Chromophore Selectivity & Multiwavelength Source Research & Development
Chromophore Selectivity:
Chromophore selectivity represents a major research focus in PARS imaging. Chromophore selectivity is pursued through the use of multiwavelength imaging and spectral unmixing. Spectral unmixing is a source separation technique that makes use of the unique spectral absorption characteristics of chromophores. In biological tissue, endogenous absorption characteristics can be used for bio-media identification. In addition to visualizing tissue structures, this research opens the doors to functional imaging, such as measuring oxygen saturation and metabolic rates in blood. This has applications in tumor assessment and functional brain imaging for cognitive neuroscience research.
Multiwavelength Source Research & Development:
To access the broad range of optical absorption characteristics afforded by absorbing bio-media, a multiwavelength PARS imaging source is being researched and developed. Other sources such as supercontinuum lack the necessary pulse energy after spectrally filtering, and multiwavelength lasers on the market have slow pulse repetition rates and poor (and varying by wavelength) beam quality. In order to practically use a multiwavelength source for PARS imaging, it must produce a beam of excellent quality, have sufficient pulse energies, and operate at pulse repetition rate that lends itself to fast imaging. Stimulated Raman scattering (SRS), a non-linear optical interaction that occurs in silica fibers, generates light in a broad range of wavelengths. By optimizing key parameters of the fiber and pump laser, SRS can be used to create a source capable of providing multi-wavelength excitation at pulse energies in excess of what is necessary for PARS imaging.
Chromophore selectivity represents a major research focus in PARS imaging. Chromophore selectivity is pursued through the use of multiwavelength imaging and spectral unmixing. Spectral unmixing is a source separation technique that makes use of the unique spectral absorption characteristics of chromophores. In biological tissue, endogenous absorption characteristics can be used for bio-media identification. In addition to visualizing tissue structures, this research opens the doors to functional imaging, such as measuring oxygen saturation and metabolic rates in blood. This has applications in tumor assessment and functional brain imaging for cognitive neuroscience research.
Multiwavelength Source Research & Development:
To access the broad range of optical absorption characteristics afforded by absorbing bio-media, a multiwavelength PARS imaging source is being researched and developed. Other sources such as supercontinuum lack the necessary pulse energy after spectrally filtering, and multiwavelength lasers on the market have slow pulse repetition rates and poor (and varying by wavelength) beam quality. In order to practically use a multiwavelength source for PARS imaging, it must produce a beam of excellent quality, have sufficient pulse energies, and operate at pulse repetition rate that lends itself to fast imaging. Stimulated Raman scattering (SRS), a non-linear optical interaction that occurs in silica fibers, generates light in a broad range of wavelengths. By optimizing key parameters of the fiber and pump laser, SRS can be used to create a source capable of providing multi-wavelength excitation at pulse energies in excess of what is necessary for PARS imaging.