A compelling way to demonstrate the differences in diffraction patterns by changing the wavelength.
Interference for Different Colors Experiment
This experiment uses the Green Diode Laser and the Red Diode Laser in the Sensor-based Diffraction Kit to demonstrate the differences in the interference patterns caused by changing the wavelength.
At right is the scan of the pattern produced by passing a red laser beam through a double slit. Below that scan is the pattern produced by passing a green laser beam through the same double slit. Note that the green laser light (wavelength = 532 nm) is diffracted to a smaller angle than the red laser light (wavelength = 650 nm).
At bottom right are actual pictures of the interference patterns corresponding to the above scan. Students will be able to clearly visualize the differences caused by changing wavelengths.
Graph and actual photo of red and green laser interference patterns, clearly illustrating the green laser light is diffracted to a smaller angle than red.
The PASCO Solution
PASCO introduces its new Green Diode Laser to expand the capabilities of our Sensor-Based Diffraction Kit. Together with the Red Diode Laser in the Diffraction Kit plus your choice of ScienceWorkshop or PASPORT electronic measurement systems, you have the solution for taking your interference investigations the next big step.
Solution at a Glance
Sensor-Based Diffraction System (OS-8452)
Green Diode Laser (OS-8458)
This solution also requires software and an interface or a standalone datalogger. For more information or to order products separately, see below.
Better than a laser pointer
Unlike a laser pointer, this green diode laser plugs into the wall, so there is no worry about batteries going dead during lab.
While most green laser pointers are 5 mW, we designed this one to be less than 1 mW so it is safer for classroom use.
Easy laser alignment
The laser is mounted at the correct height to match other components on the optics bench in the PASCO Basic Optics System. Alignment of the beam through the slits is made easy by the adjustment screws on the back of the laser. The beam can be aimed through the slits using these two thumb screws. Once the beam is aligned, either the laser or the slits can be removed from the optics bench are returned to the bench without re-aligning the beam.
PASCO's unique diffraction pattern scanning system
The Sensor-based Diffraction Kit (OS-8452) make sensors an integral part of the optics bench, allowing the diffraction patterns to be scanned into the Xplorer GLX or any computer equipped with a PASCO interface.
Light intensity patterns are scanned into the computer in real time
In this unique scanning system, the diffraction pattern is scanned using a light sensor attached to a Rotary Motion Sensor. As the wheel on the Rotary Motion Sensor is rotated by hand, the Rotary Motion Sensor moves along a gear rack (called the Linear Translator). Students make the association between the diffraction pattern they see and the real-time graph of the light intensity versus position.
Change slits in the dark without re-aligning everything
The slit wheels eliminate the frustration of trying to change the slits in a darkened room. To change the slit being illuminated by the laser, the slit wheel is simply rotated to the next positive click to lock another slit into position. The alignment of the disk only has to be done once; thereafter all the slits on that wheel will be in alignment.