Long optical cavities for open-path monitoring of atmospheric trace gases and aerosol extinction Varma, Ravi M. ; Venables, Dean S. ; Ruth, Albert A. ; Heitmann, Uwe ; Schlosser, Eric ; Dixneuf, Sophie Abstract Publication: Applied Optics Pub Date: January 2009 DOI: 10.1364/AO.48.00B159 Bibcode: 2009ApOpt..48..159V