Eric Mazur - Research

Research

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.

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.