Optics Lecture Notes

GTU 2030 & UTHM

  • GTU stands for Global Technopreneur University 2030.
  • UTHM: Universiti Tun Hussein Onn Malaysia, established 1993-2023 (30 years).
  • Motto: AMANAH PROFESIONAL INOVATIF (Trustworthy - Professional Innovative).
  • QS STARS™ RATING SYSTEM: Excellent.

Introduction to Optics

  • Ordinary light seems white but consists of a spectrum of colors, visible through a prism.

What is Optics?

  • Optics: The science of light.
  • It explains phenomena like:
    • Rainbows.
    • Light reflection off mirrors.
    • Light refraction through glass or water.
  • Optics is both a science and an engineering field.
  • Applications include:
    • Eyeglasses.
    • Cameras.
    • Telescopes.
    • Microscopes.
  • Modern application: Light travels through thin optical fibers (glass or plastic) for long-distance communication (phone calls, Internet).

Light and Electromagnetic Energy

  • Light travels from the Sun to Earth (149 million km) at 300,000300,000 km per second.
  • Light we see is a portion of the energy the Sun produces that our eyes can detect.
  • Energy travels as electromagnetic waves (vibrating patterns of electricity and magnetism).

How Light Behaves

1. Reflection

  • Light reflects off objects, allowing us to see them.
  • Without light, objects disappear.
  • Types of Reflection:
    • Specular reflection: Clear reflection (e.g., seeing your face in a mirror).
    • Diffuse reflection: Scattered reflection (e.g., not seeing your face).

Reflection – Mirrors

  • Three possible interactions when light hits an object:
    • Pass through (transparent objects).
    • Sink in/disappear (opaque, darkly colored objects).
    • Reflect back (shiny, light-colored, reflective objects).

Looking in a Mirror

  • Light reflects off your body in all directions.
  • Light rays travel to the mirror in straight lines.
  • Light reflects off the silver coating on the back of the mirror in an orderly way (specular reflection).

2. Refraction

  • Refraction: Bending of light when it passes through different mediums.

  • Example: A straw appearing bent in water.

  • Light travels in straight lines in a vacuum.

  • When light enters denser materials (water, glass, plastic), it slows down.

  • This change in speed causes light waves to bend.

Applications of Optics

1. Blind Spot Mirror/Convex Traffic Mirror

  • Provides a better view of traffic.
  • Enhances safety during car parking.
  • Helps see the blind spot.
  • Allows visibility of pedestrians behind the car.

2. Dentist Mirror

  • Provides indirect vision of the oral cavity.
  • Helps dentists avoid improper sitting posture.

Laser

  • Laser: Light Amplification by Stimulated Emission of Radiation.
  • A device that amplifies light and produces highly directional light.
  • Lasers can generate visible, ultraviolet, or infrared light.

Laser Usage

1. Tools

  • Cutting tools.
  • Medicine: Blasting cancer tumors, cataract treatment.

2. Communications

  • Grocery store barcode scanners.
  • Sending vast streams of data over the Internet.