Wavelength-Resolved

Overview

In wavelength-resolved mode, the wavelength distribution of the emitted light is analyzed. Light collected from the specimen is focused onto the entrance slit of a spectrograph that disperses light by wavelength (energy) using a pixelated detector to record a wavelength spectrum—a histogram displaying the intensity of light by wavelength.

Sometimes referred to as hyperspectral cathodoluminescence analysis or wavelength imaging.

Data collection

Wavelength-resolved spectrum: The wavelength distribution of emitted light is recorded from a point or region of the sample exposed to the electron beam of the electron microscope. One-dimensional data is displayed by plotting a histogram of count rate (intensity) versus wavelength or energy—wavelength and energy being inversely proportional.

Wavelength-resolved spectrum image: The electron beam is scanned across the specimen surface in a pre-defined pattern, and a wavelength-resolved spectrum is recorded at each location, creating hyperspectral (3D) data.

Uses

Identify compounds and phases, determine the electronic structure, reveal and determine trace elements, map composition, and/or stress.

An example 3D spectrum image data construct (x,y,λ) recorded from a polished zircon grain. At each pixel in the image, a complete wavelength-resolved spectrum has been recorded and is displayed as a true-color representation based on the analysis of the measured spectrum. At each spatial location (x_n,y_n) a full wavelength-resolved emission spectrum may be extracted from the data construct.


Determining photonic band structure by energy-momentum spectroscopy in an electron microscope	Cathodoluminescence techniques for the geosciences