Conveners
Photonics: Non-Specialist Lecture
- Gurthwin Bosman (Stellenbosch University)
Photonics: Quantum Optics I
- Hermann Uys (National Laser Centre, CSIR)
Photonics: Classical Optics I
- Cosmas Mafusire (University of Pretoria)
Photonics: Classical Optics II
- Carmelo Rosales-Guzman (University of the Witwatersrand, Johannesburg)
Photonics: Imaging and Spectroscopy I
- Tjaart Krüger (University of Pretoria)
Photonics: Biophotonics II
- Pieter Neethling (Laser Research Institute, University of Stellenbosch)
Photonics: Quantum Optics II
- Christine Steenkamp (University of Stellenbosch)
Photonics: Imaging and Spectroscopy II
- Adam Valles (School of Physics, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa)
Photonics: PISA and Rental Pool Discussion
- There are no conveners in this block
Photonics: Photonics Division Meeting
- Andrew Forbes (U. Witwatersrand)
Dr
Tjaart Krüger
(University of Pretoria)
04/07/2017, 10:00
Track C - Photonics
Oral Presentation
When exposed to intense sunlight all organisms performing oxygenic photosynthesis implement various photoprotective strategies to prevent potentially lethal photodamage. The rapidly responding photoprotective mechanisms, occurring in the light-harvesting pigment-protein antennae, take effect within tens of seconds, while the dramatic and potentially harmful light intensity fluctuations...
Ms
Bereneice Sephton
(CSIR National Laser Centre; Wits Physics Department)
04/07/2017, 11:10
Track C - Photonics
Oral Presentation
Computational power available with classical computers has become increasingly limited for the scope required by many applications such as simulation and modelling in developmental research as well as factorization of large numbers. The solution for many of these problems lies in the development of quantum computers for which the physical implementation of quantum walks (QW) has been shown to...
Mr
Nicholas Bornman
(University of the Witwatersrand)
04/07/2017, 11:30
Track C - Photonics
Oral Presentation
Quantum ghost imaging is one of the many unanticipated and yet wonderful peculiarities arising from quantum mechanics. The basic proposal behind it is using a pair of entangled photons, one of which strikes an arbitrary object, and being able to reconstruct an image of the object by observing the other photon. In this study we use an experimental setup involving a couple of tiers of crystals...
Mr
Isaac Nape
(Structured Light Lab, School of Physics, University of Witwatersrand)
04/07/2017, 11:50
Track C - Photonics
Oral Presentation
Wave-particle duality is one of the most intriguing features of quantum mechanics that has been traditionally investigated through modern variations of Young’s double slit experiment. When the paths of the double slit are marked with orthogonal polarisations of light, the path information is revealed and no interference pattern is observed. However, the interference can be erased with a...
Dr
Cosmas Mafusire
(University of Pretoria)
04/07/2017, 14:00
Track C - Photonics
Oral Presentation
The Nijboer-Zernike diffraction theory was devised to solve imaging problems in which the phase is represented as a linear combination of Zernike circle polynomials. The extension of the theory to create the Extended Zernike-Nijboer (ENZ) theory gives an allowance for the analysis of imaging systems with high numerical aperture and strong defocus. We investigate the implementation of circular...
Mr
Prince Mredlana
(Student)
04/07/2017, 14:20
Track C - Photonics
Oral Presentation
The coherence of optical fields is a defining factor in how they are represented and characterised, in this work we employ the Wigner Distribution Function (WDF) for a generalized optical field characterisation method. We characterize a Gaussian-Schell model partially coherent beam by determining the beam width, divergence, curvature and beam quality factor of the pure field from the mutual...
Ms
Hend SROOR
(University of The Witwatersrand)
04/07/2017, 14:40
Track C - Photonics
Oral Presentation
Fractal is a mathematical series that manifests replicated patterns at every scale. If the repeated patterns are identical in each scale, the fractal in this case is called a self-similar fractal. That type of fractal is described by a mathematical equation which is nowhere differentiable. Fractals have found their way in applications such as fractal antennas and transistors, digital imaging...
Ms
Bereneice Sephton
(CSIR National Laser Centre; Wits Physics Department)
04/07/2017, 15:00
Track C - Photonics
Poster Presentation
Orbital angular momentum (OAM) carrying beams are ubiquitous in many experiments being performed today and cover a wide range of research, from surface micro-structure processing to optical tweezers and communications. It follows that these beams are a significant factor in the outcome of these research areas. Characterization of OAM beams lies in the ability to identify the OAM being carried....
Ms
Anneke Erasmus
(Stellenbosch University)
04/07/2017, 15:20
Track C - Photonics
Oral Presentation
Optical tweezing is an established technique that has been developed for manipulating micron sized objects. These applications include cell sorting, studying intracellular dynamics, applying specific forces to trapped particles as well as quantitative measurement of intracellular forces, for example measuring the force exerted by molecular motors inside a living cell. Trapping occurs when the...
