Overview
Background
Dr Timo Nieminen received his PhD from The University of Queensland in 1996.
Dr Nieminen's research interests are in the fields of:
- Light Scattering
- Optical Trapping and Micromanipulation
- Computational Electromagnetics
- Photonics
- Biological and Industrial Applications of Light Scattering and the Interaction of Light and Matter
His chief research projects are in the areas of:
- Full-Wave Electromagnetic Modelling of the Production of Optical Forces and Torques in Laser Trapping
- Optical Measurement of Microscopic Forces and Torques
- Extremely Asymmetrical Scattering in Bragg Gratings
- Micro-Opto-Mechanical Systems (MOMS)
Availability
- Dr Timo Nieminen is:
- Available for supervision
Fields of research
Qualifications
- Bachelor (Honours) of Science (Advanced), The University of Queensland
- Doctor of Philosophy, The University of Queensland
Research interests
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Full-Wave Electromagnetic Modelling of the Production of Optical Forces and Torques in Laser Trapping
Optical forces and torques acting on a microparticle in a laser trap arise from the transfer of momentum and angular momentum from the trapping beam to the particle, and can be found by calculating the scattering of the trapping beam by the particle. Since laser-trapped particles are of sizes comparable to the trapping wavelength, a full electromagnetic wave solution is required.
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Optical Measurement of Microscopic Forces and Torques
An alternative to the calculation of the scattering by a laser-trapped particle is to measure the scattered light, and from this, determine the optical force and torque acting on, and the position within the trap, of the particle.
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Extremely Asymmetrical Scattering in Bragg Gratings
Extremely asymmetrical scattering is being investigated theoretically and computationally in collaboration with the Physical Optics Program, School of Physical and Chemical Sciences, Queensland University of Technology.
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Micro-Opto-Mechanical Systems (MOMS)
Theoretical development of MOMS and MOMS-related techniques.
Works
Search Professor Timo Nieminen’s works on UQ eSpace
2024
Journal Article
Tired and stressed: direct holographicquasi-static stretching of aging echinocytes and discocytes in plasma using optical tweezers
Stilgoe, Alexander, Kashchuk, Anatolii, Balanant, Marie Anne, Santangelo, Deborah, Nieminen, Timo, Sauret, Emilie, flower, robert and Rubinsztein-Dunlop, Halina (2024). Tired and stressed: direct holographicquasi-static stretching of aging echinocytes and discocytes in plasma using optical tweezers. Biomedical Optics Express, 15 (2), 656-671. doi: 10.1364/boe.504779
2023
Conference Publication
Sensing inertia with rotational optical tweezers
Watson, Mark L., Stilgoe, Alexander B., Favre-Bulle, Itia A., Nieminen, Timo A. and Rubinsztein-Dunlop, Halina (2023). Sensing inertia with rotational optical tweezers. SPIE Nanoscience + Engineering, San Diego, CA United States, 20-25 August 2023. Bellingham, WA United States: SPIE. doi: 10.1117/12.2677236
2023
Conference Publication
Optical tweezers in mechanobiology
Rubinsztein-Dunlop, Halina, Watson, Mark L., Favre-Bulle, Itia, Grant, Patrick, Nieminen, Timo A. and Stilgoe, Alexander B. (2023). Optical tweezers in mechanobiology. Optical Trapping and Optical Micromanipulation XX: SPIE Nanoscience + Engineering, San Diego, CA United States, 20-25 August 2023. Bellingham, WA United States: SPIE. doi: 10.1117/12.2682972
2023
Journal Article
Underreporting of SARS-CoV-2 infections during the first wave of the 2020 COVID-19 epidemic in Finland-Bayesian inference based on a series of serological surveys
