Carl Hepburn

Search Engine Optimisation (SEO), Physics

General Information


Carl Jason Hepburn



Britney Spears' Guide to Semiconductor Physics - a physics website for A-level students. - Turkish recipe website and blog



University of Essex: PhD. - GaInNAs Bi-directional Field-Effect Light-Emitting Devices.


University of Essex: MSc. (By Dissertation). Experimental Physics. (Temperature Dependence of Long-wavelength Vertical Cavity Surface Emitting Lasers).


University of Essex: BSc. (Hon's) 2:2 Theoretical Physics




Search Engine Optimisation Specialist - Just Search. Duties include: keyword research, competitor analysis, on-page SEO for e-commerce sites.


Search Engine Optimisation Specialist and web developer, High Position.

Sep 2006- 2007

Physics Lecturer, Suffolk College, Ipswich.


Graduate Teaching Assistant (GTA) - While studying for my PhD I lectured at the University of Essex on the subject of HTML and web design.


International Conference Secretary, Physics and Technology of Dilute Nitrides Workshop, Istanbul.

During my MSc, I have also taught physics privately and was a laboratory demonstrator for students of the Photonics and Laser Communications MSc. In addition I created and maintained the Physics Center and Optoelectronic Materials and Devices Research group web-pages at the University of Essex.


Programming Languages and Computer Experience


I am fully competent with the Microsoft Office suite of applications: Word, Excel, PowerPoint and Access.

Programming Skills

Throughout my degree and research I have programmed using many programming languages including C++. My first modelling projects were completed using FORTRAN 90 but for my final-year undergraduate project, I used Mathematica to model the minimal surfaces of soap films when confined to a cubic framework. Since then, I have used Mathematica to model many problems such as the gain in quantum well semiconductor lasers and valence band structure. I have good knowledge of Matlab, Maple and Simulink. During my PhD I learned how to use ISE TCAD, an advanced finite element optoelectronic semiconductor device simulation and process package to model current transport and emission in novel Real-Space Transfer Vertical Cavity Surface Emitting Lasers (VCSELs).


Web Developing

2D and 3D Graphics Software

I have a working knowledge of the following graphics software: Adobe PhotoShop, Corel Draw, Corel Photo Paint, Asymetrix 3Dfx, 3D Studio Max, Macromedia Flash and Actionscript along with Macromedia Fireworks.

Web Design

I have been hand coding web pages since 1999 and my knowledge has followed the development of the World Wide Web through HTML and more recently, XHTML. I use Cascading-Style Sheets (CSS) for style, layout and accessibility. I prefer to write my own code but I have used web design software including: Dreamweaver, FrontPage and Adobe Go-Live. Web-content is now more dynamic and I can write web-sites which use templates, a MySQL database and PHP to create dynamic pages. I have used other scripting languages such as CGI, Perl and of course JavaScript.I am currently involved in ethical Search Engine Optimisation (SEO) methods for increasing natural search.

The web-sites I have developed are: (newest first)


Research Experience

My experimental research has been involved in designing and characterising semiconductor optoelectronic devices such as VCSELs, edge-emitting lasers and Vertical Cavity Semiconductor Optical Amplifiers (VCSOAs).

In the past, I have investigated VCSELs that operate in the 1.55μm window, using GaInAsP/InP material systems. Dilute Nitride Semiconductors such as GaInNAs is the material of choice for semiconductor lasers operating in the 1.3 μm-1.55 μm. window. In studying these devices, I have used various experimental techniques to characterise optoelectronic devices including: photoluminescence (PL), electroluminescence (EL) and Hakki-Paoli measurements of gain spectra. Many of these techniques have been undertaken over a temperature range of 4.2 K to above 300 K to study their temperature dependence. In performing such experiments, I have become familiar with various laboratory equipment including: Nd-YAG lasers, monochromators, cryostats, vacuum systems, laser-diode controllers, optical spectrum analysers, boxcar averagers, lock-in amplifiers, pulse generators, photomultipliers, detectors, oscilloscopes, free-space optics, optical fibres and optical fibre preparation, Raman amplifiers and Erbium Doped Fibre Amplifiers (EDFAs). To acquire data, I have written interfaces to control equipment via the GPIB interface using LabView.


Development Courses:


Prizes and Awards



  1. I. Sokmen, A. O'Brien-Davies, R. Potter, C. Hepburn, A. Boland-Thoms, M.J. Adams, J, Roberts, "Hot electron VCSEL ", Proc. SPIE Conf. on Physics and Simulation of Optoelectronic Devices VII, San Jose, California, SPIE 3625, pp. 336-345 (1999)
  2. R. Sceats, C. J. Hepburn, R. J. Potter, A. Dyson, N. Balkan, M. J. Adams, "1.5μm Surface Emission from GaInAsP/InP HELLISH structure ", SPIE Conference (2001)
  3. "Temperature dependence of GaInAsP VCSELs" - SPIE Conference on Physics and Simulation of Optoelectronic Devices, San Jose, California (2001)
  4. N. Balkan, A. Serpenguzel, A. O. Brien-Davis, I. Sokmen, C. J. Hepburn, R. J. Potter, M. J. Adams J. S. Roberts, "VCSELs structure hot-electron light emitter ", Materials Science and Engineering, B47, pp 96-100 (2000)
  5. R. Sceats, A. Dyson, C. J. Hepburn, R. J. Potter, A. Boland-Thoms, N. Balkan, G. Hill, C. C. Button, S. Pinches, "Hot-electron light emission from GaInAsP/InP structures with distributed Bragg reflectors ", Physica E, 17, pp 607-609 (2003)
  6. C. J. Hepburn, R. Sceats, A. Borland-Thoms, N. Balkan, A. J. Dann, S. D. Perrin, I. Read, J. Reed, P. Cannard, M. A. Fisher, D. J. Elton, M. J. Harlow, "Temperature dependent operation of GaInAsP/InP VCSELs ", Semiconductor Science and Technology, 1, (2003)
  7. S, Mazzucato, A. Erol, C.J. Hepburn, R.J. Potter, A. Boland-Thoms, A.J. Vickers, P.R. Chalker, T.B. Joyce and T.J. Bullough , N. Balkan, "Effect of Fast Thermal Annealing on the optical Spectroscopy in MBE and CBE grown GaInNAs/GaAs QWs: Blue shift versus red shift ", IEE Proc.Optoelectronics, 151, 5, pp 284-289 (2004)
  8. C. J. Hepburn, J. Y. Wah, A. Boland-Thoms, N. Balkan, "GaInNAs and GaAs, top-hat vertical-cavity semiconductor optical amplifier (VCSOA) based on longitudinal current transport ", Physica Stat. Sol. C, 2, 8, pp 3096-3099 (2005)
  9. E. Tiras, C. J. Hepburn, N. Balkan, M. Saarinen, M. Pessa, T. Jouhti, "Performance Study of SQW GaInNAs Fabry-Perot Lasers ", Accepted ICSNN-2006 to be published in Physica Stat. Sol.C (2007).
  10. C. J. Hepburn, N.A. Zakhleniuk, M.J. Adams and N. Balkan, "Modelling of Real-Space-Transfer Optical Emitters ", (to be published 2007)


Other Interests

My hobbies include drawing and painting. I also enjoy playing the piano.