Slow Light Imaging Spectroscopy

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Researchers in the Department of Mechanical and Aerospace Engineering at Princeton University have invented a new spectroscopy technology that enables ultra-high resolution one and two dimensional spatial imaging of Rayleigh, Raman, and Thomson spectral features without the need for a spectrometer. The approach provides the capability for imaging of a single spectral feature such as a single rotational Raman line and the simultaneous elimination of background scattering. High collection efficiency provides the opportunity for single pulse time frozen images to be acquired.


This invention relies on absorption features in atomic vapors to “slow down” a specific spectral feature while absorbing or freely transmitting all light at wavelengths outside of the dispersive region. A photodetector is then time-gated to accept only the delayed light corresponding to the signal of interest. By frequency tuning the illumination laser, any desired spectral feature can be selected.


This represents a highly selective imaging technique for scattering features associated with gases, plasmas, liquids, and solids. It has immediate application in one or two dimensional imaging of a selected molecular species and imaging of a selected energy state of that species. It will provide significant enhanced capabilities for combustion and plasma diagnostics and can provide valuable information on non-equilibrium and transient phenomena. The time-delayed filter relies on the dispersion provided by the natural state of the atomic species in the filter cell without the need for optical pumping, allowing seamless integration with existing commercial devices. This method has been validated on delayed Rayleigh scattering spectroscopy.



o       One or two dimensional imaging of selected molecular species.

o       Non-equilibrium and transient phenomena imaging

o       High background systems



o       Passive filter

o       No spectrometer required

o       Low detection limit

o       High efficiency

o       Time-filter background


Intellectual Property & Development Status

o       Patent protection is pending.

o       Princeton is currently seeking commercial partners for the further development and commercialization of this opportunity.



o       N.D. Finkelstein, W.R. Lempert, and R.B. Miles, "Narrow-Linewidth Passband Filter for Ultraviolet Rotational Raman Imaging," Optics Letters, 22, 537-539 (1997).

o       R.B. Miles, W. Lempert, and J. Forkey, "Laser Rayleigh Scattering," J. of Measurement Science & Technology, Vol. 12, R33-R5 (2001).

o       L. J. Wang,  A. Kuzmich, and A. Dogariu. “Gain-assisted superluminal light propagation,” Nature 406, 277-9 (2000).

o       A. Dogariu, A. Kuzmich, and L. J. Wang, "Transparent Anomalous Dispersion and Superluminal Light Pulse Propagation at a Negative Group Velocity," Phys. Rev. A (Atomic, Molecular and Optical Physics), 63 (5), 053806-12 (2001).


The Inventors

Arthur Dogariu is a Research Scholar and Lecturer, Department of Mechanical and Aerospace Enginnering, Princeton University. He received his Ph.D. in Optical Physics from CREOL (School of Optics) at the University of Central Florida in 1997. His past positions include researcher at the University of California, Santa Barbara, research scientist at NEC Research Institute, assistant professor at the University of Washington, and currently he is a research scholar and lecturer in the Mechanical and Aerospace Engineering Departments at Princeton University. His research interests include experimental optical physics in the areas of nonlinear and ultrafast optics, biomedical optics, biosensors, remote detection techniques, plasma dynamics, photo-physics of organic materials and devices, ultrafast spectroscopy, nano-optics, quantum optics, wave propagation in dispersive media. He has authored over 80 publications in refereed journals, more than 100 conference papers, and 5 US and international patents. He is a member of the Optical Society of America, and the American Institute of Aeronautics and Astronautics.



Chris Wright • Princeton University Office of Technology Licensing

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Patent Information:
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Chris Wright
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Princeton University
Richard Miles
Arthur Dogariu