2002 Photonics Today1

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Photonics: Technological Platform for the 21st Century: 

Photonics: Technological Platform for the 21st Century Dr. Ping Koy Lam Department of Physics, The Australian National University, Canberra, ACT 0200, Australia. E-mail: Ping.Lam@anu.edu.au http://photonics.anu.edu.au

What is Photonics?: 

What is Photonics? "Photonics is the technology of generating and harnessing light and other forms of radiant energy whose quantum unit is the photon. The science includes light emission, transmission, deflection, amplification and detection by optical components and instruments, lasers and other light sources, fibre optics, electro-optical instrumentation, related hardware and electronics, and sophisticated systems. The range of applications of photonics extends from energy generation to detection to communications and information processing." (The Photonics Dictionary, Laurin Publishing)

What is Photonics in Simple Terms?: 

What is Photonics in Simple Terms? Almost everything you can do with electricity, you can do with light better! Photonics is about using light to perform tasks that we normally do with electricity and more...

Why Use Photons?: 

Why Use Photons? Photons are very small Provides fine control to many applications It is massless, yet it has momentum! Effective Mass = Planck / (Wavelength * Light speed) There is a minimum size to structures it can penetrate.

Why Use Photons?: 

Why Use Photons? Photons travel in straight lines Very handy as a ruler for measuring distance When traveling in vacuum it defines what “straightness” is! We would rather say that space is curve! But photons travel in straight lines.

Why Use Photons?: 

Why Use Photons? Photons are very fast Good for tele-communication. Speed of light is: c = 299,792,458 m/s Nothing travels faster than light It also oscillate very fast f >> 1,000,000,000,000,000 Hz is very easy.

Why Use Photons?: 

Why Use Photons? Photons have colors - Bandwidth Different colors can be use to represent different channels. We can simultaneously use many light channels. Its color (wavelength) is dependent on its frequency of oscillation. Speed of light = Color * Frequency

Why Use Photons?: 

Why Use Photons? Photons interact readily with atoms Extremely small tweezers to manipulate atoms with. Essential for future nanotechnologies. Absorption Spontaneous Emission Stimulated emission Atomic dipole interaction

Why Use Photons?: 

Why Use Photons? Photons have many other weird properties! (quantum-ness) Future Quantum Technologies! Polarization Discrete packets Nonlinear Social (Bosons) Wave-particle duality Vacuum is full of virtual photons Superpositions and Entanglement

Examples #1: 

Examples #1 Communication: Smoke signal > Homing Pigeons > Electrical Telephone > Optical Fibre

Examples #2: 

Examples #2 Clock: Hourglass > Mechanical Clock > Quartz Clock > Atomic Clock 1sec = 9,192,931,770 oscillation of 133Cs55 transition.

Examples #3: 

Examples #3 Music: Gramophone > Magnetic tape recorder > CD and DVD players DVD disc can store about 3000 songs (about equivalent to 300 vinyl record). Sound quality is higher The songs stored are more robust

Other examples: 

Other examples Business: Bar code, scanning and copying Visual arts: Laser show & holograms Medical breath analysis Distance measurement Gyroscope and GPS. Optical memory Cooling Forensics Medical surgery Dentistry Machining

Examples #4: 

Examples #4 Calculation: Stonehenge, Pyramid of Egypt, Sky measurer of China (Calculate seasons and astronomical events) Pebbles and abacus (Provide visualization of a rather abstract concept: the numbers) Jacquard loom (Programmable weaving machine for textile) 17th century mechanical calculators (Pascal, Leibniz and Schickard) 1821, Difference Engine No. 1 by Charles Babbage (First mechanical computer, not built until 1991!) 1837, Analytical engine (First proposed programmable computer) 1853, Difference Engine by George Schentz (Less accurate than Babbage’s)

Examples #4 continues…: 

Examples #4 continues… Calculation: 20th century, Alan Turing, Alonso Church, Kurt Gödel and Emil Post (Math models of computation! Free us from system constrains!) 2nd World War, Turing machine (Broke the Enigma code, perhaps won the war for the Allies) Christmas 1947, First transistor by Shockley, Bardeen and Brattain (First electronic transistor) 1965 Gordon Moore’s law (Computer speed, number of transistors and memory will double every 18 months) Moore’s law works extremely well until…

The Quantum Limit: 

The Quantum Limit Number of bits of information/transistors cannot be larger than the number of atoms. Size of computer with certain number of transistors cannot be smaller than number of atoms used to make them. Clock speed of computer cannot increase indefinitely with present technological platform. Moore’s Law will not hold for long!! Need to “shift our paradigm” to quantum computing

Quantum Computation: 

Quantum Computation Bits is replaced by Qubits: |1> or |0> One atom is sufficient to denote one qubit/transistor Need to build the first “scalable” quantum transistor!!! Quantum mechanics means natural parallel processing: Moore’s law is very easy to satisfy At the moment, there are more mathematics than physics. Quantum computers are being proposed for many systems. Diamond NV centres, Phosphorous ion in Silicon, Atom traps, Optical,Electrons in liquid Helium. QC can now factorize 15: 15 = 3 x 5.

Photonics @ the ANU: 

Photonics @ the ANU

Photonics @ the ANU: 

Photonics @ the ANU Quantum Optics (Physics, Science) Atom Optics (Physics, Science) Gravitational Wave Detection (Physics, Science) Aerophysics and Laser Diagnostic (Physics, Science) Optical Science Centre (RSPhysSE) Laser Physics Centre (RSPhysSE) Electronic Materials Engineering (RSPhysSE) Telecommunication Engineering (RSISE) http://photonics.anu.edu.au/qoptics

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