We shined our laser light through a pinhole which had a diameter of 1.1 mm.  You can see in PH#1 our image.  Notice that it isn't a perfect circle and shows a little sign of our collimator.

Image PH#1


Image PH#2                                                                        Image PH#3

You can see in our plot profile that the intensity of the pinhole image isn't that round nor does it have sharp edges.  It is a point as you would expect from a pinhole.  In PH#3 you can see a distinct horizontal line that should have appeared in our Fraunhofer plane, yet comparing it to PH#4, you that that isn't the case.  Our explanation for this is due to the almost vertical nature of the image (you can see a flat line on either side on the image).  However if you look at the middle of the FFT then you see concentric circles, not alternating light and dark spots.  This FFT is the Bessel function.

Image PH#4

This isn't the best picture to be taken, and you can't see the concentric circles of the Bessel function due to the brightness of light.  There seems to be a flare or aura around a bright center, in which might lie those elusive rings.

Pinhole with Center Blocked at the Fraunhofer Plane

Image PH#5


Image PH#6                                                                        Image PH#7

Here is one of the better pictures we were able to take.  In PH#5 you can see a hollow circle as our image, after we blocked the middle of PH#4.  You can compare PH#7 to PH#4 and see a dampened intensity in the middle of the FFT and the absence of the horizontal arms.  When we blocked the center light we used a thin vertical strip of paper.  Therefore we also would have blocked a little of the top and bottom of the Fraunhofer plane, which would have also prevented horizontal information in the image (note how PH#5 is much more round).  So in working backwards using ImageJ (see Single Slit for reference of this program) their FFT would show that we blocked horizontal arms as well.

Pinhole with Horizontal Sides Blocked at the Fraunhofer Plane

Image PH#8


Image PH#9                                                                        Image PH#10

In this case we only blocked the horizontal arms of PH#4.  As mentioned above when the horizontal arms are blocked then vertical information in the image is lost, squishing the pinhole.  The FFT in PH#10 show that all the information for PH#8 would have to be in the vertical direction since the image is along the horizontal direction.  Compare the plot profile in PH#9 to that in PH#2 and see how much more rounded the intensity has become.

Pinhole with Vertical Sides Blocked at the Fraunhofer Plane

Image PH#11


Image PH#12                                                                        Image PH#13

In the last altercation we rotated the cards and blocked the top and bottom of PH#4.  This was much harder to do and our Fraunhoffer plane, shown in PH#13, doesn't look like PH#10 rotated ninety degrees as you would expect.  However since we blocked information in the vertical part of the Fraunhofer plane then the resultant image, in PH#11, appears to be squeezed in from the sides.  The plot profile shows this squeezing by showing sharper edges on the sides and yet still the point in the middle just like in PH#2.