Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Chinese Journal of Lasers

Saturation in optically pumped far-infrared lasers

Changxin Wang, Ensheng Fu, Runwen Wang

Published Jun 1, 1988• 0 citations
OpenAlex

Abstract

The dressed-atom approach is used to analyze saturation in an optically pumped three-level system. The small-signal gain is found for the case when two different saturation factors are present, and the result can be conveniently applied to analyze the different saturation behavior of the Raman and line-center transitions in optically pumped far-infrared lasers.

Related papers

Theory of FIR tunable Raman lasers

C Wang

In this paper, we use the dressed-atom approach to derive the analytical expression of the gain of a FIR laser with a four-level system. The results indicate that the FIB laser gain spectrum generally consists of four peaks. For some ranges of pump detunings, it is possible to obtain two positive gain maxima: one at the Raman frequency and the other at the line center frequency.

Acta Optica Sinica•Jan 1, 1987•0 citations

Sub-T2optical pulse generation: Application to optically pumped far-infrared lasers

Albert T. Rosenberger, Ho Kyoon Chung, T. De Temple

Several polar molecules possessing strong far-infrared (FIR) transitions have been optically pumped by a mode-locked CO2TEA laser in a single-pass configuration. All the resulting FIR pulses are shorter than the sub-T2pump pulses; subnanosecond FIR pulses are observed. These short FIR pulses exhibit lethargic gain, stimulated Raman emission, and multiple-pulse superradiance. The experimental results are modeled by numerical solution of the Maxwell-density matrix equations for two fields interacting with a three-level system. Level degeneracy is included, and the pump is described by a multimode power spectrum with a parabolic envelope, resulting in a periodic train of pulses. Variation of the detuning of the pump from resonance allows simulation of the superradiant or Raman cases. This fully coherent model, which is the major contribution of this paper, explains key experimental observations such as the noncoincidence of the Raman peak with the pump modulation minimum and the enhancement of multiple-pulse superradiance due to remanent polarization.

IEEE Journal of Quantum Electronics•May 1, 1984•15 citations

Chaos in the Four-Level Raman Far-Infrared Lasers

Suranjana Raj, Jerald R. Izatt, Jagdish Rai +1 more

The full set of Maxwell-Bloch equations for the four-level atomic systems is numerically integrated to obtain the time dynamics. Specific applications to the CH3F optically pumped far-infrared lasers are considered.

Nonlinear Dynamics in Optical Systems•Jan 1, 1990•0 citations

Line competition and line selection in off-resonantly pumped systems

M.‐A. Dupertuis, S.A. Salito, Rainer Salomaa +1 more

For some time already it has been known that off-resonantly pumped far infrared (FIR) lasers oscillate on the Raman line [1]. This feature has led to important applications such as the realisation of widely tunable CH3F lasers (150–1200 μm) [2]. Only recently it has been shown [3] that mode competition is responsible for the fact that Raman oscillation (R) dominates line centre oscillation (LC) in a three-level system. The same considerations are valid in the equivalent situation of a single refilling transition (|0 > → |1> in Fig. 1). In certain experiments [4–7] Λ and V transitions (Fig. 1) appear in combination. For this case LC and R oscillations have been observed to exist simultaneously in one of the FIR transitions [5].

International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)•Dec 1, 1985•0 citations

A theoretical study of saturation effects in three-level laser systems

Yakir Reuven, Michael Baer

Exact numerical solution of a time-space (one dimensional) three-level lasing system (homogeneously broadened) is used to study the relevance of steady-state models to such a system. This study revealed: 1) the existence of two disconnected (quasi) steady-state regions-the small-signal gain region (slow pumping rate) and the high saturation region (large pumping rate), and 2) the spatially averaged equations for the high saturation region have a form similar to those usually employed in the small-signal gain region, except that a constant which in the latter case is unity becomes smaller than 1 in the high saturation region.

IEEE Journal of Quantum Electronics•Oct 1, 1980•7 citations

Dynamics of a detuned, optically pumped far-infrared laser

Jaume Pujol, Ferran Laguarta, R. Corbalán +1 more

The dynamic behaviour of a coherently pumped single-mode far-infrared ring laser with a homogeneously broadened three-level medium is analysed theoretically, considering detuning between amplifying transition and cavity frequencies. Phase diagrams as a function of cavity detuning and amplitude of the resonant pump field have been obtained, which show different domains of stationary, oscillatory and chaotic output. In some conditions the laser is shown to exhibit hysteresis between different regular self-pulsing regimes, i.e. the phenomenon of generalised bistability.

Journal of Physics D Applied Physics•Oct 14, 1988•7 citations
The dressed-atom approach is used to analyze saturation in an optically pumped three-level system. The small-signal gain is found for the case when two different saturation factors are present, and the result can be conveniently applied to analyze the different saturation behavior of the Raman and line-center transitions in optically pumped far-infrared lasers.
Several polar molecules possessing strong far-infrared (FIR) transitions have been optically pumped by a mode-locked CO2TEA laser in a single-pass configuration. All the resulting FIR pulses are shorter than the sub-T2pump pulses; subnanosecond FIR pulses are observed. These short FIR pulses exhibit lethargic gain, stimulated Raman emission, and multiple-pulse superradiance. The experimental results are modeled by numerical solution of the Maxwell-density matrix equations for two fields interacting with a three-level system. Level degeneracy is included, and the pump is described by a multimode power spectrum with a parabolic envelope, resulting in a periodic train of pulses. Variation of the detuning of the pump from resonance allows simulation of the superradiant or Raman cases. This fully coherent model, which is the major contribution of this paper, explains key experimental observations such as the noncoincidence of the Raman peak with the pump modulation minimum and the enhancement of multiple-pulse superradiance due to remanent polarization.
For some time already it has been known that off-resonantly pumped far infrared (FIR) lasers oscillate on the Raman line [1]. This feature has led to important applications such as the realisation of widely tunable CH3F lasers (150–1200 μm) [2]. Only recently it has been shown [3] that mode competition is responsible for the fact that Raman oscillation (R) dominates line centre oscillation (LC) in a three-level system. The same considerations are valid in the equivalent situation of a single refilling transition (|0 > → |1> in Fig. 1). In certain experiments [4–7] Λ and V transitions (Fig. 1) appear in combination. For this case LC and R oscillations have been observed to exist simultaneously in one of the FIR transitions [5].
Exact numerical solution of a time-space (one dimensional) three-level lasing system (homogeneously broadened) is used to study the relevance of steady-state models to such a system. This study revealed: 1) the existence of two disconnected (quasi) steady-state regions-the small-signal gain region (slow pumping rate) and the high saturation region (large pumping rate), and 2) the spatially averaged equations for the high saturation region have a form similar to those usually employed in the small-signal gain region, except that a constant which in the latter case is unity becomes smaller than 1 in the high saturation region.
The dynamic behaviour of a coherently pumped single-mode far-infrared ring laser with a homogeneously broadened three-level medium is analysed theoretically, considering detuning between amplifying transition and cavity frequencies. Phase diagrams as a function of cavity detuning and amplitude of the resonant pump field have been obtained, which show different domains of stationary, oscillatory and chaotic output. In some conditions the laser is shown to exhibit hysteresis between different regular self-pulsing regimes, i.e. the phenomenon of generalised bistability.