共查询到20条相似文献,搜索用时 125 毫秒
1.
We demonstrate the operation of a monomode semiconductor laser with a relative intensity noise limited by the shot-noise floor, -156 dB/Hz for a typical detected photocurrent of 1 mA, over a large frequency range from 50 MHz to 18 GHz. We achieve direct control of photon lifetime to turn an initially class-B laser into a relaxation-oscillation-free class-A one while preserving strict single-mode operation. Finally, we confirm experimentally that the laser operation in the desired class-A regime allows a dramatic filtering out of the relative intensity noise. 相似文献
2.
G. Bouwmans B. Ségard P. Glorieux P. A. Khandokhin N. D. Milovsky E. Yu. Shirokov 《Radiophysics and Quantum Electronics》2004,47(10-11):729-742
This paper is devoted to the polarization dynamics of a longitudinally monomode bipolarized Nd:YAG laser: the low-frequency polarization dynamics of a microchip laser is studied experimentally and theoretically. The intensities and the relaxation oscillation spectrum of orthogonally polarized modes versus the direction of pump polarization is observed. A phase-sensitive model of a longitudinally monomode bipolarized solid-state laser with linear polarized diode laser pump is developed to account for the experimental observations. 相似文献
3.
4.
Phase conjugation is observed in sodium vapor near the resonance lines using a monomode pulsed dye laser. The divergence of the beam strongly varies during the pulse. By combining the curvature of the pumping beams and the diameter of a pinhole, it is possible to generate pulses which are shorter than the incident pulse by a factor as large as 20. 相似文献
5.
《Optics Communications》1987,61(3):215-218
Modulated pumping of a Nd3+ doped silica monomode fibre laser has been investigated experimentally. For small modulation depths the laser exhibits a resonance at the relaxation oscillation frequency, providing pulses of a few microseconds duration at a repetition rate in the region of 10 kHz, dependent on the average pump level above threshold. As the pump modulation depth is increased, hysteresis is observed as a function of modulation frequency, along with optical bistability. For further increase in modulation depth, optical chaos and period doubling are observed. Gain-switching has also been demonstrated. 相似文献
6.
We demonstrate that the pedestal components observed in the power spectra of a directly modulated laser diode, which were interpreted as a sign of instability of the periodic regime, are an indication of the coexistence of a chaotic regime with the periodic one. We present the underlying dynamics behind the rise of these pedestals, showing two different situations in which the pedestals appear. In both, a periodic regime coexists with another attractor, a saddle cycle in one case and a chaotic attractor in the other. The random fluctuations included in the laser diode model allow the coexisting attractors to merge in the observed behavior of the laser. 相似文献
7.
Riechel S Lemmer U Feldmann J Berleb S Mückl AG Brütting W Gombert A Wittwer V 《Optics letters》2001,26(9):593-595
Optically pumped organic semiconductor lasers are fabricated by evaporation of a thin film of tris(8-hydroxyquinoline) aluminum (Alq(3)) molecularly doped with a laser dye on top of a polyester substrate with an embossed grating structure. We achieve low-threshold, longitudinally monomode distributed-feedback laser operation. By varying the film thickness of the organic semiconductor film, we can tune the wavelength of the surface-emitting laser over 44 nm. The low laser threshold allows the use of a very compact all-solid-state pump laser ( approximately 10 cm long). This concept opens up a way to obtain inexpensive lasers that are tunable over the whole visible range. 相似文献
8.
E. M. Dianov A. Ya. Karasik A. V. Lutchnikov A. N. Pilipetskii 《Optical and Quantum Electronics》1989,21(5):381-395
The effects of amplitude modulation of interacting waves at stimulated Mandelstam-Brillouin scattering (SMBS) in a monomode fibre caused by the noise origin of the initial Stokes wave are investigated both theoretically and experimentally. Depending on the determined conditions, there can taken place either a smoothing of the noise amplitude modulation or its preservation in the Stokes radiation in the deep saturation regime of SMBS. Amplitude modulation with period corresponding to the double time of radiation propagation through the fibre is observed along with noise-amplitude modulation of the Stokes and pump waves. The effect of this period prolongation is discussed. The influence of phase fluctuations on amplitude modulation of interacting waves is investigated. The role of phase correlations in the feedback regime of SMBS is considered. Experimental results are in good agreement with numerical calculations. 相似文献
9.