Nieminen, Tuomo A., Auranen, Kari, Kulathinal, Sangita A., Haerkaenen, Tommi, Melin, Merit, Palmu, Arto A. and Jokinen, Jukka (2023). Underreporting of SARS-CoV-2 infections during the first wave of the 2020 COVID-19 epidemic in Finland-Bayesian inference based on a series of serological surveys. Plos One, 18 (6) e0282094. doi: 10.1371/journal.pone.0282094
2023
Conference Publication
Aberration corrected structured light for in-house fabrication of functional micro-structures
Armstrong, Declan J., Rubinsztein-Dunlop, Halina, Nieminen, Timo A. and Stilgoe, Alexander (2023). Aberration corrected structured light for in-house fabrication of functional micro-structures. SPIE OPTO, San Francisco, CA United States, 28 January - 3 February 2023. Bellingham, WA United States: SPIE. doi: 10.1117/12.2657795
2023
Journal Article
Incidence of sinus thrombosis with thrombocytopenia—a nation-wide register study
Hovi, Petteri, Palmu, Arto A., Nieminen, Tuomo A., Artama, Miia, Jokinen, Jukka, Ruokokoski, Esa, Lassila, Riitta, Nohynek, Hanna and Kilpi, Terhi (2023). Incidence of sinus thrombosis with thrombocytopenia—a nation-wide register study. Plos One, 18 (2). doi: 10.1371/journal.pone.0282226
2022
Journal Article
Spin–orbit interaction in non-paraxial Gaussian beams and the spin-only measurement of optical torque
Nieminen, Timo A., Watson, Mark Liam, Loke, Vincent L. Y., Stilgoe, Alexander and Rubinsztein-Dunlop, Halina (2022). Spin–orbit interaction in non-paraxial Gaussian beams and the spin-only measurement of optical torque. Journal of Optics, 24 (12) 124001, 1-10. doi: 10.1088/2040-8986/ac9c6e
2022
Journal Article
Improved two-photon photopolymerisation and optical trapping with aberration-corrected structured light
Armstrong, D. J., Stilgoe, A. B., Nieminen, T. A. and Rubinsztein-Dunlop, H. (2022). Improved two-photon photopolymerisation and optical trapping with aberration-corrected structured light. Frontiers in Nanotechnology, 4 998656, 1-12. doi: 10.3389/fnano.2022.998656
2022
Conference Publication
Optically driven nano and micromachines in optical tweezers
Rubinsztein-Dunlop, Halina, Armstrong, Declan, Watson, Mark, Favre-Bulle, Itia, Nieminen, Timo and Stilgoe, Alexander B. (2022). Optically driven nano and micromachines in optical tweezers. SPIE Organic Photonics + Electronics, San Diego, CA United States, 21-26 August 2022. Bellingham, WA United States: SPIE. doi: 10.1117/12.2639995
2022
Journal Article
SARS-CoV-2 Vaccination and Myocarditis in a Nordic Cohort Study of 23 Million Residents
Karlstad, Oystein, Hovi, Petteri, Husby, Anders, Harkanen, Tommi, Selmer, Randi Marie, Pihlstrom, Nicklas, Hansen, Jorgen Vinslov, Nohynek, Hanna, Gunnes, Nina, Sundstrom, Anders, Wohlfahrt, Jan, Nieminen, Tuomo A., Grunewald, Maria, Gulseth, Hanne Lovdal, Hviid, Anders and Ljung, Rickard (2022). SARS-CoV-2 Vaccination and Myocarditis in a Nordic Cohort Study of 23 Million Residents. Jama Cardiology, 7 (6), 600-612. doi: 10.1001/jamacardio.2022.0583
2022
Journal Article
Controlled transfer of transverse orbital angular momentum to optically trapped birefringent microparticles
Stilgoe, Alexander B., Nieminen, Timo A. and Rubinsztein-Dunlop, Halina (2022). Controlled transfer of transverse orbital angular momentum to optically trapped birefringent microparticles. Nature Photonics, 16 (5), 346-351. doi: 10.1038/s41566-022-00983-3
2021
Journal Article
Producing near-zero-index/directivity-tunable metamaterials using transformation optics
Dehbashi, Reza and Nieminen, Timo A. (2021). Producing near-zero-index/directivity-tunable metamaterials using transformation optics. Journal of the Optical Society of America B, 38 (12), 3737-3742. doi: 10.1364/josab.440769
2021
Journal Article
Far-field subwavelength straight-line projection/imaging by means of a novel double-near-zero index-based two-layer metamaterial
Dehbashi, Reza, Plakhotnik, Taras and Nieminen, Timo A. (2021). Far-field subwavelength straight-line projection/imaging by means of a novel double-near-zero index-based two-layer metamaterial. Materials, 14 (19) 5484, 5484. doi: 10.3390/ma14195484
