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We introduce a scattering-type scanning near-field infrared microscope (s-SNIM) for the local scale near- field sample analysis and spectroscopy from room (RT) down to liquid helium (LHe) temperatures. The extension of s-SNIM down to T = 5K is in particular crucial for low-temperature phase transitions, e.g. for the examination of superconductors, as well as low energy excitations. The LT s-SNIM performance is tested with CO2-IR excitation at T = 7K using a bare Au reference and a structured Si/SiO$_2$-sample. Furthermore, we quantify the impact of local laser heating under the s-SNIM tip apex by monitoring the light-induced ferroelectric-to-paraelectric phase transition of the skyrmion-hosting multiferroic material GaV4S8 at T$_c$ = 42K. We apply LT s-SNIM to study the spectral response of GaV$_4$S$_8$ and its lateral domain structure in the ferroelectric phase by the mid-IR to THz free-electron laser-light source FELBE at the Helmholtz-Zentrum Dresden-Rossendorf, Germany. Notably, our s-SNIM is based on a non-contact atomic force microscope(AFM), and thus can be complemented in-situ by various other AFM techniques, such as topography profiling, piezo-response force microscopy (PFM) and/or Kelvin-probe force microscopy (KPFM). The combination of these methods support the comprehensive study of the mutual interplay in the topographic, electronic and optical properties of surfaces from room temperature down to 5K.
Liquid Helium is used widely, from hospitals to characterization of materials at low temperatures. Many experiments at low temperatures require liquid Helium, particularly when vibration isolation precludes the use of cryocoolers and when one needs t
This note presents a method to tune the resonant frequency $f_{0}$ of a rectangular microwave cavity. This is achieved using a liquid metal, GaInSn, to decrease the volume of the cavity. It is possible to shift $f_{0}$ by filling the cavity with this
We revisit laser intensity noise in the context of stimulated Raman scattering (SRS), which has recently proved to be a key technique to provide label free images of chemical bonds in biological and medical samples. Contrary to most microscopy techni
Helium has the lowest boiling point of any element in nature at normal atmospheric pressure. Therefore, any unwanted substance like impurities present in liquid helium will be frozen and will be in solid form. Even if these solid impurities can be ea
We developed an impedance bridge that operates at cryogenic temperatures (down to 60 mK) and in perpendicular magnetic fields up to at least 12 T. This is achieved by mounting a GaAs HEMT amplifier perpendicular to a printed circuit board containing