Sub-wavelength microscopy, imaging, and lithography

Information and Communication

Project Description

The measurement of small distances is a fundamental problem since the early days of science. It has become even more important due to recent interest in nanoscopic and mesoscopic phenomena. There is a great interest in achieving nanometer distance measurements by using optical illuminating far-field imaging. Recently, we proposed a scheme to measure the distance between two adjacent atoms by driving them with a standing wave laser field and measuring the far field resonance fluorescence spectrum. The fundamental limit in optical microscopy is the Rayleigh limit λ/2. Our method showed that inter-particle distances are in the range from λ/2 to about λ/550. Another related problem is the precision lithography. In optical lithography, the feature size in which scientists can write the circuits is limited to half the wavelength of the light due to diffraction. Many attempts have been made to advance this field beyond the current limit sat by the wavelength of the laser used. In a joint work with scientists from KACST and texas A&M we have developed a method for optical sub-wavelength lithography based on Rabi oscillations that is only a single preparation step away from the currently implemented lithographic process. This method allows, in principle, to write a pattern with an accuracy better than a millionth of the wavelength of the light used.

Despite the simplicity of our novel schemes, the experimental realization remains a challenge. The basic difficulty arises due to the fact that the suggested processes, such as Rabi oscillations, take place during the coherence time. Any incoherence will destroy the process. An experimental realization would therefore requires a detailed analysis that takes care of the loss mechanisms and other decoherenec effects in addition to finding the right kind of materials. Our thrust in the proposed project will be a study of quantum optical systems best suited to an experimental realization of sub-wavelength microscopy and lithography leading to a precision beyond what has been achieved with conventional methods. Our work will have a great impact on the field of microelectronics and optical imaging. These are among the research areas that lie at the frontiers of modern science and technology.

Team Members