Optically-addressed phase modulator for electron beams
An electron beam phase plate is provided where patterned radiation is provided to the phase plate to creates a corresponding electrical pattern, This electrical pattern provides a corresponding patterned modulation of the electron beam. Such modulation can be done in transmission or in reflection. This approach has numerous applications in electron microscopy, such as providing phase and/or amplitude shaping, aberration correction and providing phase contrast.
1. Apparatus for providing patterned phase modulation of an electron beam, the apparatus comprising:
a planar radiation-sensitive device configured to interact with an electron beam;
a radiation source configured to provide a pattern of incident radiation to the planar radiation-sensitive device;
electron optics configured to provide the electron beam to the planar radiation-sensitive device;
wherein the planar radiation-sensitive device provides a pattern of electric potential in response to the pattern of incident radiation;
wherein interaction of the planar radiation-sensitive device with the electron beam provides a patterned phase modulation of the electron beam corresponding to the pattern of electric potential.
2. The apparatus of claim 1 , wherein the planar radiation-sensitive device interacts with the electron beam by transmission of the electron beam through the planar radiation-sensitive device.
3. The apparatus of claim 1 , wherein the planar radiation-sensitive device interacts with the electron beam by reflection of the electron beam from the planar radiation-sensitive device.
4. The apparatus of claim 1 , wherein the planar radiation-sensitive device is selected from the group consisting of: photoelectric devices, photothermal devices, pyroelectric devices, photodissociation devices, photovoltaic devices photochemical devices, and plasmonic devices.
5. The apparatus of claim 1 , wherein the planar radiation-sensitive device is a photovoltaic device selected from the group consisting of: PN diodes, PIN diodes and Schottky diodes.
6. The apparatus of claim 1 , wherein the planar radiation-sensitive device includes a passive pixelation pattern, whereby lateral crosstalk in the pattern of electric potential is reduced.
7. An electron microscope including at least one electron beam phase modulator, wherein the at least one electron beam phase modulator is an apparatus according to claim 1 .
8. The electron microscope of claim 7 , wherein the at least one electron beam phase modulator provides one or more functions selected from the group consisting of: amplitude shaping, phase shaping, aberration correction, and phase contrast.
9. The electron microscope of claim 7 , wherein the at least one electron beam phase modulator is configured to provide a single pixel electron microscope.
10. The apparatus of claim 1 , further comprising a voltage source configured to provide an electrical bias to the planar radiation-sensitive device.
11. The apparatus of claim 10 , wherein the electrical bias is pulsed.
12. The apparatus of claim 11 , wherein the planar radiation-sensitive device is a photodiode, wherein the pattern of incident radiation is pulsed, and wherein the pulsed electrical bias reverse biases the photodiode synchronously with the pattern of incident radiation.
13. The apparatus of claim 1 , wherein the pattern of incident radiation is a pattern of incident light.
14. The apparatus of claim 1 , wherein the pattern of incident radiation is a pattern of incident electrons.
15. The apparatus of claim 14 , wherein the pattern of incident electrons is a pattern of the electron beam, whereby self-phase modulation of the electron beam is provided.