Decomposing Spatial Mode Superpositions with a Triangular Optical Cavity - Santos, Gustavo; Salles, Daniel Carvalho de; Damaceno, Maria Gabriela; Menezes, Bernard Teles de; Silva, Cassia Corso; Martinelli, Marcelo; Ribeiro, P. H. Souto; Araújo, Renné Medeiros de (Physical Review Applied, 2021)