[Laser] Some History of the ~100 year old LED !!

[J. Forster]

When I took semiconductor physics lab in the early 1960s, there were
experiments demonstrating both recombination light and optical pair
injection...  emission and detection.

Best,

-John

================


> I think I cut off his last name!
>
> Oleg Vladimirovich Losev
>
> And the title of his first paper documenting the effect:
>
> "Luminous carborundum (silicon carbide) detector and detection with
> crystals, published 1927.
>
> So Oleg was uing the same crystal as both an emitter and detector !!!
>
> Perhaps this is where Mims got the idea of using LEDs as detectors or
> maybe
> it was one of those forgotten ideas that was re-discovered???  Although
> Mims
> is credited with '-discovering-' the effect (using an LED as a detector),
> it
> appears as though the effect was known and documented many years before by
> Oleg.
>
> Oleg passed away in 1942, two years before Mims was born.
>
> =====
>
> ----- Original Message -----
> From: "laser" <laser at codeadam.com>
> To: "Free Space LASER Communications" <laser at mailman.qth.net>
> Sent: Thursday, November 18, 2010 10:50 PM
> Subject: [Laser] Some History of the ~100 year old LED !!
>
>
>> =====
>> ----- Original Message -----
>> From: "Tim Toast" <toasty256 at yahoo.com>
>> To: <laser at mailman.qth.net>
>> Sent: Thursday, November 18, 2010 9:06 PM
>> Subject: Re: [Laser] led trx
>>
>>>  I'm still not sure if it isn't
>>> the first single optic transverter though?? - something to hash
>>> out maybe!
>>>
>>> -toast
>> =====
>>
>> I think that was done in 1980 by Forrest M. Mims III (born 1944).
>>
>> http://en.wikipedia.org/wiki/Forrest_Mims
>>
>> =====
>> "Using LEDs as narrow band light sensors
>>
>> Among Forrest Mims many accomplishments, he was the first person to
>> realize
>> that LEDs (Light Emitting Diodes) had the ability to not only emit
>> light,
>> but also to sense light. This dual-action (emission/detection) of LED's
>> or "Mims Effect" was unknown before his discovery.
>>
>> While studying government (my major) in college, I found that certain
>> silicon photodiodes can emit near-infrared radiation that can be
>> detected
>> by
>> similar photodiodes. I managed to send modulated tones between such
>> photodiodes. In 1971 I demonstrated the ability of many LEDs to detect
>> light
>> while experimenting with an optical fiber communication system. By
>> placing
>> a
>> single LED at each end of the fiber, it was possible to send signals
>> both
>> ways through the fiber with only a single, dual purpose semiconductor
>> device
>> at each end of the fiber.
>>
>> In 1980, Mims demonstrated the dual use concept of LEDs by building a
>> bi-directional LED voice-communication circuit that allowed two people
>> to
>> transmit speech optically through the air and also through a 100-meter
>> section of optical fiber. This demonstration was done at 1325 L Street
>> in
>> Washington D.C. - exactly the same site where Alexander Graham Bell
>> invented
>> lightwave communications exactly 100 years earlier! Present for the
>> demonstration, which was sponsored by the National Geographic Society,
>> were
>> representatives from National Geographic, the Smithsonian Institution
>> and
>> Bell Labs."
>> =====
>>
>> I think the hardware was featured as a construction project by Mims in
>> Popular Electronics around the same time.
>>
>> Something else I learned quite some time ago is that the LED is approx.
>> 100
>> years old!!!  Yes ONE HUNDRED !!! Most people think LEDs have only been
>> around since the 60's.
>>
>> http://en.wikipedia.org/wiki/Oleg_Losev
>> and
>> http://www.orc.soton.ac.uk/fileadmin/downloads/100_years_of_optoelectronics__2_.pdf
>>
>> If for some reason the links don't work to a search for:
>>
>>> Oleg Vladimirovich carborundum crystal LED
>>
>> I remember stumbling across this effect many years ago (not quite a 100
>> but
>> it seems like it :-^) when I was playing around with crystal sets and
>> cat
>> whisker detectors using various mineral rocks as detectors.  Of course
>> my
>> favorite was galena, (iron pyrite) also known as fool's gold.  Although
>> I
>> managed to improve the sensitivity of the galena detector by applying a
>> slight bias (I could hear weaker stations) I kind of lost interest in
>> the
>> effect as my primary goal was trying to improve the volume level,
>> something
>> which the bias had little or no effect.
>>
>> The shock came when I swapped the galena crystal for a chunk of
>> carborundum
>> (silicon carbide).  The carborundum crystal was always noticeably less
>> sensitive than the galena crystal so I proceeded to use the same bias
>> technique I was experimenting with on the galena crystal with the hope
>> that
>> I could make the carborundum crystal at least as sensitive as the galena
>> crystal.  Although I didn't notice it at first (because it was
>> daylight),
>> late one night as I was moving the cat whisker around in a dimly lit
>> room
>> and playing around with the DC bias I thought I saw a very dim light
>> coming
>> from the point where the cat whisker was touching the caborundum.
>> Although
>> it was difficult to re-produce on a regular basis it was always possible
>> to
>> achieve after some playing around.  And it wasn't the cat whisker or the
>> rock glowing from heat as the current wasn't high enough to heat either.
>> This was a cold light!
>>
>> Back then there was no internet so it wasn't until many years later that
>> I
>> discovered that the effect was discovered and documented by Oleg
>> Vladimirovich and published in 1927 in the journal Telegrafiya i
>> Telefoniya
>> bez Provodov (Wirelsss Telegraphy and Telephony) in Nizhniy Novgorod,
>> Russia.  He published 16 papers on the effect between 1924 and 1930.  He
>> even modulated the emitted light at frequencies up to 78.5 Khz by
>> applying
>> AC current to the contact.
>>
>> Most remarkable for a technician with no academic qualifications!!!
>>
>> So when someone brings up the subject of subcarriers and LEDs it's
>> really
>> not as new as most people think!!!  Nor is using an LED as a detector or
>> using the same device as both emitter and detector!
>
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