Output, use and disdavantages of semiconductor laser

Output of semiconductor laser: The output powers of about 10mW are achieved in continuous wave operation and in pulsed opration the peak power runs to 100W. It has output wavelength from 8200 to 9000 angstroms. So the wavelength of semiconductor laser lies in the infrared region.

Advantages/Applications: Semiconductor lasers are compact and have efficiency of about 50-60%. They can be used as sources for light wave communication systems. They  expected to find applications in optical radar equipment and space communications.

Disadvantages. It is difficult to control the mode pattern and mode structure of the semiconductor laser action due to small size of laser region that is junction region.

As in semiconductor, the laser emission occurs between two bands of energies instead of two well defined energy levels (like in He-Ne laser), thus the laser emission is not as monochromatic as that from a gas laser.

Reference: This article is referred from my authored book “Optics and lasers” having ISBN 978-81-272-3833-9. In case of any doubt in this article or any article of Physics, kindly post in the comment section.

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Working of semiconductor laser

In my earlier articles, I have explained the construction of semiconductor laser. Toady I will discuss the working of semiconductor laser.

Achievement of population inversion: When p-n junction diode is forward biased, then there will be injection of electrons into the conduction band along n-side and production of more holes in valence band along p-side of the junction. Thus, there will be more number of electrons in conduction band comparable to valence band, so population inversion is achieved.

Figure: Energy level diagram of semiconductor laser (No biasing)

Figure: Energy level diagram of semiconductor laser (with biasing) Continue reading “Working of semiconductor laser”

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