Podcast
Questions and Answers
What is the main limitation of traditional photography that holography overcomes?
What is the main limitation of traditional photography that holography overcomes?
Who developed the concept of holography and received a Nobel Prize for it?
Who developed the concept of holography and received a Nobel Prize for it?
What does the term 'Holos' in Greek refer to in the context of holography?
What does the term 'Holos' in Greek refer to in the context of holography?
What is the role of the reference wave in the construction of a hologram?
What is the role of the reference wave in the construction of a hologram?
Signup and view all the answers
What type of recording does a hologram represent?
What type of recording does a hologram represent?
Signup and view all the answers
What characterizes the core of a graded-index optical fibre?
What characterizes the core of a graded-index optical fibre?
Signup and view all the answers
How is the attenuation of an optical signal quantitatively represented?
How is the attenuation of an optical signal quantitatively represented?
Signup and view all the answers
What is the main consequence of dispersion in optical fibres?
What is the main consequence of dispersion in optical fibres?
Signup and view all the answers
Which of the following is NOT an application of optical fibres?
Which of the following is NOT an application of optical fibres?
Signup and view all the answers
What aspect of light is lost in conventional photography?
What aspect of light is lost in conventional photography?
Signup and view all the answers
Which of the following best describes optical communication?
Which of the following best describes optical communication?
Signup and view all the answers
What is the primary purpose of the cladding in an optical fibre?
What is the primary purpose of the cladding in an optical fibre?
Signup and view all the answers
In holography, what type of recording is typically lost in conventional photography?
In holography, what type of recording is typically lost in conventional photography?
Signup and view all the answers
What is the primary function of the cladding in an optical fibre?
What is the primary function of the cladding in an optical fibre?
Signup and view all the answers
Which of the following is NOT a characteristic of optical fibres?
Which of the following is NOT a characteristic of optical fibres?
Signup and view all the answers
What is the main advantage of using optical fibres for transmitting information?
What is the main advantage of using optical fibres for transmitting information?
Signup and view all the answers
How is the numerical aperture (NA) of a fibre useful in comparison to the acceptance angle?
How is the numerical aperture (NA) of a fibre useful in comparison to the acceptance angle?
Signup and view all the answers
In a step-index optical fibre, what characteristics are associated with the core and cladding?
In a step-index optical fibre, what characteristics are associated with the core and cladding?
Signup and view all the answers
What material compositions are typically used in the core of optical fibres?
What material compositions are typically used in the core of optical fibres?
Signup and view all the answers
Which of the following correctly describes the function of the protective jacket in an optical fibre?
Which of the following correctly describes the function of the protective jacket in an optical fibre?
Signup and view all the answers
What are the diameter ranges typically found in optical fibre cores?
What are the diameter ranges typically found in optical fibre cores?
Signup and view all the answers
Study Notes
Introduction to Fibre Optics
- Optical fibre used for light wave propagation due to its high transmittance and lack of interference from natural elements
- Optical fibre is a thin, flexible transparent glass or plastic filament
- Light is transmitted through multiple total internal refections
- Optical fibre consists of a core, cladding, and a protective jacket
- The core, which transmits light, has a higher refractive index than the cladding
- The cladding prevents light from escaping the core by total internal reflection
- The jacket protects the fibre from external damage
- Typical core diameter ranges from 5µm to 100µm while the cladding diameter is approximately 125µm
Numerical Aperture
- Used to describe the acceptance angle and refractive indices of the core and cladding
Step-Index Optical Fibre (SI Fibre)
- Core has a homogenous, constant refractive index
- Cladding also has a constant, but lower, refractive index
Graded-Index Optical Fibre (GRIN Fibre)
- Core has a non-uniform refractive index gradually decreasing from the centre to the edge
- Cladding has constant refractive index
Attenuation in Optical Fibre
- Reduction in signal strength during light propagation due to losses in the fibre
- Fibre attenuation (ααα) is calculated using the formula: α=10logPiP0Lα = \frac{10 log \frac{P_i}{P_0}}{L}α=L10logP0Pi
- PiP_iPi is input optical power, P0P_0P0 is output optical power, and LLL is the length of the fibre (km)
Dispersion in Optical Fibres
- Broadening of light pulses during propagation
- Causes distortion in signal due to different wavelengths travelling at different speeds through the fibre
Optical Communications
- Transferring information using light waves
- High information-carrying capacity makes it a unique communication system
Applications of Optical Fibres
- Optical Communication: high-speed data transmission over long distances
- Medical Applications: endoscopy and fibre optic surgery for internal visualisation
- Military Applications: covert communication and data transfer
- Entertainment/Television Applications: cable television and high-speed internet services
- Industrial Applications: remote sensing and control, process monitoring
- Computer Networking: backbone networks and high-speed internet connections
Introduction to Holography
- Photograph is a two-dimensional representation of a three-dimensional scene
- Conventional photography records only the intensity of light, losing phase information
- This results in a loss of depth perception and parallax information
Basic Principle of Holography
- Records the complete wave field, including both intensity and phase of the light scattered by the object
- Developed by Dennis Gabor (Nobel Prize in 1971)
- Converts phase information into intensity variations using coherent illumination
- Produces a three-dimensional image from a two-dimensional recording
Construction and Reconstruction of Image on Hologram
- The holographic recording process involves the interference of the object wave (scattered light) and a reference wave (plane wave)
- This interference pattern is recorded on a photographic plate, creating a hologram
- The hologram contains information on both the phase and amplitude of the object wave
- Unlike a photograph, a hologram does not resemble the object and contains coded information
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the fundamentals of fibre optics, including how optical fibres transmit light through multiple total internal reflections. Learn about the components of optical fiber, such as the core, cladding, and protective jacket, alongside the concepts of numerical aperture and different types of optical fibres like step-index and graded-index.
