Raman Spectroscopy

The authors review the operating principles of a silicon Raman laser and show that by introducing a longitudinal variation of the waveguide width in the cavity, the lasing efficiency can be increased significantly.

Confocal Raman microscopy can be useful when applied to all samples that are heterogeneous on the micrometer to millimeter scale and that generally can be investigated by Raman spectroscopy. This article presents examples of confocal Raman microscopy from various fields of application including pharmaceutical analysis and stress measurements in semiconductors.

A new system for multitechnique spectral searching is described that utilizes analysis of several hit lists resulting from spectral similarity searches performed simultaneously in reference databases for multiple complementary analytical techniques. This paper demonstrates the benefits of this multitechnique approach using the complementary techniques of IR and Raman spectroscopy.

Compounds of magnesium and calcium are common components of pharmaceutical formulations. Spectroscopic imaging can provide a complete understanding of a formulation. This paper compares two spectral imaging techniques — energy dispersive X-ray fluorescence (EDXRF) microscopy and Raman microscopy.

The authors present a novel technique for obtaining very high stability and reproducibility of a Raman spectrum, using grating corrected laser stabilization. An externally stabilized laser with a grating spectrometer provides exceptional quantum efficiency in the entire dynamic range. These components then are used to build a library of pharmaceutical raw materials and tested on samples of unknown material.

Due to its high information, vibrational content, the Raman spectrum provides important and specific molecular information. In this article, Raman microanalysis and instrumentation is discussed with specific application to the forensic science laboratory, where evidence integrity is of the utmost importance.

The acquisition of Raman spectra can be eased greatly through the use of surface-enhanced Raman spectroscopy (SERS). In this article, the authors discuss a new substrate technology that delivers reliable and consistent surface enhancement.

Raman spectroscopy has been employed to detect Bacillus cereus spores, an anthrax surrogate, collected from a letter as it passed through a mail sorting system. Raman spectroscopy also has the ability to identify many common substances used as hoaxes. A three-step method also is described for the detection of dipicolinic acid extracted from surface spores by SERS.

This article compares different CCD platforms by outlining CCD and EMCCD noise sources as well as an explanation of the two calculations to arrive at the signal-to-noise ratio for each. The data presented will show that a liquid nitrogen-cooled CCD camera still is the proper choice for low light level applications, such as Raman spectroscopy.

Recent advances in thin-film filter technology have enabled dramatic improvements in the performance of filters for laser-based analytical instrumentation.

Recent advances in thin-film filter technology have enabled dramatic improvements in the performance of filters for laser-based analytical instrumentation.

Recent advances in thin-film filter technology have enabled dramatic improvements in the performance of filters for laser-based analytical instrumentation.

The authors discuss how the Raman microscope is being used successfully to characterize pharmaceuticals, analyze disease states, and to characterize semiconductors and nanotechnologies.

This article examines advances that have been made to combine existing analytical techniques with Raman instrumentation. Some of these methods offer enhanced sample visualization, while others provide complementary vibrational spectroscopic information from a single sample point.

The authors discuss several sample types encountered in their laboratory for which Raman spectroscopy is the only reliable method of analysis. The technique is shown to be a routine and cost-effective tool for the industrial laboratory.

The authors review a surface enhanced laser Raman spectroscopy study of lung surfactant protein interaction with bacterial lipopolysaccharide.

This article overviews several recent advancements in Raman components that are enabling high analytical performance in low-cost Raman instruments.

The authors show how a multivariate curve resolution algorithm, called SIMPLe-to-use Interactive Self-modeling Mixture Analysis (SIMPLISMA), can facilitate the quantitative and qualitative analysis of difficult samples, and apply the algorithm to a technically challenging Raman spectra series for carbamazepine polymorphs.

Raman spectroscopy is used routinely by the agencies tasked with homeland defense, and current research using surface enhanced Raman spectroscopy shows promise for the detection of chemical warfare agents and other toxic chemicals. This article overviews some of the latest developments in the field.

Raman microspectroscopy is an ideal method for the examination of marketable gemstones because of the lack of sample preparation involved and the nondestructive nature of Raman analysis.

A "Technical Note" article.