Gain saturation of CW laser pumped FIR laser gases

The saturation behavior of the 70 μm and the 119 μm transitions in CH3OH has been investigated both experimentally and theoretically. This knowledge is essential for constructing a complete model of the CW laser pumped FIR laser. Saturated gain measurements made in a single pass amplifier cell were found to be in good agreement with the theory of a quantum-mechanical three-level system in resonant interaction with two coherent fields. The calculation of the gain using the density matrix formalism yields a pump intensity dependent saturation, a result which is not predicted by the rate equation models.     

New CW FIR laser action in optically pumped vinyl chloride

Thirty-four new FIR lasing lines are reported in vinyl chloride optically pumped by a CO2laser. Ten of them are observed when using pump lines belonging to the 10.8 μm hot band.     

Gain of a CW optically pumped far-infrared laser with sandwich resonator

The FIR laser gain of CW optically pumped HCOOH was measured and compared to theoretical calculations. Since the laser has a transversely pumped parallel-plate (or “sandwich”) waveguide, the pump field is the same for oscillating and amplifying operation. Therefore, “true” FIR-gains were measured. The theory takes into account several phenomena, that are frequently simplified when considering FIR lasers, such as the pump and the FIR beam's spatial distribution, power broadening of the pump absorption, as well as heat and molecular diffusion. As a result, good quantitative agreement between theory and measurement was achieved.     

CW laser pumped emerald laser

A CW laser pumped emerald laser is reported, A 34 percent output power slope efficiency is observed with longitudinal pumping by a krypton laser in a nearly concentric cavity. The laser has been tuned from 728.8 to 809.0 nm, Losses in emerald are larger than those of alexandrite determined in a similar cavity. Our data also indicate that the excited state absorption minimum is shifted from that of alexandrite.     

Quantum mechanical features of optically pumped CW FIR lasers

Quantum mechanical predictions for the gain of an optically pumped CW FIR laser are presented for cases in which one or both of the pump and FIR transitions are pressure or Doppler broadened. The results are compared to those based on the rate equation model. Some of the quantum mechanical predictions are verified in CH3OH.     

Optically pumped CW CF3BR FIR laser. New emission lines and tentative assignments

Eight new CW FIR lines from the CF₃Br molecules pumped by a¹²C¹⁶O₂ laser are reported. Tentative assignments have allowed to assign eight among the ten lines reported.     

New CW FIR laser lines obtained in ammonia pumped by a CO2 laser,using the Stark tuning method

We report fifty seven CW FIR emissions observed in NH₃, by resonant pumping with a CO₂ laser. Exact coincidences between IR absorption lines of the gas and emission lines of the CO₂ laser have been carried out by Stark tuning. IR frequency shifts, up to 30 GHz, have allowed the pumping of forty three NH₃ transitions. These FIR emissions correspond to thirty one different wavelengths in the 50–400 μm range; eighteen ones of them are new emitted wavelengths by pumping with the CO₂ laser.     

CW ruby laser pumped by an argon ion laser

A simple CW ruby laser pumped by a 514.5-nm argon ion laser, utilizing an uncoated ruby rod (no external mirrors), is described. The output does not exhibit spiking, but does show a low amplitude ∼1 percent) of modulation.     

FM-noise measurements on an optically pumped FIR laser

We report the noise measurements performed on a synthesized signal at 761 GHz starting from a 5 MHz quartz oscillator, as well as the investigation of the frequency noise of an optically pumped FIR laser and the possible origin of this noise. Bandwidth requirements for phase-locking an FIR laser are obtained.     

Injection locking of an optically pumped FIR laser

Phase locking of optically pumped far-infrared lasers to highly stable synthesized signals is an interesting goal, at least for metrological purposes. In this paper, the possibility of obtaining such a stabilization by injection of the reference signal into the laser is investigated, and from the results obtained, it is inferred that this technique can be efficiently used in the frequency range up to 1 THz.     

High-power operation and scaling behavior of CW optically pumped FIR waveguide lasers

High-power far infrared (FIR) laser operation at the 10- 100 mW level is described for wavelengths throughout the 40 μm-1.22 mm spectral region. These data correspond to order of magnitude improvements in converting CO2laser energy into FIR laser output. This improved FIR laser performance is attributed to a waveguide laser geometry with reduced losses for the CO2pump and also to a new method of output coupling. The basic design concept of the efficient laser resonator is discussed as well as the prospect for further increases in laser performance through improved efficiency and sealing.     

