1. A device comprising: a. a diode laser excitation means for irradiating a sample and generating an optical signal comprising a plurality of Raman wavelengths, b. a Bragg grating means for providing optical feedback to said diode laser excitation means, c. a temperature controller means for setting the temperature of said diode laser excitation means to a predetermined plurality of temperatures in a serial manner wherein said plurality of predetermined temperatures comprises at least a first temperature, a second temperature, and a third temperature, d. a dispersive spectrometer means for acquiring said optical signal where said dispersive spectrometer means comprises an optical dispersion means for dispersing said plurality of Raman wavelengths into a plurality of spatially resolved Raman wavelengths and said dispersive spectrometer means comprises a multi-element detector for simultaneously detecting said plurality of spatially resolved Raman wavelengths, e. a synchronization means for synchronizing said dispersive spectrometer means and said temperature controller means.