Tahmina Ajmal

Harvesting energy from ambient radio signals: A load of hot air?

Harvesting energy from ambient radio signals is claimed to hold much innovation potential. Advances in ultra-low power electronics, an appetite for reducing the environmental footprint of technology and the business need for enabling new applications such as sensing in inaccessible locations are widely believed to be drivers. We review these drivers, and recent technological advances to reveal what potential there is by harvesting energy from ambient radio signals. Particular attention is given to the possibility of powering smart meters in this way.

Experimental Demonstration of a Macroscopic Cryptography Technique

Physical layer cryptography offers the unique possibility of certifiably secure data transmission between remote locations. We present here for the first time, to our knowledge, the experimental results of a secure full Poincare occupancy polarization encrypted data transmission system. The scheme uses an approach to macroscopic physical layer cryptography based on combining a multilevel polarisation modulation cipher with a differential phase shift keying data transmission technique. Depolarized noise is added to the encrypted data so as to hide both the data and key from a potential eavesdropper. Experimental results prove the effectiveness of the technique over amplified optical transmission links. The technique hence opens up new avenues for long distance secure data transmission over fibre links

Stokes Encrypted Secure Communication over Optically Amplified Links

We describe an innovative polarization-based optical fibre physical layer cryptography technique capable of highly secure data transmission over amplified optical links. It offers completely opaque communication over trans-oceanic distances, gigabit date rates and multiple wavelengths.

Nanoantenna arrays combining enhancement and beam control for fluorescence-based sensing applications

This paper presents measured fluorescence enhancement results for ∼250×250 element aluminum nanoantenna arrays fabricated using electron beam lithography. The arrays have been designed to use diffractive coupling to enhance and control the direction of fluorescent emission. Highly directional emission is obtained at the designed angles with beam widths simulated to be in the range of 4-6°. Angle-resolved spectroscopy measurements of dye-coated nanoantenna arrays were in good agreement with finite difference time domain modeling. Critically, these results were obtained for near UV wavelengths (∼360  nm), which is relevant to a number of biosensing applications.

Application of water quality index for pollution detection at Luton Hoo Lake

This study investigated contamination problems through physical and chemical surface water monitoring. The physical parameters were temperature, conductivity and turbidity while the chemical parameters were dissolved oxygen, pH and ammonium. These parameters were measured at two locations on the lake to monitor the water quality and possible sources of contamination. We evaluated the relationship of the measured parameters to contamination sources and its effect on the water quality. The collected data from the installed multi parameter sensors were analyzed to assess the difference in values at the different sensor locations based on a water quality index.

Surface water quality prediction system for Luton Hoo lake: A statistical approach

Lake monitoring is a necessity for aquatic healthy living. Stakeholders are particularly interested not just in the aesthetics but also in the quality of water bodies. Our work tends to initially analyze historic data of the sensed water quality parameters at Luton Hoo lake to detect outliers. Dissolved oxygen has been predicted from available data since its one of the major surface water contaminants.

Design of a 10Gbps optical burst mode DPSK receiver for data and clock recovery

We present a 10 Gbps DPSK burst mode receiver with zero latency clock synchronization. Concatenated phaseshift and resonator techniques maintain an NRZ data clock component over >1024 bit guard intervals.

Phase-Encrypted Secure Communication technique for GPONs

We present an FPGA-based physical layer phase-encryption technique suitable for applications in high speed passive optical networks. The macroscopic cryptography technique offers completely opaque communication over transoceanic distances, gigabit date rates and multiple wavelengths.