# Publications

# 2019

### Beyond the display: phase-only liquid crystal on Silicon devices and their applications in photonics [Invited]

*Optics Express*

##### Lazarev G., Chen P., Strauss J., Fontaine N., and Forbes A.

Existing for almost four decades, liquid crystal on Silicon (LCOS) technology is rapidly growing into photonic applications. We review the basics of the technology, from the wafer to the driving solutions, the progress over the last decade and the future outlook. Furthermore we review the most exciting industrial and scientific applications of the LCOS technology. Found Here

### Quantitative orbital angular momentum measurement of perfect vortex beams

*Optics Letters*

##### Pinnell J., Rodríguez-Fajardo V., and Forbes A.

Perfect (optical) vortices (PVs) have the mooted ability to encode orbital angular momentum (OAM) onto the field within a well-defined annular ring. Although this makes the near-field radial profile independent of OAM, the far-field radial profile nevertheless scales with OAM, forming a Bessel structure. As yet, the quantitative measurement of the OAM of PVs has been elusive, with current detection protocols opting for more qualitative procedures using interference or mode sorters. Here, we show that the OAM content of a PV can be measured quantitatively using optical modal decomposition… Found Here

### Free-space optical communication link with shape-invariant orbital angular momentum Bessel beams

*Applied Optics*

##### Mphuthi N., Gailele L., Litvin I., Dudley A., Botha R., and Forbes A.

We present an alternative orbital angular momentum (OAM) solution for free-space optical communications in the form of shape-invariant Bessel beams. We use a generalized approach for generating these long-range self-healing beams with a phase-only element encoded on a spatial light modulator and imbue them with OAM. We study the performance of helical OAM beams as well as these long-range Bessel-like OAM beams over a real-world outdoor optical link of 150 m and show comparable performance. In the process, we characterize the link and its impact on modal cross-talk. Found Here

### A compact acoustic spanner to rotate macroscopic objects

*Scientific Reports*

##### Toninelli E., Cox M., Gibson G.M., Brown S.D., Edgar M.P., Forbes A. and Padgett M.J.

Waves can carry both linear and angular momentum. When the wave is transverse (e.g. light), the angular momentum can be characterised by the “spin” angular momentum associated with circular polarisation, and the “orbital” angular momentum (OAM) arising from the phase cross-section of the beam. When the wave is longitudinal (e.g. sound) there is no polarization and hence no spin angular momentum. However, a suitably phase-structured sound beam can still carry OAM. Observing the transfer of OAM from sound to a macroscopic object provides an excellent opportunity to… Found Here

### Multi-dimensional entanglement transport through single-mode fibre

*arXiv*

##### Liu J., Nape I., Wang Q., Valles A., Wang J. and Forbes A.

The global quantum network requires the distribution of entangled states over long distances, with significant advances already demonstrated using entangled polarisation states, reaching approxi- mately 1200 km in free space and 100 km in optical fibre. Packing more information into each photon requires Hilbert spaces with higher dimensionality, for example, that of spatial modes of light. However spatial mode entanglement… Found Here

### Classically Entangled Light

*Progress in Optics*

##### Forbes A., Aiello A. and Ndagano B.

The concept of entanglement is so synonymous with quantum mechanics that the prefix “quantum” is often deemed unnecessary: there is after all only quantum entanglement. But the hallmark of entangled quantum states is nonseparability, a property that is not unique to the quantum world. On the contrary, nonseparability appears in many physical systems, and pertinently, in classical vector states of light: classical entanglement? Here we outline the concept of classical entanglement… Found Here

### The Resilience of Hermite- and Laguerre-Gaussian Modes in Turbulence

*Journal of Lightwave Technology*

##### Cox M., Maqondo L., Kara R., Milione G., Cheng L. and Forbes A.

Vast geographical distances in Africa are a leading cause for the so-called “digital divide” due to the high cost of installing fibre. Free-Space Optical (FSO) communications offer a convenient and higher bandwidth alternative to point-to-point radio microwave links, with the possibility of re-purposing existing infrastructure… Found Here

### Coiling free electron matter waves

*New Journal of Physics*

##### Pierce J., Webster J,. Larocque H., Karimi E., McMorran B. and A Forbes A.

Here we demonstrate particle beams that spiral in free space devoid of external fields. The beams consist of electrons in two lobes that twist around each other along the optical axis, such that each electron can be described by a two-lobed probability distribution that rotates as it propagates. Furthermore, we demonstrate that this twisting distribution can … Found Here

### A versatile quantum walk resonator with bright classical light

*PlosOne*

##### Sephton B., Dudley A., Ruffato G., Romanato F., Marrucci L., Padgett M., Goyal S., Roux F., Konrad T. and Forbes A.

