Nano Bugle

A window into applied science supported by INL

Follow the light in the discovery of the wonders of nano

Ellipsometry is a versatile, non-destructive technique that works in real time in any transparent medium, based on the fact that when light is reflected from a surface of a material its polarization state undergoes some change depending on its own characteristics.

The word ellipsometry was first introduced in a scientific publication by Alexander Rother in 1945, and is based on the fact that the polarization of the light is generally elliptical. In the last years of the XIX century, Paul Drude derived the mathematical equations that allowed the calculation of the optical constants. In the 60’s, due to the availability of computers for numeric processing, ellipsometry suffered a renaissance. Besides measuring the thickness of a film of few nanometers or its optical constants, today, ellipsometry finds applications in different areas like semiconductor and data storage solutions, biosensors, optical coatings, microelectronics, surface chemistry.

The one recently acquired by INL is a spectroscopic imaging ellipsometer. With spectroscopy it is possible to know the optical constants as a function of the wavelength of light, enlightening to greater detail the secrets of complex materials. The imaging feature enables, for example, analyzing biochips without any labeling of the probes, an advantage when compared with techniques based on fluorescence or radioactivity. It is thus possible to examine the surface structure of, for instance DNA, on substrates like glass, silicon or gold with high spatial resolution and also in real-time to measure adsorption reactions by using diverse solid-liquid cells for in vitro conditions.

Follow the light in the discovery of the wonders of nano and be amazed with the beauty!

The photos show INL Engineer, Adelaide Carvalho, the author of this post, monitoring ellipsometry tests. The spectroscopic imaging ellipsometer, recently acquired by INL. Testing the equipment has been her main concern for the last couple of months.

December 20, 2010 Posted by | INL Campus, INL Community, INL Project | 1 Comment