RESUMEN
We report the development of a novel laser spectrometer for high-sensitivity detection of methane and nitrous oxide. The system relies on a quantum-cascade laser source emitting wavelength of around 8.06 microm, where strong fundamental absorption bands occur for the considered species and their isotopomers. The detection technique is based on audio-frequency and radio-frequency modulation of laser radiation. First experimental tests have been performed to estimate the achievable detection limits and the signal reproducibility levels in view of possible measurements of (13)C/(12)C, (18)O/(16)O, (17)O/(16)O and (15)N/(14)N isotope ratios.
Asunto(s)
Isótopos de Carbono/análisis , Monitoreo del Ambiente/métodos , Metano/análisis , Isótopos de Nitrógeno/análisis , Óxido Nitroso/análisis , Isótopos de Oxígeno/análisis , Espectrofotometría Infrarroja/métodos , Monitoreo del Ambiente/instrumentación , Rayos Láser , Metano/química , Óxido Nitroso/química , Espectrofotometría Infrarroja/instrumentaciónRESUMEN
We demonstrate the generation of cw tunable far-infrared radiation by mixing a quantum cascade laser and a CO>(2) laser in a W-Ni metal-insulator-metal diode. The first known spectroscopic application to the recording of an H(79)Br transition near 4.47 THz is reported.
RESUMEN
Measurements of the optical spectra of semiconductor injection lasers with deformed cylinder resonators show strong indications of the classical Kolmogorov-Arnold-Moser transition from integrability to chaos for devices with small deformation. At larger deformation, evidence for laser action on scar modes is obtained. The diode lasers operate with TE polarization, resulting in laser action on (partially) chaotic whispering-gallery modes for all deformations.