2020
Journal Article
Optical force measurements illuminate dynamics of Escherichia coli in viscous media
Armstrong, Declan J., Nieminen, Timo A., Favre-Bulle, Itia, Stilgoe, Alexander B., Lenton, Isaac C. D., Schembri, Mark A. and Rubinsztein-Dunlop, Halina (2020). Optical force measurements illuminate dynamics of Escherichia coli in viscous media. Frontiers in Physics, 8 575732. doi: 10.3389/fphy.2020.575732
2020
Journal Article
Machine learning reveals complex behaviours in optically trapped particles
Lenton, Isaac Christopher David, Volpe, Giovanni, Stilgoe, Alexander, Nieminen, Timo A. and Rubinsztein-Dunlop, Halina (2020). Machine learning reveals complex behaviours in optically trapped particles. Machine Learning: Science and Technology, 1 (4) abae76, 045009. doi: 10.1088/2632-2153/abae76
2020
Journal Article
OTSLM toolbox for structured light methods
Lenton, Isaac C.D., Stilgoe, Alexander B., Nieminen, Timo A. and Rubinsztein-Dunlop, Halina (2020). OTSLM toolbox for structured light methods. Computer Physics Communications, 253 107199. doi: 10.1016/j.cpc.2020.107199
2020
Journal Article
Swimming force and behavior of optically trapped micro-organisms
Armstrong, Declan J., Nieminen, Timo A., Stilgoe, Alexander B., Kashchuk, Anatolii V., Lenton, Isaac C. D. and Rubinsztein-Dunlop, Halina (2020). Swimming force and behavior of optically trapped micro-organisms. Optica, 7 (8), 989-994. doi: 10.1364/optica.394232
2020
Conference Publication
Direct Force Measurement with Reflective and Conductive Particles in Optical Tweezers
Lenton, Isaac C., Nieminen, Timo A., Reece, Peter J., Stilgoe, Alexander B. and Rubinsztein-Dunlop, Halina (2020). Direct Force Measurement with Reflective and Conductive Particles in Optical Tweezers. 14th Pacific Rim Conference on Lasers and Electro-Optics (CLEO PR 2020), Sydney, NSW Australia, 3–5 August 2020. Washington, DC United States: Optical Society of America. doi: 10.1364/CLEOPR.2020.C12E_1
2020
Conference Publication
Understanding particle trajectories by mapping optical force vortices
Lenton, Isaac C. D., Stilgoe, Alex B., Nieminen, Timo A. and Rubinsztein-Dunlop, Halina (2020). Understanding particle trajectories by mapping optical force vortices. Complex Light and Optical Forces XIV, San Francisco, CA, United States, 1-6 February 2020. Bellingham, WA, United States: SPIE. doi: 10.1117/12.2550418
2019
Journal Article
Orientation of swimming cells with annular beam optical tweezers
Lenton, Isaac C. D., Armstrong, Declan J., Stilgoe, Alexander B., Nieminen, Timo A. and Rubinsztein-Dunlop, Halina (2019). Orientation of swimming cells with annular beam optical tweezers. Optics Communications, 459 124864, 124864. doi: 10.1016/j.optcom.2019.124864
Funding
Current funding
Supervision
Availability
- Dr Timo Nieminen is:
- Available for supervision
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Available projects
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PhD project: Active matter with physical interactions in 1, 2, and 3D
Self-propelled active matter particles take energy from their environment and use it for motion and/or other purposes. Interaction between the active matter particles can result in collective motion such as flocking, schooling, and swarming, as seen with birds, fish, insects, and bacteria. The interactions can be behavioural ("Which way are my neighbours flying? How close are they?") or physical (e.g., bacteria). One important question is to what extent can artificial active matter particles, with purely physical interactions between them, mimic the complex collective motion driven by behaviour. Light can be uses as the energy source for artificial active matter particles, with optical and thermal forces producing motion. Interaction can be optical, hydrodynamic, or thermal.
