I have already explained the construction, working and wavelength of helium neon laser. Today I will explain the output, disadvantage and applications of helium neon laser.
Output: The helium neon laser output is continuous and it lies between 1mW and 50 mW for input of about 5-10 W.
Disadvantage: As internal mirrors are used in He-Ne laser to act as optical resonators, but these mirrors are usually eroded by the gas discharge and have to be replaced.
This problem is eliminated by placing two windows at the ends of the discharge tube at the Beflectrewster angle. For such windows, the light which is polarised in the plane of figure passes through without suffering any reflection loss while light with perpendicular polarisation suffers reflection. Due to use of these windows, the output laser beam is polarised.
Applications: He-Ne lasers are used in research, spectroscopy, holography, communications and weaponry.
Note: In case of any problem in this article or any other physics article, post in the comment section.
After reading this post, you will be able to answer following questions:
- What is the output of Helium Neon laser?
- Write the disadvantages of He-Ne lasers.
- Write the applications of He-Ne laser.
- Why and how light is polarised in He-Ne laser?
Reference: This article is referred from my authored book “optics and lasers” having ISBN 978-81-272-2948-2
In the earlier articles, I have explained the construction of helium neon laser. Today let us discuss the working of helium neon laser:
Pumping of He atoms: When electric discharge is passed through the gas mixture of He and Ne, electrons are accelerated down the discharge tube in which mixture of He-Ne is placed. These accelerated electrons collide with helium atoms and excite them to higher energy levels (let us say F2 and F3).
Continue reading “Working of Helium Neon Laser”
The helium-neon laser was the first gas laser to be operated successfully. It was fabricated by Ali Javan and his co-workers in Bell Telephone Laboratories in the USA in 1961.
Helium neon laser used a mixture of 10:1 for its active medium. It consists of a long and narrow discharge tube of diameter of about 1 cm and about 80 cm long. The mixture is at a pressure of about 1 mm of Hg, the partial pressure of helium gas being 5 to 10 times that of neon.
Active medium: The gas mixture of He and Ne forms the active medium. Ne act as active center.
Pumping Source: Electric discharge method is used for pumping and achieving population inversion.
Optical resonator system: A set of mirrors form the optical resonator system.
Reference: This article is referred from my authored book “optics and lasers” having ISBN 978-81-272-2948-2. Try to make the construction figure. In case of any doubt, post in comment section.
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