Specialty photonics packaging company !%PD-LD Inc.%! of Pennington, N.J., has been granted US Patent No. 7,982,869, which protects the use of dual laser sources for 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. CEO Vladimir Ban said that the patent will allow PD-LD to offer Raman excitation sources that extend portable and lab-based instruments, and that the patent is particularly relevant to the life sciences and security industries, where fluorescence is widespread.