You will:
- Model collective behaviour in 1, 2, and 3D systems of artificial active matter particles
- Develop models of physical interactions between active matter particles that provide both realistic accuracy and computational simplicity
- Use these models to compare collective behaviour in active matter based on simple behavioural models and physical models
Note: This project is primarily computational and mathematical, but experimental work can be included in this project.
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PhD project: Optical forces on deformable particles
Optical tweezers have revolutionised biophysics, offering non-contact micromanipulation, and the measurement of forces in biophysical systems down to single-molecule levels. Computational light scattering gives us means of calculating the optical forces, and relating these to the size, shape, and composition of the trapped particles. This is useful for designing experiments, understanding measurements and observations, and more. However, many biological (and other) particles are soft, and will be deformed by the optical forces acting on them. This is a much more complex problem, as it involves the simultaneous modelling of the optical forces acting on the particle, which are affected by the particle's shape, and the particles shape, which is affected by the optical forces.
You will:
- Develop methods for calculating the optical stress on the surface of soft particles
- Develop iterative methods using alternating calculations of optical force and deformation
- Determine the accuracy and applicability of simple models for the deformation and/or optical stress
- Compare surface and volume methods in terms of accuracy and computational efficiency
Note: This project is primarily computational and mathematical, but experimental work can be included in this project.
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PhD project: Computational methods for multiple scattering
In principle, brute-force methods such as finite-difference time-doman (FDTD), the finite element method (FEM), and the discrete dipole approximation (DDA) allow us to computationally model multiple scattering problems. However, the computational demands of solving such problems for many particles can make them thoroughly infeasible. Methods making use of the single-scattering solutions for the individual particles can be much faster. However, the convergence and correctness of some of those memthods are unknown.
You will:
- Explore the computational and mathematical behaviour of methods for multiple scattering that build on single-scattering models, with an emphasis on T-matrix methods in spherical wavefunctions
- Compare results with methods such as DDA
- Determine how accurately cases with resonances and evanescant coupling are modelled
- Develop fast reliable methods for multiple scattering that allow us to calculate optical forces on the individual particles as they interact with an incident laser beam and each other.
Project type: Computational
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PhD project: Single and multiple scattering and the Rayleigh hypothesis
Hilbert space methods, such as the T-matrix method, for the scattering of electromagnetic or other waves by particles typically involve representing the fields as sums or integrals of a basis set of modes. Two mathematical issues need to be considered in these methods. First, the sum or integral over the of modes used is only guaranteed to converge to the fields in certain regions. For example, the scattered field represented in spherical wave modes is only guaranteed to converge outside the circumscribing sphere enclosing the scattering particle, and not between the circumscribing sphere and particle surface. Second, the infinite set of modes is truncated for practical computations, and might not converge subject to such truncation, even if convergence is guaranteed given infinite modes. Despite these two issues, the scattering problem can often be solved, giving a correct and convergence result for the far field. Some methods assume that the fields converge everywhere outside the scattering particle, even though such convergence is not guaranteed - this is the "Rayleigh hypothesis". Other methods will give essentially identical results in the far field without making such assumptions.
You will:
- Compare the near fields for single and multiple scattering using Hilbert space methods and other, Rayleigh hypothesis free, methods,
- Determine conditions under which we can obtain good far field result field without convergence of the near field,
- Develop fast computational methods for multiple scattering using the T-matrix method and/or other Hilbert space methods.
