Doctor Christopher G. Leburn - Research Fellow

Christopher obtained his first degree (BSc. Physics) from St Andrews University in 2000. He then went on to do a Masters degree in Optoelectronics and Laser Devices, which was run jointly by St. Andrews University and Heriot-Watt University in Edinburgh. This course culminated in a three-month industrial project at QinetiQ, Malvern. He completed his Ph.D. at the University of St Andrews as part of the Ultrafast Photonics Collaboration, with a thesis entitled "Femtosecond Lasers for Datacommunications Applications". He then then went on to take charge of the day-to-day running of the collaboration as the Assistant Programme Director, which came to an end in June 2007. Christopher's research involves designing and implementing a range of different ultrafast laser sources in the near infra-red for a wide range of applications. The scope of his current project is also allowing him to investigate the possibilities of expanding the controlability and capability of various laser systems to provide peformance levels that go above and beyond current comercial solid-state laser systems.

Recent publications

A.A. Lagatsky, C.G. Leburn, C.T.A. Brown, W. Sibbett, S.A. Zolotovskaya and E.U. Rafailov
"Ultrashort-pulse lasers passively mode locked by quantum-dot-based saturable absorbers"
Progress in Quantum Electronics, Vol. 34, pp. 1-45 (2010).

Abstract: Some key recent achievements in the development of novel saturable absorbers that are based on semiconductor quantum-dot (QD) structures for the passive mode locking of near-infrared lasers are outlined. These are group IV–VI semiconductor nanoparticles (quantum dots) in glass matrices and self-assembled semiconductor quantum dots (group III–V) grown on semiconductor mirrors (QD-SESAMs). The performance of solid-state (Yb3+, Nd3+ and Cr4+-based), Yb-doped fibre and monolithically integrated semiconductor lasers has been described within the context of ultrashort-pulse generation using these types of QD-based modulators. Particular attention has been paid to the nonlinear parameters of the QD-based saturable absorbers that determine the quality of the mode locking in such laser systems.
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M. P. Lumb, E. M. Clarke, E. Harbord, P. Spencer and R. Murray
F. Masia, P.Borri and W. Langbein
C. G. Leburn, C. Jappy, N. K. Metzger, C. T. A. Brown and W. Sibbett
"Ultrafast absorption recovery dynamics of 1300 nm quantum dot saturable absorber mirrors"
Applied Physics Letters: 95, (4), 041101 (2009).

Abstract: We compare the performance of two quantum dot saturable absorber mirrors with one device operating at the quantum dot ground state transition whereas the other operates at the first excited state transition. Time-resolved photoluminescence and heterodyne four-wave mixing experiments demonstrate faster recovery of the excited-state device compared to the ground-state device. Femtosecond pulses were achieved with both devices, with the ground-state device producing 91 fs pulses and the excited-state device producing 86 fs pulses in a Cr:forsterite laser. The fast absorption recovery dynamics indicates the potential of devices exploiting excited-state transitions for use in high repetition rate lasers.
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M. P. Lumb, P. N. Stavrinou, E. M. Clarke and R. Murray
C. G. Leburn, C. Jappy, N. K. Metzger, C. T. A. Brown and W. Sibbett
"Dispersionless saturable absorber mirrors with large modulation depths and low saturation fluences"
Applied Physics B: Lasers and Optics: 97, pp.53-60, (2009).

Abstract: We show that it is possible to eliminate group delay dispersion over wide bandwidths in low-finesse, resonant saturable absorber mirrors, whilst maintaining a low saturation fluence and a high modulation depth. By modelling the mirror structure we demonstrate that these properties can be produced by capping a resonant device with a single dielectric layer of carefully selected refractive index. We show that a specially capped dispersionless structure minimises the temporal broadening of femtosecond pulses reflected from the mirror. We compare this device against uncapped-resonant and anti-resonant structures. The superior performance of the capped, dispersionless device was verified experimentally by comparing resonant, anti-resonant and dispersionless quantum-dot (QD) saturable absorber mirrors incorporated into a Cr4+:forsterite laser system. We found that a minimum pulse duration of 86 fs could be achieved for the dispersionless structure at 1290 nm with an output power of 55 mW compared to 122 fs in an anti-resonant structure and several-picosecond pulses for a resonant structure.
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N. K. Metzger, C. G. Leburn, A. A. Lagatsky, C. T. Brown, S. Calvez, D. Burns, H. D. Sun, M. D. Dawson, J. C. Harmand, and W. Sibbett
"Femtosecond pulse generation around 1500nm using a GaInNAsSb SESAM "
Optics Express, 16, (23): 18739-18744 (2008).

