Optics > Interference > Two Source Interference DCS# 6D10.11 v 2
INTERFERENCE AND DIFFRACTION PATTERNS WITH A CMOS CAMERA

APPARATUS
 
optical breadboard
 015A
laser 202-21-B6
CMOS camera, attenuator, USB cable, mount
 015A
laptop with BeamView software
 206
two front surface mirrors on mounts
 015A-03-C
for single slit diffraction:
     adjustable slit
 202-21-B6
for double slit:
     Cornell plate in lens holder 202-21-B6
for pinhole:
     brass pinhole aperture (0.5 mm) in cylindrical mount
 202-21-B6
     lens holder
 202-21-E4
for Poisson bright spot:
     ball bearing on microscope slide
 202-21-E4
     filter holder
 202-21-E4
     20 mm lens
 202-21-E4
     200 mm lens
 202-21-E4

DESCRIPTION Use the laser with various apertures and obstructions to produce interference and diffraction patterns on the detector.  The software displays a two-dimensional intensity profile, and plots of I vs x and I vs y, as can be seen in the screen shot above.
NOTES
To set up the camera, use the USB cable to connect it to the laptop and launch the BeamView software.  Start with the fixed attenuator in place.  Select "play" in the software and adjust the attenuation using the fixed attenuator, and the variable attenuator knob on the side for fine control.  Keep the lens cap on the camera when not in use.

The Poisson bright spot requires a beam expander, and works best with the ball bearing in the location shown here.
         

Remove the beam expander for the pinhole.



See the single slit diffraction page for a description of the Cornell plate.