Path to mass-produced, low-cost lasers opened
Transcript of Path to mass-produced, low-cost lasers opened
Bromley: not neglecting small science
The budget puts the National Science Foundation back on track to doubling its funding by 1994, with an 18% increase to $2.7 billion. And in contrast to previous years, Bromley says, this year the increase is finding its way down to basic science, with a 16% increase to $2.1 billion for the conduct of research. At the National Institutes of Health, basic research funding would rise 7% to $5.5 billion, which he says will allow for an increase of 9% in research project grants for individual investigators.
Bromley also expects individual investigators to be the principal beneficiaries of the requested increase of 71%, to $125 million, for the Department of Agriculture's national research initiative. He expects a similar benefit from a requested rise of 34%, to $903 million, for an expanded energy technology R&D program that emphasizes displacing oil in the transportation sector, improving energy efficiency in buildings and industry, and advancing new electricity technologies.
Another major emphasis in this year's budget is mathematics, science, and engineering education at precollege through postdoctoral levels. The 1992 budget includes $1.94 billion for this area—an increase of $225 million, or 13%, over the 1991 budget. Moreover, the $1.94 billion represents the first coordinated interagency budget in science and
mathematics education that has ever been produced by the federal government.
Budget details for this area are presented in a report issued last week by the Committee on Education & Human Resources (CEHR), under the Federal Coordinating Council for Science, Engineering & Technology. A product of seven months of deliberations by the 16-agency CEHR, the report includes detailed budget crosscuts going back to fiscal 1990, as well as program descriptions from all participating agencies or institutions.
The report, which is titled "By the Year 2000," reflects one of the national goals set by the President and state governors following a 1989 education summit: "By the year 2000, U.S. students will be first in the world in science and mathematics achievement." Says Secretary of Energy James D. Watkins, CEHR chairman: "This budget puts resources where they can do the most to reach the goals—in precollege education, with greatest emphasis on our teachers."
Missing from the 1992 budget proposal is any major initiative designed to address the research infrastructure problem. In fact, the budget requests no funding at all to con-t inue NSF's new $20 mi l l ion Research Facilities Modernization Program.
Janice Long
Path to mass-produced, low-cost lasers opened Scientists at IBM's Zurich Research Laboratory in Switzerland have developed technology making it possible to fabricate up to 20,000 diode lasers on a 5-cm diameter semiconductor wafer. This is the first time, IBM says, that it's been possible both to mass-produce and to test the so-called semiconductor lasers on a complete wafer.
For the electronics industry, this achievement could lead to mass-produced, low-cost lasers for compact disc players, laser printers, magneto-optic read-write data storage discs, and fiber-optic data transmission systems. For chemists, it could lower
the cost of powerful absorption- and fluorescence-based detectors for academic, industrial, and clinical diagnostic instruments, which also could incorporate fiber optics.
"This is super-significant," physical chemistry professor Richard N. Zare of Stanford University tells C&EN. "The ability to make diode lasers much the way one makes chips offers the possibility of a revolutionary reduction in the price of lasers." And although these diode lasers emit 30- to 40-MW light from 830 to 850 nm—which is near-infrared—passage through nonlinear optical media could shift that to 415 to 425 nm, a useful, visible range for analytical chemistry. Says Zare, "If we have cheap blue light that's coherent, we'll be able to do all types of chemical analyses."
The team at the IBM lab in the Zurich suburb of Ruschlikon, led by Peter Vettiger, deposited layers of aluminum gallium arsenide epitaxi-ally onto gallium arsenide wafers to form the direct band-gap junctions and optical resonators of lasers. The team used reactive ion-beam etching to incise trenches 400- to S00-iim long and 5- to 6-Atm deep through lithographic resists. It coated these with a semitransparent reflective material to act as mirrors.
In each laser, passage of a current produces light, which is reflected back and forth between mirrors and finally passes out of the device through the semitransparent reflec-
5-cm-diameter wafer holds 5000 lasers
February 11, 1991 C&EN 5
News of the Week
tive medium. The IBM scientists also fabricated waveguides and photo-diodes next to each laser on wafer surfaces. Thus all lasers could be tested for flaws simultaneously on the uncut wafers in an automated system.
In the future, the technique could be used to combine lasers with other components on optoelectronic chips that use both light and current to process and transmit data. Among such components are concave mirrors to focus laser light, and convex mirrors to dilate beams for more efficient coupling into thicker optical fibers.