In a Quantum Walk (QW) the “walker” follows all possible paths at once through the principle of quantum superposition, differentiating itself from classical random walks where one random path is taken at a time. This facilitates the searching of problem solution spaces faster than with classical random walks, and holds promise for … Found Here

### Concepts in quantum state tomography and classical implementation with intense light: a tutorial

*Advances in Optics and Photonics*

##### Toninelli E., Ndagano B., Vallés A., Sephton B., Nape I., Ambrosio A., Capasso F., Padgett M.J., and Forbes A.

A tomographic measurement is a ubiquitous tool for estimating the properties of quantum states, and its application is known as quantum state tomography (QST). The process involves manipulating single photons in a sequence of projective measurements, often to construct a density matrix from … Found Here

### Quantum mechanics and classical light

*Contemporary Physics*

##### Konrad T. and Forbes A.

The similarities between quantum mechanics and paraxial optics were already well-known to the founding fathers of quantum mechanics; indeed knowledge of paraxial optics partly informed quantum mechanics as a wave theory. Likewise quantum mechanical methods have been employed to better understand optics, for example… Found Here

### Generation of structured light by multilevel orbital angular momentum holograms

*Optics Express*

##### Vijayakumar A., Rosales-Guzmán C., Rai M. R., Rosen J., Minin O. V., and Forbes A.

Structured light has been created by a myriad of near-and far-field techniques and has found both classical and quantum applications. In the case of orbital angular momentum (OAM), continuous spiral phase patterns in dynamic or geometric phase are often employed with the phase patterns existing across the entire transverse plane. Here, we exploit the uncertain relationship between OAM and angle in order to create… Found Here

### Engineering Structured Light from Lasers

*IEEE Photonics Society News*

##### Forbes A.

It recent years it has become possible to exercise tremendous control over light’s spatial profile, the “pattern of light”, tailoring it to produce spatially variant polarization states, exotic phase structures and customized intensity profiles. These advances have been driven by both fundamental science as well as engineering applications, and made possible by an extensive “toolkit” available to us, allowing … Featured here and the article is on page 4

### Amplification of higher order Poincaré sphere beams through Nd:YLF and Nd:YAG crystals

*Applied Physics B*

##### Sroor H., Litvin I., Naidoo D., and Forbes A.

Scalar and vector orbital angular momentum modes, generally described by the higher order Poincaré sphere (HOPS), have found many applications to date, but limited to low-power levels. It has thus become topical to consider amplification of such structured light modes. Here, we employ recently developed characterisation tools for HOPS beams… Found Here

### Optical orbital angular momentum under strong scintillation

*Physical Review A*

##### Mabena C. and Roux F. S.

The evolution of classical optical fields propagating through atmospheric turbulence is investigated under arbitrary conditions. We use the single-phase screen (SPS) method and the infinitesimal propagation equation (IPE), a multiphase screen (MPS) method, to compute the optical power fractions retained in an input Laguerre-Gauss (LG) mode or transferred to higher-order LG modes… Found Here

### Entanglement distillation by Hong-Ou-Mandel interference with orbital angular momentum states

*APL Photonics*

##### B. Ndagano and Forbes A.

Entanglement is an invaluable resource to various quantum communication, metrology, and computing processes. In particular, spatial entanglement has become topical, owing to its wider Hilbert space that allows photons to carry more information. However, spatial entanglement is susceptible to decay in the presence of external perturbations such as … Found Here

### Fractal light from lasers

*Physics Review A*

##### Sroor H., Naidoo D., Miller S., Nelson J., Courtial J., and Forbes A.

The efficient creation and detection of spatial modes of light has become topical of late, driven by the need to increase photon bit-rates in classical and quantum communications. Such mode creation/detection is traditionally achieved with tools based on linear optics. Here we put forward a new spatial mode detection technique based on the nonlinear optical process of sum-frequency generation… Found Here

