Bijoy Dey is a student at Brainware University studying CSE with a focus on AI and ML. His student code is BWU/BTA/21/117. He is working on a topic about Helium-Neon lasers for his Physics class. A He-Ne laser uses a gas mixture of helium and neon to produce a visible red laser light through population inversion. It was the first continuous laser and is commonly used for applications like barcode scanning and holography due to its stability, low cost, and ability to operate at higher temperatures than other lasers. However, it also has low efficiency and power limitations.

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