(color online) (a) The t– curve that the detached electron can reach the detector. The photon energy , the oscillating electric field parameters are as follows: , a.u., φ = 0. The detector is localized at the point ( a.u.). The black line represents the down orbit and the red line denotes the up orbit. (b) Two up orbits of the detached electron which are emitted from the origin and arrive at the detector at the same final time t = 2.0 ps. (c) Two down orbits of the detached electron arrived at the detector at the same final time t = 2.0 ps.