Lab 4 Laser - Institutt for elektronikk og telekommunikasjon - NTNU

Chapter 1
Lab exercise:
From pink light to red LASER
This lab exercise gives insight into the fundamentals of laser operation. A
HeNe-discharge tube is used and aligned with a mirror to construct a laser.
The fundamental properties of this laser are then investigated.
1.1 Laser safety
A laser can be a powerful and harmful device. It is therefore very important
that the laser is handled with outmost care and that your eyes always are
protected. Never look into the laser aperture nor into the reflected light from
the brewster window.
1.1.1 Electrical hazard
The HeNe laser is pumped with a very high voltage: 1900 Volts!! Therefore:
Do not touch any connectors on the HeNe discharge tube. The PSU (power
supply unit) feeds the tube with 7mA. This is enough to kill you if you touch
both wires!! Therefore, again: Do not tamper with any of the electrical wires
concerning the discharge tube!
1.1.2 Light hazard
Do NOT stare into laser light!!
This is the first and most important rule for operating lasers. A laser provides
high intensity light and may just burn a hole in your retina if you look into the
laser light.
Since the first laser was made in 1960 it has been clear that laser emissions
are a hazard to the eye and skin, more of a hazard than most other light
sources. Lasers are hazardous because they produce intense directed energy
that can damage living tissues. There are other common light sources strong
enough to cause permanent eye or skin damage, including: direct sunlight, arc
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