Is it permissible for the Imam to stamp the ground to signal to the deaf to rise from prostration, or to use an electric lamp for this purpose?

The deaf person praying behind the Imam should follow the Imam by seeing him, or by seeing the other congregants, or by sensing their movements. If he is unable to do so, there is no harm in using a permissible means to inform him of the Imam's transitions, such as a light tap or turning on a light. It is preferable for the deaf person to pray in rows with those who can hear, so he can follow their movements.