A miniaturized hyper-spectral imager is enabled with image sensor integrated with dispersing elements in a very compact form factor, removing the need for expensive, moving, bulky and complex optics that have been used in conventional hyper-spectral imagers for decades. The result is a handheld spectral imager that can be installed on miniature UAV drones or conveyor belts in production lines. Eventually, small handhelds can be adapted for use in outpatient medical clinics for point-of-care diagnostics and other in-field applications.
A miniaturized hyperspectral imager is enabled with image sensor integrated with dispersing elements in a very compact
form factor, removing the need for expensive, moving, bulky and complex optics that have been used in conventional
hyperspectral imagers for decades. The result is a handheld spectral imager that can be installed on miniature UAV
drones or conveyor belts in production lines. Eventually, small handhelds can be adapted for use in outpatient medical
clinics for point-of-care diagnostics and other in-field applications.
The use of Raman spectroscopy to provide characterization and diagnosis of biological tissues has shown increasing
success in recent years. Most of this work has been performed using near-infrared laser sources such as 785 or 830 nm,
in a balance of reduced intrinsic fluorescence in the tissues and quantum efficiency in the silicon detectors often used.
However, even at these wavelengths, many tissues still exhibit strong or prohibitive fluorescence, and these wavelengths
still cause autofluorescence in many common sampling materials, such as glass. In this study, we demonstrate the use of
1064 nm dispersive Raman spectroscopy for the study of biological tissues. A number of tissues are evaluated using the
1064 nm system and compared with the spectra obtained from a 785 nm system. Sampling materials are similarly
compared. These results show that 1064 nm dispersive Raman spectroscopy provides a viable solution for measurement
of highly fluorescent biological tissues such as liver and kidney, which are difficult or impossible to extract Raman at
Shifted Excitation Raman Difference Spectroscopy (SERDS) implemented with two wavelength-stabilized laser diodes
with fixed wavelength separation is discussed as an effective method for dealing with the effects of fluorescence in
Raman spectroscopic analysis. In this presentation we discuss the results of both qualitative and quantitative SERDS
analysis of a variety of strongly fluorescing samples, including binary liquid mixtures. This application is enabled by the
Volume Bragg Grating® (VBG®) technology, which allows manufacturing of compact low-cost high-power laser
sources, suitable for extending the SERDS methodology to portable Raman spectrometers.
We report on a variety of BaySpec’s newly developed Raman spectrometers and microscopes combining multiple
excitation wavelengths and detection ranges. Among those there are the world’s first dual-wavelength near infrared
(NIR) and infrared miniature Raman spectral engines built with Volume Phase Gratings (VPGTM), and the world’s first
three-wavelength (532, 785, and 1064-nm) excitation Raman microscope. Having multiple wavelength excitations in one
unit offers extreme flexibility and convenience to identify the best laser wavelength and investigate a great variety of
real-world samples. In real-world Raman measurements, fluorescence is the biggest obstacle which significantly reduces
the quality of the Raman spectra. We demonstrate many examples spanning from explosives to street drugs to conclude
that for those samples, 1064-nm Raman is fluorescence-free and best suited for identification. Other types of
miniaturized Raman spectrometers have been realized, enabling handheld, portable, or at-line/ on-line applications for
real-world sample measurements, such as threat determination of explosives, chemical and biological materials, quality
assurance and contamination control for food safety, and forensics such as evidence gathering, narcotics identification,