The first Swedish snow! And polar lights!

Polar lights! (Green laser, actually ...)

 Yesterday I really saw the first Swedish snow! And even polarlights! Nah ok we created it in the lab. :( But it looked cool nevertheless. ;)

The lab exercise was about Raman spectroscopy and photoluminescence (excitation) spectroscopy. What thaaat?! Well just a short description and then fancy pictures. ;)

In Raman spectroscopy a material is excited with a laser. (This means that electrons absorb energy from the laser and start to dance inside the sample.) After some time the electrons relax to their former state and release their energy from before. So we see a peak at their excitation energy. But apart from that there are more peaks! While dancing the electrons can collide with atom nuclei and give them some of their energy. The lattice then starts to vibrate. This is called a phonon. So now the electrons have less energy than before and of course now they can only emitt less energy. => Another peak. This works the other way around as well so there is another peak with higher energy than before.

SNOOOW!1!

The photoluminescence spectroscopy we did with quantum wells. Small energy valleys in a material. Shooting at the sample with a laser again electrons are lifted to another energy state (conduction band) and at the same time holes (a lacking electron) is created in a lower energy state (valence band). Both of them can be created at almost any level in their respective bands. Afterwards they move to the lowest energy level as all things do and after some more time they recombine. (Electron + missing electron -> electron gone ;) - only in the area where we are looking of course) This again emits energy and that is all the joke about photoluminesence spectroscopy.

With both you can investigate materials. (Solid state) physicists like to do this. ;)

Back to brains

Subject of my bachelor thesis:
The Raspberry Pi that replaced the board on the right.

No, this is not another Halloween anecdote but rather a step back to my bachelor time. A few days ago I stumbled upon an article on medicalxpress where it is said that scientists found out that the dendrites in the brain are not mere "wires" as was assumed so far but that they show spiking capabilities as well! This menas that they can actively process and generate information! If this would happen in your PC it would mean that its wires work as processors as well. Sounds great and could bring some interesting properties of the brain with it. It seems to be proven that this plays a role e.g. in the brain's visual activities so this is not another physics gimmick. ;)

Now why is this of special interest to me? As some might remember I wrote my bachelor thesis in this area of research and I did an internship in the same research group in Heidelberg. Still I am not detached of the matter and who knows? Maybe I will do a phd on this subject? ;)

What "my" research group (Electronic Vision(s)) actually does is building a brain based on electrical circuits. Awesome! With this you can perform experiments afterwards and test your theories about how the human brain works. This again can give rise to new computer techniques (which will not only serve the NSA ...), an understanding of brain illnesses and maybe ways to cure them. (The music of future ...) Besides, it would incredibly awesome to understand how a brain works!

In the end of course I have to use this occasion to promote my incredibly steep scientific career at this point and provide you with my bachelor thesis. ;)

A Raspberry Pi controlling neuromorphic hardware - just in case you are interested ... (In any case there are some nice pictures in it!)