About This Project

We are completing a prototype of an optical analogue audio recorder / player and we want to finish and test it. It uses phase-stepping interferometric holography, alongside direct electronic modulation (intensity level) to modulate a laser interference pattern.

The optical modulation technique utilized should allow us to record an optical track in a much smaller space than a soundtrack on film stock, and with better dynamic range also; to record 30-60 min of hi-fi sound in an optical disc.

Ask the Scientists

What is the context of this research?

This is a new kind of gadget for anyone who does anything related to audio signals.

It will look like an old sound camera, used in the early days of sound film to record sounds synchronized with the image in an analog way, but it will have the modern look and functionality of the new optical and photographic equipment.
We reverse-engineered all methods of sound recording and measurement, and designed an optical transducer that could be considered the "optical version" of a stereo cutter head (for vinyl records).
After that, we spent a year and a half learning about optical components until we came up with a streamlined design of an optical table or fixture that could be retrofitted to a traditional laser engraving machine - to which we also added a turntable to engrave a photopolymer disc.

What is the significance of this project?

We are trying to make what it could be the best analogue recording and playback format for audio that is feasible to do.

If this goal is achieved, then analogue signals could be closer to digital in terms of reliability, and compete for the same market. Higher frequency signals could be recorded too, using reflective piezo exciters to modulate the phase of the signal, instead of audio motors, and a higher recording speed.

These signals could also be transmitted though optical fiber; and as another end goal of our project is to make an analogue optical modem for audio and video.

What are the goals of the project?

It is intended, once the prototype is built, to make a recording. This would validate the proposed technology.

We want to record a track 80 micron wide, recorded with a horizontal laser line of ~80micron x ~1 micron, on 3M PCB photopolymer. These disks could be then transfered to copies as it is done with masters holograms and gramophone masters, then read optically.

Our main goal is to update the recording and playback technology in a purely analog way, hoping to obtain a sound that surpasses the digital technology.

The recording head itself that can be seen an optical oscillator; which did not existed before. This could make optical communications more powerful than currently than mostly are limited to discrete signals or simple modulations.