Fair enough, the last comment was unnecessary. I thought we, including everyone else in this thread, were trying to gain more understanding of the topic. My original reply to the parent was to point a slight discrenpancy in someone else's post. This often occurs to me, so I assumed it was reasonable.
I was never trying to appear smarter than you, but I'm not sure what kind of response you were expecting to your previous post. Well whatever, think what you will.
The cavity is very large compared to the lasing wavelength(s). Therefore, it will have resonances at several wavelengths/frequencies. Each emitting layer has gain at a different wavelength, which can couple to the corresponding resonance of the cavity.
In the case of the Argon laser, you were using the cavity to force the source to emit light at a slightly different wavelength. You wouldn't be able to tune too much since the source has limited bandwidth, unlike the quantum cascade laser which uses multiple sources.
Yes you should, because what you have written doesn't prove anything.
I never said that solid-state/crystal lasers are exactly the same as semiconductor lasers. I only said that crystal lasers and semiconductor lasers both use crystals.
You should also learn that having books on your shelf doesn't make you knowledgable. You try reading them.
The light you see coming out the laser is a steadt state condition. Although there is a small transient time when the device is first "turned on", it would be very short. Therefore, you would never see that difference.
The timing of the light being emitted by the material does not matter since the resonance cavity, through multiple reflections, and the materials, through gain stimulated emission, will cause the light of a single wavelength to be in phase.
The only thing that is different between semiconductor lasers and crystal-based lasers is the method of pumping (and required electronics etc.) and the materials.
But in both cases, crystals are the source and the amplification medium.
Feel free to pick up a Solid State Physics book, you will see that semiconductors are crystals.
Explain to me where the light comes from then, in a ruby laser.
Oh wait, let me.
The crystal is pumped, with light or electrically, and generates light. The generated light leaves the crystal, hits a mirror, and re-enters the crystal. That is when the stimulated emission begins to occur. This effect is reinforced be multiple reflections by the mirros which is how all the light becomes in phase.
In semiconductors lasers, the same exact thing happens except the crystal fills the entire cavity.
The previous poster was right, the photons at the lasing wavlength *do* have the same phase.
Power is proportional to the square of the amplitude, not the energy.
The energy at a single wavelength increases because the photons add in-phase. The photons themselves do not increase in energy. If they did they would be a different wavelength. Energy is conserved because you only get as energy out (in the form of coherent light) as you out in (in the form of electrical/optical pumping). What the laser does is force the nearly all of the generated light to occupy the same state, creating the coherent intense beam of light.
The whole point of a laser is to get an intense and highly directional beam of light. The reason for this would be for coupling to an optical fiber or other such application. Also, since the energy density of the spot would be auite large compared to an LED, you would never want to use it as a light source. The naked eye would be damaged.
I agree. The majority of Mac users have zero interest in the command line. Most of them with have no clue that OS X is based on a *NIX and couldn't care.
I'm not passing judgement as to whether this is right or not, it's juts the way it is.
...one of two things has to happen. The average user must become more computer savvy, including being able to deal with a command line and wanting to understand to some degree what the OS is doing.
The other thing is Linux will have to become more like a the black box that other OSes are. Everything is hidden and little to no knowledge of what is going on is required.
It is unfortunate but if you look at other technologies, similar things have occurred. For example, look at the automobile. The complexity of them has gotten to the point that the average driver has little idea of the inner workings and they don't really want to know anyway. I realize this is a bad analogy but hoepfully it makes some sense.
The last part about the radio (or other electric device) falling into a tub is not quite right. Depending on the water in your area there can be quite a bit of mineral content that would make the water conductive. Even if this is not the case, the stuff (ions, etc.) that comes of the human body in the water will make it conductive. If you don't believe that then give it a shot.
You could add phone and wireless capabilities to a Visor through the expansion slot in the back. Also, you have an mp3 player, digital camera, and a whole mess of other stuff. Palm is the one that is just a PDA.
