Specialty photonics packaging company !%PD-LD Inc.%! of Pennington, N.J., has received US Patent No. 7,982,869, which protects the use of dual laser sources for the analysis of a single substance. The technique, based on proprietary VBG (volume Bragg grating) laser wavelength stabilization, provides the underlying mechanism for shifted excitation Raman differential spectroscopy, an analytical technique that the company says represents a significant development in the capabilities of Raman spectroscopy. CEO Vladimir Ban said that the patent will allow PD-LD to offer Raman excitation sources that extend portable and lab-based instruments.