Bell Labs

Two Bell Labs employees, Russell Ohl and George Southworth, were trying in the late 1930s to detect ultrahigh-frequency radio waves with vacuum tubes, and like Skinner on the other side of the Atlantic, had no success. So, Southworth, a radio ham since childhood, remembered his early silicon-and-cat s-whisker deviees and managed to retrieve some old ones from a seeondhand radio store. Just as they did... 

Ohl demonstrated his results to Kelly early in 1940 Kelly felt that his instincts had been proved justified. Thereupon, Bell Labs had to focus single-mindedly on radar and on silicon rectifiers for this purpose. It was not till 1945 that basic research restarted. This was the year that the theorist John Bardeen was recruited, and he in due course became inseparable from Walter Brattain, an older man and a fine experimenter who had been with Bell since the late 1920s. William Shockley formed the third member of the triumvirate, though from an early stage he and Bardeen found themselves so mutually antagonistic that Bardeen was sometimes close to resignation. But tension can be productive as well as depressing. 

John Bardeen was a truly remarkable scientist, and also a very private, taciturn man. Pippard (1995) in his obituary of Bardeen, recounts how John returned home from the Bell Labs and walked into the kitchen to say We discovered something today to (his wife) Jane s regret, all she could find in reply to what proved a momentous statement was That s interesting, but I have to get dinner on the table . ... 

The role of the Bell Labs metallurgists in the creation of the early transistors was clearly set out in a historical overview by the then director of the Materials Research Laboratory at Bell Labs, Scaflf (1970). 

In the early years, physicists, metallurgists and chemists each formed their own community at Bell Labs, but the experience of collaboration in creating semiconductor devices progressively merged them and nowadays many of the laboratory s employees would rate themselves simply as materials scientists. 

These brief examples of developments in semiconductor technology and optoelectronics are offered to give the flavour of recent semiconductor research. An accessible technical account of MBE and its triumphs can be found in an overview by Cho (1995), while a more impressionistic but very vivid account of Capasso and his researches at Bell Labs is in a popular book by Amato (1997). A very extensive historical survey of the enormous advances in optical and optoelectronic physics , with attention to the materials involved, is in a book chapter by Brown and Pike (1995). 

At the age of sixteen, Townes entered Furman University and received two bachelor s degi ees (modern languages and physics) in 193.S. He continued his education, receiving a master s at Uuke University in 1937 and a doctorate at Cal Tech in 1939. In the summer of 1939, Bell Labs hired him. Numerous lines of research were being undertaken simultaneously at Bell Labs. Most of the work done by Townes initially dealt with basic research and the transmission of telephone and television signals. Worldwide political events, however, soon changed this emphasis. 

Just as the intellectual atmosphere of Bell Labs shaped Toivnes s career, the cosmopolitan diversity of New York City molded his personal life. He enjoyed the many theaters, niuselims, and restaurants there. He signed up for voice and music theoi y lessons at... 

Juilliard. And most significantly, he met Frances Brown, an activity director at the International House at Columbia University, whom he married in May 1941. The couple had four daughters. His work at Bell Labs had one downside—it often took him away from his family for trips to Florida where the radar bombing system was tested and re-tested. 

In 1957, Townes developed the equation that showed that this same process could also obtain much smaller wavelengths (in the infrared and visible light range). Townes collaborated with Aithur Schawlow, a research assistant in his laboratoiy from 1949 to 1951, who then moved on to become a physicist at Bell Labs where Townes was still doing consulting work. Wlien he was a postdoctoral fellow at Columbia, Schawlow met Aurelia, Townes younger sister, who had come there to study singing. Soon the two married. 

Schawlow continued working on his laser at Bell Labs. He had rejected ruby as an active medium because he felt it would not reach population inversion. By pumping the ruby with the light from a photographer s flash lamp, however, Maiman succeeded, created the world s first laser in June 1960. 

A further step has been taken by a group at Bell Labs, who built an all printed device on an ITO-coaled polyester substrate [631 all the subsequent layers,... 

I was working at Bell Telephone Laboratories at that time. Much of the radar development came out of applied work in industrial laboratories, and so did microwave spectroscopy. I persuaded the Bell Laboratories to let me do microwave spectroscopy, and so it started at Bell Labs, but it also started at General Electric, where a friend of mine began it. He did a little bit of work, but then the General Electric people said, no, you must stop, it s not going to have any use for us, we have no applications. So this work had to stop at General Electric. At RCA, another important electrical company, a friend of mine started it there, and he worked on it for a while, and the company said, no, that s of no value to us, we won t pay you anything for it, you must stop. 

I talked with one or two of my students about it. Also, I was consulting at that time with Bell Laboratories, and I had a very good, very happy consulting job. Bell Labs said, just come here one day every two weeks and talk with people here, you know, talk with them about what they re doing. We just want you to interact. That was a good idea from Bell Labs point of view, I guess, and it was a happy idea for me. So my brother-in-law Arthur Schawlow was there at the time and I went around and talked with him, of course - I got paid for talking with my brother-in-law about science - wow And I told him about this optical maser idea that I d had. He said, well, you... 

The reed switch was first invented by Bell Labs in the late 1930s. Most of the manufacturers of reed switches today produce very high quality and very reliable switches. This has given rise to unprecedented growth. 

Figure 3. Schematic of present and potential future optical lithography systems (a) Perkin Elmer Micralign (10), (b) Bell Labs printer (11), (c) reduction step-and-repeat (Censor, Electromask, GCA, Optimetrix, Philips), (d) IX step-and-repeat (Ultratech), (e) IX stripe scan, and (f) reduction step-scan, R indicates object and image orientations. Lenses are indicated only schematically. (Reproduced with permission from Ref. 30)...

Silicon s tetravalent pyramid crystalline structure, similar to tetravalent carbon, results in a great variety of compounds with many practical uses. Crystals of sihcon that have been contaminated with impurities (arsenic or boron) are used as semiconductors in the computer and electronics industries. Silicon semiconductors made possible the invention of transistors at the Bell Labs in 1947. Transistors use layers of crystals that regulate the flow of electric current. Over the past half-century, transistors have replaced the vacuum tubes in radios, TVs, and other electronic equipment that reduces both the devices size and the heat produced by the electronic devices. 

To a significant extent, the theoretical basis of modern communication theory arose from the work of Claude Shannon at Bell Labs. [80]. In these seminal works, the concept of the information entropy associated with an arbitrary signal arose. In 1981, Watanabe realised the close association between entropy minimization and pattern recognition [81]. An association between entropy minimization and the principle of simplicity is also recognized [82]. The basic mathematical form of signal... 

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