Sound Laser? Focus Sound Like Laser?

[Tregg Smith]

Is there anything that focuses sound like is done with a lazer? That is where you wouldn't be able to hear anything unless you were in the beam path and maybe the intensity would be magnified.

 

[berkeman]

Is there anything that focuses sound like is done with a lazer? That is where you wouldn't be able to hear anything unless you were in the beam path and maybe the intensity would be magnified.

You going to talk to the geese to tell them to leave?

You can use a large parabolic dish to direct sound fairly effectively, at least out to some reasonable distance. There is a neat demo at the Exploratorium in San Francisco, where two parabolic dishes (IIRC, about 8 feet in diameter each) are set up about 50' across the room from each other. You have two people sit with their head at the focus of each dish, and you can talk quietly and hear each other across the room. Pretty neat.

 

[boneh3ad]

They have using ultrasonic waves. It is called a uaser (pronounced "wazer").

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

http://www.engr.uiuc.edu/news/index.php?xId=068908160784

 

[berkeman]

They have using ultrasonic waves. It is called a uaser (pronounced "wazer").

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

http://www.engr.uiuc.edu/news/index.php?xId=068908160784

Interesting angle on "stimulated emission" of ultrasonic waves...

 

[I like Serena]

Interesting topic!

Makes me wonder if you can *zap* stuff over long distances with your uaser.

 

[berkeman]

Interesting topic!

Makes me wonder if you can *zap* stuff over long distances with your uaser.

"You can call dogs from over a mile away..."

 

[I like Serena]

"You can call dogs from over a mile away..."

 

[Studiot]

I understood that lazing action was about coherence, not focus?

 

[berkeman]

I understood that lazing action was about coherence, not focus?

Yeah, the SE in LASER is the stimulated emission part, which is what I found surprising about the UASER article. They seem to be implying that they have been able to come up with a stimulated emission analog mechanism at ultrasonic frequencies. I haven't read the UASER article in a lot of detail yet, though, so I can't say much about their claim.

 

[poor mystic]

a stimulated emission analog mechanism at ultrasonic frequencie.

maybe this could be done with powdered or gaseous chemistry

 

[cpt_carrot]

Also don't forget the http://news.cnet.com/8301-17912_3-10267528-72.html" which creates a coherent beam of phonons

 

[Redbelly98]

Yeah, the SE in LASER is the stimulated emission part, which is what I found surprising about the UASER article. They seem to be implying that they have been able to come up with a stimulated emission analog mechanism at ultrasonic frequencies. I haven't read the UASER article in a lot of detail yet, though, so I can't say much about their claim.

Wouldn't a simple microphone+amplifier+speaker provide the sound analog of light amplification by stimulated emission? The speaker emits amplified sound in phase with the sound that hits the microphone.

I'm not sure of the benefits of this, other than it's a cool thing to research. It's not necessary to amplify ultrasound in order to generate a nice coherent beam; you can generate the beam with powerful enough electrical signals connected to ultrasonic transducers.

Also don't forget the http://news.cnet.com/8301-17912_3-10267528-72.html" which creates a coherent beam of phonons

That's pretty neat -- terahertz (ultra)sound!