Laserlab-NSC (Jyväskylä, Finland)
Laser Laboratory of the Nanoscience Center, University of Jyväskylä
The laboratory of Laserlab-NSC is equipped with three femtosecond laser systems and with more than ten other spectroscopic setups enabling various experiments in time- and frequency domains, with nearfield imaging option (SNOM). Our expertise lay on four-wave-mixing, including ultrafast laser processing of 2D-materials, ultrafast time-resolved spectroscopy in visible and MIR region, and polariton chemistry.
Research highlights
The potential of ultrafast laser techniques in manipulating 2D layered materials. Credit: Aleksei Emelianov
Thermal disorder prevents the suppression of ultra-fast photochemistry in the strong light-matter coupling regime, 2024 Nature Communications, https://doi.org/10.1038/s41467-024-50532-5
Thermal relaxation time and photothermal optomechanical force in sliced photonic crystal silicon nanobeams, 2024 Optics express, https://doi.org/10.1364/OE.533897
NIRis: A low-cost, versatile imaging system for near-infrared fluorescence detection of phototrophic cell colonies used in research and education, 2024 PLoS ONE, https://doi.org/10.1371/journal.pone.0287088
Expertise
2D-materials
We apply optical spectroscopic and microscopic methods for studying nano-materials and -objects. We combine spectroscopy, microscopy, nanofabrication and nanocharacterization methods and theoretical simulations to reveal new phenomena in nanoscale. Currently, we are strongly focusing on laser modification of 2D materials. A long-term goal is development of an interface between nerves and machines from graphene.
Silicon optomechanics
We aim to couple the spins to silicon optomechanical structures, allowing for optical readout and phononic coupling between spins. Silicon photonic crystals give us a flexible method to both guide light on chip and concentrate it in cavities where light-matter interaction can be maximised. We study photonic crystal structures to combine them with emitters in silicon that also have a spin degree-of-freedom. Special interest lies in helical waveguide structures. We also develop readout methods for donor spins based on a resonant spin-dependent bound exciton transition which we will excite using resonant lasers and detect using on-chip detectors based on the silicon quantum dot devices.
Polariton chemistry
When photoactive molecules interact strongly with confined light modes, new hybrid light–matter states, polaritons, are formed. We develop a theory taking into account all the molecular degrees of freedom, which are many times neglected in theories, and carrying out experiments demonstrating the efficiency of strong coupling between confined light, like surface plasmon polaritons and cavity photons, and molecules.
Biomolecular spectroscopy
We characterize spectroscopic properties of biological photosensors and aim to understand the capability of plant-associated microbes to perform anoxygenic photosynthetic processes in aerobic environments.
Equipment offered to external users
Scattering-type near-field optical microscopy (SNOM). Credit: Eero Hulkko
Near-field nanospectroscopy and imaging
Scattering-type near-field optical microscopy (SNOM). Credit: Eero Hulkko
The equipment for nanospectroscopy consists of scattering-type near-field optical microscopy (SNOM) which is based on enhancement of the electromagnetic field close to a nanotip. It can image samples at 10 nm spatial resolution over the fingerprint infrared spectral region (1000 – 2300 cm-1).
Ultrafast fluorescence upconversion spectroscopy
Time-resolved fluorescence techniques are essential for studying the excited-state dynamics of molecules and materials, as well as their interactions with the surrounding media. Fluorescence upconversion provides femtosecond time resolution, but its limited spectral coverage often restricts its application. Broadband variants of fluorescence upconversion spectroscopy (FLUPS) offer improved spectral coverage but require balancing spectral bandwidth against signal strength. It offers high signal-to-noise levels, minimal background interference, and excellent time resolution down to <100 fs.
2D-material processing with ultrafast lasers
Ultrafast lasers offer a way to overcome the challenges of thermal heating caused by continuous-wave (CW) and long-pulsed laser irradiation. They allow the patterning of 2DM on diverse substrates without inducing significant heating effects, finding applications in biology, medicine, etc. In our laboratory, we mainly concentrate on graphene and have demonstrated the capability for optical forging and doping of graphene surfaces.