Is it possible to reflect a laser beam off a condenser microphone capsule??

Thread Starter

Ts2012

Joined Jul 22, 2018
3
i am working on this small project where I need to detect the acoustic vibrations from a capsule of condenser microphone using laser pointer beam. Can the capsule material reflect the beam. What type of material will do so. As gold sputtered condenser microphones will do the job but they are very expensive
 

Papabravo

Joined Feb 24, 2006
16,509
i am working on this small project where I need to detect the acoustic vibrations from a capsule of condenser microphone using laser pointer beam. Can the capsule material reflect the beam. What type of material will do so. As gold sputtered condenser microphones will do the job but they are very expensive
I wouldn't think so, but who knows yours might be different than the rest.
 

oz93666

Joined Sep 7, 2010
737
Almost certainly it will reflect the beam , but my understanding is the surface is not a plane surface, in the operation of the mike the surface becomes concave/convex so this will not reflect the laser as a tight beam , it will diverge/converge and may quickly lose it's intensity if your detector is not at the right distance . Putting the detector close to the mike may help.
 

drc_567

Joined Dec 29, 2008
1,135
There is an interesting optical phenomenon that can be produced by reflecting a ray or beam of light off of a small piece of mirror. The said mirror is to be glued to a scrap of balloon that has been stretched over one end of a can which has had both ends removed. The acoustic input is slmply directed into the open end of the can. If the noise is a reasonably simple combination of frequencies, such as a wind instrument, the image that is reflected from the mirror will be an interesting pattern, a figure 8, as I recall.

... probably requires some additional modifications for your purpose.
 

Ramussons

Joined May 3, 2013
1,031
What is the intention? If you intend to pick sound vibrations why not reflect a laser from a plain diaphram? Why a mic at all?
Or is it something else altogether?
 

Thread Starter

Ts2012

Joined Jul 22, 2018
3
What is the intention? If you intend to pick sound vibrations why not reflect a laser from a plain diaphram? Why a mic at all?
Or is it something else altogether?
Hii,
I am studying the acoustic vibrations using laser interferometer but the problem is I need to use a microphone diaphragm instead of a mirror in interferometer so laser beam is going to be received at a photo detector by reflecting off a microphone diaphragm and one mirror. I need to use the condenser microphone diaphragm for the reflecting laser beam. And it has the aluminium case so will it reflect or not.
 

Thread Starter

Ts2012

Joined Jul 22, 2018
3
Almost certainly it will reflect the beam , but my understanding is the surface is not a plane surface, in the operation of the mike the surface becomes concave/convex so this will not reflect the laser as a tight beam , it will diverge/converge and may quickly lose it's intensity if your detector is not at the right distance . Putting the detector close to the mike may help.
Thank you
 

Bordodynov

Joined May 20, 2015
2,890
And have you not heard about the spy device - a laser microphone that catches the vibration of the window glass at a distance of tens of meters. The glass vibrates under the influence of sound. I understand that your task is much easier! I think that it is necessary to modulate laser radiation at a frequency of 50-100 kHz and take this high-frequency optical signal. Then use the demodulator.
 
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