CW operation of an intracavity pumped molecular submillimeter-wave laser

The 373-μm line of CH3CN was operated in a CW mode in an arrangement where the submillimeter (SMM)-wave laser is placed inside the resonator of the CO2pump laser. 1 mW of CW output power was obtained; this is five times the power of a comparable SMM-wave laser in the common extracavity arrangement. In a pulsed mode, a peak power of 46 mW was measured.     

FIR gain measurements in cw laser pumped CH3OD

Direct measurements of small signal and saturated gain in cw laser pumped CH₃OD are reported for three lasing transitions of 57 μm, 82 μm and 103 μm. The 57 μm transition has a measured gain of 0.6/m, the strongest gain in methanol reported so far. Moreover small gain saturation of this line makes it to be one of the strongest known cw FIR laser lines.     

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.     

Fiber-DFB laser array pumped with a single 1-W CW Yb-fiber laser

A 50-GHz grid fiber distributed feedback laser wavelength-division-multiplexing transmitter source is demonstrated pumped by a single continuous-wave Yb-fiber laser source at 977 nm. Up to 21 mW of output power is achieved per channel with maintenance of key operational parameters. The performance of this single Yb-fiber laser pump configuration is also compared with that of a semiconductor pump configuration which shows no degradation for all the important parameters.     

半导体激光泵浦固体激光器的增益开关效应

用功率大于100mW的二极管激光器列阵泵浦Nd:YAG固体激光器,实现了DPL的增益开关作用。研究了增益开关的动态特性,得到峰值功率大于80mW的1.06μm激光输出,与计算结果一致。提出了三阶梯泵浦的高增益开关新方法,得到峰值功率大于150mW、脉冲宽度小于0.2μs的固体激光输出。     

The optically pumped hydrazine FIR laser: Assignments and new laser lines

Strong far-infrared (FIR) lasing action has been observed in hydrazine optically pumped with isotopic CO2lasers and the N2O laser. The wavelengths of 13 new laser lines have been determined. The results of a recent infrared-microwave double resonance study of hydrazine have been used to assign the transitions involved in the production of five of these new lines and nine of the previously observed laser lines.     

Modeling of longitudinally pumped CW Ti:sapphire laser oscillators

Longitudinal pumping of CW Ti:sapphire oscillators is considered to predict the power output of such oscillators using folded, astigmatically compensated cavities. The model predicts how the oscillator performance is affected by the selection of Ti³⁺ concentration, material figure of merit, rod length, and pump and cavity mode waists. Experimental results for broadband CW oscillators pumped by CW argon ion lasers are reported, and these are shown to be in excellent agreement with theory. Nearly 30% slope efficiency is achieved with a four-mirror folded cavity and even higher efficiencies are predicted for optimized pumping     

FIR Stark spectroscopy on optically pumped CH3OH laser

An extensive theoretical and experimental analysis of the absorption and emission spectrum of a CH₃OH FIR-laser excited by a conventional CO₂ laser is presented. Particular interest is devoted to the Stark shifts of the pump and lasing lines and to the electric field dependence of the Fir-laser output of the various lines. The offsets with respect to the exciting radiation and the Stark shifts of the IR absorption (pump) lines are measured by means of the transferred Lamb dip technique. The theoretical behaviours of the Stark patterns are calculated for several choices of the quantum numbers and selection rules involved in the transitions. A large variety of experimental results are reported and compared to theory. Non-linear Stark shifts have been observed for the 37.5μm FIR laser line and for the IR-pump transitions excited by the 9-P(38) and 10-R(38) CO₂ laser Lines. Line assignments are proposed and new FIR laser lines are reported.     

Theoretical study of multi-mode optically pumped NH3 FIR laser

The two or multi-mode optically pumped NH₃ FIR laser had been studied theoretically. The NH₃ molecular gas was assumed to be a three-level system and obeyed the time-dependent behavior of the density matrix equations. Considering the situation of playing the two or multi-mode optical pumping and the FIR laser field were same polarized. The gain coefficient and the output FIR power of the system could be calculated by using the iteration method. It had been predicted that the two or multiple longitudinal mode optically pumped NH₃ FIR laser could have a greater output power or higher lasing efficiency than single mode pumped FIR laser under suitable selected operating parameters of laser.