Microscopy Progress






Historically, most microscopy has been achieved by means of conventional optical microscopy. Conventional optical microscopes are unable to resolve features that are less than about 200 nm in size.


Image distortion, illustrated in the accompanying figure, occurs when images are formed conventionally. The size of each image feature is roughly the same as the size of the undistorted (ideal) image feature plus the size of the spot formed by the imaging system (lens). Such imaging, when done very well, is said to be diffraction limited. Until recently, the diffraction of light has placed a fundamental limit (the diffraction limit) on the minimum size of objects that can be observed. Resolution is seriously limited.





Non-optical microscopy techniques, such as electron microscopy and atomic force microscopy, have been used to resolve features that are less than about 200 nm in size. However, these techniques are often destructive in nature. Furthermore, some samples (such as cellular samples) require that samples be fixed in place. This fixation is unsatisfactory for many purposes.




Advances in optical microscopy have yielded increased magnification and resolution, allowing observation of ever smaller objects at ever decreasing scales. Thus, Super-Resolution Microscopy has been developed recently (during the past 20 years, approximately) to circumvent some of the adverse effects of diffraction and resolve features as small as about 20 nm. Expectations are that super-resolution microscopy will continue its downward trajectory, revealing details at ever smaller scales. In particular, technologies such as STED Far-Field Nanoscopy, STORM and PALM are thought to show great promise. Nevertheless, resolution associated with super-resolution microscopy is diffraction limited.




Mulith Inc.’s RIF-Scope is an application of the company’s proprietary RIF technology. When RIF technology is used, the bandwidth of the light used for image formation is well within the passband of the imaging system that is used. This light is transferred, without amplitude or phase distortion, through the imaging system. All components of the light needed for image formation contribute to image formation. The commonly accepted optical diffraction limit is entirely avoided when RIF is used. No fundamental resolution limit exists. Resolution is complete.






The length of the green arrow shown in the accompanying illustration is magnified by a simple lens, such as a hand-held magnifying glass. The magnification can be changed by varying the distance between the lens and the object and adjusting the distance between the lens and the eye so that a clear image forms. Changing the magnification in this manner is a common experience.





Magnification can be achieved readily and is not a significant concern. However, avoiding the optical diffraction limit is not so easily done unless RIF is used.




Mulith Inc.'s competitors include producers of super-resolution optical microscopes and non-optical microscopes, such as atomic force microscopes and electron microscopes. However, there is currently no nanoscale microscope on the market that competes well relevant to the benefits associated with Mulith Inc.'s RIF-Scope.