Experimental Measurement And Study Of The Electricmegnatic Wave Propagetd At The Metal/media Interface In The Visible Range

It was since the 17^th century, Snell law had been established as one of the most fundamental princples in optics. However, determination of an angle of refraction for a ray passing through a boundary between transparent and stronglyoptically-absorbing media is still quite difficult. In this case, the refractive index (?) of the absorbing medium is complex, so the angle of refraction is complex too. The Snell law of refraction is:n₁,sinα=(?) sin(?), where a andβis the angle of incidenceand refraction, respectively.The complex angle only has the mathematical meaning and the actual physical path of the light propagated at the interface should be a real number.Therefore, in this work, the hard effort has been made to measure the effective value of the refractive angleβafter the ray passing through the absorbing-media/air interface. Afterwards, the effective refractive index n₂ is reduced to obtain therelationship in the frame of the conventional Snell law, and to make the Snell law be more properly applied in all conditions.The earliest work studied on this problem was described in the paper of Kudykina et al[1]. In the later time, some equations were developed to deal with the law of refraction for the absorbing medium. Quite different results [2] can be obtained by replacing the real refractive index n with n→n(1+ik) to obtain the angle ofβand the effective refractive index according to the equations given by Born and Wolf. These problems have been discussed in the research of this work.In terms of the study of the most fundamental and interesting problem in optics, the result given in this work has the practical and significant meaning to help people understand more about the Snell's law based on the phenomena of the light transmitting through the interface consisting of two different media in wider physical conditions.This work will stimulate the effort to study those problems more deeply in the future. Some related research topics (negative refractive [4-7], LHM materials [8-10], optical crystal material [11-13], SRR, surface plasma [14-15] and so on) have become the hottest research issues in recent years with the paper often reported on the world-class journals like Nautre, Science, Physical Review Letters and so on. With intensive experimental and theoretical research works being carried out by many groups around the world, the final answer to these hard core optical problems and myth will be reached hoipefully soon in the near future.In summary, by using a way to mutiply extend the light path and making a series of samples with different weldged angles, the refractive angles of the light transmitted through the metal/air interface have been measured successfully. The Au/air interface was measured at first. By improving the experiment conditions and and methods, more data for both of Au/air and Ag/air interface were systematically measured with higher presicion. At last, some simulations based on the models and equations given by previous works were made to explore the origin of the effect with the conclusion given at last in the paper.