Helium-Neon-LASER

Helium Neon LASER and Uses of LASER

Helium-Neon LASER

The most common type of laser used in physics laboratories is the helium-neon laser. It consists of a discharge tube fitted with 15% neon gas and 85% helium gas. The neon is the lasing or active medium. Helium and neon have nearly identical metastable states. Helium is located at the level of 20.61 eV and neon at 20.66 eV.

Helium-Neon-LASER-2

Working of Helium-Neon LASER

The high voltage electric discharge excites the electron in some helium atoms to 20.61 eV state.

The laser population inversion in neon is attained by the direct collision with the same energy electrons of helium atoms. Thus, excited helium collides with neon atoms. Rach atom transfers its own 20.61 eV of energy to an electron in the neon atom along with 0.05 eV of K.E from the moving atom.

LASER Action

Spontaneous emission from neo atoms starts laser action and stimulated emission causes electrons in the neon to drop from 20.66 eV to 18.70 eV level and red laser light of wavelength 632.8 nm corresponding to 1.96 eV energy is produced.

LASER-Action

Uses of LASER

LASER technology has a wide range of uses in the modern world. Some of them are given below:

Medicinal Uses
  • Surgical Instruments

Lasers are used in many surgical equipments especially in ophthalmology. Laser is used in eye correction such as short-sightedness, long-sightedness, welding of the retina, etc.

  • Destroy harmful tissues

The narrow and intense beam of a laser can be used to destroy tissue in a particular area.

  • Disease diagnosis

Helium-neon laser beam is used to diagnose the diseases of the eyes.

  • Cure Cancer

Fine focused and intense beam of laser is used to destroy cancerous, precancerous or tumor cells.

The heat of the laser is used to seal off capillaries and lymph vessels to prevent the spread of disease.

Other uses
  • Welding and Drilling

The intense heat produced in a small area by laser is used for arc welding and drilling tiny holes in hard materials.

  • Lining up the equipment

The precise straightness of the laser beam is also useful to surveyors for lining up equipment.

  • Fusion Reactions

Lasers are a potential energy source for inducing fusion reactions.

  • Telecommunications
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Laser is used in telecommunication in fiber optics for fast and safe transmission of data without loss.

Telecommunications

  • Scanners/ Bar code Readers

Helium-neon laser produces a narrow red beam which is used in shopping centers, supermarkets, grocery stores, pharmacies to read or scan bar codes.

  • Holography

Holography

It is a scheme of recording the phase and intensity of waves from objects. This type of image formation is called holography which means the entire picture and the image produced as a result is called a hologram.

  • Laser beams are used to produce three-dimensional images of objects.

