Cellular processes are intrinsically complex and dynamic, in which a myriad of cellular components including nucleic acids, proteins, membranes, and organelles are involved and undergo spatiotemporal changes. Label-free Raman imaging has proven powerful for studying such dynamic behaviors in vivo and at the molecular level. To construct Raman images, univariate data analysis has been commonly e...

Compared with carbon nanotubes and graphene, graphene oxide (GO) exhibits excellent water solubility and biocompatibility in addition to the characteristic G band in Raman spectra. Therefore GO might be able to act as a flexible Raman probe to image cells or tissues through Raman mapping. However, the weak intensity of the G band restricts such applications of GO. Here we decorated GO with Au n...

Developing ultrasensitive Raman nanoprobes is one of the emerging interests in the field of biosensing and bioimaging. Herein, we constructed a new type of surface-enhanced resonance Raman scattering nanoprobe composed of an Ag nanoshell as a surface-enhanced Raman scattering-active nanostructure, which was encapsulated with 4,7,10-trioxa-1,13-tridecanediamine-functionalized graphene oxide as a...

Recent results are presented of the application of imaging micro-Raman spectrometers in cellular biophysics and biomedical research. Various micro-Raman spectrometers have been developed that are now routinely applied in these Ðelds. Results are presented that were obtained with a linescan Raman microspectrometer and with a Raman imaging microscope. Applications of Raman linescan spectrometry c...

A Raman spectrometer extensively modified for deep ocean use was used to measure synthetic hydrates formed in an ocean environment. This was the first time hydrates formed in the ocean have been measured in situ using Raman spectroscopy. Gas hydrates were formed in situ in the Monterey Bay by pressurizing a Pyrex cell with various gas mixtures. Raman spectra were obtained for sI methane hydrate...

Raman spectra of materials subject to strong electric field gradients, such as those present near a metal surface, can show significantly altered selection rules. We describe a new mechanism by which the field gradients can produce Raman-like lines. We develop a theoretical model for this "gradient-field Raman" effect, discuss selection rules, and compare to other mechanisms that produce Raman-...

Alkynes can be metabolically incorporated into biomolecules including nucleic acids, proteins, lipids, and glycans. In addition to the clickable chemical reactivity, alkynes possess a unique Raman scattering within the Raman-silent region of a cell. Coupling this spectroscopic signature with Raman microscopy yields a new imaging modality beyond fluorescence and label-free microscopies. The bioo...

A variation of the conventional combined Raman-elastic backscatter lidar method, the 1-2-3 lidar method, is described and analyzed. This method adds a second transmitter wavelength to the conventional combined Raman-elastic backscatter lidar. This transmitter wavelength is identical to that of the Raman receiver. One can generate the transmitted beam at this wavelength by Raman shifting the las...

A novel tip-enhanced Raman spectroscopy setup with longitudinal field excitation generated by a plasmonic lens is investigated. A symmetry-breaking structure plasmonic lens that is expected to realize a strong longitudinal electric field focus has been designed to generate suitable excitation for enhancement in a tip antenna. The focusing performance of the plasmonic lens is theoretically simul...

We have investigated the Raman gain for different pump wavelengths and maximum gain is achieved for pump wavelength of 1451.2 nm for the input signal source at 1550 nm. Also the effect of both pump power and Raman fiber length on gain saturation in fiber Raman amplifiers(FRAs) was studied without using any booster before Raman fiber. We have numerically simulated the gain of a FRA for different...