This project will produce a more sensitive and more flexible version of a previously developed laser/Schottky-diode based 600-900 GHz heterodyne receiver for the CSO. The improvements will make feasible a broad range of astronomical projects. The new receiver will be used to make exploratory studies of high frequency submillimeter lines to investigate problems in the study of photodissociation regions, ultra-dense star-forming regions, and hot molecular outflows from protostars. Part of the plan involves making the high frequency capability of the CSO receiver available to other members of the community. This effort is part of a collaborative effort to produce an SIS system using a frequency- agile laser as the first L.O.
