animation for spontaneous emission and phase noise in optics

[katwalatapan]

Hello,

First of all thank you very much for this service, its really helpful for students in their presentations and research work. 

I am a graduate student at dalhousie university.  I have a presentation to make on spontaneous emission and phase noise and non linearities in optics.  I could not find any animations that i could put in my presentation on the topics.  Basically i would like to see an atom in excited state and then with spontaneous emission it releases a photon in random direction and with stimulated emission it releases the photon in the direction of the incident light. 

Also related animations on phase noise and non linearities in optics would be really helpful.  My main intention of this is to put it in my presentation.  Please do help me on this issue.

Thank you.

Regards,

Tapan.

[Fu-Kwun Hwang]

What you asked for is not a simulation, but an animation.
Are you trying to talk about Laser?
I can help you create an animation with EJS. But I need to know in more detail about the animation.
How to present the ideas. Using many particles to represent atom? What about the positions of the particles; randomly distributed or structured distributed? Does the incident light always coming from the same direction?

If you need simulation about phase noise and non-linearities in optics (this is a broad topic) , you need to provide more specific information: what exactly you want to present (model/relation/...). 

[katwalatapan]

Dear Mr. Hwang,

Thank you for your response.  You are right, i need an animation of the stimulated and spontaneous emission process.  What exactly i'd like to show, is the how an atom gets excited and goes to another energy level and then upon receiving energy from an incident light in particular direction emitts two photons in the same direction. This is for stimulated emission.  It would be ok if it would be presented using one particle or many particles as long as the incident light direction and emitted light direction is same and the atom returns to ground state. 

For the spontaneous emission process, i'd like to present the atom moving to a higher state upon being excited and then automatically returns to the ground state emitting a photon in random direction.

The particles could be randomly distributed. It would be fine and the incident light would come from the same direction.

About the animation for phase noise and non linearities in optics, my intention is to present how these effects are stochastic in nature.  So any animation representing these effects to make it easier for the audience to understand the process would be fine.

I hope this would help.  Please do let me know if you need any details.  And thank you very much for your initiative.

Regards,

Tapan.

[Fu-Kwun Hwang]

For the simulation, I can work on the code as long as I know the model (relations/equations).
But for the animation, I will need to know the detail script to be able to know what should be done next.

For example:

how an atom gets excited and goes to another energy level and then upon receiving energy from an incident light in particular direction emits two photons in the same direction. This is for stimulated emission.

How and why an atom gets excited (by what kind of process? or do not matter?)?
How to present the excited and unexcited state?
 Can I just draw two energy level and draw particle jump from one level to another ? or you have other requirement?

For the spontaneous emission process, I'd like to present the atom moving to a higher state upon being excited and then automatically returns to the ground state emitting a photon in random direction.

What cause the atom moving to a higher state? How to present this? Many particles will be needed to show photon emitted in random direction. And normally, most of the atoms should be at the ground state instead of excited state.

It will be even better if you can provide simple drawing (attached image files, perhelp )

I am working on this using my spare time. I can not design an animation for you just from your intension. For me, the most difficult process is design phase, not the programming. I need detail model or script, otherwise,  I would not be able to help.

The purpose is for your presentation.
I am willing to help and I will try my best to help, but you need to do your design work first.
(I am not good in design animation.)
We need to reach some common understanding on the presentation/animation.  :-)

[katwalatapan]

Dear Mr. Hwang,

I completely understand your dilemma.  Probably inserting the picture of spontaneous and stimulated emission would help understand the process.  Following is the figure of stimulated emission process. I am not sure if the picture would be inserted in the post, so i have also attached a link to the picture. 

1.) http://www.technology.niagarac.on.ca/people/mcsele/lasers/images/StimulatedEmission.jpg
2.) http://micro.magnet.fsu.edu/primer/java/lasers/electroncycle/laserfigure1.jpg

It basically shows the process for one atom.  For the animation it could be fine if one particle or many particles be used according you your convinience.

Here's my description of what happens in the stimulated emission process.

Step 1:  A blue colour particle in ground state representing unexcited state.
Step 2:  A photon (incident light) hits the blue unexcited particle and it goes to a higher excited state turning red.
Step 3:  Another photon hits the partice in same direction.
Step 4:  The red excited particle now returns to the unexcited ground state turning blue and releasing two photons in the same direction as they were hit.
Step 5:  This process goes on repeatedly, using one or many particles how ever would be convinient for you.

Following is the spontaneous emission process

Step 1:  A blue colour particle in ground state representing unexcited state.
Step 2:  A photon (incident light) hits the blue unexcited particle and it goes to a higher excited state turning red.
Step 3:  After sometime a few one second or so, the red excited particle goes down to the unexcited ground state turning blue and emitts one photon in random direction.
Step 4:  This process goes on repeatedly, using one or many particles how ever would be convinient for you.

For both the processes, if you would be using multiple particles, then it would be great to see then getting excited and and unexcited independently.  It would just make it more natural.  Of course if it would be ok with you or showing the process with just one particle would also be ok.

About the simulation of phase noise and nonlinearities, its relation involves very complex physics, which would not be needed to explain.  So it would be fine, i'll try and explain something for it.

Please do let me know if you have any questions about the stimulated and spontaneous emission animation steps.

Thank you very much for spending time for this project.  I really appreciate it.

Regards,

Tapan.

[Fu-Kwun Hwang]

Registed user can get files related to this applet for offline access.
Problem viewing java?Add http://www.phy.ntnu.edu.tw/ to exception site list
If java program did not show up, please download and install latest Java RUN TIME

This is what I have created according to your description:

You can change the probability between stimulated emission and spontaneous emission with slider.
Click the check box if you want to see the energy level.
You can click on the square box near the top to trigger the emission of incoming ray if you want, otherwise, it will be generated randomly (with selected probability).



I hope the animation is what you want. Let me know what you would like to be modified. :-)

Registed user can get files related to this applet for offline access.
Problem viewing java?Add http://www.phy.ntnu.edu.tw/ to exception site list
If java program did not show up, please download and install latest Java RUN TIME

[katwalatapan]

Dear Mr. Hwang,

Thank you very much for your effort.  This is a very good animation that you have developed.  Really showcases your skill in the software development area.  It would be very helpful in the presentation.  It is really appreciated. 

Regards,

Tapan.

[katwalatapan]

Dear Mr. Hwang,

I had one question though.  How do I put the animation from the html page into a powerpoint presentation as it is developed in java?

Regards,

Tapan.

[Fu-Kwun Hwang]

Please check out LiveWeb - insert and view web pages real-time.

I modified the code a little so there is one more adjustable parameter-- probability to trigger incoming ray.
Please download new version again.

About the simulation of phase noise and nonlinearities, I will need the topic you are interested in and related model in order to create simulations for it.