Spectral imaging, i.e. the acquisition of the spectrum emitted from each sample location, is a powerful tool for a wide variety of applications in science and technology. For biomedical applications, spectral imaging is important for accurate analysis of a biological specimen and for assisting clinical diagnosis, however it could be challenging mainly due to the typically low damage thresholds and strict time constraints. Here, we present a fiber-based technique termed spectrally encoded spectral imaging (SESI), in which a fully emitted spectrum is captured from each resolvable point of a specimen using an additional lateral scanning of the spectrally encoded line. The technique is demonstrated by capturing spectral data cubes of a color print and of a green leaf, and its potential advantage in signal-to-noise ratio is theoretically discussed. Using a miniaturized grating-lens configuration, SESI could be conducted endoscopically, allowing minimally invasive color and spectral imaging in remote locations of the body.
Spectrally encoded endoscopy (SEE) uses miniature diffractive optics to encode space with wavelength, allowing video-rate three-dimensional imaging through sub-millimeter, flexible endoscopic probes. Here we present a new approach for SEE in which the illumination and the collection channels are separated in space, and spectral encoding is present only in the collection channel. Bench-top experiments using spatially incoherent white light illumination reveal significant improvement in image quality and considerable reduction of speckle noise compared to conventional techniques, and show that the new system is capable of high sensitivity fluorescence imaging of single cells. The presented new approach would allow improved functionality and usability of SEE.
Using a single optical fiber and miniature distal optics, spectrally-encoded endoscopy (SEE) has been demonstrated as a promising, three-dimensional endoscopic imaging method with a large number of resolvable points and high frame rates. We present a detailed theoretical study of the SEE prototype system and probe. Several key imaging parameters of SEE are thoroughly derived and formulated, including the three-dimensional point-spread function and field of view, as well as the system's optical aberrations and fundamental limits. We find that the point-spread function of the SEE system maintains a unique relation between its transverse and axial shapes, discuss the asymmetry of the volumetric field of view, determine that the number of lateral resolvable points is nearly twice than what was previously accepted, and derive an expression for the upper limit for the total number of resolvable points in the cross-sectional image plane.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.