Relative optical interference intensity method

The Relative Optical Interference Intensity Method presented in Section 2.2 was hrst developed by Professor Luo (one of the authors of this book) and his colleagues in 1994 [4,5], for measuring the nanoscale lubricant him thickness. 

As described in the article on the theory of surface plasmon resonance, surface plasmons create a surface-bound evanescent electromagnetic wave which propagates along the surface of an active medium (usually a thin metallic film), with the electric field intensity maximized at this surface and diminishing exponentially on both sides of the interface. As a consequence of this property, the phenomenon has been utilized extensively in studies of surfaces and of thin dielectric films deposited on the active medium. Although numerous other optical techniques have also been applied to such systems (e.g. ellipsometry, interferometry, spectrophotometry, and microscopy the surface plasmon resonance (SPR) method has some important advantages over all other optical techniques, as follows. The method utilizes a relatively simple optical system, it has a superior sensitivity, and the complete system of measurement is located on the side of the apparatus that is remote from the sample, and thus there is no optical interference from the bulk medium. Furthermore, the surfaces of the sample need no extra treatment to increase... 

In order to produce surface-relief electro-optic gratings, Munakata et compared two fabrication methods of SRG inscription. In the first, the SRG was produced with an interference pattern of cw laser, with relatively modest intensities. The gratings so recorded were photo- and thermally erasable, and efficient writing was polarization dependent. In the second method, a phase mask was employed to provide the periodic intensity modulation of a pulsed laser, the 3rd-order harmonic (at 355 nm) of a Nd YAG laser. The SRG was produced with a single laser pulse, allowing a very short fabrication time (less than Is). The direshold for ablation was 500 mj/(em pulse), and the amplitude of the SRG increased with pulse energy. A depth of up to 300 rim could be achieved, leading to a smooth but not sinusoidal surface modulation. 

The Metoclopramide hydrochloride concentration was determined by the optical sensor europium doped in the sol-gel matrix. The absorption and emission spectra of Metoclopramide hydrochloride and Europium were measured in sol-gel matrix. The method depends on the enhancement of the intensity of the emission spectrum of Eu doped in sol-gel especially at 617 nm band. The mechanism depends on the energy transfer from triplet energy state of Metoclopramide hydrochloride to the excited energy state of Eu. In comparison with other spectrofluorimetric techniques, this method is simple, relatively interference free from coexisting substances and can successfully be applied to the determination of Metoclopramide hydrochloride in pharmaceutical preparations and in serum samples the data are summarized in Table 14.3 [53]. 

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