High resolution microscopic imaging using a phase SLM

This paper presents a technique to increase the resolution beyond the diffraction limit by the use of an off-axis illuminating beams from a phase Spatial Light Modulator (SLM). The illuminating system consists of an afocal arrangement with two lenses, the SLM placed at the front focal plane of the first lens and the specimen placed at the back focal plane of the second. In the proposed arrangement, the off-axial beams reflected from the SLM pass through exactly the same zone of the sample. Using four different tilt directions the four image frames are fused together to obtain an image of the test object with a resolution beyond the diffraction limit. The salient features of the proposed technique are that the achievable resolution may be controlled by adjusting the parameters of the illuminating system and is independent of the magnification of the microscope objective.

As the test specimen an off-the-shelf microscope objective is used and a standard microscopic resolution target is employed as the target. The experimental results presented are encouraging.