physics

Rubin Braunstein

Rubin Braunstein is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Rubin Braunstein rather than just read about it. In short: Rubin Braunstein (1922–2018) was an American physicist and educator. In 1955 he published the first measurements of light emission by semiconductor diodes made from crystals of gallium arsenide (GaAs), gallium antimonide (GaSb), and indium phosphide (InP).

Key takeaways

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Reference excerpt

Rubin Braunstein (1922–2018) was an American physicist and educator. In 1955 he published the first measurements of light emission by semiconductor diodes made from crystals of gallium arsenide (GaAs), gallium antimonide (GaSb), and indium phosphide (InP). GaAs, GaSb, and InP are examples of III-V semiconductors. The III-V semiconductors absorb and emit light much more strongly than silicon, which is the best-known semiconductor. Braunstein's devices are the forerunners of contemporary LED lighting and semiconductor lasers, which typically employ III-V semiconductors. The 2000 and 2014 Nobel Prizes in Physics were awarded for further advances in closely related fields.

Early life and education Braunstein was raised in New York City. He earned a doctorate in physics from Syracuse University in 1954.

Career After university, he joined the research laboratory of the RCA Corporation, which was among the most active industrial laboratories at the time. In the following decade at RCA Laboratories he published broadly on semiconductor physics and technology. Beyond his seminal work with light emission from III-V semiconductors, in 1964 he exploited newly invented lasers to publish the first paper on two-photon absorption in semiconductors. Typically, only individual photons (particles of light) with some minimum energy are absorbed by a given semiconductor. For very high intensity beams of light, two photons, each with half that minimum energy, can be absorbed simultaneously. He also published highly cited foundation papers on the electronic, optical, and vibrational properties of III-V semiconductors, silicon, and germanium. In 1964 Braunstein became a professor of physics at University of California, Los Angeles (UCLA), where he remained for the rest of his career. His research there continued his RCA work with optoelectronic properties of semiconductors as well as contributions related to the optical properties of highly transparent materials such as tungstate glasses. Some of Braunstein's work was theoretical, including the proposal that neutral atoms could be scattered by a sufficiently intense standing wave of light. Since light is an electromagnetic wave, it had long been known that charged particles like electrons would be scattered. The effect with neutral atoms is much weaker, but was finally observed nearly 20 years after the proposal of Braunstein and his co-authors.

Braunstein was selected as a Fellow of the American Physical Society in 1964.

See also Light-emitting diode#History List of Syracuse University people

References

Further reading Braunstein, Rubin (1955). "Radiative Transitions in Semiconductors". Physical Review. 99 (6): 1892–1893. Bibcode:1955PhRv...99.1892B. doi:10.1103/PhysRev.99.1892. Braunstein, R.; Ockman, N. (20 April 1964). "Optical Double-Photon Absorption in CdS". Physical Review. 134 (2A): A499. Bibcode:1964PhRv..134..499B. doi:10.1103/PhysRev.134.A499. Rubin Braunstein describing work at RCA on YouTube. Family video. Herbert Kroemer, whose office at RCA adjoined Braunstein's and who later won the Nobel Prize in Physics, has told an anecdote about Braunstein's early use of an infrared emitting GaAs diode to transmit information. See Kroemer, Herbert (Sep 16, 2013). "The Double-Heterostructure Concept: How It Got Started". Proceedings of the IEEE. 101 (10): 2183–2187. doi:10.1109/JPROC.2013.2274914. S2CID 2554978. Braunstein had set up a simple optical communications link: Music emerging from a record player was used via suitable electronics to modulate the forward current of a GaAs diode. The emitted light was detected by a PbS diode some distance away. This signal was fed into an audio amplifier and played back by a loudspeaker. Intercepting the beam stopped the music. We had a great deal of fun playing with this setup. Pascoe, Sue (November 19, 2014). "Palisadian Rubin Braunstein's LED Discovery Cited". Palisades News. Archived from the original on 2019-03-30.

Illustrations

Worked examples

Example 1 — a first encounter with Rubin Braunstein

Start with the simplest possible case. Write down what Rubin Braunstein claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Rubin Braunstein before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Rubin Braunstein ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Rubin Braunstein

In research: Rubin Braunstein appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Rubin Braunstein in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Rubin Braunstein is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1922 births, 2018 deaths, 20th-century American physicists, so understanding it makes those chapters shorter.
In everyday life: Look for Rubin Braunstein outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Rubin Braunstein in 20 minutes

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Frequently asked questions

What is Rubin Braunstein in simple terms?

Why does Rubin Braunstein matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Rubin Braunstein?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Rubin Braunstein.