Interferometric frequency measurements of 130Te2 transitions at 486 nm

Doppler-free spectra of ¹³⁰Te₂ have been investigated in the region of 486 nm, close to the Balmer-β transitions atomic hydrogen and deuterium. The frequency ratios between a 633 nm He-Ne laser stabilized to the 11-5 R(127) “i” transition in ¹²⁷I₂ and two of these ¹³⁰Te₂ Doppler-free components have been measured interferometrically to a precision of 2 parts in 10¹⁰ (one standard deviation). These measured components constitute useful transfer standards for the measurement of absolute frequencies of both the Balmer-β transitions and the 243-nm two-photon 1S-2S transitions in hydrogen and deuterium.     

New FIR laser lines from an optically pumped far-infrared laser with isotopic 13C16O2 pumping

A ¹³C¹⁶O₂ laser optically pumping a FIR laser has resulted in 17 new FIR cw emissions from 78.5 μm to 917 μm. The FIR media were: CD₃OD, CH₃OD, CD₃OH, NH₃ and ¹⁵NH₃. Interesting effects have been observed with a combination of NH₃ and CD₃OD resulting in a new FIR emission. Two new FIR emissions at 181.5 μm and 355.5 μm have been observed with a ¹²C¹⁶O₂ laser optically pumping CD₃OD.     

Frequencies of cw FIR laser lines from optically pumped CH2F2

The frequencies of 48 optically pumped cw FIR CH₂F₂ laser lines have been measured relative to stabilized CO₂ lasers. Uncertainties are estimated to be about 5 parts in 10⁷.     

New far infrared laser lines in optically pumped CD3F

Summary Using a high pressure CO₂-laser we have studied laser action in¹²CD₃F stimulated by R-branch pumping. We used an arrangement with low-feedback mirrors as suitable for Raman laser action. However, no Raman laser action has been observed in¹²CD₃F though similar experimental conditions were met as for¹²CH₃F and¹³CH₃F. The reason for the different behavior of the gases is not yet clear.Instead of Raman laser action we found 15 FIR resonant laser lines with 13 of them unknown up to now in the frequency range from 50 cm^–1 to 68 cm^–1. We reached FIR pulse energies up to 900 J, corresponding to a photon conversion efficiency of 12%. For our arrangement the optimum operation pressure varied from 40 torr at low J values (J=36) to 70 torr at high J values (J=49).     

Characteristics of an optically pumped COF2 laser

An optically pumped COF₂ laser^1,2 has been used for experiments with NbN Josephson junctions at NPL³. Its characteristics are described in this paper, with particular reference to results of output power stability and output power level⁴.     

Optically pumped continuous I2 molecular laser

Continuous laser oscillation was observed for various B ³Π_0⁺u → X ¹Σ_0⁺g transitions of molecular iodine in the wavelength range of 583.0 nm to 1338 nm excited by a single frequency 514.5 nm argon laser. For pump powers of 3W output powers up to 250 mW were obtained. Some properties of the laser system are discussed.     

Submillimeter emission lines from CD2Cl2 optically pumped lasers

Fifty-five new submillimeter laser lines from optically pumped CD₂Cl₂, have been obtained in a FIR metallic waveguide resonator. Twenty-seven lines, ranging from 184 m to 1387 m, and twenty-eight lines, from 219 m to 888 m, have been observed when using CW CO₂ laser and CW N₂O laser optical pumping, respectively. The accuracy of wavelength measurements are of the order of 3.10^–3.     

Assignments of optically pumped CH3OD laser lines

Fifteen laser lines from CH₃OD pumped by a CO₂ laser are assigned to specific rotational energy transitions. These assignments have been obtained from the approximation that, except for one constant, the molecular constants in the excited CO stretching state are same as those in the ground state.     

Assignments of optically pumped CD3OH laser lines

Six FIR laser lines from CD₃OH pumped by the 10R(36) and the 10R(18) CO₂ laser lines are assigned to specific rotational energy levels in the excited C–0 stretch state. It is found that their upper laser levels are shifted by a Fermi resonance between the C–0 stretch vibration and the third and forth harmonics of the torsional mode. The Fermi resonance shifts are +0.332 cm^–1 and +2.251 cm^–1 for the upper laser levels pumped by the 10R(36) and the 10R(18) CO₂ laser lines, respectively. Calculated frequencies of the pump and the laser transitions agree with those of the pump CO₂ laser lines and the observed FIR laser lines within estimated accuracy.     

High power FIR lasing in 15NH3 optically pumped with an isotopically enriched CO2 laser

We report high efficiency high power cw FIR lasing in ¹⁵NH₃ optically pumped with a ¹³C¹⁶O₂ laser.     

New cw two-photon pumped and Raman fir laser lines in 14NH3 and 15NH3

Application of infrared-microwave two-photon pumping on ¹⁴NH₃ and ¹⁵NH₃ yields 17 new cw laser lines in the far infrared. In addition a new Raman laser line in ¹⁵NH₃ is found.     

