RESUMO
We report on phase locking of two continuous wave IR laser sources separated by 100 THz emitting around 1029 and 1544 nm, respectively. Our approach uses three independent harmonic generation processes of the IR laser frequencies in periodically poled MgO:LiNbO3 crystals to generate second and third harmonics of those two IR sources. The beat note between the two independent green radiations generated around 515 nm is used to phase lock one IR laser to the other, with tunable radio frequency offset. In this way, the whole setup operates as a mini-frequency comb emitting four intense optical radiations (1544, 1029, 772, and 515 nm), with output powers at least three orders of magnitude higher than the available power from each mode emitted by femtosecond lasers.
RESUMO
In this paper, we report on the metrological capabilities of CO (2)/OsO(4) optical frequency standards operating around 29 THz. Those frequency standards are currently involved in various fields, such as frequency metrology, high resolution spectroscopy, and Rydberg constant measurements. The most impressive features of the standards lies in the 10(-15) level frequency stability allied to a long-term reproducibility (1 yr) of 1.3x10 (-13).
RESUMO
We report on 120-mW directly measured cw power at 532 nm from a tunable alpha -distributed-feedback laser diode near 1.064 microm frequency doubled in a KTP crystal operating room temperature inside a ring cavity. Our experimental setup allows us to scan frequencies up to 2 THz in the green-light domain and thus is extremely useful for iodine spectroscopy. We show good agreement between experimental results and theoretical predictions for the second-harmonic generation process.
RESUMO
We report as much as 6-micro W upconverted cw radiation at lambda = 778 nm from the sum-frequency mixing of a 50-mW diode laser at lambda = 842 nm and a 200-mW CO(2) laser at lambda = 10.2 microm by use of a 15-mm-long silver thiogallate crystal. This nonlinear material provides a convenient connection between IR and visible/near-IR optical standards. We describe simple frequency chains based on this upconversion process that permit the absolute frequency measurement of many visible or near-IR possible standards at the 10(-12) accuracy level. Transposition of terahertz-scale frequency-difference measurements from the near IR to the 10-microm domain is also proposed.
RESUMO
We report our recent progress on detection of large frequency difference (up to 1.028 THz, Deltalambda = 2.5 nm) between two laser diodes at 852 nm, using a Schottky diode as harmonic mixer/detector. Using the 11th harmonic of a klystron operating at 93.5 GHz or the 991-GHz line of an optically pumped HCOOH far-infrared laser, we were able to observe a signal-to-noise ratio of 2 dB in a 1-MHz-resolution bandwidth.
RESUMO
We report a doubly resonant continuous-wave CO(2) laser frequency-quadrupling device that generates 200nW of 2.55-mum (4?) and as much as 2mW of 5.1-mum (2?) radiation out of 1.7-W fundamental radiation at 10.2 mum (?). The quadrupling process results from two resonant cascading second-harmonic generations by use of a walk-off-compensated twin AgGaSe(2) device (??2?) and a ZnGeP(2)nonlinear crystal (2??4?).
RESUMO
An extended set of 321 frequencies of vibration-rotation lines of the nu(3) band of SF(6) has been measured by saturation spectroscopy using various isotopic species of CO(2). A least-squares fit of these data has been performed using an effective Hamiltonian written either with a spherical tensor or with a cubic tensor formalism. We have derived correspondence formulas between the parameters in the two approaches and checked that both formalisms give the same results up to the seventh order. Corrected parameters are given for the fit with a fifth-order Hamiltonian. An accurate representation of the band is obtained at the tenth order (standard deviation approximately 12 kHz) with a remarkable predictive power (better than 40 kHz) for J values