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Dr Lincoln Turner

Lincoln Turner

Monash Research Fellow

BSc (Hons), Flinders University (1998)
PhD, University of Melbourne (2004)
Phone +61 (3) 9905 1726 FAX +61 (3) 9905 3637
Room 114, Building 26

Email:lincoln.turner@sci.monash.edu.au

RESEARCH INTERESTS

Lincoln's interests are in the areas of atomic, molecular and optical physics. He is particularly interested in applying ultracold matter and Bose-Einstein condensates to enable precision measurements of magnetic fields, and of the spin properties of novel states of cold matter.

Lincoln is also interested in novel methods of measuring Bose-Einstein condensates with minimal heating of the condensate. He developed a holographic imaging method which reconstructs images of cold atom clouds from diffraction pattern images, and enables high-resolution imaging with minimal heating of the ultracold gas. Recently, Lincoln lead a team at the US National Institute of Standards and Technology (NIST) which demonstrated the first continuous measurement of the spin state of a Bose-Einstein condensate.

Current projects include:

  • Ultraprecise magnetometry with optically-trapped Bose-Einstein condensates
  • Spontaneous and measurement-induced spin squeezing in spinor BEC (with Yingmei-Liu and Paul Lett, NIST)
  • Theory of adiabatic evolution of non-linear spinor systems (with honours student Lucas Rutten)
  • Two-colour squeezing from four-wave mixing in hot atomic vapours (collaboration with Martijn Jasperse and Robert Scholten, University of Melbourne)
  • High-bandwidth high-quantum efficiency photodetectors for quantum optics (with Paul Lett, NIST)
  • Low-light shot-noise limited autobalanced photodetectors
  • Simplified designs for narrow linewidth external-cavity diode lasers
Crossed dipole Sodium glow

Sodium atoms in a crossed optical dipole trap. Four high-power laser beams overlap to form four potential wells for cold atoms. At this stage the atoms are cold (~100 microkelvin) but not "ultracold". Ten seconds of evaporative coolng in this trap produces four separate Bose-Einstein condensates (Laser cooling and trapping group, National Institute of Standards and Technology). Dr Turner is building a spinor Bose-Einstein condensation laboratory at Monash which will produce optically trapped condensates of rubidium atoms.

Yellow light at the sodium D-line wavelength scatters of mirrors and other optics surrounding a vacuum chamber containing the site of the Bose-Einstein condensate. The chamber is hidden by the forest of support optics that forms the magneto-optical trap and guides the high-power dipole trapping lasers. Since a single yellow photon has sufficient momentum to eject an atom from the condensate, the yellow cooling light is extinguished before the BEC forms.

PhD and honours positions available

Projects are available for students interested in either experimental or theoretical work. Projects can be tailored to include a mix of theory and experiment, and are available at honours and PhD level. An honours project might include one of the topics listed below, while a PhD project would span several. If you're interested in a related area and want to know if there's a relevant project, just ask!

Possible honours and PhD projects are listed below, along with the areas of expertise you'll develop in each one. Note that knowledge of these ares is not a pre-requisite, it's what you can expect to learn during the project. You'll also be involved in other work in the lab and learn a wide range of physics and experimental techniques along the way.

Experimental projects

  • Design of a high-flux rubidium oven and beam characterisation using pseudo-random bit sequence Doppler fluorescence (vacuum engineering, photodetection, data acquisition and signal processing)
  • Zeeman slower with multiple ion pumps for producing a cold atomic beam (magnetic design and simulation, optimisation theory, vacuum engineering)
  • A novel dipole trap using a filtered master-oscillator power amplified (MOPA) laser (optics, spectroscopy, working with laser-cooled atom clouds)
  • Computer-controlled offset-lock to stabilise laser frequencies (optics, analog and digital electronics, LabVIEW programming)
  • Two-watt high-power semiconductor laser system development (optical and optomechanical design, CAD/solid modelling, some electronics)
  • Fast digital control of intensity and frequency of laser light: development of computer-controlled acousto-optic modulator drivers (radiofrequency and digital electronics, LabVIEW and microcontroller programming, lab optics)
  • High-resolution aspheric lens systems for standard and holographic imaging of cold atoms (lens design, optical engineering, aberration theory, inverse problems, holography, phase retreival)
  • Magnetic trap design (high-current electronic design, magnetostatics, CAD, control theory and some plumbing!)
  • Autobalancing photodetectors: detecting light at the shot-noise limit, despite noisy lasers (precision analog electronics, circuit simulations with PSPICE, spectrum and noise analysis, some control theory)

Theory projects

  • Statistical mechanics of a hybrid magnetic-quadrupole optical-dipole trap (monte carlo simulations, atomic collision physics, statistical mechanics)
  • Quantum limits of magnetometry (quantum stochastic equations, estimation theory)
  • Chaos in nonlinear quantum systems (chaos theory, stochastic quantum theory, simulations)

Computational projects

  • A real-time data analysis system for a BEC laboratory (GUI programming in python, LabView and/or IDL, interprocess communication, some hardware interfacing)
  • Signal processing for quantum magnetometry (digital signal processing, estimation theory, wavelets, chirplets)
  • Web 2.0 in the Lab: Laboratory blogging and wikis for online sharing and presentation of ideas, designs and results (web service configuration, wiki design, blog writing, through to model-view-controller web application development as interested)

Interested students should contact Lincoln Turner at any time to discuss potential projects.

SELECTED PUBLICATIONS

LD Turner, S Jung, AT Black, E Gomez and PD Lett, Continuous Faraday measurement of a spinor BEC in Quantum-Atom Optics Downunder, OSA Technical Digest (Optical Society of America, 2007), paper QTuB4.

AT Black, E Gomez, LD Turner, S Jung and PD Lett, Spinor dynamics in an antiferromagnetic spin-1 condensate, Phys Rev Lett 99 070403 (2007). arXiv:0704.0925v2 [cond-mat.other]

E Gomez, AT Black, LD Turner, E Tiesinga and PD Lett, Light forces in ultracold photoassociation, Phys Rev A 75 013420 (2007). arXiv:physics/0611175v1 [physics.atom-ph]

LD Turner, KFEM Domen and RE Scholten, Diffraction-contrast imaging of cold atoms, Phys Rev A 72 031403(R) (2005). arXiv:physics/0501057v3 [physics.atom-ph]

LD Turner, Holographic Imaging of Cold Atoms, PhD thesis, University of Melbourne (2004).

LD Turner, BB Dhal, JP Hayes, AP Mancuso, KA Nugent, D Paterson, RE Scholten, CQ Tran and AG Peele, X-ray phase imaging: Demonstration of extended conditions for homogeneous objects, Opt Express 12 2960 (2004).

LD Turner, KP Weber, D Paganin, RE Scholten, Off-resonant defocus-contrast imaging of cold atoms, Opt Lett 29 232 (2004).

LD Turner, KP Weber, CJ Hawthorn, RE Scholten, Frequency noise characterisation of narrow linewidth diode lasers, Opt Commun 201 391 (2002).

LD Turner, V Karaganov, PJO Teubner, RE Scholten, A sub-Doppler bandwidth atomic optical filter, Opt Lett 27 500 (2002).