Interferometric setup for measurements of expansion of whisker-like samples

We describe a simple technique for study of (thermal) expansion of whisker-like samples. At the heart of the method is the measurement of the shift of the sample middle, which is lifted over the substrate, while the ends of the sample are fixed at the substrate. The optical interference technique allows one to detect the relative length change about 5×10 −7 . Simultaneous electric measurements of the sample can be performed. We illustrate the technique with the study of TaS 3 , a quasi-one-dimensional conductor with charge-density waves: thermal expansivity has been measured and hysteresis in thermal expansion is found.