### Super-resolution with quantum light

*Nature Photonics*

##### Forbes A. and Rodriguez-Fajardo R.

Quantum correlations from photon antibunching enhance the resolution of image scanning microscopy in biological imaging by twofold, four times beyond the diffraction limit. Found Here

### Spatial mode detection by frequency upconversion

*Optics Letters*

##### Sephton B., Vallés A., Steinlechner F., Konrad T., Torres J., Roux F. S., and Forbes A.

The efficient creation and detection of spatial modes of light has become topical of late, driven by the need to increase photon bit-rates in classical and quantum communications. Such mode creation/detection is traditionally achieved with tools based on linear optics. Here we put forward a new spatial mode detection technique based on the nonlinear optical process of sum-frequency generation… Found Here

### A high-speed, wavelength invariant, single-pixel wavefront sensor with a digital micromirror device

*arXiv*

##### Cox M., Toninelli M., Cheng L., Padgett M., and Forbes A.

The wavefront measurement of a light beam is a complex task, which often requires a series of spatially resolved intensity measurements. For instance, a detector array may be used to measure the local phase gradient in the transverse plane of the unknown laser beam. In most cases the resolution of the reconstructed wavefront is determined by the resolution of the detector, which in the infrared case is severely limited… Found Here

##### 2018

Ndagano B. and Forbes A. (2018). Characterization and mitigation of information loss in a six-state quantum-key-distribution protocol with spatial modes of light through turbulence. *Physical Review A , 98, 062330. Download *

Bhebhe N, Williams P., Rosales-Guzmán C., Rodriguez-Fajardo V., and Forbes A. (2018). A vector holographic optical trap *Scientific Reports , 8, 17387. Download *

Mabena C. and Roux F. S. (2018). High-dimensional quantum channel estimation using classical light. *Physical Review A , 96, 053860. Download *

Sorelli G, Shatokhin V. N., Roux F. S., and Buchleitner A. (2018). Diffraction-induced entanglement loss of orbital-angular-momentum states. *Physical Review A , 97, 013849. Download *

Prabhakar S., Mabena C., Konrad T., and Roux F.S. (2018). Turbulence and the Hong-Ou-Mandel effect. *Physical Review A , 97, 013835. Download *

Roux F. S. (2018). Combining spatiotemporal and particle-number degrees of freedom. *Physical Review A , 98, 043841. Download *

Otte E., Nape I., Rosales-Guzmán C., Vallés A., Denz C., and Forbes A. (2018). Recovery of nonseparability in self-healing vector Bessel beams. *Physical Review A , 98, 053818. Download *

Rosales-Guzmán C., Ndagano B., and Forbes A. (2018). A review of complex vector light fields and their applications. *Journal of Optics , 20(12), 123001. Download *

Dorrah A., Rosales-Guzmán C., Forbes A., and Mojahedi M. (2018). Evolution of orbital angular momentum in three-dimensional structured light. *Physical Review A , 98, 043846. Download *

Nape I., Otte E., Vallés A., Rosales-Guzmán C., Cardano F., Denz C., and Forbes A. (2018). Self-healing high-dimensional quantum key distribution using hybrid spin-orbit Bessel states. *Optics Express , 26(21). Download *

Cox M., Cheng L., Rosales-Guzmán C., and Forbes A. (2018). Modal Diversity for Robust Free-Space Optical Communications. *Physical Review Applied , 10, 024020. Download *

Naidoo D., Litvin A. I. and Forbes A. (2018). Brightness enhancement in a solid-state laser by mode transformation. *Optica , 5(7). Download *

Ruffato G., Girardi M., Massari M,. Mafakheri E., Sephton B., Capaldo P., Forbes A. and Romanato F. (2018). A compact diffractive sorter for high-resolution demultiplexing of orbital angular momentum beams. *Scientific Reports , 8, 10248. Download *

Perez-Garcia B., Hernandez-Aranda I. R., Forbes, A and Konrad T. (2018). The first iteration of Grover’s algorithm using classical light with orbital angular momentum. *Journal of Modern Optics , 65 (16). Download *

