Chirped Pulse Control of Raman Coherence in Atoms and Molecules

A novel chirped pulse control scheme is presented based on Coherent Anti-Stokes Raman Spectroscopy (C-CARS) aiming at maximizing the vibrational coherence in atoms and molecules. The scheme utilizes chirping of the three incoming pulses, the pump, the Stokes and the probe, in the four-wave mixing process of C-CARS to fulfill the adiabatic passage conditions. The derivation of the scheme is based on simplifying the four-level system into a 'super-effective' two level system via rotating wave approximation and adiabatic elimination of the excited state manifold. The robustness, spectral selectivity and adiabatic nature of C-CARS method may prove useful for sensing, imaging, and detection. It is demonstrated that the selectivity in excitation of vibrational degrees of freedom can be controlled by carefully choosing the spectral chirp rate of the pulses. The C-CARS control scheme is applied to a surrogate methanol molecule to generate an optimal anti-Stokes signal backscattered from a cloud of molecules a kilometer away. The theory is based on the solution of the coupled Maxwell-Liouville von Neumann equations and focuses on the quantum effects induced in the target molecules by the control pulse trains. The propagation effects of pulses through the medium are evaluated and the buildup of the molecular-specific anti-Stokes signal is demonstrated numerically. A deep learning technique, using Convolutional Neural Networks (CNN), is implemented to characterize the control pulses and evaluate time-dependent phase characteristics from them. The effects of decoherence induced by spontaneous decay and collisional dephasing are also examined. Additionally, we present the technique of Fractional Stimulated Raman Adiabatic Passage (F-STIRAP) and demonstrate that it can be utilized for remote detection in a multi-level system by creation of a maximally coherent superposition state

Frequency-Doubling of Femtosecond Pulses in “Thick” Nonlinear Crystals With Different Temporal and Spatial Walk-Off Parameters

We present a comparative study on frequency-doubling characteristics of femtosecond laser pulses in thick nonlinear crystals with different temporal and spatial walk-off parameters. Using single-pass second harmonic generation (SHG) of 260 fs pulses at 1064 nm from a high-average-power femtosecond Yb-fiber laser in 5-mm-long crystals of β-BaB2O4 (BBO) and BiB3O6 (BIBO), we find that for comparable values of temporal and spatial walk-off parameters in each crystal, the optimum focusing condition for SHG is more strongly influenced by spatial walk-off than temporal walk-off. It is also observed that under such conditions, the Boyd and Kleinman theory commonly used to define the optimum focusing condition for frequency-doubling of cw and long-pulse lasers is also valid for SHG of ultrafast lasers. We also investigate the effect of focusing on the spectral, temporal, and spatial characteristics of the second harmonic (SH) radiation, as well as angular acceptance bandwidth for the SHG process, under different temporal and spatial walk-off conditions in the two crystalsPeer ReviewedPostprint (author's final draft

Local existence of analytical solutions to an incompressible Lagrangian stochastic model in a periodic domain

We consider an incompressible kinetic Fokker Planck equation in the flat torus, which is a simplified version of the Lagrangian stochastic models for turbulent flows introduced by S.B. Pope in the context of computational fluid dynamics. The main difficulties in its treatment arise from a pressure type force that couples the Fokker Planck equation with a Poisson equation which strongly depends on the second order moments of the fluid velocity. In this paper we prove short time existence of analytic solutions in the one-dimensional case, for which we are able to use techniques and functional norms that have been recently introduced in the study of a related singular model.Comment: 32 page

Surface plasmon induced quantum interference at meta-material interface

In this work we investigate quantum interference in a four-level atom coupled to a negative index meta-material (NIMM) plasmonic reservoir that supports both TE and TM polarized surface plasmons (SP). This provides more options to control SP interaction with emitters and hence more control of spontaneous emission decays and spectrum. The spectrum depends critically on parameters like the reservoir parameters, mode frequency, frequency dependent electric permittivity and magnetic permeability, and the location of the atom. We report orders of magnitude enhancement in the reservoir-modified decays and spectrum compared to free space case. The rich atomic and plasmonic parameters provide a wide range of flexibility and more options to control emission spectrum that suits practical applications.Comment: 30 pages , 8 figures , research wor

A graph-based unified technique for computing and representing co-efficients over finite fields

This paper presents the generalized theory and an efficient graph-based technique for the calculation and representation of coefficients of multivariate canonic polynomials over arbitrary finite fields in any polarity. The technique presented for computing coefficients is unlike polynomial interpolation or matrix-based techniques and takes into consideration efficient graph-based forms which can be available as an existing resource during synthesis, verification, or simulation of digital systems. Techniques for optimization of the graph-based forms for representing the coefficients are also presented. The efficiency of the algorithm increases for larger fields. As a test case, the proposed technique has been applied to benchmark circuits over GF2. The experimental results show that the proposed technique can significantly speed up execution time. Finite or Galois fields, decision diagrams, coefficients, polynomials

