A Stimulated Emission Source at 0.34 Millimetre Wave-length

Gebbie, H. A.; Stone, Nick; Findlay, F. D.

doi:10.1038/202685a0

Cited by 115 publications

(14 citation statements)

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“…2), corresponding to a total power of 34 µW by taking into account the symmetry of the laser. Lasing is also obtained with seven other transitions: saQ(2,1), (3,1), (4,4), (5,2), (5,3), (6,5), and (8,7).…”

Section: -2mentioning

confidence: 99%

“…Despite investigations and progress, cryogenic cooling is still needed 2,3 which is bulky and expensive. THz molecular lasers have been demonstrated long time ago [4][5][6] but until now they are also too bulky and expensive for a wide use in applications. Laser oscillation is obtained by electrical or optical pumping of a molecular gas at room temperature and low pressure.…”

mentioning

confidence: 99%

“…Discrete frequencies can then be generated in 0.1-10 THz range covering submillimeter, THz, and far-infrared waves. In the case of electrical pumping, 4,5 vibrational excitation is obtained through the use of an electrical discharge through the gas. However this simple approach has several drawbacks: (I) the excitation is not specific and leads to low efficiencies; (II) population inversion in continuous wave (CW) is generally due to selective relaxation, only few molecules can be pumped following this way, and consequently only 50 laser lines were demonstrated since fifty years; and (III) a gas flow is needed because the molecules are dissociated by the discharge.…”

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confidence: 99%

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Low-threshold terahertz molecular laser optically pumped by a quantum cascade laser

2016

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We demonstrate a low-threshold, compact, room temperature, and continuous-wave terahertz molecular laser optically pumped by a mid-infrared quantum cascade laser. These characteristics are obtained, thanks to large dipole transitions of the active medium: NH3 (ammonia) in gas state. The low-power (<60 mW) laser pumping excites the molecules, thanks to intense mid-infrared transitions around 10.3 μm. The molecules de-excite by stimulated emission on pure inversion “umbrella-mode” quantum transitions allowed by the tunnel effect. The tunability of the quantum cascade laser gives access to several pure inversion transitions with different rotation states: we demonstrate the continuous-wave generation of ten laser lines around 1 THz. At 1.07 THz, we measure a power of 34 μW with a very low-threshold of 2 mW and a high differential efficiency of 0.82 mW/W. The spectrum was measured showing that the linewidth is lower than 1 MHz. To our knowledge, this is the first THz molecular laser pumped by a solid-state source and this result opens the way for compact, simple, and efficient THz source at room temperature for imaging applications.

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Section: -2mentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Low-threshold terahertz molecular laser optically pumped by a quantum cascade laser

2016

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“…Mathias and Crocker [2] extended this list to thirty-two wavelengths between 16 and 120 microns. Gebbie et al [3] found SMASER action in several vapors containing CN using a pulsed discharge in a 9m long tube of 6.5 cm inner diameter. Repeating this experiment, Mathias et al [4] found SMASER action at eleven wavelengths between 126 and 375 microns.…”

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confidence: 99%

Submillimeter gas laser

Flesher

Müller

1966

Proc. IEEE

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power possible ranges from 900 watts at 30 Gc/s to 15 watts at 150 Gc/s. Both the output power and efficiency are enhanced by magnetic focusing as compared to space-charge focusing. Heat-transfer calculations and experimental evidence have shown that the coupledcavity circuit is capable of handling the high-power densities to be experienced in the magnetically focused EIO.The use of a magnetically focused electron beam in the E10 will increase the effectiveness of collector depression since a larger proportion of the electron beam will reach the collector. Collection of the beam a t a reduced velocity will increase the overall efficiency of the device by as much as a factor of two. CONCLUSIONSThe extended interaction oscillator fulfills the requirement for a small light-weight efficient low-noise source of power a t millimeter wavelengths. I t is ideally suited to applications requiring power in the severalhundred-milliwatt to several-hundred-watt range, such as parametric amplifier pumping, CW Doppler radar, secure communications, and beacon transmitters. ACKNOWLEDGMENTThe authors wish to acknowledge the contribution of L. H. Sandstrom, who performed the mechanical design of the extended interaction oscillators described in this paper.Abstract-The characteristics of a laser operating in the submillimeter wave region is described. The laser is capable of CW or pulse operation.

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“…n.(cm-3 )dl(cm). (1) We report a technique for obtaining better than 1/100 of a fringe sensitivity in a focused Michelson interferometer. It is also shown that such a far infrared, fractional fringe interferometer can be applied to a large plasma device of thermonuclear significance, Burnout V, at ORNL.…”

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confidence: 99%

Fractional Fringe HCN Laser-Interferometer

Olsen

1971

Review of Scientific Instruments

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An HeN laser-inte~ferometer is report.ed with better than 1/100 of a fringe phase shift sensitivity at a wavelengt~ ~; 33~:-Apphed to plasm~ densl~y measur~men~ this corresponds to electron density line integrals of ~.3 X 10 em ?r lower: The fractional frmge techmque mvolves sinusoidally driving the reference path mirror m a focused Mlc~el~on mterferomet~r; changes in the effective path length alter the relative magnitude of even and odd harmomcs m the resultant mterferometer signal. Results are shown from application of this diagnostic to the Burnout V plasma.

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A Stimulated Emission Source at 0.34 Millimetre Wave-length

Cited by 115 publications

References 2 publications

Low-threshold terahertz molecular laser optically pumped by a quantum cascade laser

Low-threshold terahertz molecular laser optically pumped by a quantum cascade laser

Submillimeter gas laser

Fractional Fringe HCN Laser-Interferometer

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