Curious question about light/photons

[JG Questions]

Hi there,

If a photon wavelength (yellow) is isolated from the other wavelengths that sunlight emits (once it gets to earth), can that particular particle/photon be distorted slightly into a wavelength that is shorter (perceived as green)?

If yes; please explain.
If no; please explain.

Thank you!

 

[mfb]

What does "isolated" mean here?

To perceive it as green, you need (a) a rocket moving towards sun at relativistic speeds or (b) a neutron star or black hole, blueshifting the wavelength. Not so practical.

 

[JG Questions]

I guess my responses to your answer are:

1. Can you separate/isolate certain wavelengths of light from the total spectrum that our star gives off (after that light goes through our atmosphere)?

2. If that isolated light has a wavelength of about 570 nm (yellow) can it be manipulated or distorted to equal a slightly shorter wavelength of about 510 nm (green)?

Please explain why if yes or no, if possible.

Thank you so much,

 

[blue_leaf77]

1. Can you separate/isolate certain wavelengths of light from the total spectrum that our star gives off (after that light goes through our atmosphere)?

Use the so-called monochromator, which basically consists of a light decomposer (e.g. diffraction grating or prism) followed by a slit to let through only the wavelength of interest.

2. If that isolated light has a wavelength of about 570 nm (yellow) can it be manipulated or distorted to equal a slightly shorter wavelength of about 510 nm (green)?

It might be possible by utilizing Raman anti-Stokes scattering.

 

[ChrisVer]

1. Can you separate/isolate certain wavelengths of light from the total spectrum that our star gives off (after that light goes through our atmosphere)?

you can filter the wavelengths when you observe them on the Earth.. there are different types of filters that allow certain wavelengths to go through them.

2. If that isolated light has a wavelength of about 570 nm (yellow) can it be manipulated or distorted to equal a slightly shorter wavelength of about 510 nm (green)?

mfb already gave the answer... 1 of them was the Doppler effect on light to measure a different wavelength \lambda_m than the oiginal source's one \lambda_o...

 

[mfb]

It might be possible by utilizing Raman anti-Stokes scattering.

You can also collect the sunlight with a solar cell and operate a light bulb with its electricity. I'm just not sure if that counts. You can also send the photon through a few million acousto-optic modulators, neglecting the efficiency issue.

All those things are not slight modifications. Most of them capture the light and then produce new light.

 

[JG Questions]

monochromator

Does a monochromator weaken the energy of the desired frequency?

 

[JG Questions]

you can filter the wavelengths when you observe them on the Earth.. there are different types of filters that allow certain wavelengths to go through them.
mfb already gave the answer... 1 of them was the Doppler effect on light to measure a different wavelength \lambda_m than the oiginal source's one \lambda_o...

This application requires i stay put.. Are you saying that mfb answered the only ways that one frequency of light can be distorted into another frequency?
In the doppler effect and in a rocket, that is relativistic, not practical, am i right? Please explain, if possible.

 

[JG Questions]

Raman anti-Stokes scattering.

Can you please explain how it would be possible using this and if any energy is lost in the process? Thank you

 

[JG Questions]

You can also collect the sunlight with a solar cell and operate a light bulb with its electricity. I'm just not sure if that counts. You can also send the photon through a few million acousto-optic modulators, neglecting the efficiency issue.

All those things are not slight modifications. Most of them capture the light and then produce new light.

It appears that the "acousto-optic modulators" use radio frequencies and sound waves, so I am guessing that there will be loss of energy in this scenario?

Is there any way to use a material to physically distort red light (650 nm) to be 651nm?, possibly by speeding up its wavelength through a medium or any other way to prevent loss of energy?

 

[blue_leaf77]

Does a monochromator weaken the energy of the desired frequency?

A monochromator necessarily reduces the total beam energy because you are extracting a group of photons having certain small frequency interval out of the entire input bandwidth.

