Spread Out Resolution For Free

According to Rayleigh's criterion, the resolution of an optical microscope is defined as the minimum distance between two point sources such that their presence can be distinguished in the image (1).Thus Rayleigh's resolution limit is an inadequate performance criterion for current quantitative imaging techniques.

The highest angular resolutions can be achieved by arrays of telescopes called astronomical interferometers: These instruments can achieve angular resolutions of 0.001 arcsecond at optical wavelengths, and much higher resolutions at x-ray wavelengths.

To achieve the maximum (theoretical) resolution in a microscope system, each of the optical components should be of the highest NA available (taking into consideration the angular aperture). In addition, using a shorter wavelength of light to view the specimen will increase the resolution.

Be aware that the diffraction-like spreading of light is due to the limited diameter of a light beam, not the interaction with an aperture.So diffraction limits the resolution of any system having a lens or mirror. Telescopes are also limited by diffraction, because of the finite diameter D of their primary mirror.

The limit of resolution (or resolving power) is a measure of the ability of the objective lens to separate in the image adjacent details that are present in the object. It is the distance between two points in the object that are just resolved in the image.Thus an optical system cannot form a perfect image of a point.

The resolving power of a telescope can be calculated by the following formula resolving power = 11.25 seconds of bow/ d, where d is the periphery of the objective expressed in centimetres.

These resolution limitations are often referred to as the diffraction barrier, which restricts the ability of optical instruments to distinguish between two objects separated by a lateral distance less than approximately half the wavelength of light used to image the specimen.

"higher" resolution doesn't mean better, it means only bigger objects can be resolved; but we want to be able to resolve small objects, such as the angular distance between a pair of double stars. So small is better in this situation.

The resolving power of an objective lens is measured by its ability to differentiate two lines or points in an object. The greater the resolving power, the smaller the minimum distance between two lines or points that can still be distinguished. The larger the N.A., the higher the resolving power.

In order to increase the resolution (d=03bb/2 NA), the specimen must be viewed using either shorter wavelength (03bb) light or through an imaging medium with a relatively high refractive index or with optical components which have a high NA (or, indeed, a combination of all of these factors).