The laser diodes in laser pointers cannot be used for a number of reasons, here are a couple: 1) Wrong wavelength: you need lasers with a wavelength near either 1.3 microns or 1.55 microns to take advantage of the disperison and attentuation minimums of optical fiber. Laser pointers have wavelengths in the visible, near 650nm. 2) Very narrow linewidth is need to reduce pulse spreading . Laser pointer devices are relatively broad.
There are others but I can't think of them right now.
All this was said about MTV during its beginning, now look at it. IMHO, they suck but they are a strong cultural force in general and in the music industry like it or not. A video game channel would start out the same way, showing the same things over and over until a broad enough audience was generated. If you look at all the stupid stations you can get on broadband I don't think its much of a stretch for a vieo game channel.
How can this possibly be offtopic? Right in the story its talks about it being a repeat. Why don't you friggin' moderators tell me what the appropriate forum would be for this type of comment? I'm sick of getting modded down for stupid shit....well anyway end of rant. I probably just blew more karma, oh well.
Why isn't there a moderation system set up for the stories that are posted? What I mean is the stories themselves should be modded just like the comments. I think that would make the most open system possible. Also, the editors would have an additional measure to the types of stories that people respond to. That way things like this would be modded down as a repeat and ignored much easier.
This is not meant as a Troll, just constructive criticism.
It wouldn't. what I meant was if you had say LOTR that you wanted to display through one sheet of e-paper. You have to store the additonal text somewhere, while you read a page/line at a time. This is where some sort of storage would be necessary and high density storage isn't very flexible right now.
I think, as with most technology, things are developed in baby steps. To make such an all purpose single "e-page" would require additional electronics and a buttload of additional memory. All of that would make the things quite bulky and wouldn't be a considered a single page anymore. This is the just the first step to a truly stand alone, high-capacity electronic reader. Probably in ten to twenty years we could expect those. But, as I said, baby steps.
Slashdot Mirror
Sounds good. I'm an EE, about to graduate. Looking forward to the real world. Why did you leave physics?
Fair enough, the last comment was unnecessary. I thought we, including everyone else in this thread, were trying to gain more understanding of the topic. My original reply to the parent was to point a slight discrenpancy in someone else's post. This often occurs to me, so I assumed it was reasonable.
I was never trying to appear smarter than you, but I'm not sure what kind of response you were expecting to your previous post. Well whatever, think what you will.
The cavity is very large compared to the lasing wavelength(s). Therefore, it will have resonances at several wavelengths/frequencies. Each emitting layer has gain at a different wavelength, which can couple to the corresponding resonance of the cavity.
In the case of the Argon laser, you were using the cavity to force the source to emit light at a slightly different wavelength. You wouldn't be able to tune too much since the source has limited bandwidth, unlike the quantum cascade laser which uses multiple sources.
Yes you should, because what you have written doesn't prove anything.
I never said that solid-state/crystal lasers are exactly the same as semiconductor lasers. I only said that crystal lasers and semiconductor lasers both use crystals.
You should also learn that having books on your shelf doesn't make you knowledgable. You try reading them.
The light you see coming out the laser is a steadt state condition. Although there is a small transient time when the device is first "turned on", it would be very short. Therefore, you would never see that difference.
The timing of the light being emitted by the material does not matter since the resonance cavity, through multiple reflections, and the materials, through gain stimulated emission, will cause the light of a single wavelength to be in phase.
The only thing that is different between semiconductor lasers and crystal-based lasers is the method of pumping (and required electronics etc.) and the materials.
But in both cases, crystals are the source and the amplification medium.
Feel free to pick up a Solid State Physics book, you will see that semiconductors are crystals.
Explain to me where the light comes from then, in a ruby laser.
Oh wait, let me.
The crystal is pumped, with light or electrically, and generates light. The generated light leaves the crystal, hits a mirror, and re-enters the crystal. That is when the stimulated emission begins to occur. This effect is reinforced be multiple reflections by the mirros which is how all the light becomes in phase.
In semiconductors lasers, the same exact thing happens except the crystal fills the entire cavity.
This isn't quite correct.
The previous poster was right, the photons at the lasing wavlength *do* have the same phase.
Power is proportional to the square of the amplitude, not the energy.
