Multi-resonant optical parametric oscillator without mirrors based on 1D and 2D-PPLT nonlinear photonic crystalSafia Mohand Ousaid, Mahmoud Chakaroun, Kai-hsun Chang, Thierry Billeton, L-Han Peng and Azzedine BoudriouaEPJ Web Conf., 238 (2020) 11003DOI: https://doi.org/10.1051/epjconf/202023811003