This thesis presents a method for detection of material properties such as refractive index, permittivity and conductivity of a remote object by using laser beams. The method is demonstrated for planar dielectric media in which properties of reflected and refracted wave information is known via Snell’s law. The reflection coefficient of
a laser beam on an object is shown to depend on the angle of incidence, the beam frequency and material constants such as electrical permittivity and conductivity. By measuring the intensities of the incident and the reflected waves, reflection coefficients are determined. The reflection coefficient is then used to calculate the refractive index of the material at an accurate level. By varying the parameters such as the angle of incidence and the beam frequency, non-linear complex polynomial equations are
obtained which are solved to estimate the unknown conductivity and permittivity of the medium.
The results are generalized and applied to rough surfaces which are referred to as diffuse media. In this case, only partial information of the reflected field can be obtained. This partial information yields a scaling factor ‘s’, which we have termed as the diffuse parameter. Finally, by constructing appropriate numbers of nonlinear
equations, the permittivity, the conductivity and the diffuse parameter are determined.
The estimation of the material properties, made from the proposed method,are verified through experimental results. To achieve this, a series of experiments are carried out in which the angle of incidence is changed with fixed frequency of the incident wave and vice versa. Low power laser sources with wavelengths typically
between 400 and 900 nm are used for these applications. Refractive index, electrical permittivity and conductivity of an aluminium sheet are measured through the experiment. The experimental results and the theoretical results are observed to vary by less than 10%. This work realized successfully that optical and electrical properties of materials can be calculated directly through laser applications.