Mr
Lucas Gailele
(Csir)
05/07/2017, 11:10
Track C - Photonics
Oral Presentation
Optical communication systems optimize multiplexing in polarization and wavelength both transmitted in fiber and free-space to attain high bandwidth data communication. We are expected to reach a bandwidth ceiling in the near future due to non-linear effects in fiber. Communications using orbital angular momentum (OAM) carrying modes offers infinite dimensional states, providing means to...
Mr
Mitchell Cox
(University of the Witwatersrand)
05/07/2017, 11:30
Track C - Photonics
Oral Presentation
Mode Division Multiplexing (MDM) is an emerging technology which harnesses the spatial degree of freedom of laser beams to significantly increase the overall capacity of optical communication systems. Current research typically focusses on the use of Orbital Angular Momentum (OAM), however, MDM research has also been done into the use of orthogonal Laguerre-Gaussian (LG) or Hermite-Gaussian...
Mr
NKOSIPHILE ANDILE BHEBHE
(UNIVERSITY OF THE WITWATERSRAND)
05/07/2017, 11:50
Track C - Photonics
Oral Presentation
Structured or custom optical fields have become useful tools for research and other technological applications. Of particular interest in many of these applications is the simultaneous generation of multiple beams (multiplexing). Technological advances have provided computer-controlled devices capable of generating a great variety of beam shapes that can be multiplexed and controlled...
Ms
Nancy Payne
(Stellenbosch University)
05/07/2017, 14:00
Track C - Photonics
Oral Presentation
Ultrafast electron diffraction (UED) is used to study photo-induced structural phase transitions and dynamics in crystalline materials. UED uses the pump-probe technique: the sample is optically excited by a laser pulse and then its structure is probed by an electron pulse, effectively acquiring a sub-ps snapshot of the crystal structure in time. By changing the time delay between pump and...
Mr
Bart Smit
(Stellenbosch University)
05/07/2017, 14:20
Track C - Photonics
Oral Presentation
The 1-dimensionally conductive organic material Cu(DNCQI)2 has been a subject of interest due to its exotic macroscopic (conductivity) properties and the tuneability thereof. Depending on chemical composition, the crystal loses many orders of magnitude of conductivity within 1 K upon cooling. This phase transition is associated with a structural (‘Peierls’) transition of the...
Mr
Shane Smith
(Physics Post Graduate Student)
05/07/2017, 14:40
Track C - Photonics
Oral Presentation
Terahertz time-domain spectroscopy is a powerful spectroscopic tool. Due to the long wavelength of terahertz radiation, it has a high penetration depth, thus allowing for high resolution at low intensity, and low photon energy, making it ideal for non-destructive spectroscopy. Normally terahertz spectroscopy is performed in transmission, due to the simplicity of such a setup and extracting...
Dr
Wilfrid Innocent Ndebeka
(Laser Research Institute, University of Stellenbosch)
05/07/2017, 15:00
Track C - Photonics
Oral Presentation
Optical second harmonic generation (SHG) is widely used as non-invasive technique to probe surfaces and interfaces of centrosymmetric materials, e.g. silicon/silicon dioxide (Si/SiO2) and the bulk crystal structure of non-centrosymmetric materials such as silicon carbide (SiC). The time-dependent SHG observed at the Si/SiO2 interface of a bulk Si is caused by multiphoton excitation of...
Mr
Ruan Viljoen
(Stellenbosch University)
05/07/2017, 15:20
Track C - Photonics
Oral Presentation
A number of different techniques utilizing a coherent supercontinuum from a photonic crystal fibre to produce a single-beam coherent anti-stokes Raman scattering (CARS) signals from a variety of samples have been demonstrated. In this presentation, we compare some of these techniques, employing amplitude, phase, and polarisation modulation techniques on our supercontinuum pulse to produce...
Mr
Eric Chekwube Aniogo
(Laser Research Centre, University of Johannesburg)
06/07/2017, 10:00
Track C - Photonics
Oral Presentation
Cancer is one of the common diseases that affect and threatens our human existence. Breast cancer is an invasive heterogeneous disease and the second most common disease among woman worldwide. Virtually, curative degenerative diseases like cancer employ multiple therapeutic agents that targets different pathological processes. For this reason, combination therapy remains an alternative...
Mr
Sandy Jere
(Laser Research Center, University of Johannesburg)
06/07/2017, 10:20
Track C - Photonics
Oral Presentation
The Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) signaling pathway consists of four JAK and seven STAT family members. It is involved in the transmission of external signals via receptors to the nucleus, resulting in transcription and downstream events such as cellular proliferation and migration. Wound healing is coordinated by complex signaling cascades involving...
