Optical properties diffraction gratings

Finally, further research effort is worth being made on materials for recording optically switchable diffraction gratings. Optical control of optical properties, such as the diffraetion, is not only academic curiosity but required for the... 

A grating ruled on a spherical surface combines the properties of the diffraction grating with the focusing ability of the optical surface. Such a device, with radius of curvature R, focuses spectra as images of the entrance (primaiy) slit on the circumference of a circle of diameter R, when the entrance slit is also located on the circumference of the circle.z... 

In order to study the optical properties of microstructures it is helpful to crmsider periodic structures (Fig. 1). Periodic surface-relief structures are called diffraction gratings in an optical context. By regularly repeating a surface-relief in one or two directions one-dimensional (ID) or two-dimensi(Mial (2D) surface-relief gratings are formed. The spacing between the repeated structures is called period A. Because of the periodic structure the incident radiation is diffracted into diffraction orders... 

Fig. 1 The period-to-wavelength ratio defines the optical properties of a diffraction grating (a)...

The method of manipulating these ultrathin trilayer solid-fluid-solid films is likely to depend on the final application of the film. These films could find application as a method of testing the mechanical properties of the thin solid layers [12, 38]. Furthermore, the creation of regular corrugated structures could lead to optical applications, such as diffraction grating or optical sensors [12]. However, the unique feature of these ultrathin solid-fluid-solid films (over other thin-film systems) is the final structures that consist of isolated pockets of fluid. It would, therefore, be highly desirable to exhibit some control over these pockets and guide the structures to form ordered channels of fluid. 

As seen from the grating equation, the actual ratio Xq/A required for zero-order diffraction only depends on the refractive indices and the angle of incidence. If only zero-order diffraction occurs, the inhomogeneous region II can be regarded as an effective medium with homogeneous optical properties. 

The main objective of a monochromator is to divide and transmit a narrow portion of the optical signal that has been selected from a vrider range of wavelengths available at the input. In its simplest form, the monochromator is composed of two slits (entrance and exit) and a dispersion element (prism or diffraction grating). The main purpose of the entrance slit is to define the geometric properties... 

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