Generation, amplification, and detection of infrared and optical radiation by quantum-mechanical systems

Басов, Н. Г.; Крохин, О. Н.; Popov, Yurii M

doi:10.3367/ufnr.0072.196010a.0161

Cited by 46 publications

(9 citation statements)

References 10 publications

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“…The shape of the lines obtained in [4,5] shows that the quality factor is of the order f~~r/kT and has the value 10 3 ata temperature of 10 ~ K. Utilizing the magnetic field ir becomes possible to change the radiation frequency in eH case of values of the order A~~-~-- [14], which for fields HN 10 4 gausses, mc forms 10~o of the radiation frequency in the case of Germanium.…”

Section: Resultsmentioning

confidence: 99%

“…As it was pointed out earlier [5] the condition of producing the negative coefficicnt of absorption in a medium being in the state with a negative temperature, relative to the transition under consideration, is that the radiation induced by the light quantum propagated in the medium must exceed absorption of that quantum at other levels of the system being in the state with a positive tcmperature.…”

Section: Indirect Interband Transitions and Radiation Absorption By Tmentioning

confidence: 99%

“…The impulse method put forward in the paper [1] for obtaining such states is based on a considerable difference of the time of recombination and the slowing-down time of nonequilibrium carriers in the bands [4]. The conditions for producing the states with negative temperatures with these methods ate as follows: large lifetimes of nonequilibrium carriers, high densities of excitation and low temperatures of the sample [5]. All this strongly restricts selection of the semiconductors and creates a number of technical difficulties.…”

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confidence: 99%

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Negative absorption coefficient at indirect transitions in semiconductors

1962

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In this paper a method for obtaining states with negative temperature in semiconductors is discussed; as shown this method requires relatively small densities of excitation.Ac present three different methods ate proposed for obtaining the states with negative temperatures in semiconductors [1--3]. The impulse method put forward in the paper [1] for obtaining such states is based on a considerable difference of the time of recombination and the slowing-down time of nonequilibrium carriers in the bands [4]. The conditions for producing the states with negative temperatures with these methods ate as follows: large lifetimes of nonequilibrium carriers, high densities of excitation and low temperatures of the sample [5]. All this strongly restricts selection of the semiconductors and creates a number of technical difficulties.The method of obtaining the states with negative temperatures in semiconductors proposed in the paper by B. LAx [2] is based on the Landau levels not being equidistant in strong magnetic fields. The comparatively short times of relaxation of the noncquilibrium carriers of these levels make ir difficult to create the states with negative temperatures using the above method.In the present paper the method for obtaining states with negative temperatures in semiconductors put forward in the paper [3] will be studied in detail. As it will be shown below, this method requires relatively small densities of excitation.

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Section: Resultsmentioning

confidence: 99%

Section: Indirect Interband Transitions and Radiation Absorption By Tmentioning

confidence: 99%

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confidence: 99%

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Negative absorption coefficient at indirect transitions in semiconductors

1962

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“…At high gas pressure and homogeneous broadening (see below), the saturation of the gain can be accounted for approximately, assuming (cf. [9]) that 1 g(x) (13) ImSe…”

Section: The Saturation Effectmentioning

confidence: 99%

Lens effect in the waveguide gas laser

et al. 1999

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The radiation field of a planar waveguide laser with a nonuniformly heated gas causing the lens effect was studied. Conditions were found at which the losses at the walls and nonlinearity of the active medium (saturation) became essential. Calculations of the lasing of a xenon laser were performed with regard for the concurrence of modes. The radiation field distributions in the near and far diffraction zones were calculated. The results of calculations correlate qualitatively with experimental data.

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“…(Wir nehmen an, dass der p--n • schroff ist.) Eine negative Temperatur wird nur dann in Band-Band 8 beobachtet, wenn die Quasi-Fermi-Niveaus, die der Nichtgleichgewichtskonzentration der Elektronen und LScher entsprechen, folgende Ungleichung befriedigen [1] ge + gp > A, …”

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