High Power Optically Pumped Far Infrared Lasers

Plant, T.K.; Newman, Leon; Danielewicz, E.; DeTemple, T. A.; Coleman, Paul D.

doi:10.1109/tmtt.1974.1128410

Cited by 60 publications

(3 citation statements)

References 8 publications

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“…It has been forty years since the pioneering work of Chang and Bridges [1] demonstrated generation of submillimeter radiation via stimulated emission from optically-pumped methyl fluoride (CH 3 F) gas. Since then, a rich spectrum of laser lines through the 50 μm -2 mm wavelength region have been obtained from a variety of different molecular gases [2][3][4][5][6][7][8][9][10]. These developments have made this class of lasers-usually referred to as optically-pumped far infrared (OPFIR) lasers-a central resource for many scientific and technological applications.…”

Section: Introductionmentioning

confidence: 99%

“…These developments have made this class of lasers-usually referred to as optically-pumped far infrared (OPFIR) lasers-a central resource for many scientific and technological applications. The physical mechanism underlying the operation of conventional OPFIR lasers has also been extensively studied in past decades [2][3][4][5][6][7][8][9][10][11][12][13][14][15]. In essence, the gain in these systems derives from an optically-driven population inversion between two rotational states in an excited vibrational level of a gas molecule; the laser emission frequency is determined by the frequency of the transition between these two rotational states.…”

Section: Introductionmentioning

confidence: 99%

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Spatio-temporal theory of lasing action in optically-pumped rotationally excited molecular gases

Chua¹,

Caccamise²,

Phillips³

et al. 2011

Opt. Express

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We investigate laser emission from optically-pumped rotationally excited molecular gases confined in a metallic cavity. To this end, we have developed a theoretical framework able to accurately describe, both in the spatial and temporal domains, the molecular collisional and diffusion processes characterizing the operation of this class of lasers. The effect on the main lasing features of the spatial variation of the electric field intensity and the ohmic losses associated to each cavity mode are also included in our analysis. Our simulations show that, for the exemplary case of methyl fluoride gas confined in a cylindrical copper cavity, the region of maximum population inversion is located near the cavity walls. Based on this fact, our calculations show that the lowest lasing threshold intensity corresponds to the cavity mode that, while maximizing the spatial overlap between the corresponding population inversion and electric-field intensity distributions, simultaneously minimizes the absorption losses occurring at the cavity walls. The dependence of the lasing threshold intensity on both the gas pressure and the cavity radius is also analyzed and compared with experiment. We find that as the cavity size is varied, the interplay between the overall gain of the system and the corresponding ohmic losses allows for the existence of an optimal cavity radius which minimizes the intensity threshold for a large range of gas pressures. The theoretical analysis presented in this work expands the current understanding of lasing action in optically-pumped far-infrared lasers and, thus, could contribute to the development of a new class of compact far-infrared and terahertz sources able to operate efficiently at room temperature.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spatio-temporal theory of lasing action in optically-pumped rotationally excited molecular gases

Chua¹,

Caccamise²,

Phillips³

et al. 2011

Opt. Express

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“…Only one CH31 level is pumped, the other allowed pump transitions being separated by large frequency differences. The spectral width of the output of a 3 m long ASE type laser operating with CH31 was measured to be 100 MHz FWHM [23] which is quite narrow when compared with the CH3F [6] -[lo] and Dz 0 [24] results. The energy output from the CH3 I gas in all our laser systems was always at least a factor of 10 below the output from CH3 F or Dz 0 in the same systems.…”

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confidence: 99%

High power optically pumped far infrared laser systems

Drozdowicz

Woskoboinikow

Isobe

et al. 1977

IEEE J. Quantum Electron.

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Single mode, 60-80 ns pulse width, 50-70 kW peak power laser oscillators operating on the 384.6 pm line of DzO have been developed. The characteristic linewidths of these oscillators are less than 25 MHz full width at half maximum which favorably compares with the intrinsic width of 6-8 MHz associated with the pulse length of about 6 0 ns. A 12.7 mJ, 195 kW, 384.6 pm D2O laser oscillatoramplifier combination has been constructed and tested. Although single longitudinal mode operation is attained from this oscillatoramplifier system, amplified spontaneous emission (superradiance) from the amplifier adds low power level wide-bandwidth background radiation. Studies of far infrared lasing action in CH3F and CH31 are also described. T HE potential application of high power narrow linewidth far infrared radiation (FIR) for determination of ion temperature in tokamak plasmas by Thomson scattering was proposed [ l ] , [2] after the first demonstration of optically pumped laser action in CH3F [3] and the subsequent production of higher power outputs from mirrorless lasers [4], [5]. At present it appears that power levels on the order of 1 MW, pulse energies on the order of 200 mJ, and full linewidth of 20-40 MHz between 10 dB points are required. Also full widths of less than 100 MHz at the 30 dB and 200 MHz at the 50 dB points are required for Thomson scattering measurements of tokamak plasmas and other hot plasmas with electron densities of about 1014 ~m-~. In this paper we discuss various means of achieving high power, narrow linewidth output from a FIR laser system. Attempts have been made to generate high power narrow linewidth radiation in CH3F by pumping it with the 9.55 pm P(20) line of high power pulsed C02 lasers. Reasonably good power conversion efficiencies were obtained in amplified spontaneous emission (ASE) type lasers [6]-[ 101. A variety of linewidths were reported for these lasers, all of them in the

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List of the Optically Pumped Laser Lines of D20

DeTemple

1984

Reviews of Infrared and Millimeter Waves

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High Power Optically Pumped Far Infrared Lasers

Cited by 60 publications

References 8 publications

Spatio-temporal theory of lasing action in optically-pumped rotationally excited molecular gases

Spatio-temporal theory of lasing action in optically-pumped rotationally excited molecular gases

High power optically pumped far infrared laser systems

List of the Optically Pumped Laser Lines of D20

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