13CD3OH and12CD3OH optically pumped by a13CO2 laser: Observations and assignments of FIR laser lines

In this work we report the first observation of FIR laser lines from¹³CD₃OH pumped by the¹³CO₂ isotope laser. Using the same pump we have also found 3 new lines from¹²CD₃OH. Tentative assignments for the absorption and emission transitions of the observed lines are also proposed.Work supported by FAPESP. CNPq, FAEP/UNICAMP-Brasil and NSF-USA     

Assignments of laser lines in optically pumped CH3CN

A careful analysis of the rotovibrational spectroscopic data of CH₃CN is presented taking into account Fermi and Coriolis interactions. A large majority of the FIR lines obtained by optical pumping is assigned. New values are proposed for some molecular constants and the need of more accurate experimental investigation is pointed out.     

CW infrared laseraction of optically pumped Co2+:KZnF3

The optical properties of KZnF₃:Co²⁺ were investigated by means of absorption and emission spectroscopy in the visible and infrared spectral region. This system is suitable for laseraction between the lowest ⁴T₁(⁴F)-⁴T₂(⁴F) Co²⁺ phonon sidebands. CW laseraction of more than 20 mW (85K) was observed at 1.95 μm when pumped with an Ar⁺-laser at 514 μm (1.5W). The system is at least tunable between 2.05 μm to 1.85 μm.     

New optically pumped FIR laser lines in CD3OH

In this work we report laser action in 69 new FIR laser lines in CD₃OH optically pumped by a regular cw CO₂ laser. We have performed measurements of laser wavelength, optimum pressure of the gas, relative polarization and intensity on all lines, including some previously known.     

Frequency measurements of far infrared cw lasing lines in optically pumped CHCl2F

The wavelengths, frequencies, and relative polarizations of 15 FIR cw lasing lines obtained by optically pumping CHCl₂F with a cw CO₂ laser have been measured. The lines are in the wavelength range from 340.3 to 905.4 m and were pumped by P- and R-branch laser lines in the 9 m band of CO₂.Supported in part by a joint grant with the U. S. National Science Foundation grant # INT80-19014 and the Brazilian Consellio Nacional de Pesquisas (CNPq)Contribution of the U. S. Government, not subject to copyright.     

New CH2F2 FIR laser lines pumped by a tunable WG CO2 laser

8 new large offset FIR laser lines of CH₂F₂ have been discovered by pumping with a high tunability waveguide CW CO₂ laser. Optoacoustic measurements of CH₂F₂ have also been performed and the pump offsets of the new and of previously known lines have been measured and checked. Some assignments are proposed and a few assignments found in literature are checked     

Assignment of laser lines in an optically pumped submillimeter and near millimeter laser: (H2CO)3

A large number of emissions is obtained in the submillimeter and near millimeter range with the (H₂CO)₃ laser optically pumped by a CO₂ laser. A study of the microwave absorption spectrum of the molecule carried out simultaneously with the submm analysis allows us to assign six of the laser lines in thev ₅ excited state of the molecule and to determine the rotational constants and vibrational energy ofv ₅.     

DCOOD optically pumped by a 13CO2 laser: new terahertz laser lines

In this work we report on new optically pumped THz laser lines from deuterated formic acid (DCOOD). An isotopic ¹³CO₂ laser was used for the first time as a pump source for this molecule, and a Fabry–Perot cavity was used as a THz laser resonator. Optoacoustic absorption spectra were used as a guide to search for new THz laser lines. We could observe six new laser lines in the range from 303.8 μm (0.987 THz) to 725.1 μm (0.413 THz). The lines were characterized according to wavelength, relative polarization, relative intensity, and optimum working pressure. The transferred lamb-dip technique was used to measure the frequency absorption transition for both of these laser lines. Furthermore, we also present a catalogue of all THz laser lines generated from DCOOD.     

Characteristics of a far-infrared molecular laser optically pumped by a high-power CO2 laser

A molecular far-infrared (FIR) laser optically pumped by a high-power CO₂ laser, which is a powerful source for testing detectors and mixers and for FIR spectroscopy, is constructed and the performance is examined through experiments. At frequencies between 580GHz and 4.25THz, FIR output power is more than 2030m W by pumping power of 3581W. Amplitude stability of ±3% is obtained at 100m W output at 2.52THz for over 30 minutes when the FIR tube is cooled at 5°C by a chiller.As an application to testing mixers, FIR laser lines up to 4.25 THz are detected by Schottky barrier diodes (SBD). Further, using a SBD, performance of absolute frequency stability at 693GHz of HCOOH oscillation is measured by harmonic mixing with a 115.5GHz millimeter wave from a phase-locked Gunn oscillator. The resultant center-frequency stability is 100kHz per 10 minutes.