Total embedding distributions of Ringel ladders

The total embedding distributions of a graph is consisted of the orientable embeddings and non- orientable embeddings and have been know for few classes of graphs. The genus distribution of Ringel ladders is determined in [Discrete Mathematics 216 (2000) 235-252] by E.H. Tesar. In this paper, the explicit formula for non-orientable embeddings of Ringel ladders is obtained

Fourier finite element modeling of light emission in waveguides: 2.5-dimensional FEM approach

We present a Fourier finite element modeling of light emission of dipolar emitters coupled to infinitely long waveguides. Due to the translational symmetry, the three-dimensional (3D) coupled waveguide-emitter system can be decomposed into a series of independent 2D problems (2.5D), which reduces the computational cost. Moreover, the reduced 2D problems can be extremely accurate, compared to its 3D counterpart. Our method can precisely quantify the total emission rates, as well as the fraction of emission rates into different modal channels for waveguides with arbitrary cross-sections. We compare our method with dyadic Green's function for the light emission in single mode metallic nanowire, which yields an excellent agreement. This method is applied in multi-mode waveguides, as well as multi-core waveguides. We further show that our method has the full capability of including dipole orientations, as illustrated via a rotating dipole, which leads to unidirectional excitation of guide modes. The 2.5D Finite Element Method (FEM) approach proposed here can be applied for various waveguides, thus it is useful to interface single-photon single-emitter in nano-structures, as well as for other scenarios involving coupled waveguide-emitters.Comment: 11 pages, 4 figures, Optics Express, 201

Hong-Ou-Mandel interferometry on a biphoton beat note

Hong-Ou-Mandel interference, the fact that identical photons that arrive simultaneously on different input ports of a beam splitter bunch into a common output port, can be used to measure optical delays between different paths. It is generally assumed that great precision in the measurement requires that photons contain many frequencies, i.e., a large bandwidth. Here we challenge this well-known assumption and show that the use of two well-separated frequencies embedded in a quantum entangled state (discrete color entanglement) suffices to achieve great precision. We determine optimum working points using a Fisher Information analysis and demonstrate the experimental feasibility of this approach by detecting thermally-induced delays in an optical fiber. These results may significantly facilitate the use of quantum interference for quantum sensing, by avoiding some stringent conditions such as the requirement for large bandwidth signals

A Colour Design Tool Based on Empirical Studies

A colour design tool targeted at both unskilled consumers and professional designers is currently under development, on the basis of psychophysical studies into semantic associations of colour, the cultural influences and colour harmony. From experimental results for single-colour associations, 3 underlying factors were identified: “warm-cool”, “heavy-light” and “active-passive”, which were found to agree well with those identified by earlier research. For colour-combination associations, an “additive property” of colour association was discovered: the semantic score of a colour combination can be determined by averaging semantic scores of each constituent colour in that combination. According to the experimental results, there were 4 general patterns of colour harmony: similarity in hue and chroma, difference in lightness, high lightness and the hue effects. While the proposed colour design tool is still in its development stage and has a number of shortcomings, the system is believed to provide practical assistance and support not only for unskilled users but also for designers. Keywords: colour design; colour harmony; colour association; cross-cultural study; e-shopping; colour decision-making; design process; psychophysical method</p

Colour Design for Carton-Packed Fruit Juice Packages

The present research studies the relationships between observers’ expectations for 7 fruit juice packages and the colour design of the package. To do this, a two-stage experiment was conducted. At the first stage, we studied perceived colours for the fruit images shown on each package. At the second stage, fruit juice packages with 20 package colours were rated using 5 bipolar scales: colour harmony, preference, freshness, naturalness and product quality. The experimental results show that the observers tended to perceive fruit image colours lighter and more saturated than those measured using colour measuring instruments. Using factor analyses, we classified the 5 bipolar scales into 2 factors: Product Preference and Freshness. Package colour design was found to have significant impacts on both factors: similarity in chroma and hue between package colour and perceived fruit colour would lead to high product expectations. Keywords: colour design; colour harmony; product expectation; perceived image colour</p