Finish theoretical work on electron acceleration scheme, run the last simulations, and then write up and publish the results!

And that day isn’t today. I’m gonna backburner this while other, much more successful projects play out!

I’ve now come up with a scheme based on vector diffraction theory that I think should work pretty well. Ironically enough, I think that generating the field this way will likely be a lot less computationally intensive on the computer than the way that I was originally planning on doing it! Plus, I have much greater flexibility with what I can do with those fields.

The only thing is that I may need to resolve the equations of motion AGAIN.

I need to slog through a lot of integrals now (various incarnations of the Stratton-Chu integral, to be exact). Being an experimentalist, it’s gonna take me some time.

This is my side project, a theoretical thing that I attack every now and again when I have the time, energy, and motivation… Usually, all three are in short supply.

And it looks these days that I have all of that. Plus, I finally found some publications describing phenomena that I knew had to be possible but I couldn’t prove myself. One of them was written by a guy who just joined our group as a visiting professor, so it’s an awesome opportunity to have somebody around to ask for help, finally!!!!

Today, I’m going to see if I can understand these publications and extend their derivations to include effects that I need to include for my purposes.

at least the memory for my laptop comes in either today or tomorrow; this will make my computer a lot faster, especially the simulations.

oh WHY can I not get myself into doing this again???

Vacuum acceleration schemes are only now being hailed as a possibility, so the window is opening. It’s only a matter of time before somebody else comes up with this… especially since my coworker on the project gave an informal seminar on this at the Max Planck Institute for Quantum Optics.

I think I need to find a way out of lab for a week to get back into this in earnest.

I understand vector diffraction theory now. Next step is to code in a routine that executes the Stratton-Chu vector diffraction integral and use this to figure out what in tarnation the fields are doing at the focus.

I found a reference that claims to give a means by which to do it in a computationally efficient fashion: Torok et al., “Rigorous near- to far-field transformation for vectorial diffraction calculations and its numerical implementation.” JOSA A23, 713 (2006).

But, I might start with Stratton and Chu: Phys Rev., 56, 99 (1939)

Today, I learned scalar diffraction theory. This was actually pretty easy. I’m now learning the vectorial theory.

It’s also useful to other things—electromagnetic wave propagation is nearly identical to acoustic wave propagation (the main difference being that acoustic waves can be purely longitudinal and electromagnetic can’t).

I’d forgotten how much I love Electromagnetism. Man, it’s a beautiful theory!

I’ve decided that I really wanna do this RIGHT. Last I remembered, I need to read up on vectorial diffraction theory, and then code up a program that does electromagnetic wave propagation (and still respects Maxwell’s equations, on top of the wave equation). This is all because our scheme relies upon a very special adaptive diffractive optic and when we try to publish, we are bound to get critisized by people who think that this scheme somehow violates the Woodward-Lawson-Palmer theorem. So, it all needs to be done extremely carefully.

Perhaps the easiest is to try and code a program that can propagate the field from the origin of the SLM pixel to the point of observation (where the electron is momentarily), then generate the true field by a linear superposition of all the different pixels. I had been propagating focussing Gaussian pulses… but this is leaving strange artifacts, and besides I am not convinced that it is able to fully capture the effects of the SLM.

This task is gonna be HARD and completing it may be a publication in and of itself… we’ll see. :p

by the Boss Man, at least after I get my labmate up and running so that she can take data with the setup I’ve built. I should be able to start in on it full steam ahead next week!

Just finished getting MATLAB working on my computer again. I’m looking forward to feeling productive again and finishing this!