1) Lasers work by stimulating the emission of radiation through light amplification. They produce coherent, intense beams of light in visible, infrared, or ultraviolet wavelengths. 2) Key characteristics of lasers include coherence, high intensity that can be focused in a small area, high directionality within 1mm per meter, and high monochromaticity within a 1nm wavelength spread. 3) Lasers are constructed with a lasing medium like Nd:YAG surrounded by an optical cavity including mirrors to produce stimulated emission through optical pumping.

1. LASERS
PRESENTED BY:
HARISH BABU.KAVERI
CSE-B
20G21A0573

2. Light
Amplification by
Stimulated
Emission of
Radiation

3. WHAT IS A LASER ?
A laser is a device that transforms
light of various frequencies into a
chromatic radiation in the visible,
infrared, and ultraviolet regions with
all the waves in phase capable of
mobilizing immense heat and power
when focused at close range.

5. CHARACTERISTICS OF LASER
COHERENCE
 HIGH INTENSITY
HIGH DIRECTIONALITY
HIGH MONOCHROMATICITY

6. 1 COHERENCE :
The wave trains which are identical in phase and
direction are called coherent waves.
2 HIGH INTENSITY :
Due to the coherent nature of laser, it has the
ability to focus over a small area of 103
3 HIGH DIRECTIONALITY :
The angular spread of a laser beam 1mm/meter.

7. 4. HIGH MONOCHROMATICITY :
 The light from a normal monochromaticity
source spread over a range of wavelength
of the order 100nm.but, the spread is of
the order of 1nm for laser.

8. STIMULATED AND SPONTANEOUS
Stimulated
• It is not a random process.
• The photon get multiplied
through chain reaction.
• It is a controllable process.
• More intense.
• Monochromatic radiation.
Spontaneous
• It is random process.
• The photon do not get multiplied
through chain reaction.
• It is a not controllable process.
• Less intense.
• Polychromatic radiation

10. CONSTRUCTION :
Nd yag rod and krypton flash lamp are enclosed inside in
ellipsoidal reflector.
In order to make the entire flash radiation to focus on the
laser rod.
The Nd yag rod is placed t one focal axis and the flash
lamp at the other focal axis of the ellipsoidal reflector.

11. WORKING :
The flash lamp switched on.
The optical pumping excites the ions from the ground energy
state E0 to the higher energy Level E3 and E4 by absorbing
radiation .80μm and .73μm,respectively.
 The energy level E4 to E2 is the non radiative transition.
 The E2 state is meta stable state.
Any of the spontaneously emitted photon will make the
excited ion to undergo a transition between E2 E1 state.

12. The transitions E2 E1 yields an intense and
Coherent laser beam of wavelength 1.064μm.
These laser give beam continuously.
The ions then make a transition between E1 E0.
The flash lamp is used to excite the ions, while the rest
heats up the crystal.
Thus, the system can be cooled by either air or water
circulation.

13. APPLICATION OF LASER
A) IN INDUSTRY :
1) For welding and melting.
2) For cutting and drilling holes.
3) To test the quality of the material.
B) IN MEDICINE :
1) Used for treatment of detached retinas.
2) Used in performing micro and bloodless surgery

14. C) MILITARY APPLICATIONS:
1) The laser beam can serve as war weapon,
i.e. A power full laser beam can be used to destroy in few
second, the big size object like aero planes, missiles etc.
D) SCIENCE AND ENGINEERING APPLICATIONS :
1)Fiber optic communication.
2)It is used to holography.
3)Communication between planets is possible with laser.
4) It is used to accelerate some chemical reaction.
5) It is used to drill minute holes in cell walls without
damaging the cell itself.