Can you please explain how it would be possible using this and if any energy is lost in the process? Thank you

The energy levels diagram for this process looks like

Here you need two input beams, one with frequency $\omega_{pump}$ (which is equal to $\omega_{probe}$, so the pump and probe beams have the same frequency) and another one with $\omega_{Stokes}$. The two frequencies are chosen such that $\omega_{pump}-\omega_{Stokes} = \omega_{vib}$. The material is first excited by $\omega_{pump}$ to a virtual level (left dotted line), then $\omega_{Stokes}$ beam triggers stimulated emission of frequency $\omega_{Stokes}$ bringing the medium to a higher level than the starting one. Then the medium is re-excited by the probe beam to another virtual level (right dotted line). Upon going back to the starting level, the medium emits a light of frequency $\omega_{CARS}$ which is larger than the input $\omega_{pump}$. You can find more about this process by searching Coherent Anti-Stokes Raman Scattering (CARS).

 

[JG Questions]

A monochromator necessarily reduces the total beam energy because you are extracting a group of photons having certain small frequency interval out of the entire input bandwidth.

Definitely. So, of the desired frequency interval that i choose, will there be a loss of energy within that frequency or will that frequency remain unchanged? Also, is there a way to filter the desired frequency WITHOUT dispersing the rest of the electromagnetic spectrum? In the end, i would like to marry them back together actually.

(I will research CARS right now, thank you very much)

 

[blue_leaf77]

A loss of energy may come from the efficiency of the monochromator, if a prism is used, then the main loss is due to the reflection on the faces of the prism. If a grating is used, then the fact that the beams are separated into different diffraction orders upon diffracting limits the efficiency.

 

[mfb]

Does a monochromator weaken the energy of the desired frequency?

No, it just blocks all frequencies apart from a narrow range. Well, at least for an ideal monochromator.

This sounds like an x-y-question. What do you actually want to do?

 

[JG Questions]

No, it just blocks all frequencies apart from a narrow range. Well, at least for an ideal monochromator.

This sounds like an x-y-question. What do you actually want to do?

Haha, after reading this: http://meta.stackexchange.com/questions/66377/what-is-the-xy-problem
You might be right.

2-fold:

1. I want to explore possible creation of a basic Arithmetic Logic Unit for a CPU inspired design, deconstructed of course. By isolating sections of the electromagnetic spectrum i hope to channel (at first) 6-8 different fixed frequencies with a starting point and ending point (spatially) Point A to Point B. With code, and then CPU, frequency will at point B represent computations from Point A by effectively raising, lowering or staying the same the frequency between point A and B. The end result basically would have thus have created a computation represented by the degree of change in frequency leading to; output from the Arithmetic Logic Unit. I can go more into depth with this if you would like, its a bit hard to put into writing without explaining the method of computations and processes i would like to tackle after success of this feat. In a CPU the ALU is what does the grunt work, and its difficult to keep pace for other components to store that information. (this is after the ridiculous cramming of near atomically measured systems). However: (http://gizmodo.com/a-new-light-based-memory-chip-could-change-the-fundamen-1731307674) and other ways to store light were created, thus giving the possibility to eventually fully eliminate the 0 & 1 binary system down the line and develop a new system with infinite degrees of exponential assignments, exponential computations, results, and possibly compute faster than basically anything, with minimal use of conventional devices.

Meeting with physics teachers, professionals in the field, and other trusted people has generated great excitement between us, but also lead me to some other exciting thoughts:

2. If you could manipulate the spectrum of light that is of significance to creating sustainable energy, with less loss of energy than standard methods of deriving power from light (photovoltaics or others), you could potentially:
a. divorce each frequency-or-'sections of frequency' into respective filters
b. shorten each sections wavelength in an incremental and respective step sequence
c. marry the energy back together at a single shortest frequency possible, thus forcing greater energy efficiency generated entirely from sunlight.

 

[cave man]

Light is an electromagnetic force. Or one effected by magnetism. That is why it is given a "frequency". How do you tune a radio frequency to one you desire? The same principle can be applied to tuning light frequencies. Lights frequencies can be received just as radio frequencies can. It all depends upon your receiver's ability to convert the signals into what you want to tune. In short, you have to convert light into a prismatic range of frequencies that are presented to you. Once you do that you can select the one you want. You then amplify this into a projection device to achieve your color. The projection device should be able to do this conversion by identifying the frequency as given to it and referenced to the spectrum of light. The prism in the device would match the total wavelengths of white light and only project that light selected by the frequency sent to it.

