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Measuring time dynamics with time-resolved cathodoluminescence

Posted by Delmic on Jul 17, 2019 10:37:00 AM

time-resolvedCathodoluminescence has established itself as a powerful technique for measuring and understanding various properties of light. In the previous blog posts, we explained how intensity mapping can be used to measure amplitude of the electromagnetic waves, hyperspectral CL for wavelength measurements, angle-resolved CL for wave vector, and polarimetry for polarization. These properties of light are not static, which means that there is time dynamics associated with light, which can also be studied. How? Keep reading!

Time-resolved cathodoluminescence imaging observes exponential probability distribution for light decay at a particular time delay. This is possible to achieve by using electrostatic or laser triggered pulsed electron microscopy, which are the most common practices. 

Lab Cube is an additional SPARC module for decay trace imaging. Filters inside of the Lab Cube allow to measure intensity or/and colour, while single photon detector (such as PMT) detects photons and sends the signal to the time correlator. Repeating the experiment allows reconstructing an exponential decay and extract the lifetime. 

g2_curves-01

Another configuration of the Lab Cube consists of two single-photo detectors, which allows observing how photons are distributed in time. This function is called g(2) imaging. With this technique three characteristic behaviours can be observed: coherent (for a coherent source, such as laser), antibunching (for quantum emitter, such as single molecule or quantum dot), and bunching (for incoherent emitters). Additionally, with g(2) function it is possible to measure the lifetime and the excitation probability. 

This technique can be successfully applied to a wide range of materials and devices, such as nanostructured semiconductors, phosphors, ceramics, quantum emitters and even geological materials. To learn more about this technique, please download the technical note below.

 SPARC tech note g(2) thumbnail

Read technical note: CL g(2) imaging

Topics: cathodoluminescence, SPARC, cathodoluminescence sem, scanning electron microscope