We study the mean field properties of a solid-state monomode laser containing a saturable absorber which can undergo only two-photon transitions. Even when the cavity is tuned to the atomic line center there are two classes of stationary solutions, one of which is tuned to the microscopic frequency whereas the other one is always detuned. Furthermore optical bistability arises either between two tuned states or between a tuned and a detuned state. 相似文献
10.
F. Queiroga W. Soares Martins V. Mestre I. Vidal T. Passerat de Silans M. Oriá M. Chevrollier 《Applied physics. B, Lasers and optics》2012,107(2):313-316
We report a simple and robust technique to generate a dispersive signal which serves as an error signal to electronically stabilize a monomode continuous-wave laser emitting around an atomic resonance. We explore nonlinear effects in the laser beam propagation through a resonant vapor by way of spatial filtering. The performance of this technique is validated by locking semiconductor lasers to the cesium and rubidium D2 lines and observing long-term reduction of the emission frequency drifts, making the lasers well adapted for many atomic physics applications. 相似文献
11.
We present the results of an experiment on light
scattering from an elongated Bose-Einstein condensate interacting
with far off resonant laser light. Due to superradiant Rayleigh
scattering a coherent superposition of two atomic wavepackets with
different momenta forms in the presence of a single laser beam.
Varying the intensity of a weak counterpropagating laser beam we
observe the transition from the pure superradiant regime to the
Bragg scattering regime, where Rabi oscillations in a two-level
system are observed. The process is limited by the decoherence
between the two atomic wavepackets. 相似文献
12.
E. Weidel 《Optics Communications》1974,12(1):93-97
A new method of producing a small cylindrical glass lens on the end of a glass fibre is described. The intensity distribution in the focal plane of such a lens formed on the end face of a monomode fibre was measured. An improvement factor of 2.5 in the coupling efficiency into the fibre from a stripe geometry GaAs laser was observed. The tolerances of the coupling laser-fibre are carefully measured. In contrast to previous work it is shown that the improvement in coupling efficiency is obtained only at the expense of much tighter alignment tolerances. 相似文献
13.
We realize a laser with a cloud of cold rubidium atoms as gain medium, placed in a low-finesse cavity. Three different regimes of laser emission are observed corresponding, respectively, to Mollow, Raman, and four-wave mixing mechanisms. We measure an output power of up to 300 microW and present the main properties of these different lasers in each regime. 相似文献
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15.
The conditions for optimum 611.8 nm laser operation are obtained and a convenient method for indicating 3.39 µm suppression is proposed. Single longitudinal mode 611.8 nm generation is obtained using higher gas-mixture pressure and application of an axial magnetic field. Several milliwatt monomode output power and 0.75 multimode-to-monomode power conversion coefficients are obtained without an internal iodine cell. A comparison of the experimental results with a single-mode laser theory is given. 相似文献
16.
K. Kuetemeyer J. Baumgart H. Lubatschowski A. Heisterkamp 《Applied physics. B, Lasers and optics》2009,97(3):695-699
Femtosecond laser based nanosurgery of biological tissue is usually done in two different regimes. Depending on the application,
low kHz repetition rates above the optical breakdown threshold or high MHz repetition rates in the low-density plasma regime
are used. In contrast to the well understood optical breakdown, mechanisms leading to dissection below this threshold are
not well known due to the complexity of chemical effects with high numbers of interacting molecules. Furthermore, the laser
repetition rate may influence their efficiency. In this paper, we present our study on low-density plasma effects in biological
tissue depending on repetition rate by static exposure of porcine corneal stroma to femtosecond pulses. We observed a continuous
increase of the laser-induced damage with decreasing repetition rate over two orders of magnitude at constant numbers of applied
laser pulses or constant laser pulse energies. Therefore, low repetition rates in the kHz regime are advantageous to minimize
the total delivered energy to biological tissue during femtosecond laser irradiation. However, due to frequent excessive damage
in this regime directly above the threshold, MHz repetition rates are preferable to create nanometer-sized cuts in the low-density
plasma regime. 相似文献
17.
