Laser Beams

Abstract

The fog machine makes the beam visible.
The fog machine makes the beam visible.

A laser beam is made visible by the mist from a fog machine

Portable

Yes

Principles Illustrated

Laser beams are coherent light that is nearly monochromatic. They do spread out with distance (contrary to popular perception) but the spreading angle is very small.

NCEA & Science Curriculum

JNR SCI, SCI 1.3, SCI 2.9, PHYS 1.4, PHYS 2.3

Instructions

We have lots of lasers and quite a few laser-related demos such as TIR in a water stream and others. The best approach is a laser show of which this is one component. Contact us to arrange a suitable laser show. During a visit to Victoria University we can sometimes arrange for students to see the huge research lasers in one of the MacDiarmid labs. This will need to be arranged in advance. We also have disassembled He-Ne lasers that students can look at.

Safety

One of our He-Ne lasers
One of our He-Ne lasers

Lasers have been in the news quite a lot lately. One can purchase really quite dangerous lasers on the internet. Be sure your laser is low power and safe, and be very careful with it.

Individual teachers are responsible for safety in their own classes. Even familiar demonstrations should be practised and safety-checked by individual teachers before they are used in a classroom.

Related Resources

Whiteboard Optics

Notes

A laser in operation in the Raman Spectroscopy lab at Victoria University
A laser in operation in the Raman Spectroscopy lab at Victoria University

LASER is an acronym that stands for Light Amplification by Stimulated Emission of Radiation. Stimulated emission, in which a suitable photon interacts with an atom in an excited state, results in the production of a pair of essentially identical photons. To make a laser beam, you have to get the majority of atoms that produce the laser beam in the same excited state. This is called a population inversion and it is not easy to achieve.

Teaching Resources

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Credits

This teaching resource was developed with support from

The MacDiarmid Institute
Faculty of Science, Victoria University of Wellington
School of Chemical and Physical Sciences, Victoria University of Wellington

Copyright

Copyright and fair use statement