The authors would like to acknowledge that this review on high WPE,high power,and high brightness quantum cascade semiconductor lasers operating at high temperature is based on results obtained at the Center for Quantum Devices(CQD)at Northwestern University.CQD was founded in 1992 by Professor Manijeh Razeghi,and has benefited from the dedication and contributions of numerous undergraduate and graduate students,postdoctoral researchers,faculty,and visiting scientists over the years.We gratefully acknowledge the support of various U.S.government agencies including the Department of Defense(DoD),Department of Homeland Security(DHS),NASA,and the National Science Foundation(NSF).We are also deeply thankful for the support of the Walter P.Murphy Chair Professorship at the McCormick School of Engineering,Northwestern University.Co-author Professor Feihu Wang formerly a Research Assistant Professor at CQD/Northwestern University and currently based in China gratefully acknowledges the support of Guangdong Basic and Applied Basic Research Foundation(2023A1515012793,2024B1515020117),and his students and postdocs Q.Lai and Z.Chen's assistance of completing the manuscript. （CQD）