Rayleigh-Criterion: The Resolution of Optical Instruments

that the Rayleigh criterion the resolution of optical instruments the Rayleigh criterion defines the maximum

resolution of an optical instrument to examine this criterion we observe the true point light

sources through a telescope if by decreasing the aperture on the resolution limit is reached we expect the points of light to blur the

experimental setup in detail the realize that point light sources we use a thin plate In this plate we drill 2 holds with a diameter of 200

micro meters at a distance of 550 micrometres these

holes are illuminated with a strong halogen lamp whose light is focused by a lens to increase the

intensity we observe this set up

from a distance of 8 meters through a telescope the who's aperture can be reduced by an iris here is a

schematic overview of the set up

during the experimental procedure 1 can

see the view through the telescope in the upper half the size of the

adjustable aperture and the

intensity distribution of the light sources along a central cut now the Epicureans gradually closed the originally clearly separable peaks get wider finally they merged together since the like efficiency gets less the sensitivity of the camera is increased continuously for a

quantitative evaluation we examine the state at the beginning of the procedure

1st both peaks can be separated easily the intensity profile of the single peaks can be described by a diffraction of bundle behind a circular hole by overlaying both diffraction patterns 1 gets the result matching the observation if the iris is closed further the light points start to blur and separating them gets harder the most interesting

point is reached when the diffraction minimum of the 1st light source coincides

with the maximum of the 2nd this is the resolution limit defined by Rayleigh the examining the state in the experimental set up 1 sees that the opening of the iris is reduced from originally 5 centimeters 2 now 1 centimeter the the well-known formula to calculate the distance of 2 points that can just be separated approximated for small angles is shown here the coefficient 1 . 2 0 2 is the location of the 1st 0 calculated analytically to verify our experiment we compare our result with this value the we compute a coefficient of 1 . 2 7 that matches the theoretical expectations within the accuracy of measurement