Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 3rd Semester (Third Semester) 2017-2018 ROE033 Laser Systems And Applications Question Paper
Paper ID: 9 0 1 1 RollNo.
B. Tech
(SEM-III) THEORY EXAMINATION 2017-18
LASER SYSTEMS AND APPLICATIONS
T ime.? 3H0urs Max. Marks: 70
Note: Attempt all Sections. Assume missing data, if any.
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1. Attempt all questions in brief: 2 x 7 = 14
a. What do you mean by Polarization of X-ray?
b. What is tunnel effect?
c. Why spontaneous emission of radiation is incoherent?
d. What is function of optical cavities in a laser?
6. What do you mean by population invertion?
f. What are characteristics properties of argon ion laser?
g. Can we get hologram with ordinary light?
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2. Attempt any three of the following: 3 X 7 = 21
a. What do you mean by black body? Explain features of black body spectrum.
b. What are puming techniques? Discuss different types of pumping techniques in
different types of laser.
c. What is Q switched laser? Discuss various methods.
With necessary diagram explain construction and working of Nd:YAG laser.
6. Explain laser welding and its advantages over conventional welding techniques.
Brie?y explain, how laser are useful in drilling and cutting?
SECTION C
3. Attempt any one part of the following: 1 X 7 = 7
(a) Explain Bohr theory of hydrogen atom. If an electron transit from third orbit to
first orbit. Find the wavelength of electron in hydrogen atom.
(b) Solve Schrodinger wave equation to find Eigen value and Eigen function for a
particle in an infinite potential well.
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4. Attempt any one part of the following: 1 X 7 = 7
(a) What are important features of stimulated emission of radiation?
Discuss essential conditions for producing laser beam. Find population ratio
between two energy states in Ruby laser producing a laser light of wavelength
7000A at 330K.
(b) What do you know about threshold condition for laser oscillation? Find an
expression for threshold condition for lasing.
5. Attempt any one part of the following: 1 X 7 = 7
(a) What are main components of laser? Discuss each component in detail.
(b) With the help of suitable diagram describe three level laser actions. If population
ratio of two states is 3x10'40 in He-Ne laser, produces light of wavelength 6328A.
Find temperature of energy states.
6. Attempt any one part of the following: 1 X 7 = 7
(a) What are molecular gas lasers? Describe construction, working and application of
carbon dioxide laser.
(b) Explain the working of semiconductor laser. Differentiate between Homojunction
and Heterojunction laser.
7. Attempt any one part of the following: 1 X 7 = 7
(a) What is LIDAR? Discuss its components and their role. How atmospheric
pollutants are measured using LIDAR?
(b) Discuss how the laser can be used in optical communication.
Physical Constants
Rest mass of electron m0 = 9.1 x 10'31 kg
Rest mass of Proton mp = 1.67 x 10'27 kg
Speed oflight c = 3 x 108 m/s
Planck Constant h = 6.63 x 10'34 J -s
Charge on electron e = 1.6 x 10'19 C
Boltzmann Constant k =1.38 x 10'23 J K'1
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This post was last modified on 29 January 2020