Time-resolved cathodoluminescence is a technique in which you look at the time dynamics of the cathodoluminescence emission process. To introduce the time-resolved technique, Toon focuses on two main types of imaging: lifetime imaging (or emission decay) and g(2) imaging, which is also known in physics as the second-order correlation function. He explains how these two imaging techniques can be performed. The lifetime is determined by how the light emission process occurs after the material is excited by the electron beam. Another approach for imaging the dynamics is using the g(2) function. g(2) imaging tells us how the photons emitted from a material are distributed in time. This can tell us, for example, the probability of finding two photons at the same time.

Both of these techniques have a wide range of applications and are valuable in fields such as photonics, materials science, geology and even biology. For instance, lifetime is very strongly linked to the material quality, so you can characterize materials and determine their performance. g(2) analysis can be used to look at quantum emitters. One advantage of this technique is that it can be performed using a continuous electron beam.

The SPARC is a high-performance cathodoluminescence detection system, which also provides hardware and software for performing time-resolved imaging. The modular design of the SPARC system provides different possibilities for imaging. There are two optical modules, which can be configured to measure in the entire wavelength range from the NIR, through visible, to the UV. The SPARC also offers a range of measurement options like fast panchromatic and colour-filtered PMT imaging, spectroscopy, polarimetry, light outcoupling via a fiber, and a developer module for more specialized applications.

The integrated design of the SPARC allows you to acquire high quality data on the time dynamics, enabling the study of both the intrinsic material properties, as well as the local density of states (LDOS). Information obtained on the carrier dynamics, for example, is very valuable in designing semiconductor materials for optoelectronic devices. The ability to track lifetime processes at the nanoscale, combined with the power of high resolution SEM, makes this a great technique to characterize materials and optical behavior at the nanoscale.

If you are interested in learning more about the SPARC system optical modules and their possibilities, we encourage you to download the technical note below:

Technical Note: Optical modules in the
SPARC cathodoluminescence system