Project type: Computational and mathematical
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Honours project: Single and multiple scattering and the Rayleigh hypothesis
Hilbert space methods, such as the T-matrix method, for the scattering of electromagnetic or other waves by particles typically involve representing the fields as sums or integrals of a basis set of modes. Two mathematical issues need to be considered in these methods. First, the sum or integral over the of modes used is only guaranteed to converge to the fields in certain regions. For example, the scattered field represented in spherical wave modes is only guaranteed to converge outside the circumscribing sphere enclosing the scattering particle, and not between the circumscribing sphere and particle surface. Second, the infinite set of modes is truncated for practical computations, and might not converge subject to such truncation, even if convergence is guaranteed given infinite modes. Despite these two issues, the scattering problem can often be solved, giving a correct and convergence result for the far field. Some methods assume that the fields converge everywhere outside the scattering particle, even though such convergence is not guaranteed - this is the "Rayleigh hypothesis". Other methods will give essentially identical results in the far field without making such assumptions.
You will: Compare the near fields for single and multiple scattering using Hilbert space methods and other, Rayleigh hypothesis free, methods, Determine conditions under which we can obtain good far field result field without convergence of the near field.
Project type: Computational and mathematical
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Honours project: Physical versus behavioural interactions in collective motion in active matter
Self-propelled active matter particles take energy from their environment and use it for motion and/or other purposes. Interaction between the active matter particles can result in collective motion such as flocking, schooling, and swarming, as seen with birds, fish, insects, and bacteria. The interactions can be behavioural ("Which way are my neighbours flying? How close are they?") or physical (e.g., bacteria). One important question is to what extent can artificial active matter particles, with purely physical interactions between them, mimic the complex collective motion driven by behaviour. Light can be uses as the energy source for artificial active matter particles, with optical and thermal forces producing motion. Interaction can be optical, hydrodynamic, or thermal.
You will: Develop models of physical interactions between active matter particles that provide both realistic accuracy and computational simplicity Use these models to compare collective behaviour in active matter based on simple behavioural models and physical models
Project type: Computational and mathematical
-
Honours project: Energy considerations in bacterial locomotion
General principles of motion, such as driving and resistive forces, and energy requirements, can be used study the scaling of the motion of organisms with size, fluid properties, etc. Such models can apply across many orders of magnitude of size, etc., from bacteria to macroscopic animals.
You will:
- Review existing models, including those developed bacterial for motion, and other organisms
- Use suitable methods, modified as appropriate, to study the effect of interactions with surfaces (and other bacteria? on the motion of bacteria such as E. coli
- Compare cases such as the swimming of single-flagellated E. coli and multi-flagellated E. coli, motion in bulk fluids vs motion next to surfaces, and motion in thin films, etc.
Project type: Computational and mathematical, can include experimental work
-
Honours project: Computational methods for multiple scattering
In principle, brute-force methods such as finite-difference time-doman (FDTD), the finite element method (FEM), and the discrete dipole approximation (DDA) allow us to computationally model multiple scattering problems. However, the computational demands of solving such problems for many particles can make them thoroughly infeasible. Methods making use of the single-scattering solutions for the individual particles can be much faster. However, the convergence and correctness of some of those memthods are unknown.
You will:
- Explore the computational and mathematical behaviour of methods for multiple scattering that build on single-scattering models, with an emphasis on T-matrix methods in spherical wavefunctions
- Compare results with methods such as DDA
Project type: Computational
-
Honours project: Probe microscopy for surface characterisation with optical tweezers
Optical tweezers-based probe microscopy of surfaces has an already-long history. One aspect that has been little-explored is to measure the change in the trap potential occupied by the particle, including the effect of the surface being probed. In this way, Brownian motion becomes a source of information, rather than a source of uncertainty. This can allow weaker traps to be used, enabling the characterisation of softer surfaces without damage. Deformable surfaces can also be studied.
You will: Use computational modelling for a feasibility study of surface characterisation based on measuring the potential confining an optically-trapped particle, as modified by the surface. Model the measurement of deformable surfaces and structures, with free particles and with attached particles Compare the use of 2D-only position measurements of the probe particle vs 3D measurements.
