Fig. 7: Schematic of implementation of coherent superpositions of various sequences of additions and subtractions of N photons18,42,43.
From: Experimental preparation of multiphoton-added coherent states of light
Detection of N photons at the photon number resolving detector D1 heralds the addition of N photons. Photons can be subtracted both before and after the addition using two unbalanced beam splitters BS1 and BS2. Detector D2 projects the two polarization modes onto a specific pure N-photon polarization state which erases the which-way information and creates coherent superposition of various sequences of \({\hat{a}}^{N-j}{\hat{a}}^{\dagger N}{\hat{a}}^{j}\).
