Our goal is to develop and characterize optical measurement technology to enable accurate quantification of
greenhouse-gas emissions from distributed sources and sinks. We are constructing a differential absorption LIDAR
(DIAL) system that will be sensitive to the three primary greenhouse gases, carbon dioxide, methane, and nitrous oxide.
Our system uses a high energy optical parametric oscillator (OPO) operating from 1585 nm to 1646 nm. Here we
describe this OPO system and initial characterization of its output. The OPO uses a Rotated Image Singly-Resonant
Twisted RectAngle (RISTRA) design. The commercially available RISTRA cavity is machined from a solid block of
aluminum. The compact single piece cavity design requires no mirror adjustments and image rotation provides efficient
light conversion efficiency and excellent beam quality. The injection seeded OPO has demonstrated total output energy
of 50 mJ/pulse when pumped with 220 mJ/pulse of 1064 nm radiation. The pump laser has a repetition rate variable
from 1 Hz to 100 Hz and a temporal pulse width of 4.2 ns. In the current configuration the seed laser is locked to a mode
of the cavity.