Dispersion-engineered silicon nitride waveguides for mid-infrared supercontinuum generation covering the wavelength range 0.8-6.5 mu m

We numerically demonstrate the generation of a mid-infrared supercontinuum (SC) through the design of an on-chip complementary metal oxide semiconductor (CMOS) compatible 10-mm-long air-clad rectangular waveguide made using stoichiometric silicon nitride (Si 3 N 4 ) as the core and MgF 2 glass as its lower cladding. The proposed waveguide is optimized for pumping in both the anomalous and all-normal dispersion regimes. A number of waveguide geometries are optimized for pumping at 1.55 μ m with ultrashort pulses of 50-fs duration and a peak power of 5 kW. By initially keeping the thickness constant at 0.8 μ m, four different structures are engineered with varying widths between 3 μ m and 6 μ m. The largest SC spectral evolution covering a region of 0.8 μ m to beyond 6.5 μ m could be realized by a waveguide geometry with a width of 3 μ m. Numerical analysis shows that increasing width beyond 3 μ m by fixing thickness at 0.8 μ m results in a reduction of the SC extension in the long wavelength side. However, the SC spectrum can be enhanced beyond 6.5 μ m by increasing the waveguide thickness beyond 0.9 μ m with the same peak power and pump source. To the best of our knowledge, this is first time report of a broad SC spectral evolution through numerical demonstration in the mid-infrared region by the silicon nitride waveguide. In the case of all-normal dispersion pumping, a flatter SC spectra can be predicted with the same power and pump pulse but with a reduced bandwidth spanning 950–2100 nm

The effect of time manipulation on immersion in digital games

Many empirical studies look into identifying factors that influence the quality of experience in video games. In this paper, we present research into the effect of playing time and players’ perception of the time on their immersion in the game. We invited 20 participants to play a puzzle game Bejeweled 2 for 7 min. They played the game in two conditions, namely, correct time (timer was programmed to be exactly 7 min) and wrong time (the countdown was set to be for 6 min, but was presented as a 7 min timer to the player). Players’ immersion scores were measured after the game using the IEQ. The results show no significant difference in immersion scores between the two conditions and participants’ comments also revealed that they perceived no difference in playing time between the conditions. This suggests that there is a dissociation between gaming time and subjective experience of gaming. Further research is required to investigate the relationship between playing time and positive gaming experiences

Multiphoton excitations in vibrational rotational states of diatomic molecules in intense electromagnetic field

A theory is presented and a calculational procedure is outlined for evaluating transition amplitudes of multiphoton excitations of vibrational-rotational levels in diatomic molecules. This theory can be utilized in studying behavior of molecules in intense electromagnetic fields

Characteristics of FeCuAl Powder Compacts Sintered at Different Schedules

This paper presents the characteristics of FeCuAl powder compacts formed through uniaxial die compaction process and sintered at different schedules. Elemental iron, copper, and aluminum powders were blended mechanically and the blended powder mass was subsequently compacted at..

Pembinaan konstruk instrumen penilaian pasca penghunian untuk perumahan bertingkat yang dibina menggunakan kaedah Sistem Binaan Berindustri (IBS)

Post Occupancy Evaluation (POE) is an activity of the building evaluation process with a focus on quality, operational performance and satisfaction of the occupants. The POE is important to evaluate completed and occupied buildings to identify weaknesses and potential for future improvement. To date, there have been various variations of POE instruments and tools to evaluate occupied buildings. However, the POE instrument for assessing high-rise housing constructed using the industrialized building system (IBS) method has not been developed specifically. In this regard, this study aims to discuss the construction of an effective POE instrument to measure the quality and performance of high-rise housing built using the IBS method. For this purpose, the 3 round Delphi method was adapted by involving 15 experts selected based on their background and experience related to IBS. The results of a three-round Delphi study found that 33 out of all sub-constructs were dropped because of low mean scores (<4.2 in two rounds) while 75 sub-constructs were identified as final items. The results of the Delphi study also found that all 10 constructs were 1) Spatial; 2) Design and aesthetics; 3) Physical; 4) Building materials; 5) Quality of work; 6) Comfort and well-being; 7) Environment and health; 8) Maintenance; 9) Value and 10) Cost is the most significant construct for developing PPP instruments. Accordingly, an effective Post-Occupancy Assessment Instrument for measuring the quality, performance and value of a home built using the IBS method should include all of these constructs

Pulse-induced acoustoelectric vibrations in surface-gated GaAs-based quantum devices

We present the results of a numerical investigation which show the excitation of acoustoelectric modes of vibration in GaAs-based heterostructures due to sharp nano-second electric-field pulses applied across surface gates. In particular, we show that the pulses applied in quantum information processing applications are capable of exciting acoustoelectric modes of vibration including surface acoustic modes which propagate for distances greater than conventional device dimensions. We show that the pulse-induced acoustoelectric vibrations are capable of inducing significant undesired perturbations to the evolution of quantum systems.Comment: To be published in Phys. Rev.