The energy at a single wavelength increases because the photons add in-phase. The photons themselves do not increase in energy. If they did they would be a different wavelength. Energy is conserved because you only get as energy out (in the form of coherent light) as you out in (in the form of electrical/optical pumping). What the laser does is force the nearly all of the generated light to occupy the same state, creating the coherent intense beam of light.
FYI, semiconductors are crystals.
The whole point of a laser is to get an intense and highly directional beam of light. The reason for this would be for coupling to an optical fiber or other such application. Also, since the energy density of the spot would be auite large compared to an LED, you would never want to use it as a light source. The naked eye would be damaged.
I agree. The majority of Mac users have zero interest in the command line. Most of them with have no clue that OS X is based on a *NIX and couldn't care.
I'm not passing judgement as to whether this is right or not, it's juts the way it is.
The users that use other OSes, like windows and MacOS, don't really needto understand the OS because the installer does all the work.
Yeah, I don't quite understand it myself...
...one of two things has to happen. The average user must become more computer savvy, including being able to deal with a command line and wanting to understand to some degree what the OS is doing.
The other thing is Linux will have to become more like a the black box that other OSes are. Everything is hidden and little to no knowledge of what is going on is required.
It is unfortunate but if you look at other technologies, similar things have occurred. For example, look at the automobile. The complexity of them has gotten to the point that the average driver has little idea of the inner workings and they don't really want to know anyway. I realize this is a bad analogy but hoepfully it makes some sense.
Why does this apply to only tech companies?
During my short history on this planet, every single place I have worked seems to have this problem. Not just tech companies.
It seems to be human nature to not want to deal with the messy social part of management and handle only the relatively easy business part.
Just my 2 cents I guess.
The last part about the radio (or other electric device) falling into a tub is not quite right. Depending on the water in your area there can be quite a bit of mineral content that would make the water conductive. Even if this is not the case, the stuff (ions, etc.) that comes of the human body in the water will make it conductive. If you don't believe that then give it a shot.
Let me know what happens if you can....
The last piece I need for my Apple ][e mp3 jukebox!
j/k
You could add phone and wireless capabilities to a Visor through the expansion slot in the back. Also, you have an mp3 player, digital camera, and a whole mess of other stuff. Palm is the one that is just a PDA.
The laser diodes in laser pointers cannot be used for a number of reasons, here are a couple: 1) Wrong wavelength: you need lasers with a wavelength near either 1.3 microns or 1.55 microns to take advantage of the disperison and attentuation minimums of optical fiber. Laser pointers have wavelengths in the visible, near 650nm. 2) Very narrow linewidth is need to reduce pulse spreading . Laser pointer devices are relatively broad.
There are others but I can't think of them right now.
Just fyi...
All this was said about MTV during its beginning, now look at it. IMHO, they suck but they are a strong cultural force in general and in the music industry like it or not. A video game channel would start out the same way, showing the same things over and over until a broad enough audience was generated. If you look at all the stupid stations you can get on broadband I don't think its much of a stretch for a vieo game channel.
Just my 2 cents.
How can this possibly be offtopic? Right in the story its talks about it being a repeat. Why don't you friggin' moderators tell me what the appropriate forum would be for this type of comment? I'm sick of getting modded down for stupid shit....well anyway end of rant. I probably just blew more karma, oh well.
Why isn't there a moderation system set up for the stories that are posted? What I mean is the stories themselves should be modded just like the comments. I think that would make the most open system possible. Also, the editors would have an additional measure to the types of stories that people respond to. That way things like this would be modded down as a repeat and ignored much easier.
This is not meant as a Troll, just constructive criticism.
lol...
It wouldn't. what I meant was if you had say LOTR that you wanted to display through one sheet of e-paper. You have to store the additonal text somewhere, while you read a page/line at a time. This is where some sort of storage would be necessary and high density storage isn't very flexible right now.
I think, as with most technology, things are developed in baby steps. To make such an all purpose single "e-page" would require additional electronics and a buttload of additional memory. All of that would make the things quite bulky and wouldn't be a considered a single page anymore. This is the just the first step to a truly stand alone, high-capacity electronic reader. Probably in ten to twenty years we could expect those. But, as I said, baby steps.