Bhebhe N., Rosales-Guzman C. and Forbes A. (2018). Classical and quantum analysis of propagation invariant vector flat-top beams. *Applied Optics , 57 (19). *

Mphuti, N., Botha, R. and Forbes, A. (2018). Are Bessel beams resilient to aberrations and turbulence? *Journal of the Optical Society of America , 35 (6). *

Lavery, M., Abadi, M., Bauer, R., Brambilla, G., Cheng, L., Cox, M., Dudley, A., Ellis, A., Fontaine, N., Kelly, A., Marquardt, C., Matlhane, S., Ndagano, B., Petruccione, F., Slavík, R., Romanato, F., Rosales-Guzmán, C., Roux, F., Roux, K., Wang, J. and Forbes, A. (2018). Tackling Africa’s digital divide. *Nature Photonics , 12. *

Sroor, H., Nyameko, L., Naidoo, D., Litvin, I., and Forbes, A. (2018). Purity of vector vortex beams through a birefringent amplifier. *Physical Review Applied , 9, 044010. Download *

Otte, E., Rosales-Guzman, C., Ndagano, B., Denz, C., and Forbes, A. (2018). Entanglement beating in free space through spin-orbit coupling. *Light: Science & Application , 7, 18009. Download *

Haddadi, S., Bouzid, O., Fromager, M., Hasnaoui, A., Harfouche, A., Cagniot, E., Forbes, A., and Ait-Ameur K. (2018). Structured Laguerre-Gaussian beams for mitigation of spherical aberration in tightly focused regimes. *Journal of Optics , 20 (4). Download *

Ndagano, B., Nape, I.,Cox M., Rosales-Guzmán C. and Forbes, A. (2018). Creation and detection of vector vortex modes for classical and quantum communication. *Journal of Lightwave Technology , 36 (2). Download *

Nape, I., Kyeremah, C., Vallés, A., Rosales-Guzmán, C., Buah-Bassuah, P., and Forbes, A. (2018). A hybrid quantum eraser scheme for characterization of free-space and fiber communication channels. *Optics Communications , 408. Download *

##### 2017

Ndagano, B., Nape, I., Perez-Garcia, B., Scholes, S., Hernandez-Aranda, R.I., Konrad, T., Lavery, M.P. and Forbes, A. (2017). A deterministic detector for vector vortex states. *Scientific reports , 7(1), 13882. Download *

Bouzid O., Haddadi, S., Fromager, M., Cagniot, E., Ferria, K., Forber, A. and Ait-Ameur, K. (2017). Focusing anomalies with binary diffractive optical elements, *Applied Optics 56, 9735.* Mabena, C. and Roux, F. (2017). High-dimensional quantum channel estimation using classical light,

*Phys. Rev. A*

*. 96, 053860. Download*Ndagano, B., Mphuthi, N., Milione, G. and Forbes, A. (2017). Comparing mode-crosstalk and mode-dependent loss of laterally displaced orbital angular momentum and Hermite–Gaussian modes for free-space optical communication. *Optics letters , 42(20), 4175-4178. Download*

Rosales-Guzmán, C., Bhebhe, N. and Forbes, A. (2017). Simultaneous generation of multiple vector beams on a single SLM. *Optics express , 25(21), 25697-25706. Download*

Zhang, Y., Agnew, M., Roger, T., Roux, F.S., Konrad, T., Faccio, D., Leach, J. and Forbes, A. (2017). Simultaneous entanglement swapping of multiple orbital angular momentum states of light. *Nature Communications , 8(1), 632. Download*

Vetter, C., Dudley, A., Szameit, A. and Forbes, A. (2017). Real and virtual propagation dynamics of angular accelerating white light beams. * Optics express , 25(17), 20530-20540. Download*

Rosales-Guzmán, C. and Forbes, A. (2017). How to shape light with spatial light modulators. SPIE.SPOTLIGHT Download

Forbes, A. and Botha, L., (2017). Laser Isotope Separation. Laser Beam Shaping Applications (2nd ed.), *Ch. 7*, eds. F.M. Dickey and T. Lizotte. CRC Taylor & Francis Group (New York) Download

