simultaneously absorbed into a molecule. When that molecule relaxes from this excited state to its ground state, only one photon is emitted. This is a type of fluorescence. In resonance Raman spectroscopy, certain parts of molecules can be targeted by adjusting the wavelength of the incident laser beam to the “color” (energy between two desired electron quantum levels) of the part of the molecule that is being studied. This is known as resonance fluorescence, hence the addition of the term “resonance” to the name “Raman spectroscopy”. Some excited states can be achieved via single or double photon absorption. In these cases, however, the use of double photon excitation can be used to attain more information about these excited states than would a single photon absorption. There are some limitations and consequences to both resonance Raman and resonance hyper Raman spectroscopy. Both resonance Raman and resonance hyper Raman spectroscopy employ a tunable laser. The wavelength of a tunable laser can be adjusted by the operator to wavelengths within a particular range. This frequency range, however, is dependent on the laser’s design. Regular resonance Raman spectroscopy, therefore, is only sensitive to the electron energy transitions that match that of the laser used in the experiment. The molecular parts that can be studied by normal resonance Raman spectroscopy is therefore limited to those bonds that happen to have a “color” that fits somewhere into the spectrum of “colors” to which the laser used in that particular device can be tuned. Resonance hyper Raman spectroscopy, on the other hand, can excite atoms to emit light at wavelengths outside the laser’s tunable range, thus expanding the range of possible components of a molecule that can be excited and therefore studied. Resonance hyper Raman spectroscopy is one of the types of “non-linear” Raman spectroscopy. In linear Raman spectroscopy, the amount of energy that goes into the excitation of an atom is the same amount that leaves the electron cloud of that atom when a photon is emitted and the electron cloud relaxes back down to its ground state. The term non-linear signifies reduced emission energy compared to input energy. In other words, the energy into the system no longer matches the energy out of the system. This is due to the fact that the energy input in hyper-Raman spectroscopy is much larger than that of typical Raman spectroscopy. Non-linear Raman spectroscopy tends to be more sensitive