C. Masoller M. Oriá 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,58(2):191-196
In this paper we discuss the spectral behavior of monomode semiconductor laser systems whose output amplitude is constant,
but whose frequency may be bistable, multistable, locked or present instabilities. The explored configurations are: (i) a
laser diode (Fabry-Pérot) under orthogonal filtered optical feedback; and (ii) an extended-cavity diode laser with an intracavity
strongly-saturated resonant vapor. Starting from rate equations for the carrier density and for the radiation field oscillating
in the cavity of these systems we describe spectral features which are in very good quantitative agreement with experimental
observations. 相似文献
18.
用全量子理论研究二能级原子单模腔耦合系统,通过理论推导和数值计算得出系统的自发辐射光谱和平均粒子数密度.共振时腔与原子的发射光谱在强耦合与弱耦合区域有所不同,腔发射光谱分裂只出现于强耦合区域,而原子发射光谱由于腔感应透明效应在弱耦合区域出现了缺口.本文系统地研究了原子与腔在失谐时的发射光谱,在好腔机理(腔线宽小于原子线宽g)原子与腔即使在大失谐时腔发射出腔频率的光子,这给当前实验上困惑的特性提供了一个理论依据.为了给腔感应透明效应一个新的深入了解,还研究了原子与腔平均粒子数密度随时间的演化,以及平均粒子数密度与光强度之间的关系.
关键词:
自发辐射
强耦合
腔感应透明
好腔机理 相似文献
19.
Side-pumped fiber laser 总被引:1,自引:0,他引:1
A neodymium-doped side-pumped double-clad fiber laser operating at 1.06 µm is described. We report here, what is, to our knowledge, the first exclusively repetitive side-pumping scheme with two monomode laser diodes. Side-pumping has been realized by prism-fiber couplers. A pump-light-loss analysis at the pump positions has been performed. An output power of 13.5 mW is obtained with both diode lasers. The highest slope efficiency of 66% with respect to absorbed pump power at 809 nm is achieved when pumping with only one diode. 相似文献
20.
N. P. Vagin D. G. Karapetyan A. F. Konoshenko P. G. Kryukov V. S. Pazyuk V. N. Tomashov N. N. Yuryshev 《Journal of Russian Laser Research》1994,15(3):213-242
Results of an experimental investigation of a chemical oxygen-iodine laser (COIL) are presented. We determine the factors
influencing the efficiency of a chemical singlet-oxygen generator (SOG) of the bubbler type operating on the chlorination
of an alkaline solution of oxygen peroxide. We describe SOG constructions. A cw COIL with output power up to 400 W is developed
on the basis of the investigated SOG. The feasibility of a modular construction of high-power COIL is demonstrated. A power-output
level of 1 kW was achieved with a two-section laser. The feasibility is analyzed of COIL operation in a pulsed regime by pulsed
bulk accrual of iodine atoms. We show that in this regime the laser can be operated without a low-temperature trap. An advantage
of such a regime is also the possibility of controlling, in a wide range, the lasing pulse duration. A strong influence of
molecular chlorine on the energy content of the active medium is observed when alkyliodides are used as iodine donors. The
possibilities of using a pulsed COIL for controlled thermonuclear fusion are discussed.
Translated from Trudy Fizicheskogo Instituta im. P. N. Lebedeva Akademiya Nauk SSSR, Vol. 194, pp. 114–147 (1989). 相似文献