Sarzała, Robert, and Włodzimierz Nakwaski. “Inverted-Relief Cavity Used in VCSELs to Suppress Higher-Order Transverse Modes”. Photonics Letters of Poland, vol. 6, no. 1, Mar. 2014, pp. pp. 29-31, doi:10.4302/photon. lett. pl.v6i1.438.