Activities

The group of microscopy is active in different directions here we outline our present main interest

MEASURING ORBITAL ANGULAR MOMENTUM
( toward single electron experiments?)

Inspired by a similar optical device we are working on a sorter of Orbital Angular Momentum (OAM). This device transform an electron OAM in a linear momentum through a coordinate transformation operated through 2 holograms

More details are available
https://arxiv.org/abs/1609.09129

sorter2

We have also proposed a device based on conductive cylinder that could measure the azimuthal current in a conductor.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.154801

 

HOLOGRAPHIC BEAM SHAPING

yanblazed

We created the first phase hologram to change the phase of an electron wavefunction.

In particular thanks to the use of a triangular shaped groove we could generate vortex beams at high efficiency.
We also generated Bessel beam by holographic methods

bes1 Bes2

We also created the first giant vortex beam with Orbital Angular Momentum L=200h

giantOAMspectrum

Here you can see the experiment , the simulation , the map of the singularity and the spectrum of the actual L distribution.

 

SPIN-ORBITAL ANGULAR MOMENTUM THEORY AND EXPERIMENTS

We created the first multislice simulation based on Pauli equation and described the spin-orbit interaction in a magnetic lens

animspin1-

 

QUANTITATIVE STEM

The group and in particular V.Grillo has a long experience in quantitative STEM . Grilo has created the first quantitative anlysis of composition based on STEM.

Current interest are in the direction of finding the 3D position of dopant atoms inside a matrix using variable channeling conditions.

 

TEM METHODOLOGY:
Geometric phase analysis of strain
Convegent Beam analyis
Transport of Intensity equation