Chapter 7 enumerations (COMPLETED)

Essential features of camera

1. Convex lens

2. Diaphragm

3. Aperture

4. Shutter

5. Focusing ring

6. Film

Main features of human eye

1. Eyelid

2. Cornea

3. Aqueous humour

4. Vitreous humour

5. Iris

6. Pupil

7. Ciliary muscles

8. Retina

Common defects of vision

1. Farsightedness (hyperopia)

2. Nearsightedness (myopia)

Lenses in compound microscope

A compound microscope has at least two convex lenses:

1. An objective lens

2. An eyepiece lens.

Main types of electron miscroscope

1. The Scanning Electron Microscope (SEM)

2. The Transmission Electron Microscope (TEM)

Types of telescope

1. Astronomical telescope

2. Terrestrial telescope

The refracting astronomical telescope consists of:

1. An objective of long focal length

2. An eyepiece of short focal length

Light and optics applications in our daily life

1. Reflection and refraction of light in mirrors and lenses

2. Other real-world instruments such as:

   1. Microscope

   2. Telescope

   3. Lasers

   4. Spectrometer

   5. Fibre optics

Types of lasers

Lasers are classified into five main types:

1. Gas lasers

2. Solid-state lasers

3. Fiber lasers

4. Liquid lasers (dye lasers)

5. Semiconductor lasers (laser diodes)

Essential elements in a laser

In practice, a laser contains three essential elements:

1. Laser medium

2. Power supply (for pumping process)

3. Optical cavity.

The laser medium (gain medium) can be:

1. Gas

2. Liquid

3. Crystalline solid

4. Semiconductor crystal

Mirrors in optical cavity

The optical cavity consists of two highly reflective mirrors.

1. One mirror with reflectivity of almost 100% (perfect reflector) completely reflects the light.

2. The other mirror with a reflectivity of about 80 to 90% (partial reflector) reflects most part of the light, but allows some part of the light to come out as a laser beam.

Essential processes to initiate a laser action

Two essential processes to initiate a laser action are:

1. Stimulated emission

2. Population inversion.

Characteristics of laser light

1. The output lasers beam is narrow.

2. The emission is coherent.

3. The light is monochromatic.

4. A typical beam divergence is around a milliradian.

5. One of the unique properties of a laser beam is coherence.

Applications of laser

1. Various applications:

   1. Bloodless surgery

   2. Destroying kidney stones

   3. Eyelens curvature corrections

   4. Cancer diagnosis and therapy

   5. Fibre-optic endoscopy to detect ulcers in the intestines

   6. In dentistry and cosmetic treatments

2. In communication, laser light is used in optical fibre communications to send information over large distances and also used in space communication such as radars and satellites.

3. Laser range finders are used to determine the distance to an object.

4. In industries, high power lasers are used to cut metals, drill aerosol nozzles and orifices with the required precision.

5. In shops and business establishments, laser light is used to collect the information from the bar code printed on the product.

6. Lasers are used in the semiconductor industries for photolithography, in computer printers and to store and retrieve information in compact disc (CD).

Layers in an optical fibre

An optical fibre is composed of two concentric layers, called:

1. The core

2. Cladding, which surrounds the glass fibre core.

Disciplines spectrometer is used for

1. Biology

2. Chemistry

3. Agriculture

4. And more

Optical spectrometer consists of…

The optical spectrometer consists of:

1. Light source

2. Collimator

3. Dispersion elements

4. A telescope

Dispersion elements

The collimated beam from a specific light source is dispersed by dispersion elements such as:

1. Prism

2. Or grating.

Most common optical spectrometers

Three of the most common optical spectrometers are:

1. Spectrophotometers (UV-Vis spectrometer)

2. Spectrofluorometers

3. Raman spectrometers.

Main photometric quantities

In photometry, there are four main photometric quantities. They are:

1. Luminous flux

2. Luminous intensity

3. Luminance

4. Illuminance.