RESUMO
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.
Assuntos
Isótopos de Carbono/análise , Monitoramento Ambiental/métodos , Metano/análise , Isótopos de Nitrogênio/análise , Óxido Nitroso/análise , Isótopos de Oxigênio/análise , Espectrofotometria Infravermelho/métodos , Monitoramento Ambiental/instrumentação , Lasers , Metano/química , Óxido Nitroso/química , Espectrofotometria Infravermelho/instrumentaçãoRESUMO
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.
RESUMO
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.