Mr
Chemist Mabena
(University of the Witwatersrand and CSIR)
06/07/2017, 11:10
Track C - Photonics
Oral Presentation
The effect of turbulence on the Hong-Ou-Mandel (HOM) is analysed theoretically. The analysis is performed with two types of entangled input states, a Bell state and a spontaneous parametric down converted input state. In this work, two scenarios have been considered. The first scenario is when only one of the entangled photons is sent through the turbulence and the second scenario is when both...
Dr
Shashi Prabhakar
(School of Physics, University of the Witwatersrand, Johannesburg 2000, South Africa)
06/07/2017, 11:30
Track C - Photonics
Oral Presentation
In this work, the effect of turbulence on the Hong-Ou-Mandel (HOM) effect is investigated experimentally. For this purpose, we produce entangled photonic states generated by spontaneous parametric down-conversion. In our experiment, the entangled photons propagate through different turbulent media, which are simulated using spatial light modulators. The atmospheric turbulence is simulated...
Mr
Bienvenu Ndagano
(University of the Witwatersrand)
06/07/2017, 11:50
Track C - Photonics
Oral Presentation
Intensity fringes are characteristic features of optical interference between spatially coherent fields. At the quantum level, interference expresses the distinguishability of a given observable. A classic illustration is Young’s double slit experiment; the two slits are indistinguishable, causing the two paths taken by a single photon to interfere on a screen. However, the ability to measure...
Dr
Konstantin Zloshchastiev
(Durban University of Technology)
06/07/2017, 12:10
Track C - Photonics
Oral Presentation
It is shown that sustainability is a universal quantum-statistical phenomenon, which emerges during propagation of photons inside different dissipative media, such as waveguides, metamaterials or biological tissues. These quantum effects occur due to the interaction of electromagnetic (EM) waves or photons with their environment, which can be described by means of the reduced density operator...
Dr
Adam Valles
(School of Physics, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa)
06/07/2017, 12:30
Track C - Photonics
Oral Presentation
By making use of frequency-entangled photons we present a new type of optical coherence tomography (OCT) scheme, where the reflectivity of the sample translates in a change of coherence. We call this new approach induced optical coherence tomography (iOCT). This new scheme allows probing the sample with one wavelength and measuring light with another wavelength. As a result, we can gain...
Dr
Igor Litvin
(CSIR NLC)
06/07/2017, 12:50
Track C - Photonics
Oral Presentation
We propose a novel laser beam shaping technique based on the manipulation of the transverse gain profile in the laser crystal. The method allows controllable reshaping of a laser output beam into a desired beam profile. The proposed technique was successfully tested by both laser and laser amplifier systems with controllable gain. Two laser diodes were used to pump the crystal and to create a...
Ms
Ratsimandresy Holinirina Dina Miora
(Laser Research Institute, Sellenbosch University)
06/07/2017, 14:00
Track C - Photonics
Oral Presentation
Fluorescence microscopy is an imaging technique capable of resolving very tiny objects which are not within the resolution range of the normal eye. This technique uses the fluorescence properties of the object in order to get direct knowledge of the particle object and indirect knowledge of the substance in which the object is embedded [1]. In our work, a fluorophore is used as a probe object...
Mr
Adrian Wyngaard
(Cape Peninsula University of Technology)
06/07/2017, 14:20
Track C - Photonics
Oral Presentation
We report on the measurement and analysis of the magnetic sub-levels of Rubidium 85 and 87 observed in the presence of a weak magnetic field. Included is the standard hyperfine interaction which is a prerequisite measurement for this analysis. The experiment was performed using a saturated absorption spectroscopy setup. A solenoid was placed around the Rb vapour cell in order to generate the...
Mr
George Okyere Dwapanyin
(Stellenbosch University)
06/07/2017, 14:40
Track C - Photonics
Oral Presentation
Nonlinear Optical microscopy (NLOM) has been used in recent years in probing biological tissues both in vivo and in vitro due to its numerous advantages such as intrinsic 3D imaging with submicron spatial resolution, decreased photodamage, increased depth of penetration and the ability to perform label-free imaging. The integration of a broadband supercontinuum (SC) light source...
Ms
Charmaine Sibanda
(Stellenbosch University)
06/07/2017, 15:00
Track C - Photonics
Oral Presentation
Photophysics and photochemistry in polymer science has been of central areas of interest in understanding the structure and dynamics of polymers. The physical properties of polymers especially the dynamical properties close to the phase transition from rubbery to the glassy state are complex and have not been completely understood despite experimental and theoretical studies over the past...
Mr
Mabuti Jacob Radebe Radebe
(Necsa)
06/07/2017, 15:20
Track C - Photonics
Oral Presentation
Digital neutron imaging (radiography and tomography) is a powerful non-destructive analytical tool and has demonstrated its importance in industrial and research applications world-wide. The standardization process, to certify digital thermal neutron imaging as a standard practice in industry, entails standardized performance characterization methods. Spatial resolution is one of the key...