INTERLEUKIN-18 GENE POLYMORPHISM AND SOME RISK FACTORS IN IRAQI PATIENTS WITH BREAST CANCER

Objective: Breast cancer is the most diagnosed cancer in women, which leads to death in a lot of women with breast cancer. The major risk factors associated with breast cancer risk related to family history, age, clinical history, lifestyle factors, long-period hormonal exposure, and single nucleotide polymorphisms in many genes showed possible links with breast cancer incidence risk in different people populations. Our study aimed to figure out the correlation between smoking, lodging and family history, and other factors with the risk of breast cancer.Methods: Blood sample from female patients with breast cancer and healthy individuals were collected and subjected to tetra-amplification refractory mutation system–polymerase chain reaction (T-ARMS-PCR) technique for −607 C/A mutation of an interleukin (IL-18) gene and SPSS 18 software analyzed the results statically.Results: Results showed no association between lodging and smoking with risk of breast cancer, (p>0.05), while the association between the risk and family history were obvious (p<0.05).Conclusion: The results obtained by T-ARMS-PCR technique did not show the association between −607 C/An alternation of IL-18 gene and breast cancer (p>0.05) in the individuals examined in our study.Keywords: Interleukin-18, Gene, Polymorphism, Tetra-amplification refractory mutation system–polymerase chain reaction, Mutations

Comparison of the traditional outdoor and recirculation indoor rearing systems on survival rate and growth performance of common carp (Cyprinus carpio) larvae during early development

The larvae of common carp (Cyprinus carpio L.) were studied for 6 weeks in an indoor recirculatory system (RAS) and an outdoor earthen pond to compare their effects on growth performance and survival rate. Larvae reared in outdoor earthen ponds achieved significantly higher total length, weight, weight gain, and length increments than indoor groups (P?0.05). However, the indoor recirculatory system had the highest survival rate (83±1.9%) than outdoor earthen ponds (42±3.6%) (P?0.05). The results of the present study revealed that the raising system has a significant impact on the survival and growth performance of the larvae in common carp, and the best growth performance was in the outdoor earthen ponds, while the better survival rate was recorded in the indoor recirculatory system. Therefore, to minimize mortality and maximize survival rate, it is suggested that the larvae were released after hatching into closed and controlled rearing systems before being reared into earthen ponds after starting the exogenous feeding

Thick film electronic ceramic sensors for civil structures health monitoring

Buildings, roads, bridges and structures in general suffer many kinds of damages due to overstress caused by settlements of foundations, high winds, dynamic forces, passing traffic, vibration and unexpected external loads beyond the safe design forces. The damages manifest itself by cracks, falling of plaster and render uneven roads and some time complete collapse. The cost of maintaining and fixing damages caused by the above is quite high for the building and construction industry. The same phenomenon is common to many other structures like airplanes, wind turbine and machinery in general.Structural Health Monitoring (SHM) is the engineering branch, which aims to give, at every moment during the life of a structure, a diagnosis of the "state" of the constituent materials, of the different parts of a structure. The state of the structure must remain in the domain specified in the design, although this can be altered due to usage or due to normal aging by the action of the environment, and by accidental events. By using special electronic sensors to monitor the unexpected high concentration of stresses or changes of these stresses throughout the life of the structure and pavement, reduces the cost of maintenance and repair. Historic buildings would also benefit from using such sensors to monitor the overstress in the old and frugally stones and bricks. The sensors can be embedded in the lime mortar joints and an electronic meter is used periodically to check for any unusual overstress during the life of the building.The main aim of the proposed research project is to investigate the possibility of using thick-film technology stress sensors in masonry, concrete and building materials in general to monitor overstress and instability throughout the life of the structures. The sensors could be used in brick, block, stone, and concrete and they could be mounted on the surface or embedded in the materials.There are many research studies on strain gauge devices in structural monitoring; Thick Film (TF) piezo-resistive sensors are proposed as a direct alternative to the widely used metal Foil Strain Gauges (FSG). Due to the low cost of TF sensors, their ease of use, suitability to integrate electronics on board, and to have different geometrical shapes, they could be deployed at different locations in a building, road or be distributed in arrays. This offers the continuous monitoring of stresses at any time by using a data logger on two points on the surface or by using wireless electronic transmission.In this research, new thick film screen-printed ceramic piezo-resistive sensor has been developed and characterized as discrete device for deployment on surface of a structure and embedded into the structure during building material curing or after structure erection. The sensor response on different building materials has been experimented and compared. Mechanical and electronic simulation tools were used to characterise the sensor and to choose an adequate interface electronic circuit.The experimental results of the simulated sensor and circuitry, showed the suitability of the sensor to be embedded in building materials during curing period and on erected structures. Materials used were wood, concrete, brick and plaster. In addition, the overall linearity of response of the sensors applied on building material surface was asserted which makes the technology a candidate for a more wide deployment in SHM field