iSES - Internet School Experimental System: Remote Laboratory

Remote Experiments

Acknowledge yourselves with the experiment „Diffraction of electromagnetic radiation on microobjects“ (in our case, the microobject is a slit) found on the following link.
Make detailed measurements of the diffraction pattern intensity distribution , distance a = (2152 ± 1) mm from the slit. Make measurements for both sources of light (red laser of the wavelength λ₁ = (632 ± 10) nm and a green one with the wavelength λ₂ = (532 ± 10) nm) and for both sizes of slits.
Determine the magnitudes of both slits d . It is possible to use either positions of minima (equation (3)) or maxima (equation (4)). For determining of the corresponding angles of minima (maxima), it is necessary to measure the locations of maxima (minima) y_max,min ,taken by the photodiode as accurately as possible and then calculate the corresponding angles of minima (maxima) according to the following relation

For more accurate determination of magnitudes of the slits it is possible to use an optimalisation programme fitting the model dependence (1) by the measured points (for example using the software SigmaPlot, Origin, eventually program GNUPLOT - http://www.gnuplot.info).
Evaluate the errors of magnitudes of the slits.

Determine an error of the width of the slit, d, for example from a location of the first minimum value, for which from equation (3) is

as well as

Assuming that for small angles we are working with it is ( angles in arc units! )

it is possible to write the following expression for the slit width

and then for its error

Discuss, which of the quantities has the largest impact on a value of the error of the microobject.