Haldia Institute of Technology
Department of Applied Science
Assignment – III
Course: PH 201
Module2: Optics2
Polarisation
1. Define polarization phenomenon of light wave. What is linearly and
circularly
polarized light?
2. What is Polaroid? Define Brewster’s law in polarization.
3. Define ordinary ray, extra-ordinary ray and optic axis.
4. Unpolarized light is incident on two polarizing sheets placed on top of the
other. Each sheet reduces the intensity of unpolarized light by 50%. What
must be the angle between the characteristic directions of sheets if the
intensity of the transmitted light is 1/3 of the intensity
of the incident beam?
5. A quarter wave plates is fabricated with smallest possible thickness for
wavelength of 589⋅3 nm. What phase retardation will be obtained with this
plate with light having wavelength of 435⋅8 nm. You may neglect the
variations of refractive indices with wavelength for this problem.
6. Two polarizers are placed at crossed position — angle between the
polarizing planes are 90° — a third polarizer with angle θ with the first one
is
placed
between
them.
An
unpolarised
light
of
intensity I is incident on the first one and pass through all three polarisers.
Find the intensity of the light that comes out.
7. A plane polarized light is incident on a piece of quartz cut parallel to the
axis. Find the least thickness for which the ordinary and the extraordinary
rays combine to form plane polarized light given that µ 0 = 1·5442 and µ e =
1·5533, λ = 5 x10 – 5 cm.
8. What do you mean by positive and negative crystals? How can you
distinguish between an unpolarized, a circularly, elliptically and a plane
polarized light?
Laser:
1. Describe spontaneous and stimulated emission.
2. What is Einstein’s ‘A’ and ‘B’ coefficient? Relate Spontaneous and
stimulated emission probabilities and hence find out the relation between
field energy and ‘A’,’B’ coefficient.
3. What is metastable state? Define population inversion in laser.
4. Describe an optical resonator with schematic diagram.
5. Describe briefly the action of He-Ne laser with energy band diagram.
6. Describe briefly the working principle of a Ruby laser with energy band
diagram.
7. Describe some applications of laser.
8. In a He-Ne Laser transition from E3 to E2 level gives a laser emission of
wavelength 632.8 nm. If the energy of the E2 level is 15.2 10-19 J, how
much pumping energy is required if there is no energy loss in the laser?
Holography:
1. What do you mean by holography and hologram?
2. Discuss briefly the process of recording of an object and reconstruction of an
image by holography.
3. Distinguish between conventional photography and holography.
4. Discuss briefly the basic theory of holography.
5. Discuss about the various applications of holography.
Prepared by Mr. Suvankar Chakraborty