Micro-photoluminescence setup

Our microPL setup allows us to study the luminescence of single nanoparticles. The nanoparticles are excited by focussing a blue light beam (445 nm) on them. Using an objective lens, excitation-spot diameters of a few hundred of nanometres are achieved.  The luminescence is collected by the same objective lens and separated from the excitation beam using a dichroic mirror.  An imaging spectrometer allows us to either image our field of view or to measure the spectrum of individual nanoparticles. To “see” individual nanoparticles a very sensitive EMCCD camera (400-1100 nm) is used. The luminescence can also be directed towards a pair of photon counters.  These are even more sensitive than the camera and can detect single photons with an efficiency of 70% and a time resolution of 300 ps. We use the photons counters to measure the luminescence decay of single nanoparticles and  analyse the statistics of individual photon-emission events. We can study luminescence intermittency and perform time-correlation photon-counting spectroscopy.

Our system also allows us to fully control the intensity profile of the excitation beam reaching the nanoparticles. Instead of focussing the beam on a single nanoparticle, we can easily (without moving any optics) illuminate the entire field of view or even create a multitude of independent excitation beams pointing on different luminescent nanoparticles.