Lasers and Applied Optics

Lasers and Applied Optics

Members

  1. Dr Valentine T Chabata, Fibre Communication
  2. Dr Temba S Dlodlo, Quantum Optics
  3. Dr Peter Baricholo (PI), Laser Development

Current Students

Mr Proficiency Munsaka- Master of Philosophy 

Proficiency Munsaka is an M. Phil research candidate in the Applied Physics Department at the National University of Science and Technology (NUST). He joined the Department in 2018 and he is currently developing a low power erbium-ytterbium co-doped double clad fiber laser that operates in the eye safe region. 

 

About Us

The group focuses on finding laser and optical solutions to modern day society problems. Most of our research is industry related. Our research mainly involve design and development of Laser systems and LED lighting systems. Currently we are developing a Fibre Lasers system that can be operated in the eye safe region. We have previously developed CO2 lasers. We have also locally build optical systems such as Interferometers and optical coherence tomography set-ups.

Fibre optic communications is a new branch that is at its infancy and we are yet to get industrial partners to collaborate with us in research in this research area. Our current projects are in wavelength division and time division multiplexing.

We also develop LED lighting systems used for investigating effect of different wavelengths of light on micro-organisms as part of a collaborative project with Applied Biology. We have previously investigated the effect of VUV generated from dielectric barrier discharge argon excimer on E-coli.  

 

Current Research Projects

 

Fiber laser development

Fiber laser technology is attracting a great deal of attention due to its numerous applications in material processing, biology and medical science, telecommunications and in other industrial and technological applications. Fiber laser material processing technology is considered a disruptive and revolutionary change because it has impacted the entire status quo in material fabrication as it offers extremely narrow cut width, minimum distortion, high quality of cut edge and processing speeds with no tool wear due to a contact free process. The Research group embarked on the development of a low power erbium-ytterbium co-doped fiber laser in 2018.

This is an ongoing project. The pump laser has been characterized for its optimum optical parameter. The research group has successfully collimated and efficiently coupled the pump laser light into a 125 µm erbium-ytterbium co-doped double clad fiber

Optical Coherence Tomography

Optical Coherence Tomography (OCT) is an emerging optical imaging modality that has wide use in the fields of biomedical imaging, contactless materials characterisation and non-destructive inspections. The micron- scale resolution of this modality, coupled with its non-ionising and non- contact properties have made it today’s leading microstructure topography technique. The Research group embarked on the development of an OCT system in 2013 and has made considerable progress in the application of this technology to carry out contactless surface morphometry of high reflectivity optical elements. Development of a spectral domain OCT system commenced with time domain interferometry experiments using single and two-wavelength light sources and proceeded to the use of low coherent sources for spectral interferogram measurements performed in the frequency  domain Depth reflectivities of highly scattering optical elements were computed using broadband light emitting diodes and surface defects of a few microns detected.

 

Mutagenesis of cellulose producing bacteria using LED lights

Project is aimed at producing strains yielding high cellulose titres. The type of mutagenesis is random. The project is in collaboration with Department of Applied Biology and Biotechnology. Dr T. Ncube is the counterpart on this project. She leads the Biological investigations of the project. Preliminary work done is promising.

 

Completed Projects

Non-linear Optics

Previous research carried out in the area of nonlinear optics was on electromagnetic wave propagation in Photonic Crystal Fibers (PCFs). Simulations were done to study the dynamics accompanying the supercontinuum generation process in PCFs. Short pulses of relatively low energy have been propagated through PCFs of specific wavelengths.

Broadened spectra of wavelength spanning over the visible range were observed at the output. Broadened spectra of wavelength spanning over the visible range were observed at the output. This broadband output is essential for white light sources being used in Optical Coherence Tomography (OCT) and other applications. Effects of birefringence on the input pulse and the state of polarisation, as different sources have unique spectra suitable for a specifically designed application were investigated. 

Future Projects

Optical communication

New projects both at undergraduate and postgraduate, would involve using fiber optic technology for high data rates transmission to meet the ever increasing communication demands. The group’s future plans involve working with the telecommunication industry in addressing the next generation communication requirements. Research activities would concentrate on the following:

  • Transmission impairments such as chromatic dispersion, polarization mode dispersion and nonlinear effects.
  • High order modulation formats to address the next generation communications requirements.
  • Different optical demodulation techniques.
  • Fiber To The Hut Technology (FTTHT).