Rosales-Guzmán, C., Bhebhe, N., Mahonisi, N. and Forbes, A. (2017). Multiplexing 200 modes on a single digital hologram. *Journal of Optics*, 19 113501 Download

Nape, I., Kyeremah, C., Vallés, A., Rosales-Guzmán, C., Buah-Bassuah, P.K. and Forbes, A., (2017). Hybrid quantum erasure scheme for channel disturbance characterization. *Optics Communications* 408, 53-57 Download

Roux F.S. (2017). Biphoton states in correlated turbulence, *Phys. Rev. A.*Download

Nape, I., Ndagano, B. and Forbes, A., (2017). Erasing the orbital angular momentum information of a photon. *Physical Review A*, *95* (5), 053859 Download

Ismail, Y., Joshi, S., Forbes, A. and Petruccione, F., (2017). Instrumentation limitation on a polarization-based entangled photon source. *JOSA B*, *34*(6), 1084-1089 Download

McLaren, M. and Forbes, A., (2017). Digital spiral-slit for bi-photon imaging. *Journal of Optics*, *19*(4), 044006 Download

Webster, J., Rosales-Guzmán, C. and Forbes, A., (2017). Radially dependent angular acceleration of twisted light. *Optics letters*, *42*(4), 675-678. Download

Ndagano, B., Perez-Garcia, B., Roux, F.S., McLaren, M., Rosales-Guzman, C., Zhang, Y., Mouane, O., Hernandez-Aranda, R.I., Konrad, T. and Forbes, A., (2017). Characterizing quantum channels with non-separable states of classical light. *Nature Physics*, *13*(4), 397 Download

Forbes, A., (2017). Controlling light’s helicity at the source: orbital angular momentum states from lasers. *Phil. Trans. R. Soc. A*, *375*(2087), 20150436 Download

Sephton, B., Dudley, A. and Forbes, A. (2017). Quantum Walks. *Quest*, *13*(4), 15-18. Download

Forbes, A. (2017). Blurring the classical quantum divide. *Optics and photonics news*, *17*(12), 36. Download

Rubinsztein-Dunlop, H., Forbes, A., Berry, M., Dennis, M., Andrews, D., Mansuripur, M., Denz, C., Alpmann, C., Banzer, P., Bauer, T. and Karimi, E., (2016). Roadmap on structured light. *Journal of Optics*, *19*(1), 013001. Download

##### 2016

Roux, F. S. (2016). Topological charge conservation in stochastic optical fields. *Journal of Optics*, *18*(5), 054005. Download

Roux, F. S. (2016). Non-Markovian evolution of photonic quantum states in atmospheric turbulence. *Journal of Optics*, *18*(5), 055203. Download

Zhang, Y., Prabhakar, S., Rosales-Guzmán, C., Roux, F. S., Karimi, E., & Forbes, A. (2016). Hong-Ou-Mandel interference of entangled Hermite-Gauss modes. *Physical Review A*, *94*(3), 033855. Download

Zhang, Y., Prabhakar, S., Roux, F. S., Forbes, A., & Konrad, T. (2016). Experimentally observed decay of high-dimensional entanglement through turbulence. *Physical Review A*, *94*(3), 032310. Download

Sephton, B., Dudley, A., & Forbes, A. (2016). Revealing the radial modes in vortex beams. *Applied optics*, *55*(28), 7830-7835. Download

Cox, M. A., Rosales-Guzmán, C., Lavery, M. P., Versfeld, D. J., & Forbes, A. (2016). On the resilience of scalar and vector vortex modes in turbulence. *Optics express*, *24*(16), 18105-18113. Download

Perez-Garcia, B., Yepiz, A., Hernandez-Aranda, R. I., Forbes, A., & Swartzlander, G. A. (2016). Digital generation of partially coherent vortex beams. *Optics Letters*, *41*(15), 3471-3474. Download

Ndagano, B., Sroor, H., McLaren, M., Rosales-Guzmán, C., & Forbes, A. (2016). Beam quality measure for vector beams. *Optics Letters*, *41*(15), 3407-3410. Download

Trichili, A., Salem, A. B., Dudley, A., Zghal, M., & Forbes, A. (2016). Encoding information using Laguerre Gaussian modes over free space turbulence media. *Optics Letters*, *41*(13), 3086-3089. Download

