Effect of phase difference between dual laser fields on phonon amplification in a graphene

Atomic displacement fluctuation in a graphene under dual laser fields was studied by a moatttea functional integral approach. It was shown that when the field strength and the frequency were fixed, the atomic displacement fluctuation was tuned by the phase difference between dual laser fields. It was realized that the rate of change of the atomic displacement fluctuation took its positive value in measurable time ranges. This corresponded to a phonon amplification effect. The mechanism of generating the phonon amplification was discussed.