Laser Fundamentals III: Multi-wavelength argon laser - Demonstrations in Lasers and Optics Video Lecture - Electronics and Communication Engineering (ECE)

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in this next demonstration we're going
to look at the spectrum of the light
from an argon laser we know that an
argon laser lasers in several way
wavelengths simultaneously so what we're
gonna do we're gonna take the light from
the argon laser and we're going to look
at it using a simple grating to see if
indeed there are several wavelengths
that are oscillating simultaneously now
we've turned the discharge tube on and
the laser is lazy the output of the
laser is coming out from this end we
reflected by this mirror mount and this
and this mirror over here and let me
show you let me show you then the laser
beam here's a laser beam coming out from
the argon laser what we're gonna do is
reflect it again by another mirror over
here onto onto the screen now the argon
laser lasers at several wavelengths at
the same time so in order to to
demonstrate this I'm going to take this
grating here and I'm going to put it in
the in the way the beam you know it
dispersed the various colors now what
you see on the screen right now are the
various orders of the grating but it's
difficult to see the the various colors
from this from this angle so what we'll
do we'll take a close look at the
various orders and see how many lines
are are lazy so let me again repeat this
again here with it with the grating out
we only have one spot on the on the
screen then when the grating is in we
see the various orders
so now we
zoom in and and look at these various
orders so here we have a close-up of the
output of the grating and see the
various orders here is is the zero order
from the grading here is the first order
now in the second we are already
beginning to see that the dispersion see
several colors and I think in the in the
third order you're already beginning to
see in the third and fourth that they're
indeed several laser lines that are
lazing so if we can then zoom in on
these orders in this case this is the
fourth we can see that we have blue
light blue another weaker one in between
and then the green which is at fifty one
forty five angstroms so indeed that
laser is lazing at least at three three
to four lines simultaneously
you