QT Optics Laboratory

Synchrotron radiation is normally associated with high brilliance x-rays, originating from the accelerated circular motion of the electrons. The Swiss Light Source (SLS) is one of few synchrotrons that deliberately produce infrared light as well, by adding a small bending magnet along the way. This continuous-spectrum radiation extends far into the infrared, down to energies/frequencies of single millielectronvolts/hundreds of GHz. Compared to the conventional far-infrared (FIR) sources the synchrotron beam is approximately 100 times brighter while remaining a continuous beam for our practical purposes. This is unique combination which is difficult to come by.

When the beam enters the IR station it passes through a switching yard, where it can be channeled to different measurement setups. The most noticeable is the ultra-high-resolution Fourier transform infrared (UHR-FTIR) spectrometer (Bruker IFS125HR). In FTIR spectrometry the light is split into two arms, a fixed arm and a scanning one. The longer the scan, the higher the frequency resolution is. The UHR-FTIR has the longest commercially available scanning arm available, at 6.3 meters, giving it a spectral resolution of 30 MHz.

The combination of these two resources is unique in itself. Our measurement capabilities are further enhanced with the introduction of an optical-access dilution refrigerator with a base temperature of ~20mK and a 3D vector magnet.

Apart from the synchrotron beam we can also use the dilution refrigerator with a tunable pulsed laser for time-resolved measurements and with our NKT SuperK extreme source for visible to mid-infrared high power excitation.