Project type: Computational
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Honours project: Thermal forces in optical tweezers
Since the particles usually trapped with optical tweezers are highly transparent, thermal effects are often ignored. However, even in this case, there will be some absorption, and consequent heating. If absorbing particles are trapped, temperature rises can be very high. Thermal effects such as convective flow, thermophoresis (propulsive forces on particles due to temperature gradients), bubble formation, and Marangoni convection can be important.
You will:
- Survey thermal effects likely to be important in optical trapping with both high absorption and low absorption
- Identify conditions under which these effects will be important
- Review exact and approximate models for these phenomena
- Test computational implementations of appropriate models
Project type: Computational and mathematical
-
Honours project: Optical forces on soft particles
Optical tweezers have revolutionised biophysics, offering non-contact micromanipulation, and the measurement of forces in biophysical systems down to single-molecule levels. Computational light scattering gives us means of calculating the optical forces, and relating these to the size, shape, and composition of the trapped particles. This is useful for designing experiments, understanding measurements and observations, and more. However, many biological (and other) particles are soft, and will be deformed by the optical forces acting on them. This is a much more complex problem, as it involves the simultaneous modelling of the optical forces acting on the particle, which are affected by the particle's shape, and the particles shape, which is affected by the optical forces.
You will:
- Develop methods for calculating the optical stress on the surface of soft particles
- Develop iterative methods using alternating calculations of optical force and deformation
- Determine the accuracy and applicability of simple models for the deformation and/or optical stress
Project type: Computational and mathematical
Supervision history
Completed supervision
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2021
Doctor Philosophy
Double-Near-Zero Metamaterials in Transformation Optics and Imaging
Principal Advisor
Other advisors: Associate Professor Taras Plakhotnik
-
2021
Doctor Philosophy
Computational tools for simulation and control of optical tweezers
Principal Advisor
Other advisors: Professor Halina Rubinsztein-Dunlop, Dr Alexander Stilgoe
-
2019
Doctor Philosophy
Hydrodynamic forces in optical tweezers
Principal Advisor
Other advisors: Professor Halina Rubinsztein-Dunlop, Dr Alexander Stilgoe
-
2017
Doctor Philosophy
Calibration of optical tweezers for force microscopy
Principal Advisor
Other advisors: Professor Halina Rubinsztein-Dunlop, Dr Alexander Stilgoe
-
2010
Doctor Philosophy
Optically fabricated and driven micromachines
Principal Advisor
Other advisors: Professor Halina Rubinsztein-Dunlop
-
2009
Doctor Philosophy
Light Scattering in Complex Mesoscale Systems: Modelling Optical Trapping and Micromachines
Principal Advisor
-
2023
Doctor Philosophy
Probing Bacterial Dynamics with Holographic Optical Tweezers
Associate Advisor
Other advisors: Dr Itia Favre-Bulle, Professor Halina Rubinsztein-Dunlop
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2019
Doctor Philosophy
Measurement of forces in optical tweezers with applications in biological systems
Associate Advisor
Other advisors: Dr Alexander Stilgoe, Professor Halina Rubinsztein-Dunlop
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2017
Doctor Philosophy
High Resolution Measurements of Viscoelastic Properties of Complex Biological Systems Using Rotating Optical Tweezers
Associate Advisor
Other advisors: Professor Halina Rubinsztein-Dunlop
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2012
Doctor Philosophy
Dynamic properties of optical tweezers
Associate Advisor
Other advisors: Professor Halina Rubinsztein-Dunlop
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2008
Doctor Philosophy
Angular Momentum in Optical Tweezers
Associate Advisor
Other advisors: Professor Halina Rubinsztein-Dunlop, Professor Lars Nielsen
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2008
Doctor Philosophy
Optical Scatter Imaging using Digital Fourier Holography
Associate Advisor
Other advisors: Professor Aleksandar Rakic, Professor Tim McIntyre
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