MCQs

  • 1. What is the most common type of laser used in physics laboratories?
    • A) Argon laser
    • B) Helium-Neon laser
    • C) Ruby laser
    • D) Carbon dioxide laser
    • Answer: B) Helium-Neon laser
  • 2. What gases are typically used in a helium-neon laser?
    • A) Argon and helium
    • B) Helium and neon
    • C) Helium and krypton
    • D) Neon and krypton
    • Answer: B) Helium and neon
  • 3. At what energy level does helium reside in a helium-neon laser?
    • A) 18.70 eV
    • B) 20.61 eV
    • C) 20.66 eV
    • D) 1.96 eV
    • Answer: B) 20.61 eV
  • 4. What process causes laser population inversion in neon in a helium-neon laser?
    • A) Stimulated emission
    • B) Spontaneous emission
    • C) Collision with helium atoms
    • D) Electron excitation
    • Answer: C) Collision with helium atoms
  • 5. What wavelength of light is produced by stimulated emission in a helium-neon laser?
    • A) 632.8 nm
    • B) 18.70 eV
    • C) 20.61 eV
    • D) 1.96 eV
    • Answer: A) 632.8 nm
  • 6. In which field are lasers commonly used for surgical procedures?
    • A) Cardiology
    • B) Orthopedics
    • C) Ophthalmology
    • D) Neurology
    • Answer: C) Ophthalmology
  • 7. How can lasers be utilized in disease diagnosis?
    • A) Destroying tissue
    • B) Sealing off capillaries
    • C) Producing holograms
    • D) Detecting abnormalities
    • Answer: D) Detecting abnormalities
  • 8. What is the primary function of a laser in telecommunications?
    • A) Creating holograms
    • B) Welding materials
    • C) Drilling holes
    • D) Transmitting data
    • Answer: D) Transmitting data
  • 9. What is the purpose of using lasers in scanners or barcode readers?
    • A) Creating three-dimensional images
    • B) Welding materials
    • C) Scanning barcodes
    • D) Sealing off capillaries
    • Answer: C) Scanning barcodes
  • 10. What process is facilitated by the precise straightness of a laser beam in surveying?
    • A) Creating holograms
    • B) Fusion reactions
    • C) Lining up equipment
    • D) Telecommunications
    • Answer: C) Lining up equipment
  • 11. How is the heat produced by lasers utilized in medical procedures?
    • A) Destroying tissue
    • B) Creating holograms
    • C) Transmitting data
    • D) Detecting abnormalities
    • Answer: A) Destroying tissue
  • 12. What type of reaction can lasers potentially induce for energy production?
    • A) Fusion reactions
    • B) Fission reactions
    • C) Chemical reactions
    • D) Combustion reactions
    • Answer: A) Fusion reactions
  • 13. What term refers to the process of recording phase and intensity of waves from objects using lasers?
    • A) Holography
    • B) Telecommunications
    • C) Welding
    • D) Fusion
    • Answer: A) Holography
  • 14. Which laser type is commonly used in shopping centers for barcode scanning?
    • A) Ruby laser
    • B) Argon laser
    • C) Helium-neon laser
    • D) Carbon dioxide laser
    • Answer: C) Helium-neon laser
  • 15. What is the primary function of a helium-neon laser in medicinal applications?
    • A) Welding
    • B) Creating holograms
    • C) Scanning barcodes
    • D) Destroying cancerous cells
    • Answer: D) Destroying cancerous cells
  • 16. How do lasers contribute to the field of holography?
    • A) By creating holograms
    • B) By transmitting data
    • C) By destroying tissue
    • D) By sealing off capillaries
    • Answer: A) By creating holograms
  • 17. What characteristic of lasers makes them suitable for precise welding and drilling tasks?
    • A) Wide beam dispersion
    • B) Variable wavelength
    • C) Narrow, intense beam
    • D) High electromagnetic interference
    • Answer: C) Narrow, intense beam
  • 18. What medical procedure utilizes the heat of lasers to prevent the spread of disease through capillaries?
    • A) Eye correction
    • B) Tumor removal
    • C) Disease diagnosis
    • D) Sealing off capillaries
    • Answer: D) Sealing off capillaries
  • 19. How does the laser beam contribute to telecommunications?
    • A) By producing holograms
    • B) By scanning barcodes
    • C) By transmitting data
    • D) By sealing off capillaries
    • Answer: C) By transmitting data
  • 20. What wavelength of light is typically produced by stimulated emission in a helium-neon laser?
    • A) 1.96 eV
    • B) 18.70 eV
    • C) 20.61 eV
    • D) 632.8 nm
    • Answer: D) 632.8 nm
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Summary: Helium Neon LASER and Uses of LASER

The tutorial delves into the realm of Helium-Neon (He-Ne) lasers, emphasizing their significance and operational mechanisms. He-Ne lasers, comprising a discharge tube with 15% neon and 85% helium, are extensively utilized in physics laboratories due to their efficient performance. The operational process involves high-voltage discharge, exciting helium electrons to a metastable state, which then collide with neon atoms, inducing population inversion. Consequently, spontaneous and stimulated emissions generate red laser light with a wavelength of 632.8 nm.

Moreover, the tutorial highlights the diverse applications of laser technology in various fields, particularly in medicine and industry. Medicinal uses include laser surgeries for eye correction, tissue destruction, disease diagnosis, cancer treatment, and capillary sealing. In industrial settings, lasers facilitate welding, drilling, equipment alignment, and telecommunications, ensuring efficient data transmission via fiber optics. Additionally, lasers find utility in barcode scanning, holography for three-dimensional imaging, and as potential energy sources for fusion reactions.

Further Reading:  Temperature Scales and conversion of Temperature

In essence, He-Ne lasers and laser technology, in general, serve as indispensable tools across multiple domains, showcasing their versatility and transformative potential in modern applications.