P. Fischer, S. E. Skelton, C. G. Leburn, C. T. Streuber, E. M. Wright and K. Dholakia
"Propagation and diffraction of optical vortices"
Physica C-Superconductivity and Its Applications, 468, (7-10): 514-517, (2008).

S. Calvez, N. Laurand, H. D. Sun, J. Weda, D. Burns, M. D. Dawson, A. Harkonen, T. Jouhti, M. Pessa, M. Hopkinson, D. Poitras, J. A. Gupta, C. G. Leburn, C. T. A. Brown and W. Sibbett
"GaInNAs(Sb) surface normal devices"
Physica Status Solidi a-Applications and Materials Science, 205, (1): 85-92, (2008).

P. Fischer, S. E. Skelton, C. G. Leburn, C. T. Streuber, E. M. Wright and K. Dholakia
"The dark spots of Arago"
Optics Express, 15, (19): 11860-11873, (2007).

J. L. Mortensen, A. McWilliam, C. G. Leburn, P. Tidemand-Lichtenberg, M. Thorhauge, J. Janousek, C. T. A. Brown, A. A. Lagatsky, P. Buchhave and W. Sibbett
"Up to 30 mW of broadly tunable CW green-to-orange light, based on sum-frequency mixing of Cr4+ : forsterite and Nd : YVO4 lasers"
Optics Communications, 260, (2): 637-640, (2006).

A. McWilliam, A. A. Lagatsky, C. G. Leburn, P. Fischer, C. T. A. Brown, G. J. Valentine, A. J. Kemp, S. Calvez, D. Burns, M. D. Dawson, M. Pessa and W. Sibbett
"Low-loss GaInNAs saturable Bragg reflector for mode-locking of a femtosecond Cr4+:forsterite-laser"
IEEE Photonics Technology Letters, 17, (11): 2292-2294, (2005).

Y. J. Chai, C. G. Leburn, A. A. Lagatsky, C. T. A. Brown, R. V. Penty, I. H. White and W. Sibbett
"1.36-Tb/s spectral slicing source based on a Cr4+:YAG femtosecond laser"
Journal of Lightwave Technology, 23, (3): 1319-1324, (2005).

C. G. Leburn, A. A. Lagatsky, C. T. A. Brown and W. Sibbett
"Femtosecond Cr4+: YAG laser with 4GHz pulse repetition rate"
Electronics Letters, 40, (13): 805-807, (2004).

A. A. Lagatsky, C. G. Leburn, C. T. A. Brown, W. Sibbett, A. M. Malyarevich, V. G. Savitski, K. V. Yumashev, E. L. Raaben and A. A. Zhilin
"Passive mode locking of a Cr4+: YAG laser by PbS quantum-dot-doped glass saturable absorber"
Optics Communications, 241, (4-6): 449-454, (2004).

C. T. A. Brown, M. A. Cataluna, A. A. Lagatsky, E. U. Rafailov, M. B. Agate, C. G. Leburn and W. Sibbett
"Compact laser-diode-based femtosecond sources"
New Journal of Physics, 6, (2004).

A. A. Lagatsky, C. G. Leburn, C. T. A. Brown, W. Sibbett and W. H. Knox
"Compact self-starting femtosecond Cr4+: YAG laser diode pumped by a Yb-fiber laser"
Optics Communications, 217, (1-6): 363-367, (2003).

A. A. Lagatsky, E. U. Rafailov, C. G. Leburn, C. T. A. Brown, N. Xiang, O. G. Okhotnikov and W. Sibbett
"Highly efficient femtosecond Yb:KYW laser pumped by single narrow-stripe laser diode"
Electronics Letters, 39, (15): 1108-1110, (2003).

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