Gossman, D., Perez-Garcia, B., Hernandez-Aranda, R. I., & Forbes, A. (2016). Optical interference with digital holograms. *American Journal of Physics*, *84*(7), 508-516. Download

Trichili, A., Rosales-Guzmán, C., Dudley, A., Ndagano, B., Salem, A. B., Zghal, M., & Forbes, A. (2016). Optical communication beyond orbital angular momentum. *Scientific reports*, *6*. Download

Forbes, A., Dudley, A., & McLaren, M. (2016). Creation and detection of optical modes with spatial light modulators. *Advances in Optics and Photonics*, *8*(2), 200-227. Download

Perez-Garcia, B., McLaren, M., Goyal, S. K., Hernandez-Aranda, R. I., Forbes, A., & Konrad, T. (2016). Quantum computation with classical light: Implementation of the Deutsch–Jozsa algorithm. *Physics Letters A*, *380*(22), 1925-1931. Download

Naidoo, D., Roux, F. S., Dudley, A., Litvin, I., Piccirillo, B., Marrucci, L., & Forbes, A. (2016). Controlled generation of higher-order Poincaré sphere beams from a laser. *Nature Photonics*, *10*(5), 327-332. Download

Goyal, S. K., Roux, F. S., Konrad, T., & Forbes, A. (2016). The effect of turbulence on entanglement-based free-space quantum key distribution with photonic orbital angular momentum. *Journal of Optics*, *18*(6), 064002. Download

Naidoo, D., Harfouche, A., Fromager, M., Ait-Ameur, K., & Forbes, A. (2016). Emission of a propagation invariant flat-top beam from a microchip laser. *Journal of Luminescence*, *170*, 750-754. Download

Zhang, Y., Roux, F. S., Konrad, T., Agnew, M., Leach, J., & Forbes, A. (2016). Engineering two-photon high-dimensional states through quantum interference. *Science advances*, *2*(2), e1501165. Download

Brüning, R., Ndagano, B., McLaren, M., Schröter, S., Kobelke, J., Duparré, M., & Forbes, A. (2016). Data transmission with twisted light through a free-space to fiber optical communication link. *Journal of Optics*, *18*(3), 03LT01. Download

Dudley, A., Majola, N., Chetty, N., & Forbes, A. (2016). Implementing digital holograms to create and measure complex-plane optical fields. *American Journal of Physics*, *84*(2), 106-112. Download

##### 2015

Naidoo, D., Fromager, M., Ait-Ameur, K., & Forbes, A. (2015). Radially polarized cylindrical vector beams from a monolithic microchip laser. *Optical Engineering*, *54*(11), 111304-111304. Download

Brüning, R., Flamm, D., Ngcobo, S. S., Forbes, A., & Duparré, M. (2015, February). Rapid measurement of the fiber’s transmission matrix. In *SPIE OPTO* (pp. 93890N-93890N). International Society for Optics and Photonics. Download

Goyal, S. K., Roux, F. S., Forbes, A., & Konrad, T. (2015). Implementation of multidimensional quantum walks using linear optics and classical light.*Physical Review A*, *92*(4), 040302. Download

Brüning, R., Zhang, Y., McLaren, M., Duparré, M., & Forbes, A. (2015). Overlap relation between free-space Laguerre Gaussian modes and step-index fiber modes. *JOSA A*, *32*(9), 1678-1682. Download

McLaren, M., Konrad, T., & Forbes, A. (2015). Measuring the nonseparability of vector vortex beams. *Physical Review A*, *92*(2), 023833. Download

Litvin, I. A., Mhlanga, T., & Forbes, A. (2015). Digital generation of shape-invariant Bessel-like beams. *Optics express*, *23*(6), 7312-7319. Download

Schulze, C., Roux, F. S., Dudley, A., Rop, R., Duparré, M., & Forbes, A. (2015). Accelerated rotation with orbital angular momentum modes. *Physical Review A*, *91*(4), 043821. Download

Ndagano, B., Bruning, R., McLaren, M., Duparre, M., & Forbes, A. (2015) Fiber propagation of vector modes. *Optics Express*, 23(13), 17330-17336. Download

