Lasers have been a key element of Hollywood films for decades. James Bond is locked in a
cell, seemingly with no means of escape? Have no fear; the tiny laser in his wristwatch will
save the day. Hans Solo needs to make a run for his spaceship in order to escape a band
of evil storm troopers? Don't worry, he will blast his way out using his trusty laser gun. In
real life, lasers may not allow us to blast our way out of insoluble situations, but they are
helping us better understand the world around us. All molecules vibrate at different frequencies. Because of this, John C. Wright and Wei Zhao are able to use a new technique called Doubly Vibrationally Enhanced Four Wave Mixing, which builds on the astronomical technique called Infrared spectroscopy, to create "fingerprints" of various molecules. To exercise this technique, the scientists use lasers, whose light is routed through a maze of mirrors and lenses and focused onto a sample, to stimulate molecules (shown).
"The vibrational frequency is a direct reflection of the bonding that glues the atoms in a molecule or two different molecules together. For example, when an enzyme is going to facilitate a reaction, it needs to bond with the molecule it is going to change. When it bonds, new vibrational modes appear that are characteristic of the new bond," explains Wright.
These differing vibrational frequencies create unique patterns which tell scientists not only what is contained in a sample, but how the molecules in the sample interact. This new ability may eventually help scientists answer a wide range of questions related to molecular science.
Courtesy Office of News and Public Affairs, University of Wisconsin-Madison. Photo by Jeff Miller.
