13) Junichi Nishizawa and his "Semiconductor Maser" Patent
Picture: The Patent publication of the "semiconductor maser" filed
by Nishizawa (click to enlarge)
In early July, 1970 I heard for the first time of Bell Laboratory
group's achievement regarding room temperature continuous oscillation semiconductor
lasers.
I suddenly heard the telephone ring, so when I picked it up, Professor Junichi
Nishizawa of the Tohoku University Electrical Communication Institute told
me of Hayashi's success.
Nishizawa paid much attention to this, because he himself got the idea of
semiconductor laser and patented it at an old time when it was still beyond
the thought of industry.
The origin of the idea is from the result of masers in the mid 1950's. Although
the solid-state masers at that time could not yet amplify continuously, Nishizawa
thought that it might be possible for a semiconductor, and after some theoretical
calculations, he concluded that it was possible. So, in late April 1957, he
filed a patent under the name "semiconductor maser".
The photograph is the patent publication of the “semiconductor maser” patent,
and it starts in the text, "The present invention aims to provide a simple
and advantageous means for oscillation, amplification, detection, modulation,
etc. of ultra-short wave electrical signals using a semiconductor."
One unfortunate point for him was that in 1962, R.N. Hall of GE published
a paper on continuous oscillation (but at liquid nitrogen temperature), while
he had to spend much time to get research funds, and as a result his research
was a year late.
(Provided by Junichi Ishizawa)