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Task 5 – What are photons and phonons?

TI00AA16-3004, NGUYEN MAI VINH, DANCUN OGENDA, SOBHAN NIROULA 19.9.2014

First cycle

Selected problem

What are photons and phonons?

My explanation (original hypothesis)

Photons are the light and the electromagnetic radiation that are produced when there is a transition from a higher energy state to a lower energy state as a result of an atom moving to occupy holes and in the process leaving holes behind. When this happens, photons are released.

Phonons are specific sub-state of photons where levels of energy are well defined and they can play an important role in certain phenomena, hence the name phonons.

Critical evaluation

What strengths and weaknesses does your explanation have?

At current stage, we have knowledge about photons but no knowledge about phonons. What we can think of is they are derivatives of photons. There is high chance that they are important fundamentals to understand physics phenomena. That is the reason why they are given a specific name.

What I need to find out more?

What are phonons?

How it is different from photon?

How could I improve my explanation?

We need to do more research and studies about phonons

First you can list all the references to the additional material you find out in order to use them later.

http://newsoffice.mit.edu/2010/explained-phonons-0706

http://en.wikipedia.org/wiki/Phonon

Then try to understand what does it say about the problem.

In the similar way that photons are particles of light, phonons are particles of sound or heat. Basically, they are quantized energy, which shows wave-like and particle-like properties simultaneously.

Vibrating atoms or molecules around their lattices causes the phenomenon. At low frequency, phonons of sound are produced. In other hand, high frequency vibration of atoms and molecules generate phonons of heat.

There are two fundamental differences between photons and phonons:

1.In the case of photons, transition between different energy levels of electrons emits photons. The vibration of atoms and molecules produce phonons.

2. Photons (particles that carry light and electromagnetic) do not interact with each other if they have different wavelength. However, phonons at different frequencies can mix together and generate superimposed wavelength.

Second cycle

Selected problem

We already know the application of photons, what is the application of phonons?

My explanation (original hypothesis)

Just like the way LASER works, phonons can be amplified by stimulated emission of radiation. Therefore, there is high chance that phonon amplification by stimulated emission of radiation applications are almost the same as applications from laser. The only difference is that photon laser is at higher frequency and higher energy compared with phonon laser.

Critical evaluation

What strengths and weaknesses does your explanation have?

We can use analogous derivation to build a model about phonon laser. Similarity and difference are derived from current knowledge as well. However, reality check, the limitations and current development updates of phonon laser are required for better knowledge.

What I need to find out more?

Real life and potential application of phonons

How could I improve my explanation?

We need to do more research and studies about phonons

First you can list all the references to the additional material you find out in order to use them later.

Then try to understand what does it say about the problem.

Phonon laser is called Sound Amplification by Stimulated Emission of radiation and hence the name SASER. Acoustic radiation can be emitted in the same way photon radiation is emitted in LASER. The properties of SASER are almost the same as LASER.

Saser can have wide applications, which include studies and research of terahertz frequency ultrasound. Saser can also be used in optoelectronics, electrical devices that detect, control light and transmit signals the same way as fiber optics do. Another use of saser is in medical field in which high precision ultrasounds in medical imaging is highly demanded. Saser also has potential applications in semiconductors such as terahertz-frequency computer processors which is much faster than current computer chips.

CC BY-SA, SakariLukkarinen, 2014.

Media and ICT, Helsinki Metropolia University of Applied Sciences