A system is disclosed for providing a first electromagnetic field and a second electromagnetic field to vibrational analysis equipment that is responsive to a difference between first and second frequencies of the first and second electromagnetic fields respectively. The system includes a non-linear crystal that may be pumped at a high repetition rate to provide a pulsed signal field at a signal field frequency and a pulsed idler field at an idler field frequency as output. The signal field provides the first electromagnetic field and the idler field provides the second electromagnetic field. The system also includes a tuning system for permitting the difference between the signal field frequency and the idler field frequency to be changed. The system also includes an output unit for providing the first and second electromagnetic fields to the vibrational analysis equipment.