Manganite 

While I'm a bloody amateur in photography taking images is nevertheless part of my job. I'm a physicist doing mainly optical experiments. In more detail I'm doing the following: I illuminate a sample with the intense light of laser beam. In the sample the frequency of the light is doublet. So basically near infrared light is converted into visible green light. With a telephoto lens this light is imaged on a CCD camera. One example of this you can see above.

That's an image which I took several years ago from a thin Yttriummanganite crystal, which is antiferromagnetic at temperatures below -200°C and dark and bright parts are the antiferromagnetic domains. To get this contrast the light from the sample is interfered with light from quartz crystal which is used as a reference.

While the signals are rather small, one need a special CCD camera. In this case a Photometrics AT200 system with a 16-bit CCD chip with a pixel size of 26x26 µm^2 and a total number of 1024x256 pixel (the image is a crop of the original image) was used. The sensitivity of the chip is extremely large. The quantum efficiency is about 70% (which means you can detect almost single photons) and the noise is almost zero due to cooling with liquid nitrogen. I don't know the equivalent ISO value, but it must be something like several thousand or ten thousand. But in spite of this high sensitivity it needs still several minutes to take such a picture...

What else? I just thought one year at flickr is maybe a good time to tell something about me, my job and about the origin of my user name :)