Optical assembly of far-field super-resolution imaging via optical gain

The performance of an optical imaging system is fundamentally limited by the wave nature of light. More specifically the lateral resolution of an image has traditionally been dictated by Abbe's limit, to be approximately one-half of the wavelength. The pursuit of exceeding this limit is a growing interest in several research areas. The goal of these pursuits is to achieve super-resolution imaging, as in breaking what have long been thought of as insurmountable restrictions. There have been several methods proposed and demonstrated to overcome Abbe's limits. Some of the aforementioned methods include the perfect lens made from negative refractive index materials and Structured Illumination Microscopy (SIM). This paper highlights a novel approach to achieving super-resolution imaging. In this case the means to obtaining super-resolution imaging will be through optical gain by using an active objective lens. This gain will allow for the retention of spatial frequencies beyond Abbe's limit, by the conversion of evanescent waves into sustainable propagating waves. An optical assembly was constructed to verify the theory of optical gain assisted evanescent wave conversion. The experimental results show that for two specific situations, where one (Pump angle A) provides the possibility of optical gain assisted evanescent wave conversion and one (Pump angle C) does not, Pump angle A position allows for the detection of higher spatial frequency information than Pump angle C position in the far-field pattern. This confirms the hypothesis and the theory of evanescent wave conversion via optical gain, providing the potential for far-field super-resolution.