 

[FerPhys]

I'm a little unclear on the question and I'm no where near qualified to add to this since I don't even have my Bachelors yet but I'll give it a whirl.
I think what you're asking is; is there any way we can manipulate wavelengths of colors to perceive the world in a different color?
I think the answer is no. Since we are talking about light here you have a photon moving at speed c (the speed of light) with a frequency and a wavelength. In order to change the wave length and make it go down (shorter) you have to change the frequency(higher) to make it stay at the speed of light. So we would have to be moving towards the sun at an incredible velocity. I don't know how correct I am on this. Just some late night thoughts.

 

[mfb]

Why do you want to change the frequency? Changing intensity or polarization is so much easier. And even that is a very challenging task. Optical computing has some interesting applications, mainly for fast internet data transfer (where the data transmission is optical already, so you save two conversion steps). I don't think replacing a whole ALU or even the whole CPU with optical elements is a realistic option in the near-term future.

2. If you could manipulate the spectrum of light that is of significance to creating sustainable energy, with less loss of energy than standard methods of deriving power from light (photovoltaics or others), you could potentially:
a. divorce each frequency-or-'sections of frequency' into respective filters
b. shorten each sections wavelength in an incremental and respective step sequence
c. marry the energy back together at a single shortest frequency possible, thus forcing greater energy efficiency generated entirely from sunlight.

You cannot reduce entropy, and you cannot violate conservation of energy either. Upconversion of infrared light for photovoltaics is studied, but multiple layers sensitive to different wavelength ranges are possible as well.

 

[JG Questions]

How do you guys explain what we have been doing here then?
http://phys.org/news/2015-05-team-big-faster.html

 

[davenn]

How do you guys explain what we have been doing here then?
http://phys.org/news/2015-05-team-big-faster.html

so, It's taken 19 posts for you to get to the core of what this thread is all about

you said "we" ... are you stating that you are part of this engineering team ?

and what does this new info have to do with your original Q ?Dave

 

[Jon B]

How do you guys explain what we have been doing here then?
http://phys.org/news/2015-05-team-big-faster.html

JG, Your original question and this article are like apples and oranges. Originally you asked about modifying the speed of light or its frequency. The article is talking about splitting a light beam to polarize its propagation the way they use horizontal and vertical polarization to enhance microwave transmissions.

Jon B

 

[MichaelCC]

Definitely the wavelength of light can be changed, simply send it into a medium with lower speed of light (i.e. glass) but observing it is more difficult because it reverts back on exit of that medium.

 

[Jon B]

Definitely the wavelength of light can be changed, simply send it into a medium with lower speed of light (i.e. glass) but observing it is more difficult because it reverts back on exit of that medium.

MichaelCC,
Like shining a red light through blue jello? no light comes out.

Do you mean that you can use glass as a delay for light so a single beam that is split so one the goes through air can be phase shifted from the one that went through glass?
Jon B

 

[mfb]

How do you guys explain what we have been doing here then?
http://phys.org/news/2015-05-team-big-faster.html

This has nothing to do with the original question of changing the color of light.

@Jon B: The wavelength depends on the refractive index, so you get a different wavelength in the material. That is not a permanent change and does not change the color, of course, but technically it is a different wavelength while in the medium.