Perez-Garcia, B., Francis, J., McLaren, M., Hernandez-Aranda, R. I., Forbes, A., & Konrad, T. (2015). Quantum computation with classical light: The Deutsch Algorithm. *Physics Letters A*, *379*(28), 1675-1680. Download

Litvin, I. A., Mhlanga, T., & Forbes, A. (2015). Digital generation of shape-invariant Bessel-like beams. *Optics express*, *23*(6), 7312-7319. Download

McLaren, M. G., Roux, F. S., & Forbes, A. (2015). Realising high-dimensional quantum entanglement with orbital angular momentum. *South African Journal of Science*, *111*(1-2), 01-09. Download

Burger, L., Litvin, I., Ngcobo, S., & Forbes, A. (2015). Implementation of a spatial light modulator for intracavity beam shaping. *Journal of Optics*, *17*(1), 015604. Download

Milione, G., Dudley, A., Nguyen, T. A., Chakraborty, O., Karimi, E., Forbes, A., & Alfano, R. R. (2015). Measuring the self-healing of the spatially inhomogeneous states of polarization of vector Bessel beams. *Journal of Optics*, *17*(3), 035617. Download

##### 2014

Aspden, R.S. et al., 2014. Experimental demonstration of Klyshko’s advanced-wave picture using a coincidence-count based, camera-enabled imaging system. *Journal of Modern Optics*, 61(March), pp.1–5. doi: 10.1080/09500340.2014.899645 Download

Ismail, Y. et al., 2014. Characterization of a Polarisation Based Entangled Photon Source. *The African Review of Physics*, 9, pp.217–226. Download

Litvin, I. a et al., 2014. Doughnut laser beam as an incoherent superposition of two petal beams. *Optics letters*, 39(3), pp.704–7. doi: 10.1364/OL.39.000704. Download

Schulze, C. et al., 2014. Measurement of the orbital angular momentum density of Bessel beams by projection into a Laguerre-Gaussian basis. *Applied optics*, 53(August), pp.5924 – 5933. doi: 10.1364/AO.53.005924. Download

Spangenberg, D.-M. et al., 2014. White light wavefront control with a spatial light modulator. *Optics Express*, 22(11), p.13870. doi: 10.1364/OE.22.013870. Download

Trichili, A., Mhlanga, T. & Ismail, Y., 2014. Detection of Bessel beams with digital axicons. *Optics Express*, 22(14), pp.17553 – 17560. doi: 10.1364/OE.22.017553. Download

##### 2013

Boubaha, B. et al., 2013. Spatial properties of coaxial superposition of two coherent Gaussian beams. *Applied optics*, 52(23), pp.5766–72. doi: 10.1364/AO.52.005766. Download

Chaibi, A., Mafusire, C. & Forbes, A., 2013. Propagation of orbital angular momentum carrying beams through a perturbing medium. *Journal of Optics*, 15(10), p.105706. doi: 10.1088/2040-8978/15/10/105706. Download

Giovannini, D. et al., 2013. Characterization of high-dimensional entangled systems via mutually unbiased measurements. *Physical Review Letters*, 110(14), pp.1–5. doi: 10.1103/PhysRevLett.110.143601. Download

Goyal, S.K. et al., 2013. Implementing quantum walks using orbital angular momentum of classical light. *Physical Review Letters*, 110(26), pp.1–5. doi: 10.1103/PhysRevLett.110.263602. Download

Litvin, I. a, Burger, L. & Forbes, A., 2013. Angular self-reconstruction of petal-like beams. *Optics letters*, 38(17), pp.3363–5. doi: 10.1364/OL.38.003363. Download

Schulze, C. et al., 2013a. Measurement of the orbital angular momentum density of light by modal decomposition. *New Journal of Physics*, 15(July), p.073025. doi: 10.1088/1367-2630/15/7/073025 Download

Schulze, C. et al., 2013b. Reconstruction of laser beam wavefronts based on mode analysis. *Applied optics*, 52(21), pp.5312–7. doi: 10.1364/AO.52.005312. Download

##### 2012

Dudley, A. & Forbes, A., 2012. From stationary annular rings to rotating Bessel beams. *Journal of the Optical Society of America A*, 29(4), p.567. doi: 10.1364/JOSAA.29.000567. Download

