Experiment using a laser

A magnetic resonance image

Applied physics is a general term for physics which is intended for a particular technological or practical use.^[1] It is usually considered as a bridge or a connection between "pure" physics and engineering.^[2]

"Applied" is distinguished from "pure" by a subtle combination of factors such as the motivation and attitude of researchers and the nature of the relationship to the technology or science that may be affected by the work.^[3] It usually differs from engineering in that an applied physicist may not be designing something in particular, but rather is using physics or conducting physics research with the aim of developing new technologies or solving an engineering problem. This approach is similar to that of applied mathematics. In other words, applied physics is rooted in the fundamental truths and basic concepts of the physical sciences but is concerned with the utilization of these scientific principles in practical devices and systems.^[4]

Applied physicists can also be interested in the use of physics for scientific research. For instance, the field of accelerator physics can contribute to research in theoretical physics by enabling design and construction of high-energy colliders.

Computer modeling of the space shuttle during re-entry

References[link]

Physics portal

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Eric Mazur
Eric Mazur
Born	(1954-11-14) November 14, 1954 (age 57) Amsterdam, the Netherlands
Residence	U.S.
Nationality	Dutch
Fields	Physics, Applied physics
Institutions	Harvard University
Alma mater	Leiden University (doctoral) Harvard University (postdoctoral)
Doctoral advisor	Jan Beenakker (doctoral) Nicolaas Bloembergen (postdoc)
Known for	Ultrasfast Phenomena Peer Instruction
Notable awards	Presidential Young Investigator Award (1988) Esther Hoffman Beller Award (2009) Millikan Medal (2009)

Eric Mazur (b. November 14, 1954) is a prominent physicist and educator at Harvard University. Mazur is known for his work in experimental ultrafast optics and condensed matter physics and a national leader in science education. Born in Amsterdam, the Netherlands, he received his undergraduate and graduate degrees from Leiden University in the Netherlands.

Education[link]

Mazur studied physics and astronomy at Leiden University. He passed his "doctoraal examen" (equivalent to a master's degree) in 1977 and continued his graduate studies at the same institution. In 1981 he obtained his Ph.D on a thesis entitled "The structure of non-equilibrium angular momentum polarizations in polyatomic gases". Although he intended to go on to a career in industry with Philips N.V. in Eindhoven, he left Europe at the urging of his father, Peter Mazur, to pursue a postdoctoral study with recent Nobel laureate Nicolaas Bloembergen at Harvard University.

Career[link]

After two years as a postdoc, Mazur was offered a position of assistant professor at Harvard University. In 1987 he was promoted to associate professor and obtained tenure three years later in 1990. Mazur currently holds a chair as Balkanski Professor of Physics and Applied Physics jointly in the Harvard School of Engineering and Applied Sciences and in the Physics Department. He is also the Dean of Applied Physics.

Research[link]

Mazur's early work at Harvard focused on the use of short-pulse lasers to carry out spectroscopy of highly vibrationally excited molecules. Mazur and his group have made many pioneering contributions to the field of ultrashort laser pulses and their interactions with matter ("femtosecond material science"). In 1989 his group was one of the first in academia to build a colliding-pulse mode-locked laser, which generated pulses of only 70 femtosecond duration. After early measurements by Mazur’s group demonstrated conclusively that solids can undergo a structural phase transition without appreciable heating of the lattice, Mazur’s group developed a technique to measure the full dielectric function of highly excited semiconductors. Since then the group’s use of this technique and various nonlinear optical probes to study laser-induced structural phase transitions.

In parallel to the work on semiconductors, Mazur began studying the interaction of intense femtosecond pulses with transparent materials. By tightly focusing a laser pulse in the bulk of a transparent material nonlinear optical absorption occurs inside the material, leading to extreme high temperatures and material changes at the focus. This femtosecond laser micromachining technique is now widely used for data storage, fabrication of integrated optical components, and microsurgery.

A light-conducting silica nanowire wraps a beam of light around a strand of human hair. The nanowire is about one-thousandth the width of the hair. Credit: Limin Tong, Harvard University

In 1998 a serendipitous discovery in Mazur's laboratory led to the development of a new methode to form a silicon surface modification, called "black silicon" because of its very low reflectivity. After irradiation by a train of femtosecond laser pulses in the presence of a halogen containing gas, the surface of silicon develops a self-organized microscopic structure of micrometer-sized cones. The resulting material has many remarkable properties, such as an enhanced absorption that extends to the infrared below the band gap of silicon. The material has found commercial applications in a number of photodetectors.

Mazur's research continues to focus on ultrashort laser pulse interactions and novel nonlinear optical devices. In collaboration with a group from Zhejiang University in Hangzhou, China, Mazur's group was the first to develop a technique for pulling subwavelength diameter silica optical fibers. These wires guide light in the form of an evanescent wave, permit very sharp bending of the light.

Peer instruction[link]

In 1991, Mazur began designing an instructional strategy for teaching called peer instruction. In 1997, he published a book called Peer Instruction: A User's Manual which provides details on this strategy.

Peer Instruction (PI) has been found to be more beneficial than class-wide discussion or lecture. In fact, according to an article in the March/April 2009 edition of Complexity, over 90% of instructors who have tried PI plan to continue to use it and incorporate it more into teaching.^[1] The seating arrangement plays an important role in the outcome of this method. For example, when low-performing students are seated in the front, their chance to do better increases. Meanwhile, the results of high-performing students who are seated in the back are not affected. In addition, when high-performing students are seated in the outer four corners of the classroom, the performance of the class as a whole increases.

Awards[link]

Mazur has been widely recognized for his scientific work and leadership.

• 1988 – Awarded the Presidential Young Investigator Award by President Ronald Reagan.
• 1989 – Elected Fellow of the American Physical Society.
• 1999 – Award for excellence in educational research by the Council of Scientific Society Presidents
• 2006 – selected as one of 75 most outstanding American physicists by the American Association of Physics Teachers
• 2008 – Awarded the Esther Hoffman Beller Medal by the Optical Society of America.

References[link]

• Mazur, E. (1997). Peer Instruction: A User's Manual, Prentice Hall. ISBN 0-13-565441-6

• Monterola, C., Roxas, R.M., and Carreon-Monterola, S. (2008). Characterizing the Effect of Seating Arrangement on Classroom Learning Using Neural Networks. Complexity, 14(4), 26–33. ISSN 1076-2782.[1]

External links[link]

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