting large, reconfigurable optical circuits.

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