"Complete LASER Notes for RGPV Students – 2025 Exam Special"

🔷 What is LASER?

LASER is a special type of light. It is very strong, straight, and focused. You can see lasers in barcode scanners, CDs, surgeries, and internet systems.

🔷 Full Form of LASER

LASER = Light Amplification by Stimulated Emission of Radiation

It means: making light stronger using a special process called stimulated emission.

🔷 How does LASER work? (Simple Steps)

Laser works using three main steps:

1. Population Inversion

Normally, atoms stay in a low energy state. But to make a laser, we need more atoms in a high energy state. This is called population inversion.

2. Stimulated Emission

When one photon (light particle) hits an excited atom, the atom gives off another photon. Both photons are exactly the same — same direction, energy, and phase.

3. Mirrors (Optical Cavity)

The laser machine has two mirrors. Light bounces between them again and again. This makes the light stronger. One mirror lets a small part of light go out. This is the laser beam.

---

🔷 Main Features of LASER

Feature Meaning

Monochromatic Only one color (one wavelength)

Coherent All light waves move together

Directional Moves in only one straight line

Intense Very powerful and focused light

---

🔷 Types of LASER

1. Gas LASER

– Example: Helium-Neon Laser

– Used in labs and barcode scanners.

2. Solid-State LASER

– Example: Ruby Laser

– Used in defense and high-energy systems.

3. Semiconductor LASER (Diode Laser)

– Example: Laser pointer

– Used in mobile phones, CD/DVD players.

4. Chemical LASER

– Very powerful, used by military.

5. Dye LASER

– Color-changing laser used in research.

---

🔷 Where is LASER used? (Applications)

1. Medical Field

Eye operation (LASIK)

Cancer treatment

Dental treatment

2. Communication

Internet through fiber optic cable

Data transfer between satellites

3. Industry

Cutting and welding metal

3D printing

4. Science Labs

Testing materials

Nuclear research

5. Defense

Range finding

Laser-guided weapons

6. Daily Life

Barcode scanners in shops

Laser printers

CD/DVD reading

🔷 LASER vs Normal Light

Property LASER Light Normal Light

Color One color only Many colors

Direction Straight beam Spreads all around

Phase All waves same Mixed waves

Power Very strong Not very strong

🔷 Important Questions for RGPV Exam

Theory Questions:

What is LASER? Explain with working.

What is population inversion and stimulated emission?

Draw diagram of Ruby Laser.

Write uses of laser.

Numerical:

Use this formula:

E = hν = hc/λ

(Where h = Planck’s constant, ν = frequency, λ = wavelength)

🔷 Some Quick Facts

First laser made in 1960 by Theodore Maiman

LASER travels at the speed of light

LASER is used without touching anything (non-contact tool)

Diode lasers are the smallest lasers

🔷 Why is LASER important?

Laser is very useful in today’s world. It is used in:

Hospitals

Defense

Science

Everyday life

If you understand the basics and practice diagram + previous year questions, this topic can give you 8 to 10 marks easily in RGPV exam.

---

📝 Conclusion 

LASER is a powerful and interesting topic. It is easy to understand if you learn step-by-step. Remember:

Learn working + uses

Practice diagram

Prepare theory and numericals

This will

 help you score full marks in this chapter.