There is an ever-growing demand in the wood products industry for cost-effective and compact equipment to ensure wood quality measures and specifications are met. Recently, terahertz (THz) technology has begun to pave the way for new, non-destructive imaging techniques rather than the standard use of X-ray or microwave technology. A prototype THz Michelson interferometer operating at 0.102 THz was developed to measure the indices of refraction and absorption coefficients of maple, hemlock and birch. These measurements were compared to the Picometrix system, which uses conventional THz time-domain spectroscopy and has been implemented in an industrial setting for the real-time measurement of the density of OSB flakes. However, the cost and complexity of the Picometrix system prohibits its use for many industrial applications. The interferometer is cost-effective, compact and provides accurate data at low THz frequencies, thus providing an excellent alternative direction for new THz technology in the wood products industry. --Leaf ii.
Quantum teleportation has been investigated experimentally, for a variety of physical systems. However, it has been suggested that most methods of teleportation do not achieve true teleportation. This is because a complete Bell-operator measurement cannot be performed without interaction between the quantum particles involved in the teleportation. Since the Bell-operator measurement is a key factor in the teleportation procedure, teleportation cannot be realized in the manner proposed in the pioneering paper on teleportation. In this project, it is verified that, without interaction between the quantum particles involved in the teleportation procedure, true teleportation cannot be achieved.--Page ii.
The aim of this thesis is to study pollutants that are emitted from combustion systems using Terahertz time domain spectroscopy (THz-TDS). In particular, this thesis will focus on Nitric Oxide (NO), which is present in flue gases and contributes to air pollution. It is also interesting from a Physics perspective because it contains an unpaired electron in the valence shell, which leads to a complicated energy level structure, and interesting Physics. In this thesis, we aim to answer the question: “what is the detection limit of NO, using THz-TDS, and is it suitable for industrial emissions monitoring?” It is therefore necessary to look at detection limits, which in turn requires conducting THz spectroscopy at different gas pressures. ...
We investigate, in one spatial dimension, the quantum mechanical tunnelling of a diatomic, homogeneous molecule with a single bound state incident upon an external barrier. Both time-independent and time-dependent tunnelling are investigated, using analytical and numerical methods. In the time-independent case, we first derive a formal solution for the molecule's wave function. Then, using the method of variable reflection and transmission amplitudes, we find that the probabilities of reflection and transmission in the bound state decrease with decreased binding strength, while the probabilities of refection and transmission in an unbound state increase with decreased binding energy. In the time-dependent case, we consider a molecule with discrete unbound states. The molecular wave function is modeled as a Gaussian wave packet, and its propagation is calculated numerically using Crank-Nicholson integration. It is found that, in addition to reflecting and transmitting, the molecule may also straddle the potential barrier in an unbound state.
We study a diatomic homonuclear molecule incident upon a potential barrier. We allow for transitions among bound states and for molecular break-up for a molecule incident upon the barrier in a bound state. We apply an elegant method to calculate probabilities of reflection and transmission, in bound and unbound states. In the numerical work, we use a binding potential that captures the important physical features of real potentials and a single delta barrier for the potential barrier. We showed that the probabilities of reflection and transmission in unbound states were small compared to the probabilities of reflection and transmission in bound states. We also found that the probabilities of reflection and transmission decrease for large kinetic energies. For a molecule with only one bound state, it was shown, using two different binding potentials, that the probabilities of reflection and transmission in unbound states were also small. We showed that an arbitrarily weakly-bound molecule will break up upon encountering a barrier. We also discussed a shortcoming of the results and possible resolutions. Suggestions for further studies were also presented.--P.ii.
