Rotary Drag Research Articles

Role of quantum-coherence dressed states on the Fresnel–Fizeau drag and optical properties of surface plasmon polaritons through asymmetric double quantum dot-metallic plasmonic interfaces

Owing to the exceptional structural-design flexibility and tunability of physical properties of quantum dots, the manipulation of light in view of surface plasmons via dots–based hybrid nanostructures and dots-metallic interfaces finds promising device applications. Hereby, we first demonstrate theoretically the role of intense laser-excited dressed states on the light propagation, optical properties, and lateral and rotary drag of surface plasmon polaritons (SPPs), via plasmon-assisted induced transparency (PIT). For this, we employed a scheme of plasmonic interface comprising an asymmetric double quantum dot molecule GaAs/AlGaAs in the Λ − type configuration embedded in gold metallic surface. In particular, using density-matrix formulation, we present a detailed analytical solution of the quantum dot system for the required eigenvalues in view of the dressed eigenstates. The dressed states played a vital role in the formation of PIT transparency and hence the manipulation of SPPs propagation, optical properties and SPPs drag, via quantum interference. The calculated theoretical results on the optical properties such as absorption and dispersion spectrum, group index, group velocity, group delay, phase delay, wave vector, propagation length and SPPs drag are further elaborated with aid of numerical simulation. The maximum calculated lateral and rotary SPPs drag was of order ± 6.0 × 10−8 m or rad, respectively. The value of SPPs propagation lengths calculated along and perpendicular to the dot-metallic interface are 3.3 × 10−7 m and 2.0 × 10−9 m, respectively.

Comment on “Gain-assisted superluminal propagation and rotary drag of photon and surface plasmon polaritons”

In their study of superluminal propagation, rotary drag and surface polaritons [Phys. Rev. A 96, 013848 and 049906(E) (2017)], Khan et al. consider a four-level atomic arrangement with transitions in the optical domain. In fact, the values they give to the parameters lead to a probe wavelength lying in the decimeter band and we point out that, in such conditions, all their results are irrelevant.

Reply to “Comment on ‘Gain-assisted superluminal propagation and rotary drag of photon and surface plasmon polaritons”'

Hereby, we amend several spectral parameters reported in our earlier work [N. Khan et al., Phys. Rev. A 96, 013848 (2017); Phys. Rev. A 96, 049906(E) (2017)], which led to unphysical predictions to be tested experimentally. In particular, the resulting probe wavelength was in the decimeter band, as pointed out in a Comment by Macke and S\'egard [B. Macke and B. S\'egard, preceding Comment, Phys. Rev. A 99, 057801 (2019)]. After incorporating the corrected parameters, the predictions of our theoretical demonstration on the gain-assisted superluminal propagation and rotary drag of photon and that of surface plasmon polaritons are improved to a good degree of accuracy and expected to be tested realistically. In particular, even the minimum values of rotary drag for both photon and surface plasmon polaritons are on the order of few microradians, thus falling within the range of experimental testability.

The mechanics of bolt drilling and theoretical analysis of drilling parameter effects on respirable dust generation

The respirable dust generated during bolt-hole drilling can present serious health problems to the miners involved in roof drilling operations. A proactive dust control approach, different from the conventional passive approaches, is proposed. Laboratory experiments have been conducted to validate the dust reduction effects of the approach. A mechanical model has been developed to simulate the rotary drag bits drilling process under different cutter conditions. The functions of the area of the total friction, drilling power, and specific energy are all presented in the model. According to this model, drilling bite depth and bit wear condition were identified as key factors influencing the respirable dust generation and energy consumption. The relationships among drilling specific energy, airborne dust concentrations of respirable and larger (1–100 μm) particles, and drilling bite depth were established. It was found that by achieving a low specific energy with a proper drilling bite depth and by avoiding worn bit use, a significant reduction of quartz-rich respirable dust from its generation source could be achieved. Once validated, the mechanical model can be used for roof bolter drilling optimization and automation control.