 

[JG Questions]

so, It's taken 19 posts for you to get to the core of what this thread is all about

you said "we" ... are you stating that you are part of this engineering team ?

and what does this new info have to do with your original Q ?Dave

Sorry, I am mixing up my forums here. I asked the same question in another setting and i got an answer related to taking lower frequency light to split its frequency in half and shrink the wavelength of the photons which lead me on another path that wasnt listed here in this forum. I started asking questions to find an answer to sort of bend and distort a frequency of light that had been isolated from other frequencies to try to then marry that frequency back into the other light and possibly double its intensity. I was pointed towards green laser pointers and the mechanics of them, we were talking about different methods to get to the same result, and what this has to do with my original question is basically; everything! You can see my followup with my 2 fold results i was looking for, yet i believe nobody really is fully understanding what I am asking because I am not equipped with the language necessary to communicate it myself. I was early trying to get a few creative options to meet my goal and hope that someone could point me in some directions i wouldn't have previously thought of. ie - creativity, etc. Do you have anything to add? I am incredibly open to solutions to try to either split a frequency of visible light to create another frequency, or to isolate one small group of visible frequencies and somehow electromagnetically distort them even slightly so that they can be married back to the full spectrum and intensify other frequencies of light, for a purpose that's end goal would be to followup with my 2 fold question/results desired.. If that makes sense. It is quite early... Hope that makes sense

 

[JG Questions]

MichaelCC,
Like shining a red light through blue jello? no light comes out.

Do you mean that you can use glass as a delay for light so a single beam that is split so one the goes through air can be phase shifted from the one that went through glass?
Jon B

Jon, Actually I am pondering many methods of trying to slightly change the frequency of an isolated wavelength of light by using either magnetism and medium together to effect it and then marry it back to the light it was isolated from, thus intensifying certain frequencies. In this effect, i might be able to intensify the frequencies for instance; that a photovoltaic converts to electricity after it swipes all the light using the Fresnel lense.

Random thought:I wonder can you somehow put a photovoltaic inside a medium that effects light in such a way that it can be manipulated just before it enters the photovoltaic? bonkers question i know

 

[mfb]

I started asking questions to find an answer to sort of bend and distort a frequency of light that had been isolated from other frequencies to try to then marry that frequency back into the other light and possibly double its intensity.

You cannot violate conservation of energy.
Things like downconversion and upconversion in solids are possible, but you always lose intensity there.
Acousto-optic modulators are quite efficient for small changes in the frequency (~100 MHz), but again, you do not "intensify" anything there.

 

[JG Questions]

Ok, understood.

So, if you had say 1200, 1100, 1000, 900, 800, 700, 600 respectively in wavelengths of light i wish to capture from a source that emits also 1300, 1400, ... on down. collectively they equal 700 units (100 per wavelength) that i wish to focus on.

Lets say i disperse the light into a prism, at the exit of the prism the dispersed light at 1200, using (https://en.wikipedia.org/wiki/Photon_upconversion) or another method we haven't touched on here, i split the wavelenth to 600, say 5% of that light makes it to 600. Then i do that for the whole lot of frequencies below and higher. Will i have violated the conservation laws if i measure that the frequencies from 600 on up to ultraviolet range are more intense than they were previously?

 

[mfb]

collectively they equal 700 units (100 per wavelength)

Units of what?

Will i have violated the conservation laws if i measure that the frequencies from 600 on up to ultraviolet range are more intense than they were previously?

No, but the visible to UV power will be a small fraction of the infrared power you started with.

 

[JG Questions]

1st question: Units just represent % of the light that comes from source.
100% of the light from source is received after dispersion,
100% of ultraviolet range remains due to no change in wave,
5% of manipulated light emits higher frequency
marriage of the 2 sources back together
105% ultraviolet energy?

2nd: please explain?

 

[JG Questions]

MichaelCC,
Like shining a red light through blue jello? no light comes out.

Do you mean that you can use glass as a delay for light so a single beam that is split so one the goes through air can be phase shifted from the one that went through glass?
Jon B

married back together after processing to intensify one frequency

 

[mfb]

Apart from a few special conditions, you also cannot just merge two sources of light to get a higher intensity without problems. You lose some other property, e. g. you have a larger angular spread of your light afterwards. If you just care about intensity, yes, you can increase the UV intensity a bit. Where is the point?

 

[JG Questions]

Apart from a few special conditions, you also cannot just merge two sources of light to get a higher intensity without problems. You lose some other property, e. g. you have a larger angular spread of your light afterwards. If you just care about intensity, yes, you can increase the UV intensity a bit. Where is the point?