Collaborators

  • Stellenbosch University
  • African Laser Center
  • Laser Research Institute
  • The Optical Society
  • UNESCO-TWAS

 

Opportunities
Prospective Master of Philosophy and Doctor of Philosophy students are welcome to join our research group through the NUST admissions [link here]. Areas of research include but are not limited to:

  • Interferometry Non-linear Optics Laser Spectroscopy
  • Optical Coherence Tomography
  • Fibre laser development

Publications

  1. Baricholo P, M. Mathuthu, Carelse X. F., H. M. von Bergmann and A. V. Gholap. Design, development and characterisation of a CO2 gas laser system. This paper was accepted for publication by the Journal of Applied Sciences for Southern Africa (JASSA), Vol. 12, Issue 1, 2006.
  2. Baricholo P, Hlatywayo DJ, Von Bergmann HM, Stehmann T, Rohwer E and M Collier. Development of dielectric barrier discharge lamp systems for sterilization and exhaust gas remediation. Conclave of Afro-Asia young scientist, TWASS-ROCASSA proceedings.
  3. Baricholo and H. M. von. Bergmann. (2010), Development of a longitudinally excited continuous wave CO2 laser, LAP Lambert academic publishing GmbH & Co. KG, Saarbrucken , 22 cm. ISBN: 978 - 3-8383-8420-7
  4. Baricholo P, Hlatywayo D J, H M von Bergmann, Stehmann T, Rohwer E and M Collier. Influence of gas discharge parameters on emissions from a dielectric barrier discharge excited argon excimer lamp. South African Journal of Science, 2011; 107 (11/12), Art. #581, 7 pages. http://dx.doi.org/10.4102/sajs. v107i11/12.581
  5. Baricholo P, Stehmann T, Rohwer EG, Collier M, Hlatywayo DJ, Von Bergmann HM. Dielectric barrier discharge CO2 TEA laser operated at frequencies upto 400 Hz, in Proceedings of SAIP2011, the 56th Annual Conference of the South African Institute of Physics, edited by I. Basson and A. E. Botha (University of South Africa, Pretoria, 2011), pp. 2 - 7. ISBN: 978-1-86888-688-3. Available online at http:\\www.saip.org.za
  6. James F Jena, Peter Baricholo, Temba S Dlodlo and Paul K Buah-Bassuah. Propagation characteristics control by variation of PCF structural parameters in Proceedings of SAIP2014, the 59th Annual Conference of the South African Institute of Physics, University of Johannesburg, Johannesburg, 2014), pp. 2 - 7. ISBN: 978-0-620-65391-6. Available online at http:\\www.saip.org.za
  7. J. Suliali, P. Baricholo, P. H. Neethling, and E. G. Rohwer, "Non-Destructive Surface Profilometry By First Reflection Localization Using Spectral Domain Optical Coherence Tomography," in Imaging and Applied Optics 2017 (3D, AIO, COSI, IS, MATH, pcAOP), OSA Technical Digest (online) (Optical Society of America, 2017), paper JTu5A.29. https://www.osapublishing.org/abstract.cfm?URI=3D-2017-JTu5A.29
  8. Nyasha J. Suliali ; Peter Baricholo ; Pieter H. Neethling and Erich G. Rohwer " Development of a low-cost, 11 μm spectral domain optical coherence tomography surface profilometry prototype ", SPIE 10329, Optical Measurement Systems for Industrial Inspection X, 103292Q (June 26, 2017); doi:10.1117/12.2268064; http://dx.doi.org/10.1117/12.2268064
  9. Suliali N. J., Baricholo P., Neethling P. H. and Rohwer E. G. (2017). Development of a free space, LED-illuminated spectral domain optical coherence tomography setup. Universal Journal of Physics and Application, 11(3) Horizon Research Publishing.
  10. Suliali N. J., Baricholo P., Neethling P. H. and Rohwer E. G. (2017). Image resolution analysis by varying interpolation degree of k-space spectra. Proceedings of the Biophotonics 2017 Graduate Summer School, Island of Ven, DK.