Erratum: Gain-assisted superluminal propagation and rotary drag of photon and surface plasmon polaritons [Phys. Rev. A 96 , 013848 (2017)

Received 24 September 2017DOI:https://doi.org/10.1103/PhysRevA.96.049906©2017 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasCoherent controlEffects of atomic coherence on light propagationLight-matter interactionNonlinear opticsOptical coherenceQuantum opticsNonlinear DynamicsAtomic, Molecular & Optical

Gain-assisted superluminal propagation and rotary drag of photon and surface plasmon polaritons

Superluminal propagation of light is a well-established phenomenon and has motivated immense research interest that has led to state-of-the-art knowledge and potential applications in the emerging technology of quantum optics and photonics. This study presents a theoretical analysis of the gain-assisted superluminal light propagation in a four-level $N$-type atomic system by exploiting the scheme of electromagnetically induced gain and superluminal propagation of surface plasmon polaritons (SPPs) along the gain-assisted atomic-metal interface simultaneously. In addition, a theoretical demonstration is presented on the comparison between Fresnel's rotary photon drag and SPP drag in view of light polarization state rotation by rotating the coherent atomic medium and the atomic-metal interface, respectively. Analogous to photon drag in the superluminal anomalous dispersion region where light polarization rotation occurs opposite the rotation of the gain-assisted atomic medium, the rotation of the atomic-metal interface also rotates the polarization state of SPPs opposite the rotation of the interface. This further confirms the superluminal nature of SPPs propagating along the interface with negative group velocity. Rabi frequencies of the control and pump fields considerably modify both photon and SPP drag coefficients. Metal conductivity also controls SPP propagation.

Influence of assembly conditions on the static load capacity of thrust ball bearings

The influence of the assembly conditions on the rotary drag torque and static load capacity of thrust ball bearings is studied experimentally. It is found that the ball parameters and the ratio of the ball radius and the raceway radius affect the drag torque and static load capacity of the bearings. Optimal bearing geometry is established.

Interface laws for impregnated diamond tools for a given state of wear

Impregnated diamond bit has emerged as one of the most commonly used types in the extraction of underground resources in hard and abrasive formations. Despite the success and its frequent use, the drilling performance of these bits is still quite volatile and inconsistent due to a lack of fundamental understanding of the mechanisms governing the bit/rock interface. Impregnated diamond bits are rotary drag bits, in which the cutters also called segments or crowns are comprised of sintered metal powder with diamonds (natural or synthetic) uniformly distributed throughout its volume. The diamonds, which are exposed at the bit surface, are responsible for cutting away rock while the matrix provides the necessary bonds to retain the diamonds during their cutting life. Focusing our attention to evaluate performance of impregnated diamond bit, it is absolutely essential to establish interface laws, and also to establish a distinction between “topologically-invariant” and “topologically-variant” responses. Initially, specific laboratory tests are conduced with single segments and a procedure to identify topologically-invariant cutting response proposed. Interface laws for a segment are then derived, assuming that the cutting response is composed of two independent processes, pure cutting process and frictional contact or rubbing; and the rubbing process is composed by losses generated at both contact surfaces: diamond wear flat areas and matrix bearing surface. Next, impregnated diamond bit responses are investigated and the interface laws obtained, using the same logic established for segments. Finally, the parameters of the model are identified through an extensive series of laboratory tests.

Comment on ‘Evidence of slow-light effects from rotary drag of structured beams’

The paper Wisniewski-Barker E et al (2013 New J. Phys. 15 083020) is intended to distinguish experimentally between two mechanisms of pulse delay in ruby and to provide evidence in favor of the slow-light model. The proposed test is based on the idea of monitoring time delay of a ‘dark pulse’ or ‘intensity null’, rather than that of some Gaussian-like pulse. We show that, because of certain experimental inconsistencies, the results of the measurements do not allow one to prefer one of the models and, thus, are interpreted inadequately. In this comment, we propose and realize a simple modification of the experiment Wisniewski-Barker E et al (2013 New J. Phys. 15 083020), which allows us to unambiguously resolve this dilemma. We show that the effect of pulse delay in ruby is perfectly described by the simple model of pulse reshaping and does not require invoking the coherent population oscillation-based slow-light effects.

Evidence of slow-light effects from rotary drag of structured beams

Self-pumped slow light, typically observed within laser gain media, is created by an intense pump field. By observing the rotation of a structured laser beam upon transmission through a spinning ruby window, we show that the slowing effect applies equally to both the dark and bright regions of the incident beam. This result is incompatible with slow-light models based on simple pulse-reshaping arising from optical bleaching. Instead, the slow-light effect arises from the long upper-state lifetime of the ruby and a saturation of the absorption, from which the Kramers–Kronig relation gives a highly dispersive phase index and a correspondingly high group index.

A study of bit-wear in rotary drag drilling : Singh, DP Univ. Melbourne, Aus 8F, 1T. Austral. Min. V65, N1, 1973, P17–20

A study of bit-wear in rotary drag drilling : Singh, DP Univ. Melbourne, Aus 8F, 1T. Austral. Min. V65, N1, 1973, P17–20