Flamm, D. et al., 2012. Mode analysis with a spatial light modulator as a correlation filter. *Optics Letters*, 37(13), p.2478. doi: 10.1364/OL.37.002478. Download

Ismail, Y. et al., 2012. Shape invariant higher-order Bessel-like beams carrying orbital angular momentum. *Journal of Optics*, 14(8), p.085703. doi: 10.1088/2040-8978/14/8/085703. Download

Litvin, I. a. et al., 2012. Azimuthal decomposition with digital holograms. *Optics Express*, 20(10), p.10996. doi: 10.1364/OE.20.010996. Download

Naidoo, D. et al., 2012. Observing mode propagation inside a laser cavity. *New Journal of Physics*, 14(May), p.053021. doi: 10.1088/1367-2630/14/5/053021. Download

Schulze, C., Flamm, D., et al., 2012. Beam-quality measurements using a spatial light modulator. *Optics Letters*, 37(22), pp.4687–9. doi: 10.1364/OL.37.002478.

Schulze, C., Ngcobo, S., et al., 2012. Modal decomposition without a priori scale information. *Optics Express*, 20(25), pp.27866–73. doi: 10.1364/OE.20.027866. Download

Schulze, C., Naidoo, D., et al., 2012. Wavefront reconstruction by modal decomposition. *Optics Express*, 20(18), p.19714. doi: 10.1364/OE.20.019714. Download

##### 2011

Agnew, M. et al., 2011. Tomography of the quantum state of photons entangled in high dimensions. *Physical Review A – Atomic, Molecular, and Optical Physics*, 84(6), p.062101. doi: 10.1103/PhysRevA.84.062101.

Godin, T. et al., 2011. Transverse correlation vanishing due to phase aberrations. *Optics Communications*, 284(19), pp.4601–4606. doi: 10.1016/j.optcom.2011.05.062.

Lavery, M.P.J. et al., 2011. Robust interferometer for the routing of light beams carrying orbital angular momentum. *New Journal of Physics*, 13(September), p.093014. doi: 10.1088/1367-2630/13/9/093014.

Litvin, I. a., Dudley, A. & Forbes, A., 2011. Poynting vector and orbital angular momentum density of superpositions of Bessel beams. *Optics Express*, 19(18), p.16760. doi: 10.1364/OE.19.016760.

McLaren, M., Sidderas-Haddad, E. & Forbes, A., 2011. Accurate measurement of microscopic forces and torques using optical tweezers. *South African Journal of Science*, 107(9-10), pp.1–8. doi: 10.4102/sajs.v107i9/10.579.

Naidoo, D. et al., 2011. Transverse mode selection in a monolithic microchip laser. *Optics Communications*, 284(23), pp.5475–5479. doi: 10.1016/j.optcom.2011.08.017.

##### 2010 & older

Bernhardi, E.H. et al., 2008. Estimation of thermal fracture limits in quasi-continuous-wave end-pumped lasers through a time-dependent analytical model. *Optics Express*, 16(15), pp.11115–11123. doi: 10.1364/OE.16.011115.

Burger, L. & Forbes, A., 2008. Kaleidoscope modes in large aperture Porro prism resonators. *Optics Express*, 16(17), pp.12707–12714. doi: 10.1364/OE.16.012707.

Litvin, I. A. & Forbes, A., 2009. Gaussian mode selection with intracavity diffractive optics. *Optics Letters*, 34(19), pp.2991–2993. doi: 10.1364/OL.34.002991.

Litvin, I. A. & Forbes, A., 2008. Bessel-Gauss resonator with internal amplitude filter. *Optics Communications*, 281(9), pp.2385–2392. doi: 10.1016/j.optcom.2007.12.052.

Litvin, I.A. & Forbes, A., 2009. Intra – cavity flat – top beam generation. *Optics Express*, 17(18), pp.15891–15903. doi: 10.1364/OE.17.015891.

Mafusire, C. et al., 2008. Optical aberrations in a spinning pipe gas lens. *Optics Express*, 16(13), pp.9850–9856. doi: 10.1364/OE.16.009850.

Vasilyeu, R. et al., 2009. Generating superpositions of higher-order Bessel beams. *Optics Express*, 17(26), pp.23389–23395. doi: 10.1364/OE.17.023389.