SAIP 2011 Support
Demonstration of a wavelength tuneable mid-IR molecular laser
Presented by Mr. Wayne KOEN on 13 Jul 2011 from 12:30 to 12:45
Type: Oral Presentation
Track: Track C - Lasers, Optics and Spectroscopy
<p>To our knowledge, we have demonstrated the first optically pumped tunable HBr oscillator lasing on both the P- and the R-branches. Through the implementation of an intra-cavity diffractive grating, we could tune the wavelength over a range of 538 nm from 3872 nm to 4410 nm. A single-frequency Ho:YLF ring laser and amplifier system was used as pump source. The oscillator was pumped in a double pass configuration with 50 mJ, 2064 nm pulses at a repetition rate of 50 Hz. The HBr was kept at 52 mBar, 20 degrees Celsius in a 510 mm tube. The resonator cavity consisted of a flat output coupler mirror with a reflectivity of R=80% at 4 μm, and a high-reflective coating at 2 μm. The input coupler mirror had a concave curvature of 5 m and was coated to be highly reflective at 4 μm and highly transmissive at 2 μm to allow pumping of the HBr. The input coupler mirror was slightly tilted to reflect light unto a flat mirror which in turn reflected unto the diffractive grating which was blazed at 5 μm. The diffractive holographic grating therefore acted as the backreflector mirror, and the wavelength could be selected by rotating the grating. Lasing was demonstrated on eight lines of the P-branch with wavelengths ranging from 4102 nm to 4410 nm, and five lines of the R-branch ranging from 3872 nm to 3999 nm. The highest output energy for the given pump power was 1.1 mJ at 4131 nm.
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