Biocompatible and Sustainable Optical Strain Sensors for Large-Area Applications

By a simple two-step procedure, large photonic strain sensors using a biocompatible cellulose derivative are fabricated. Transient color shifts of the sensors are explained by a theoretical model that consideres the deformation of cholesteric domains, which is in agreement with the experimental results. The extremely simple fabrication method is suitable for both miniaturization and large-sale manufacture, taking advantage of inexpensive and sustainable materials.Biotechnology and Biological Sciences Research Council (David Phillips fellowship (Grant ID: BB/K014617/1)), The Isaac Newton Trust Cambridge (Grant ID: 76933), European Research Council (Grant ID: ERC-2014-STG H2020 639088

The effect of antenna position and environment on MIMO channel capacity for a 4 element array mounted on a PDA

The properties of a four element slot antenna array mounted on a PDA for a MIMO system are investigated by means of a Finite Difference Time Domain analysis and a multipath channel model. The effects of changing the positions of the antenna elements on the PDA box and the effect of the box being held in a human hand are investigated

Invited Article: Chiral optics of helicoidal cellulose nanocrystal films

Cellulose nanocrystals (CNCs) in water suspensions behave as lyotropic liquid crystals forming a chiral nematic phase above a critical concentration. Such organization can be retained in solid films and give rise to an intense colored appearance. Here, we fully characterize their optical response by applying optical and scanning electron microscopy, imaging scatterometry and angle-resolved reflectance measurements. We show that the experimental results are well explained by computational modeling using the finite-difference time-domain method, but slightly less well by Berremann’s analytical model.This work was supported by the EPSRC Cambridge NanoDTC [No. EP/G037221/1 to R.M.], the National Centre of Competence in Research “Bio-InspiredMaterials”, the Ambizione program of the Swiss National Science Foundation [No. 168223 to B.D.W.], the European Research Council [No. ERC-2014-STG H2020 639088 to S.V. and A.G.D.], and the BBSRC David Phillips fellowship [No. BB/K014617/1 to S.V.]