Equipment

The experimental infrastructure is a platform that is continuously being developed and that revolts around two axes.

One dimension is ‘time’ with two sub-classes: one the one end steady-state and on the other hand time-resolved setups where kinetic and dynamic process are monitored. These series of techniques cover a large time domain stretching from fs to seconds.

The second dimension is ‘space’ in which the spectroscopic investigation extends from single molecule level (nm-µm scale resolution) to bulk level (µm-cm scale resolution). Please click on a setup on the image to select!

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Steady-state absorption and emission spectrometers

Fs Transient Absorption Spectrometer

Fs fluorescence Up-conversion Spectrometer

Steady-state absorption uses a continuous-wave beam of light to irradiate the sample and the fraction of light absorbed is determined through transmission or reflectance measurements. more info

The chemical events are initiated by an actinic and resonant femtosecond laser pulse (pump) and the photophysical and photochemical events are probed by another ultrafast laser (probe) pulse. more info

Frequency mixing of fluorescence excited by a laser pulse with another laser pulse (gate) in a nonlinear crystal generates sum frequency radiation. This occurs only during the presence of the gate pulse. more info

Time Correlated Single Photon Counting (TC-SPC)

The method is based on the detection of single photons and the construction of a histogram of their arrival times in respect to a reference signal, usually the laser pulse used for excitation. more info

Fluorescence Lifetime Imaging (FLIM)

The setup produces an image based on the differences in the excited state decay time of fluorophores accumulated in different regions in a sample. more info

Fs Stimulated Raman Spectroscopy Spectrometer (FSRS)

Three laser pulses are involved. An actinic pump pulse excites the molecule to trigger a photochemical reaction. more info

Single Molecule fluorescence Decay and Spectra on ps-ns time scale

Harmonic light scattering set-up

Nanosecond Transient Absorption Spectrometer

The setup monitors the fluorescence decay of a sample at single molecule level via TC-SPC and records the spectra by a combination of a spectrograph and highly sensitive CCD camera detector. more info

a femtosecond laser beam is focussed on the sample and the light scattered at the double and triple frequency (harmonic frequencies) is detected simultaneously, with msec time resolution and polarization resolved. more info

The setup uses a high intensity laser pulse to produce a long-lived excited state in the sample. The perturbation in the sample causes a change in the absorption intensity over a short period of time. more info

Nanosecond Gated Luminescence Spectrometer

The apparatus provides luminescence spectra and decay traces initiated by a laser pulse as excitation source. The time resolution amounts to 3 ns and lifetimes from ns to seconds can be recorded. more info

Laser Induced Opto- Acoustic Spectroscopy (LIOAS) Setup

The sample is excited with a ns laser pulse. Relaxation to the ground state leads to a rapid heat dissipation resulting in a pressure wave which is recorded by a fast microphone. more info

Time of Flight Setup (TOF)

A laser excitation pulse produces charge carriers in a thin film which are driven to electrodes by a constant electric field applied on the film. The resulting current transient is recorded byy a digital oscilloscope. more info

SM photon anti-bunching setup

Z-scan setup

Stimulated Raman Scattering (SRS) Microscope

The fluorescence from a presumably single molecule is split by a 1:1 beam slitter, and the two signals are sent into separate detectors. The setup delivers a histogram of the difference between the arrival times of photons at both detectors. more info

Confocal Raman Microscope

A laser beam is focused and the transmittance of the sample, expected to give non-linear absorption is recorded in the far field through an aperture as a function of the distance to the focal point (Z-direction). more info

Photodissociation spectroscopy of gas phase clusters and molecules

The method is based on Stimulated Raman Scattering (SRS) in which two beams, pump and Stokes are incident on the sample. When the difference in frequency pump - Stokes matches a molecular vibration, stimulated excitation of the vibrational transition occurs. more info

Temperature dependent steady-state photoluminescence setup

The method is based on a Raman spectrometer coupled to a confocal microscope, allowing high magnification visualisation of a sample and Raman analysis with a microscopic laser spot with analysis in the XY (lateral) and Z (depth) axes. more info

A beam of clusters or molecules, produced by a laser ablation cluster source or electrospray source, and travelling through a vacuum chamber is excited by a laser beam. more info

A He flow cryostat in which the temperature can be varied from 4.2 to 300 K is used to measure the temperature evolution of PL spectra from different samples ranging from films, powders to single crystals more info