What % of light does a photovoltaic transfer into energy? 20%?

 

[mfb]

Depends on the cell and the incoming light. 20% are realistic for commercial large-scale cells with sunlight. Nearly 50% have been demonstrated in the lab, and for monochromatic light even more is possible (e. g. https://www.researchgate.net/publication/224445543_III-V_solar_cells_under_monochromatic_illumination ).
All those numbers are easy to look up.

I still don't see where this would lead to.

 

[JG Questions]

theoretically you could change the wavelength of light that isn't picked up by photovoltaic into range, and then to ensure that even on low contact periods energy is still collected, you could change longer wavelength light into ultraviolet light and raise the efficiency of the energy collected. Or, create a new way of collecting energy from wavelengths closer to x-ray/ spectrum and shift the frequencies to higher energy wavelengths to create wavelengths that we get little of here on earth

 

[mfb]

Yes, and that idea is discussed in hundreds of papers, see also post #18.
Various google results.
So far, it is more efficient to add layers that are sensitive to longer wavelengths, instead of lossy conversion processes.

 

[Neandethal00]

If a photon wavelength (yellow) is isolated from the other wavelengths that sunlight emits (once it gets to earth), can that particular particle/photon be distorted slightly into a wavelength that is shorter (perceived as green)?

Collisions (scattering) with around 25000 electrons, which is not too high compared to the path the photon will travel, will increase its wavelength from 510 nm to 570nm by Compton Scattering.

 

[JG Questions]

Yes, and that idea is discussed in hundreds of papers, see also post #18.
Various google results.
So far, it is more efficient to add layers that are sensitive to longer wavelengths, instead of lossy conversion processes.

Thank you, i think you helped me immensely

 

[JG Questions]

so, It's taken 19 posts for you to get to the core of what this thread is all about

you said "we" ... are you stating that you are part of this engineering team ?

and what does this new info have to do with your original Q ?Dave

I had a couple talks with some leaders in the advancement in quantum computing yes. I am just being curious, and my original question is incredibly related i believe.

 

[JG Questions]

Why do you want to change the frequency? Changing intensity or polarization is so much easier. And even that is a very challenging task. Optical computing has some interesting applications, mainly for fast internet data transfer (where the data transmission is optical already, so you save two conversion steps). I don't think replacing a whole ALU or even the whole CPU with optical elements is a realistic option in the near-term future.You cannot reduce entropy, and you cannot violate conservation of energy either. Upconversion of infrared light for photovoltaics is studied, but multiple layers sensitive to different wavelength ranges are possible as well.

Quantum computing needs exactly that, replacing the ALU with optical elements

 

[mfb]

Quantum computing needs exactly that, replacing the ALU with optical elements

Depends on the objects used for computation.
And for quantum computers, you do not replace the ALU. You add a quantum system to a classical computer design, in the same way today's computers have specialized floating point units.

You keep mixing unrelated concepts here.

 

[Redbelly98]

Collisions (scattering) with around 25000 electrons, which is not too high compared to the path the photon will travel, will increase its wavelength from 510 nm to 570nm by Compton Scattering.

Compton scattering was my first thought as well. But I don't follow why 25,000 would be necessary, it should be possible with one collision if the electron has the right amount of KE.

http://phys.org/news/2015-05-team-big-faster.html

Am I the only one who wonders about news titles that read "Computing at the speed of light" when talking about optical computing? To my knowledge, conventional electronic signals propagate at speeds comparable to c as well. At least that's true for signals traveling down coax lines, I'm not certain about propagation inside a chip.

 

[mfb]

Compton scattering was my first thought as well. But I don't follow why 25,000 would be necessary, it should be possible with one collision if the electron has the right amount of KE.

I guess that number was assuming electrons in solids - nearly at rest.

Am I the only one who wonders about news titles that read "Computing at the speed of light" when talking about optical computing?

It makes great news titles. Light in vacuum is indeed a bit faster than electric signals in cables, but that advantage gets lost with glass fibres.