De Broglie wavelength is a concept in quantum mechanics that describes the wave-like nature of matter. It's not specifically measured in any one particular field, but rather used as a theoretical tool in various fields where quantum effects are significant:

* Particle physics: Used to understand the wave-like behavior of elementary particles, like electrons and protons.

* Condensed matter physics: Applies to the behavior of electrons in solids and explains phenomena like superconductivity.

* Atomic and molecular physics: Crucial for understanding electron orbitals and the wave nature of atoms and molecules.

* Nanotechnology: Important in developing nanomaterials and devices, as quantum effects become significant at nanoscale.

The De Broglie wavelength itself is not directly measured, but rather inferred from other measurements:

* Electron diffraction experiments: Observing diffraction patterns of electrons passing through a crystal lattice.

* Neutron scattering: Analyzing the scattering of neutrons by materials.

* Atom interferometry: Utilizing the wave nature of atoms to create interference patterns.

So, while the De Broglie wavelength itself isn't a direct measurement, its theoretical concept is crucial for understanding and predicting the behavior of matter at the quantum level across various scientific fields.