Can a Laser and Reflective Material Create a High-Frequency Microphone?

  • Thread starter Thread starter Raven Luni
  • Start date Start date
  • Tags Tags
    Acoustic Design
AI Thread Summary
A discussion on creating a high-frequency microphone using a laser and reflective material explores the potential of detecting frequencies up to 100 kHz. The idea involves bouncing a laser off reflective material, with methods including phase shift detection through pulse width modulation and Doppler shift analysis. Key considerations include the choice of material properties such as thickness, surface area, and tension, as well as the possibility of a resonant frequency. Participants share resources, including patents and examples of existing acoustic sensors and optical detectors. The feasibility of this approach for the desired frequency range remains a central question.
Raven Luni
Messages
6
Reaction score
0
Greetings,

I've been looking for a way to create a microphone capable of picking up high frequencies (up to about 100kHz). Electrets don't tend to go that high and piezo crystals even detuned will only give a limited band.

I had the idea of bouncing a laser off a sheet of reflective material. The light can either be picked up directly, by pulsing the beam with a square wave and taking the phase shift as a form of pulse width modulation, or with a sine wave and using the doppler shift (I'll have fun experimenting with all these methods).

What I don't have any clue about is the material and what properties it should have. What kind of thickness, surface area, tension etc. would I need? Would there be a resonant frequency? Is it even possible for the frequency range in question?
 
Engineering news on Phys.org
Raven Luni, Welcome to Physics Forums! 

You may see this patent, which detects acoustic frequencies up to 100 kHz:
http://www.google.com/patents/US5146083

Here is a ready-made acoustic sensor you may learn from:
http://www.digikey.com/us/en/techzone/sensors/resources/articles/ultrasonic-mems-sensor-spm0404ud5.html
 
Last edited by a moderator:
Excellent information - thanks :)
 
Thread 'I need a concave mirror with a focal length length of 150 feet?'

Thread 'I need a concave mirror with a focal length length of 150 feet?'

I need to cut down a 3 year old dead tree from top down so tree causes no damage with small pieces falling. I need a mirror with a focal length of 150 ft. 12" diameter to 36" diameter will work good but I can't think of any easy way to build it. Nothing like this for sale on Ebay. I have a 30" Fresnel lens that I use to burn stumps it works great. Tree service wants $2000.
View full post »

Thread 'Questions about the Tesla turbine'

Hi all, i have some questions about the tesla turbine: is a tesla turbine more efficient than a steam engine or a stirling engine ? about the discs of the tesla turbine warping because of the high speed rotations; does running the engine on a lower speed solve that or will the discs warp anyway after time ? what is the difference in efficiency between the tesla turbine running at high speed and running it at a lower speed ( as fast as possible but low enough to not warp de discs) and: i...
View full post »
Thread 'Where is my curb stop?'

Thread 'Where is my curb stop?'

My water meter is submerged under water for about 95% of the year. Today I took a photograph of the inside of my water meter box because today is one of the rare days that my water meter is not submerged in water. Here is the photograph that I took of my water meter with the cover on: Here is a photograph I took of my water meter with the cover off: I edited the photograph to draw a red circle around a knob on my water meter. Is that knob that I drew a red circle around my meter...
View full post »

Similar threads

Cannot lock reference signal on lock-in amplifier
Replies
5
Views
2K
A Cavity locking using Lockin+PID technique
Replies
2
Views
3K
B What sound frequencies can pass through a hole in a wall?
Replies
31
Views
3K
Mechanical noise - A/C and radon fan standing wave hum
Replies
4
Views
4K
High frequency being transformed to a low frequency
Replies
20
Views
5K
What constitutes a closed end in acoustic resonance in tubes
Replies
8
Views
4K
Laser Lattice: Understanding Frequency & Wave Vector Effects
Replies
4
Views
1K
I Pound-Drever-Hall frequency stabilisation technique
Replies
1
Views
2K
Separating Acoustic Waves from Background Reflections
Replies
4
Views
2K
Modern Digital Audio: Understanding Dither and Oversampling in Hi-Res Age
Replies
17
Views
4K

Hot Threads

Recent Insights

Back
Top