Value Of Incident Power Research Articles

The Influence of Incident Power on the Magnetic Fluid Sensor Sensitivity Based on Optical Transmission Properties

Sensitivity is a critical characteristic of sensors, and increasing the sensitivity of the sensor is valuable for measurement study. Incident power has an important influence on the sensitivity of magnetic fluid sensors based on optical transmission properties. Variation in the magnetic field sensitivity at different incident powers was investigated by the measurement of transmitted power through the magnetic fluid sensors. As the magnetic field strength increases, the sensitivity variation of the magnetic fluid film sensor can be divided into four stages: first decreasing sharply, secondly increasing, then decreasing gradually, and finally tending toward a small stable value. The magnitudes of the change in the sensor sensitivity are influenced by the incident power, because the structural pattern of the nano-magnetic particles in the magnetic fluid sensor changes, the Soret effect and the Photonic Hall effect co-define the sensing system. In the weak magnetic field range, when a higher sensitivity is required, it is appropriate to select a larger incident power; however, in a large magnetic field range, when a higher sensitivity is required, a small incident power should be selected. Therefore, the magnetic fluid film sensor exhibits different sensitivity characteristics if different incident power values are chosen. The appropriate incident power can be selected according to the range of the magnetic field to be measured to improve the sensitivity in the magnetic field measurement study.

Incident-power-dependent optical transmission properties of magnetic fluid films

Incident power has an important effect on the optical transmission properties of magnetic fluids. Difference in the effect of the incident power on the optical transmission properties with and without an applied magnetic field was investigated by measuring the transmitted power of the incident light through the magnetic fluid film. In the absence of an applied magnetic field, an approximately linear relationship exists between the incident power and the transmitted power of magnetic fluid films, but the relationship is nonlinear when a magnetic field is applied. Moreover, variation in the optical transmission properties under a magnetic field with various incident powers was measured in experiment. As the magnetic field is enhanced, the transmitted power of the magnetic fluid film first decreases, then increases, and finally reaches saturation. The magnitude of the change in the transmitted power, and the magnetic field range correspond to decreases, increases and saturation are related to the incident power. Therefore, for the sensing applications, depending on the measuring range of the magnetic field and the required variation range of the transmitted power, magnetic fluid film sensors exhibit different characteristics if different incident power values are selected.

Surface morphology of refractive-index waveguide gratings fabricated in polymer films

The characteristic modifications are reported on the surface of polymeric waveguide film in the process of volume- grating fabrication. The light from a mode-locked 76 MHz femtosecond laser with pulse duration of 200 fs and wavelength of 800 nm is focused normal to the surface of the sample. The surface morphology modifications are ascribed to a fact that surface swelling occurs during the process. Periodic micro-structure is inscribed with increasing incident power. The laser-induced swelling threshold on the grating, which is higher than that of two-photon initiated photo-polymerization (TPIP) (8 mW), is verified to be about 20 mW. It is feasible to enhance the surface smoothness of integrated optics devices for further encapsulation. The variation of modulation depth is studied for different values of incident power and scan spacing. Ablation accompanied with surface swelling appears when the power is higher. By optimizing the laser carving parameters, highly efficient grating devices can be fabricated.

Assessment of the population of neutral and singly ionized zinc species in argon and argon—nitrogen inductively coupled plasma by atomic absorption spectrometry

Atomic absorption measurements were used to determine the relative number densities of both zinc atoms and ions in an inductively coupled plasma (ICP). Variations in the absorbance obtained with the zinc atomic and ionic resonance lines reflect the dynamic equilibrium between the number of atoms and ions in the plasma. Absorbance changes as a function of the carrier gas flow-rate were investigated at several incident power values. Ionization is drastically reduced at higher carrier gas flow-rates. Measurements at different observation heights were carried out with widely differing flow-rates of the carrier gas. The results obtained for the tail plume zone are different from those for other zones of the ICP. The characteristics of the ICP using argon-nitrogen mixed gas instead of argon alone were also examined by atomic absorption spectrometry.

Formation of AlxGa1-xAs Alloy on the Semi-Insulating GaAs Substrate by Laser Bean Interaction

ABSTRACTAlxGal-xAs alloy was obtained on semi-insulating GaAs by laser beam interaction. For this purpose, thin layers (~150 A) of AlAs and GaAs were deposited by MICVD on the semi-insulating undoped GaAs substrate and irradiated with a high power laser beam. For a certain critical value of incident power (7.1 watts/mm2), a layer of AlxGal-xAs alloy was formed. The nature of the alloy was examined by Auger and Far infrared reflectance spectroscopy. The later technique reveals the characteristic mode of AlxGal-xAs confirming its formation. Disorder induced LA mode was also observed.

Analysis of Temperature and Stress Profiles Induced by a cw Line Scanned Electron Beam in <100> Oriented Silicon

ABSTRACTEvaluation of thermal profiles along the scan direction of a line shaped e-beam as well as the topographic distribution of the thermally induced stresses have been performed by solving the heat diffusion equation for several incident power values. The resulting stresses have been computed in the “nearly isotropic” approximation but taking into account that the slip planes, in <100> oriented silicon crystals, are{lll} and the slip directions in the plane are <110>.The threshold of damage introduction has been evaluated by comparing the computed stresses with the yield stress of the material at any annealing temperature. Experimental observations based on X-Ray topography have been performed in order to study the damage introduction on <100> silicon samples annealed in the same conditions used for stress computation. A very good agreement between computed and experimental results was found.