At present, deep ultraviolet (DUV) lasers at the wavelength of fourth harmonics of 1 μm (266 nm/258 nm) and at the wavelength of 193 nm are widely utilized in science and industry. We review the generation of these DUV lasers by nonlinear frequency conversion processes using solid-state/fiber lasers as the fundamental frequency. A DUV laser at 258 nm by fourth harmonics generation (FHG) could a...

A resonant Raman study of single-wall carbon nanotubes (SWNT) using several laser lines between 0.94 and 3.05 eV is presented. A detailed lineshape analysis shows that the bands associated with the nanotube radial breathing mode are composed of a sum of individual peaks whose relative intensities depend strongly on the laser energy, in agreement with prior work. On the other hand, the shape of ...

The Raman laser is an optically pumped three-level laser in which both the pump and the laser field ~frequencies vP and vL , respectively! are far off resonance ~see Fig. 1!. This system is commonly used to produce high gain steady-state lasing emissions in the midto far infrared spectral region @1#. In addition, this system can show a very rich dynamical behavior @2#, including single-mode pul...

We have developed a methodology to use resonant Raman spectroscopy with a tunable excitation source to characterize the chirality distribution of a synthesized single-walled carbon nanotube (SWNT) material. Isolated SWNTs are either dispersed or directly grown on substrates with markers. The samples are then placed on an automatic scanning stage of a confocal Raman microscope. Resonant Raman si...

A Raman fibre laser based on phase shifted DFB structures is modelled for the first time. Using parameters of realistic devices, the model predicts low-threshold and highly-efficient laser output. The change of position and width of the phase shift were found to have a substantial impact on laser performance.

A simple, rapid and environmentally friendly method was developed for micro-Raman spectroscopy determination of pesticide residues on the surface of fruits. Raman spectra of fruits, pesticides and pericarps sprayed by pesticide solutions were acquired using a laser power of 14 mW at excitation wavelength of 780 nm. From the Raman spectra, the residual pesticides could be distinguished and deter...

Most important research results that explain why the work was done, what was accomplished, and how it pushed scientific frontiers or advanced the field. Diamond holds substantial promise as a high Raman gain laser material with outstanding power handling capability, yet despite this the highest reported output power from a diamond Raman laser prior to this project was approximat...

Overview: University of Hawaii (UH) in collaboration with NASA Langley Research Center has developed a compact portable sensor platform capable of performing remote Raman, LIBS, Fluorescence and lidar measurements from stand-off distances. The system using a 2.5 inch diameter telescope is capable of measuring Raman, LIBS, and fluorescence spectra of a mineral target from a distance of several m...

A new transient Raman thermal probing technique, frequency-resolved Raman (FR-Raman), is developed for probing the transient thermal response of materials and measuring their thermal diffusivity. The FR-Raman uses an amplitude-modulated square-wave laser for simultaneous material heating and Raman excitation. The evolution profile of Raman properties: intensity, Raman wavenumber, and emission, ...