Here, we present vFLETCHERS (visible fluorescence-encoded time-domain coherent Raman spectroscopy), which operates in the visible excitation region and overcomes the previous limitation of detectable fluorophores. vFLETCHERS employs a non-collinear optical parametric amplifier as a femtosecond excitation source. As a proof-of-concept demonstration, we acquired low-frequency Raman spectra (<1000 cm-1) of solutions containing commercial fluorophores with the absorption peaks in the 600-700 nm region. These results highlight the potential of vFLETCHERS as a versatile multiplexed imaging technique, opening up new opportunities for research in biology.
Fluorescence-encoded time-domain coherent Raman spectroscopy (FLETCHERS) is a fluorescence-encoded vibrational spectroscopy technique that boasts both high sensitivity and specificity in the probing of molecular vibrations in the lower fingerprint region. However, to date, all presented data presented so far has been from flowing samples which does not sufficiently demonstrate the method’s applicability for monitoring biological and chemical processes. To amend this, we demonstrate here FLETCHERS imaging of low-concentration samples with an expanded spectral window achieved by utilizing spatial filtering and the confocal collection of fluorescence-encoded light.
Fluorescence-encoded Raman spectroscopy has become increasingly more popular by virtue of its high chemical specificity and sensitivity. However, current fluorescence-encoding methods are narrowband and lack sensitivity in the low wavenumber region which if addressed could further enhance these methods. To overcome these limitations, we propose and experimentally demonstrate a novel broadband method for fluorescence-encoded Raman spectroscopy, termed fluorescence-encoded time-domain coherent Raman spectroscopy (FLETCHERS), which is capable of probing molecular vibrations in the lower fingerprint region (200 – 750 cm-1 ) with sample concentrations as dilute as 100 nM and laser powers as low as 20 mW.
An imaging lidar system is presented which combines the high speed of a Digital Micromirror Device (DMD) and the higher range of a 1D collimated scanning output. The system employing 1D line object illumination along with DMD placed at focal plane enables flexible optimization of system metrics, such as field of view, angular resolution, maximum range distance and frame rate.
The ray formalism is critical to understanding light propagation, yet current pedagogy relies on inadequate 2D representations. We present a system in which real light rays are visualized through an optical system by using a collimated laser bundle of light and a fog chamber. Implementation for remote and immersive access is enabled by leveraging a commercially available 3D viewer and gesture-based remote controlling of the tool via bi-directional communication over the Internet.
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