On the mechanism of transverse-mode beatings in a Fabry - Perot laser

Journal Article · Wed Jun 23 00:00:00 EDT 2010 · Quantum Electronics (Woodbury, N.Y.)

DOI:https://doi.org/10.1070/QE2010V040N04ABEH014236· OSTI ID:21471381

Kumar, N ^[1]; Ledenev, V I ^[2]

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1. Indira Gandhi Centre for Atomic Reseach, TN (India)
2. Institute on Laser and Information Technologies, Russian Academy of Sciences, Shatura, Moscow Region (Russian Federation)

The mechanism of emergence of fundamental-mode and first-mode beatings in the case of a step-wise increase in the pump rate is studied under the stationary single-mode lasing conditions. Investigation is based on the numerical solution of nonstationary wave equations in a resonator in the quasi-optic approximation and on the equation for a relaxation-type medium as well as on the use of the first two Hermite - Gaussian polynomials {psi}{sub 0,1}(x) to obtain the distribution projections I{sub 0,1}(t), g{sub 0,1}(t) of the radiation intensity and gain, respectively. It is shown that the transverse-mode beatings emerge at early stages of two-mode lasing, the appearance of radiation intensity oscillations in the active medium preceding the development of the gain oscillations. The time of the passage of two-mode lasing to the stationary regime is determined. The phase shift {pi}/2 between the oscillations I{sub 1}(t) and g{sub 1}(t) is found for the established beating regime and the modulation depth {Delta}I averaged over the output aperture of the radiation intensity in the established two-mode regime is shown to be proportional to the pump rate excess k over the single-mode lasing threshold. A scheme for controlling the mode composition of laser radiation is proposed, which is based on the rules for determining I{sub 0,1}(t) by the sensor signals. The efficiency of the scheme is studied. The scheme employs two field intensity sensors mounted inside the resonator behind the output aperture. (resonators. modes)

• OSTI ID: 21471381
• Journal Information: Quantum Electronics (Woodbury, N.Y.), Vol. 40, Issue 4; Other Information: DOI: 10.1070/QE2010v040n04ABEH014236; ISSN 1063-7818
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
APERTURES
APPROXIMATIONS
FABRY-PEROT INTERFEROMETER
HERMITE POLYNOMIALS
LASER RADIATION
LASERS
MODULATION
NUMERICAL SOLUTION
OSCILLATIONS
PHASE SHIFT
RELAXATION
RESONATORS
SENSORS
SIGNALS
WAVE EQUATIONS
CALCULATION METHODS
DIFFERENTIAL EQUATIONS
ELECTROMAGNETIC RADIATION
ELECTRONIC EQUIPMENT
EQUATIONS
EQUIPMENT
FUNCTIONS
INTERFEROMETERS
MATHEMATICAL SOLUTIONS
MEASURING INSTRUMENTS
OPENINGS
PARTIAL DIFFERENTIAL EQUATIONS
POLYNOMIALS
RADIATIONS