Helen Pask

Prof. Helen Pask

Department of Physics and Astronomy, MQ Photonics Research Centre

Research Focus & Metrics

Academic Career Length

37Years (1990-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 April 1995 in IEEE Journal of Selected Topics in Quantum Electronics
Verified
Journal Article
Closed access
HPHelen Pask
Helen Pask
RCR.J. Carman
R.J. Carman
DHD.C. Hanna
D.C. Hanna
ATA.C. Tropper
A.C. Tropper
CMC.J. Mackechnie
C.J. Mackechnie
Judith DawesJudith Dawes
Judith Dawes

1 January 2003 in Progress in Quantum Electronics
Verified
Journal Article
Closed access
HPHelen Pask
Helen Pask

18 June 2007 in IEEE Journal of Selected Topics in Quantum Electronics
Verified
Journal Article
Closed access
JPJim Piper
Jim Piper
HPHelen Pask
Helen Pask
In this paper, we review the developments of crystalline Raman lasers over the past five years. Average powers exceeding 5 W and pulse energies above 1 J in the near infrared have been demonstrated for larger scale devices. There has been a rapid development of all-solid-state sources based on the standard diode-pumped lasers, especially intracavity crystalline Raman lasers, which offer wavelength versatility at high conversion efficiencies (overall diode Stokes optical conversion efficiencies up to 17%) in the near infrared, including the 1.5- mum eye-safe band. Passively Q-switched intracavity Raman lasers based on self-Raman laser materials offer many advantages for miniaturization of short-pulse (1 ns) sources. Intracavity frequency-doubled crystalline Raman lasers have also emerged as practical and versatile sources in the yellow orange region at 1-W power levels with diode-visible efficiencies near 10%. Recent developments of all-solid-state continuous-wave (CW) intracavity crystalline Raman lasers offer many possibilities for the future: intracavity frequency doubling has already resulted in the demonstration of CW visible sources with powers approaching 1 W at 5% diode-visible efficiency.

1 January 2008 in Progress in Quantum Electronics
Verified
Journal Article
Closed access
HPHelen Pask
Helen Pask
PDPeter Dekker
Peter Dekker
RMR.P. Mildren
R.P. Mildren
DSD.J. Spence
D.J. Spence
JPJim Piper
Jim Piper

1 January 2007 in Optics Express
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Journal Article
Closed access
PDF file
PDPeter Dekker
Peter Dekker
HPHelen Pask
Helen Pask
DSDavid J. Spence
David J. Spence
JPJim Piper
Jim Piper
We report a continuous-wave self-Raman laser based on diode-pumped Nd:GdVO4 giving first-Stokes output at 1173 nm and intracavity frequency-doubled output at 586.5 nm. A maximum cw output power at 1173 nm of 2 W was obtained for diode pump powers of 22 W and a maximum cw power at 586 nm of 678 mW with 16.3 W pump power. Infrared and yellow powers were limited by thermal lensing in the gain medium and parasitic oscillations of weak Nd3+ transitions. Quasi-cw operation at 50% duty-cycle reduced the thermal load in the laser/Raman crystal, allowing cavity stability to be obtained near maximum available pump power (25.7 W) for which the maximum quasi-cw yellow output power was 1.88 W.

18 December 2008 in Optics Express
Verified
Journal Article
Closed access
PDF file
Andrew LeeAndrew Lee
Andrew Lee
HPHelen Pask
Helen Pask
PDPeter Dekker
Peter Dekker
JPJim Piper
Jim Piper
Efficient multi-Watt continuous-wave (CW) yellow emission at 586.5 nm is demonstrated through intracavity frequency-doubling of a Nd:GdVO4 self-Raman laser pumped at 880 nm. 2.51 W of CW yellow emission with an overall diode-to-yellow conversion efficiency of 12.2% is achieved through the use of a 20 mm long Nd:GdVO4 self-Raman crystal and an intracavity mirror which facilitates collection of yellow emission generated within the resonator, and reduces thermal loading of the laser crystal.