The physical properties of the ionic conductor, obtained by dissolution of lithium trifluoromethanesulphonylimide in polyethylene oxide, (PEO)nLi+((CF3SO2)2N)- have been investigated for several values of n. The phase diagram has been established from both DSC and NMR techniques. The diffusion coefficients of 7Li and 19F containing Species, determined by the pulsed magnetic field gradient (PMFG) technique, are interpreted as the measures of the cationic and anionic transport numbers, which are concentration dependent, and t+ reaches a value close to 0.3. This study is complemented by a systematic analysis of the behaviour of the 7Li relaxation time T1 versus temperature and concentration which is correlated to the glass temperature Tg.

Abstract. We study the rock fall volume distribution for three rock fall inventories and we fit the observed data by a power-law distribution, which has recently been proposed to describe landslide and rock fall volume distributions, and is also observed for many other natural phenomena, such as volcanic eruptions or earthquakes. We use these statistical distributions of past events to estimate rock fall occurrence rates on the studied areas. It is an alternative to deterministic approaches, which have not proved successful in predicting individual rock falls. The first one concerns calcareous cliffs around Grenoble, French Alps, from 1935 to 1995. The second data set is gathered during the 1912-1992 time window in Yosemite Valley, USA, in granite cliffs. The third one covers the 1954-1976 period in the Arly gorges, French Alps, with metamorphic and sedimentary rocks.For the three data sets, we find a good agreement between the observed volume distributions and a fit by a power-law distribution for volumes larger than 50 m 3 , or 20 m 3 for the Arly gorges. We obtain similar values of the b exponent close to 0.45 for the 3 data sets. In agreement with previous studies, this suggests, that the b value is not dependant on the geological settings. Regarding the rate of rock fall activity, determined as the number of rock fall events with volume larger than 1 m 3 per year, we find a large variability from one site to the other. The rock fall activity, as part of a local erosion rate, is thus spatially dependent.We discuss the implications of these observations for the rock fall hazard evaluation. First, assuming that the volume distributions are temporally stable, a complete rock fall inventory allows for the prediction of recurrence rates for future events of a given volume in the range of the observed historical data. Second, assuming that the observed volume distribution follows a power-law distribution without cutoff at small or large scales, we can extrapolate these predictions to events smaller or larger than those reported in the data sets. Finally, we discuss the possible biases induced by the Correspondence to: C. Dussauge-Peisser (carine.dussauge@ujf-grenoble.fr) poor quality of the rock fall inventories, and the sensibility of the extrapolated predictions to variations in the parameters of the power law.

The ultra-strong light-matter coupling regime has been demonstrated in a novel threedimensional inductor-capacitor (LC) circuit resonator, embedding a semiconductor twodimensional electron gas in the capacitive part. The fundamental resonance of the LC circuit interacts with the intersubband plasmon excitation of the electron gas at ω c = 3.3 THz with a normalized coupling strength 2Ω R /ω c = 0.27. Light matter interaction is driven by the quasi-static electric field in the capacitors, and takes place in a highly subwavelength effective volume V eff = 10 −6 λ 3 0 . This enables the observation of the ultra-strong light-matter coupling with 2.4 × 10 3 electrons only. Notably, our fabrication protocol can be applied to the integration of a semiconductor region into arbitrary nano-engineered three dimensional meta-atoms. This circuit architecture can be considered the building block of metamaterials for ultra-low dark current detectors. Metamaterials were introduced to enable new electromagnetic properties of matter which are not naturally found in nature. Celebrated examples of such achievements are, for instance, negative refraction 1 and artificial magnetism. 2 The unit cells of metamaterials are artificially designed meta-atoms that have dimensions ideally much smaller than the wavelength of interest λ 0 . 3 Such meta-atoms act as high frequency inductor-capacitor (LC) resonators which sustain a resonance close to λ 0 ∝ √ LC. 3 The resonant behaviour, occurring into highly subwavelength volumes, generates high electromagnetic field intensities which, as pointed out by the seminal paper of Pendry et al., 2 are crucial to implement artificial electromagnetic properties of a macroscopic ensemble of meta-atoms. Moreover, the ability to control and enhance the electromagnetic field at the nanoscale is beneficial for optoelectronic devices, such as nano-lasers 4 electromagnetic sensors 5-7 and detectors. 8-12 For instance, metamaterial architectures have lead to a substantial decrease of the thermally excited dark current in quantum infrared detectors, resulting in higher temperature operation. 11,12The LC circuit can be seen as a quantum har-