Cathodoluminescence is a great tool for obtaining valuable information about the properties of a sample. This data can help researchers and developers get a better understanding of possible defects, efficiency of the material and other properties.
The SPARC cathodoluminescence detector has 6 imaging modes which can enhance your research and provide you with an important information about your samples. Keep reading if you would like to know what exactly is possible with these modes!
Fast-intensity mapping is a method that records the cathodoluminescence intensity for every beam position using a single-pixel light detector. Together with a photomultiplier tube (PMT) light detector, it is possible to do easy rapid inspection of large areas, fast device inspection, and efficient region-of-interest finding. A filter wheel can be used for spectral differentiation. Among applications are mapping defects, radiation efficiency, and colour changes in a large variety of (doped) dielectric, ceramic, semiconductor and geological materials.
Angle-resolved cathodoluminescence spectroscopy
Angle-resolved CL spectroscopy is one of the key features of the SPARC system. The direction in which light is emitted often contains valuable information on how a (nanostructured) object emits and scatters light, gives insight into the band structure of periodic systems. It is possible to collect such information due to a paraboloid mirror: rather than focusing the light signal on a fiber or narrow opening, an image of the mirror can be projected onto an imaging camera.
The wavelength distribution (spectrum) often contains valuable information on the local optical and structural properties of the material, and there are different ways to obtain wavelength information. In hyperspectral imaging a complete spectrum is collected in a parallel manner, providing a high-resolution spectrum for every electron beam position. By scanning the e-beam across the sample, a spatially resolved hyperspectral image is produced. A variety of imaging detectors can be used to cover a spectral range of 200-1600 nm.
Besides color (energy) and momentum (propagationdirection), light is also characterized by a polarization which describes in what direction electro-magnetic fields oscillate. Polarization plays a key role in light-matter interactions and can be used to study coherence, scattering, birefringence, and chirality. Additionally, it can be used to block spurious background radiation and correct for aberrating effects in the collection optics. Using a polarizer or even a full polarimeter in the angle-resolved mode allows for the reconstruction of the polarization state (Stokesvector) of CL for different emission angles.
Time-resolved cathodoluminescence imaging
Observing time dynamics of the materials can be important for better understanding of physical processes and material properties. It is possible with g(2) imaging, which is also known as second order autocorrelation function, and lifetime imaging, which can be done with the Lab Cube. Time-resolved imaging is highly relevant for a wide range of applications, including semiconductors for photovoltaics and light-emitting devices, as well as single emitters for quantum information processing and sensing.
Energy-Momentum Cathodoluminescence Imaging is a new technique which can be applied to track the directionality through energy and momentum space with very high precision. It is a great tool for mapping the optical properties of a wide range of dispersive and anisotropic systems, paving the way for a broad range of studies on complex nanophotonic systems.
Would you like to know more? Make sure to sign up for our upcoming webinars, during which we explain cathodoluminescence and its possibilities in different fields.