|The Experimental Phaseand the 12th December, the Year 1960 Event:|
goes however, to the Bell Telephone Laboratories (BTL) management and the research
directors, every one of them known for their distinction, in facilitating every
ongoing work in the research division at
Here: As a
historical note here, within weeks time following his joining the Bell research
staff at Murray Hill, he begun to do what it would take to initiate with much
encouragement at Bell, a research project solely aimed at, what it would take
to develop, a working model of what proved as his original He-Ne laser. A Laser light source operating
with its collimated light beamat his predicted inverted transition in Neon with optical
gain, and at his predicted 1.25 μm transition in Neon. For which
What took place as it proved, followed a relentless effort, needed to investigate, prior to developing a completed design, the necessary experimental proof for this very first time, of every one of the fundamental effects and processes, predicted for this very first time as shown in above. The experiments performed were exacting. We shall give here solely the results, and shall rely on publications of everything shown, as reflected in the references to the publications given in the attached Supplement, a link to which shall be given below. And as a note here and briefly, the experiments were performed in the He gaseous discharges under the conditions developed and shown in above. This was always however, in presence of Neon as an impurity introduced in the gas discharge, where the predicted resonant energy exchange would take place, with Neon induced into its inverted energy state. This resonant energy exchange was a predicted effect which yet needed to be shown. For which much instrumentation was needed.
Much of, what had to be shown depended, and briefly here, on the energy storage properties of He in its metastable energy states, reflected in its exceptionally long life- time. As caused by the primary diffusion effect shown in above. Of which the first measurement, as a note here, took place in January-February time frame in now in 1959. A measured valueusing a special pulsed after glow method covered in its full detail in the attached supplement giving as it proved the exceptionally long life-time close to its predicted value. Measured and showing its exceptionally long-lived lifetime, τ = 3 x 10-3 second, 3 millisecond. The measurement followed not long after, with the again the exacting measurement of the cross-section σ of the resonant energy exchange effect, where Neon emerges in its excited inverted energy state. A measured value again close to its predicted value of σ = 3.6 x 10-16 cm2 as predicted in above. A value as needed as in a, b, and c in Part A in above needed to determine the number density of Neon in its predicted inverted energy state and hence the optical gain.
And much of what took place further however, were directed at determining the optimal He Ne gas discharge design conditionat which the resonant energy exchange with Neon will take place at the predicted number density that needed to be shown.
What mattered however: Was at the time, the need to have an exact measurement of the optical gain and amplification obtainable, at the predicted 1.25 μm inverted transition in Neon specifically. Please keep in mind, these days in our time, the measurement of gain and amplification in a material providing the gain is relatively simple. One merely needs to transmit a laser light beam through the material at the anticipated gain and amplification frequency, and measure the amplification and gain on the transmitted laser signal.
What took place in measuring the gain necessitated using a spectroscopic light source, of a type discussed in the attached Supplement. In particular the spectroscopic light source was necessary in Neon, with its non-collimated and incoherent spectral light at the Neon transitions. An exacting measurement, which would necessitate transmitting the generally weak, incoherent and non-collimated spectral light at the 1.25 μm spectral transition in Neon through a suitably, designed He Ne gas discharge, where the resonant energy exchange effect will take place. And collecting solely the transmitted light at the 1.25 μm Neon wavelengthnecessitating the use of a high resolution spectrometer and suitable optics. As reflected in publication of this original experiment referenced in the attached supplement. This is an abbreviated account of the experiment, which yet necessitated as shown in the publication, to detect the transmitted signal with out interference from the 1.25 μm spectral light emitted by the gas discharge itself.
For this very first time in the history in Physics, the measurement of an optical gain at a measured gain factor never known possible at any time before. As it took place again for this very first time at the 1.25 μm inverted transition in Neon.
The Historic Experiment toook place for this very First Time in the First Week in February the year 1960.
The experiment was repeated over and over again, recognizing significance of what had just been shown. And that further, the measured value of the gain factor obtainable, was necessary to develop the completed designto operate at the 1.25 μm transition in Neon.
And, because of its historical
significance, Javan original Bell laboratories Note Book in developing the
experiment in measuring for this very first time, the gain and amplification at
an optical frequency: is preserved
in the archives of the Bell laboratories in Milton, New Jersey. Preserved
together with Javan's 10 notebooks recording his
entire work at the
This is an opportunity here to acknowledge here
presently, the help and assistance of the support staff that has made possible
what is told in above and in what will now follow below. Especially I would
like to acknowledge the help of William J. Bennett, Edward Balick,
and Donald Heriot as well as the
And Further, On Interferometer Design Needed: To Regenerate Gain and Amplification -Effect:
Again with reference to the attached Supplement, at the inception of his, Ali Javan, original idea and shortly there after, and for the need regeneration of the gain and amplification: He, Javan, introduced for the very first time again, the concept of using 2 parallel, highly reflecting mirrors spaced by the length of his gas-discharge design with the optical gain. Which enabled the regeneration of the gain and amplification needed, to drive the 1.25 μm inverted transition into its self-sustained oscillation mode. However, with the then obtainable mirrors at high reflectivity available, yet a by far more exacting consideration had to be taken into account. That of the need to bring the reflecting mirrors into an exact parallelism to within a very small fraction of a wavelength needed. The available optical methods at the time that of an autocollimator would only enable to bring the high reflecting mirrors into the parallel configuration needed, hardly yet to within one or two wavelengthsat which the peripheral losses will sizably, exceed the reflection losses. For which the estimated gain factor needed, had to be sufficiently large to overcome the unavoidable peripheral and other Interferometer-lossesneeded to drive the design into its self sustained oscillation mode.
This measured gain and amplification factor at the 1.25 μm inverted neon transition had to exceed, and very briefly here, by at least a factor of 10, his estimated peripheral losses. Knowing however, that the longer the length of the gas discharge design, the larger shall be the total gain obtainable, across the full length of the gas discharge. Other considerations not covered here are a subject of special significance covered in the attached supplement.
From these, he had determined the full length of the gas discharge design, had to exceed one half of one meter. He chose one metera critical parameter in the design.
And then from which and all of the above, emerged the completed design in August-September of now the year 1960.
The Concluding Phaseand through the Historic 12 December Event:
By the beginning of October, and again as a historic