Charles Rosenblatt’s post-doctoral fellow became distracted by a telephone call and left a batch of a polymer -- which had been deposited on a glass substrate in order to align a liquid crystal -- baking in an oven for too long and at too high of a temperature.
When Rosenblatt, a professor of physics and macromolecular science at Case Western Reserve University, and his post-doc Ghanshyam Sinha subsequently looked at their sample under a microscope, instead of finding the liquid crystal molecules aligned perpendicular to the glass, they found that they were tilted.
“Hmmm,” Rosenblatt and Sinha thought. “What happened?”
So instead of scrapping the tilted liquid crystals, Rosenblatt’s research group was intrigued.
After four years of research and numerous publications characterizing the experiment gone awry, Giovanni Carbone, a current post-doctoral fellow in Rosenblatt’s research group, and Rosenblatt have put all the pieces of the puzzle together to report their findings in the article, “Polar Anchoring Strength of a Tilted Nematic: Confirmation of a Dual Easy Axis Model,” in the recent issue of Physical Review Letters.
In addition to the science associated with this phenomenon, Rosenblatt noted the potential device applications that range from displays to optical communications switches. This has piqued the interest of Nissan Chemical Industries, a Japanese firm, which last year signed a multi-year cooperative research agreement with Case for continued studies of tilted liquid crystals.
“We realized that we could create electrically switchable diffraction gratings, that is, a new method to steer laser beams.
Rosenblatt explained that in the push for optical communications, a laser beam must be directed to go from here to there. Typically this was done with mirrors, which Rosenblatt said involved a difficult mechanical process that was subject to vibrations and other problems.
Industries, developing new electronics like computer and television screens, began looking at sending the beam of light through a liquid crystal cell and having the light exit at an angle.
But liquid crystal devices involve polarized light, which has two polarization states. You see one of those states working when you wear polarized sun glasses or go to a 3-D movie and view it through special glasses.
Current liquid crystal technologies throw away one of those polarization states as it goes through the liquid crystal-based beam-steering devices, explains Rosenblatt.
The unexpected results from over-baking have proven advantageous in creating a new architecture, called an electrically switchable, polarization-independent blazed grating that can efficiently direct the light through the liquid crystals by adjusting the orientation of the tilted molecules in nanoscopically sized pixels.
Rosenblatt and researchers have reached 85 percent efficiency in transporting light through the beam-steering devices, as opposed to well under 50 percent with prior liquid crystal-based devices.
This was not the first time that one of Rosenblatt’s unintentional experimental outcomes bore fruit for the university. In 1992, Rosenblatt and colleagues Rolfe Petschek from the physics department and Michael Fisch, then a visiting professor in physics (now at Kent State University), invented a liquid crystal display technology while investigating fundamental interactions between the liquid crystal and a substrate. Over the years, their patents have generated approximately $750,000 in technology transfer revenues for the university.
“Lots of unexpected results in the lab can create new discoveries and opportunities,” said Rosenblatt. As an example, he pointed out the work of Arno Penzias’ and Robert Wilson’s accidental discovery of the Cosmic Microwave Background (CMB) left over from the Big Bang. They had been picking up curious noise while conducting some radio astronomy experiments and this noise turned out to be the CMB. For this, they won the Nobel Prize. Similarly, Alexander Fleming’s discovery of penicillin was completely serendipitous, added Rosenblatt.
While all researchers occasionally find unexpected data result during the course of their work, over his 27-year career as a physicist, Rosenblatt advised that it is important to be alert in order to turn the proverbial sow’s ear into a silk purse.
He learned that valuable lesson one day as a research physicist at the Francis Bitter National Magnet Laboratory at M.I.T. in 1984: Do not panic and scrap unexpected results from an experiment. He threw away the results from what he perceived, at first, to be poor data into a trash can, only to stay awake that night and mull over what went wrong.
Fortunately at the time, M.I.T. emptied the trash only every second day. So when Rosenblatt ran to his office the next morning, he said he breathed a sigh of relief and retrieved the lab results. His resulting publication in Physical Review Letters demonstrated the phenomenon of surface-induced layering of liquid crystal molecules.
“You can learn from your mistakes, and I’ve learned that you don’t throw anything away,” laughed Rosenblatt. “Some hidden science might be there. If you think hard enough, even what superficially appears to be incorrect data might give you a brand new idea about nature or new technology.”
Rosenblatt’s research in new liquid crystal technology, as well as other projects in the physics of liquid crystals and in microgravity effects on fluids are supported from the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Petroleum Research Fund of the American Chemical Society and Nissan Chemical Industries.
Rosenblatt joked that 95 percent of his research funding is for well-planned experiments, with the remaining 5 percent for experiments that do not proceed exactly as planned.
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