This Small Business Innovation Research (SBIR) Phase II project is to develop a prototype for a commercial two-dimensional infrared (2D IR) spectrometer and its associated mid-infrared laser system. One of the most exciting developments in the field of ultrafast spectroscopy in the last decade has been the invention of 2D IR spectroscopy. It is now being used to study problems in material science, chemical dynamics, electron transfer, biophysics, polymer structure, solar energy, analytical diagnostics and others. But while it is now recognized as a valuable research tool, it is difficult to implement since it is only being utilized by a relatively small group of ultrafast spectroscopists that specialize in infrared spectroscopy. The research objectives of this project are to design and develop a 2D IR spectrometer, including an efficient mid-infrared laser source, which requires no technical skills to operate. It will utilize mid-infrared pulse shaping, a newly designed optical parametric amplifier, and a mid-IR pump laser. The system will be mechanically robust and computer automated so that it will be used by 2D IR experts and non-experts alike.
The broader impact/commercial potential of this project is the development of a commercial 2D IR spectrometer that will be used in academic, government, and industrial research laboratories worldwide with applications spanning the biological, chemical and physical sciences. 2D IR spectroscopy provides structural and dynamical information that is difficult to obtain with other techniques, such as at inorganic/organic interfaces that are important in solar cell research or membrane proteins associated with pharmaceutical targets. There are more than 15,000 research laboratories worldwide that utilize infrared spectroscopy of some type, and 2000 labs that utilize ultrafast spectroscopy. Thus, the commercial potential is substantial. The development of this laser technology has important societal implications due to the wide range of scientific and industrial topics that this technology can be applied.
In this program we investigated the best laser sources for engineering a 2D infrared (IR) spectrometer. The first 2D IR spectrum was reported by Robin Hochstrasser in 1998, in which he collected spectra for a series of peptides. There are now research groups across the world employing this spectroscopy in the fields of material science, chemical dynamics, electron transfer, biophysics, polymer structure, solar energy, and analytical diagnostics. The wide range of subjects to which it is being applied speaks to its tremendous utility. But, while it is a valuable research tool, it is also very difficult to implement. The main difficulty is that the standard 2D IR spectrometer has four mid-infrared laser beams, all of which must be spatially and temporally overlapped in the sample. This task is especially difficult because mid-infrared light is invisible to the naked eye. The problem is compounded by inefficient laser sources, which lack engineering for robust operation. As a result, even laser spectroscopy experts must invest many months or even a year learning to implement the technique. The high barrier prevents many non-experts and less headstrong experts from entering the field. The original intent of this program was to engineer a 2D IR system, for eventual sale. However, the laser development part of the program took most of the resources and time to implement. Problems with material issues in the amplifier system, while now solved, delayed the program and led to more labor expended on the laser system than intended. Also, at the start of the program, our collaborator pulled out, and started a 2D infrared spectroscopy company. This at the end turned out to be a good thing given the overrun on the laser system, since he developed the 2D IR tool, which can use our laser source for a true 2D IR spectroscopy. The website for this device can be seen here: http://phasetechspectroscopy.com/products/2dquickarray/. In this program we engineered a laser system capable of > 500 mJ, 150 fs pulses at a 10 kHz repetition rate in the near IR. This laser has now become a KMLabs Inc. product, and been sold to a researcher at Colorado School of Mines for micromachining (figure). In our outreach efforts, we employed a K-12 teacher (through the RET program) over the summers to work on this program. His main task was to engineer and construct the thermo-electric cooled housing for the amplifier crystal. We had also enlisted the help of a 2D IR researcher at Colorado State University, to help with the program. This researcher decided to take a different laser research path which resulted in three more sales of other KMLabs Inc. products, an amplified Ti:Sapphire laser system, a Yb:Fiber laser based optical parametric oscillator, and two cryogenic Yb (Ytterbium doped laser materials) based amplifier heads. Although the program goals were not met in this program, we feel the spin-off technology from this program have generated real revenue, and several new products for our company. Our research into mid-IR ultrafast laser sources continues, and we hope to partner with our original collaborator for delivering a nicely engineered 2D IR system.
