Coherent detection spectroscopy

Various methods of optical spectroscopy are compared, with special emphasis on resolution and acceptance of the systems. It is shown that coherent detection with a laser as a local oscillator has important advantages for specific applications in astronomical spectroscopy and interferometry, especially in the infrared. The merits and disadvantages of coherent detection systems are numerically evaluated, and a recently developed laboratory system is briefly described. Future applications in stellar spectroscopy and interferometry are enumerated