Stephen Stinson
Computational chem system aims at industry A new software system for computational chemistry aimed especially at industrial users was introduced by Cray Research of Eagan, Minn., last week at the Supercomputing Europe '91 conference in Stuttgart, Germany.
The system, called UniChem, was developed jointly by Cray and a consortium of major chemical and pharmaceutical companies—including Du Pont, Eli Lilly, Exxon Research & Engineering, 3M, and Monsanto. "The result is a software environment developed and tested by chemists for use by chemists," says John A. Rollwagen, Cray chairman and chief executive officer.
Quantum chemistry software has been developed mostly in academia and has been used more widely there than in industry. "But now it's becoming a tool for the industrial chemist," says Erich Wimmer, technical director of chemistry applications at Cray, "so we need to respond to [those] needs."
However, UniChem can also be used outside industry. For example, Scripps Clinic & Research Foundation, a nonprofit research group, has ordered it. To use UniChem, scientists must either have a Cray supercomputer at their facility or gain access to a shared supercomputer facility over a network.
UniChem combines a series of quantum mechanics programs under a graphical user interface. The
programs are MNDO90, a semiem-pirical program applicable to molecules of up to about 500 atoms; DGauss, a density functional program for molecules and clusters of up to 200 atoms; and CADPAC, an ab initio program for systems of up to 60 atoms. No molecular mechanics or molecular dynamics codes are currently included, but molecular structures from other programs can be imported into the system.
A major advantage of UniChem is that it provides a single, interactive user interface for all its programs. Until now, Cray says, computational chemists have had to learn a completely different set of commands for each such program, necessitating "extensive training and study for each tool before they are able to do productive work."
One knowledgeable source in the field of computational chemistry, who requested anonymity, believes Cray faces an uphill battle marketing the new system: "Scientists would prefer to control their own computing environment. They've never liked central computing centers, and the Cray is essentially a central-computing-center situation."
However, replies David A. Dixon, research leader at Du Pont Central Research & Development, "When you want to do really big problems, you have to go to a big machine. What this technology will let you do is communicate from your desktop workstation to run a big problem when you have to."
Stu Borman
U.S. offers greenhouse emissions strategy As international negotiations aimed at a global climate protection treaty got under way last week, the Bush Administration disclosed its strategy, which it claims will hold U.S. greenhouse-gas emissions in the year 2000 at or below 1987 levels.
Environmentalists immediately criticized the strategy, calling it "nothing new" and "a smokescreen" designed to obscure the U.S/s failure to commit itself to reducing carbon dioxide emissions. "The U.S. is just counting up things that are already
happening," says Daniel F. Becker, director of the Sierra Club's global warming and energy program.
The U.S. "action agenda" is outlined in a glossy pamphlet stamped with the Presidential seal that was distributed to delegates from more than 130 nations attending the first negotiating session of the Intergovernmental Negotiating Committee on a Framework Convention on Climate Change (INC). The United Nations has charged the group—now meeting for 10 days in Chantilly, Va.—with drafting a general treaty to be ready to be signed in June 1992 (C&EN, Feb. 4, page 5).
In a letter to the delegates, President Bush described the U.S. strategy as "a series of actions which will have broad-ranging benefits—from curbing air pollution, to conserving energy, to restoring forest lands— and which will help curb net greenhouse-gas emissions."
The plan tallies the benefits for greenhouse gas reductions of certain policies that the U.S. is already committed to undertaking. Those policies include phasing out chlorofluorocar-bons and other ozone-depleting compounds, reducing air pollutants under the Clean Air Act amendments enacted last year, encouraging energy conservation, and accelerating research into nonfossil fuels.
Under the strategy, U.S. emissions of carbon dioxide—the principal greenhouse gas—are projected to rise about 15% over the next 10 years. But the Administration expects the sharp decline in CFC emissions to offset the growth in carbon dioxide.
However, last year the UN's Intergovernmental Panel on Climate Change estimated that worldwide carbon dioxide emissions must be cut 50 to 80% to stabilize the atmosphere. "There is no substitute for C0 2 emissions reductions from the U.S.," Becker stresses. "C02 is what all the other industrialized nations are committing to reduce."
No agreement on such contentious issues is expected at the first INC meeting. The delegates are setting up working groups and will reconvene in Geneva in May for the next of a total of five scheduled sessions.
Pamela Zurer
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