BIJOY DEY

1. NAME – BIJOY DEY
STUDENT CODE – BWU/BTA/21/117
DEPARTMENT – CSE (AI & ML)
SECTION – B
SUBJECT - PHYSICS
TOPIC – HE NE LASER
UNIVERSITY – BRAINWARE UNIVERSITY

2. INTRODUCTION
 A Helium-Neon laser, usually called a He-Ne laser, is a type of
small gas laser . He-Ne lasers have many industrial and
scientific uses , and are often used in laboratory
demonstrations of optics.
 He-Ne laser is a four-level laser.
 Its usual operation wavelength is 632.8 nm, in the red portion
of the visible spectrum.
 It operates in continuous working(CW) mode.
 The Helium-Neon laser was the first continuous laser.

3. CONSTRUCTION OF HE NE LASER
 Long discharge tube. Length 50 cm and diameter 1cm.
 Mixture of He & Ne in 10:1 .
 Left side is fully silvered mirror and right side is partially silvered mirror.
 It also contains radio-frequency generator.

4. WORKING OF HE NE LASER
 In He-Ne laser, we use high voltage D.C as the pump-source. A high voltage D.C
produces energetic electrons, that travels through the gas mixture.
 The energetic electrons collide with and excite the He and Ne atoms to metastable
states 20.61 ev and 20.66 ev respectively above their ground states.
 The He atom excites the ne atom by collision to its metastable state.
 It means He helps in achieving a population inversion in the Ne atoms.
 When a excited Ne atom passes spontaneously from the metastable state at 20.66
ev to the state at 18.70 ev , it emits a 6328 Angstrom photon.
 This photon moves back and forth between two reflecting ends of the tube and
stimulates all the excited atoms.
 Finally , we get a laser beam .

5. ENERGY LEVEL DIAGRAM OF HE NE LASER

6. APPLICATIONS OF HE NE LASER
 The Narrow red beam of He-Ne laser is used in supermarkets to
read bar codes.
 The He-Ne Laser is used in Holography in producing the 3D
images of objects.
 He-Ne lasers have many industrial and scientific uses, and are
often used in laboratory demonstration of optics.

7. ADVANTAGE OF HELIUM NEON LASER
• HELIUM NEON LESAR EMITS LASER LIGHT IN THE VISIBLE
PORTION OF THE SPECTRUM.
• HIGH STABILITY
• LOW COST
• OPERATES WITHOUT DAMAGE AT HIGHER TEMPERATURES.

8. DISADVANTAGE OF HE NE LASER
 LOW EFFICIENCY
 LOW GAIN SYSTEM
 HELIUM-NEON LASER ARE LIMITED TO LOW POWER TASKS.

9. THANK YOU