Досліджено характеристики мініатюрних компактних лазерів на Nd:YAG та Nd:YVO4 з діодною накачкою у режимі пасивної модуляції добротності. З використанням полімерного лазерного затвора на основі поліуретану, забарвленого барвником біс-4-діметиламінодітіобензил нікелю, реалізована генерація на довжині хвилі 1,064 мкм з частотою слідування імпульсів до 25 кГц, тривалістю 2–5 нс та потужністю до 130 мВт при накачці до 3,5 Вт. Твердотільні мінілазери з діодною накачкою і пасивною модуляцією добротності затворами сендвічевого типу є ефективними компактними джерелами коротких потужних імпульсів з високою оптичною якістю пучка.

The narrow optical resonances are widely used in ultra-high-resolution spectroscopy and precision laser metrology. The paper briefly describes the basic physical principles of narrow optical resonances, examples of implementation using advanced laser systems. The dark resonances formed at interaction of rubidium atoms with radiation femtosecond laser and frequency-modulation resonances of nonlinear absorption and nonlinear dispersion of molecular iodine, the prospects of their application are considered. Keywords: laser, nonlinear laser spectroscopy, atom, molecule, femtosecond laser.

Saturated-absorption resonances were investigated experimentally in He — Ne/127I2 lasers pumped by a transverse rf discharge. The much lower amplitude noise reduced sixfold the laser frequency instability, compared with the frequency instability of a laser pumped by a dc discharge, down to 5 × 10-13 for an integration time of 100 s. The modulation shifts of the radiation frequency of stabilised He — Ne/127I2 lasers were investigated with a high accuracy and over a wide range of frequency deviations (1.5 — 20 MHz). The nature of the asymmetry of the saturated-absorption resonances, resulting from the joint effect of the lens-like properties of the nonlinearly absorbing medium and of the elastic velocity-changing collisions of absorbing medium molecules was clarified.

The first observation of pressure exerted by laser light on molecules is reported. A beam of Na2 molecules interacting with the field of a train of short counterpropagating pulses was deflected through an angle of 7 X 10(-4) rad.

mirror, we use the evanescent wave that is formed by total internal reflection of a strong laser beam in a (glass) prism. The evanescent wave provides a strong intensity gradient, and thus combines a large potential with a very short interaction time, thereby limiting spontaneous emission even further. To reflect sodium atoms with a velocity of 1 m/s, at a detuning of 2 GHz, a laser intensity of -6 W/ cm' is required. To obtain a reasonable reflective area mirror, this means a laser power of -1 W is required, just barely within the range of commercial dye lasers. We achieve high laser intensities over a bigger spot sue by coupling the laser to a thin dielectric wave guide, that is deposited on a prism. Thus we obtain an evanescent wave which is a factor of 100-1000 stronger than would be the case for the bare prism.' We present the first measurements using such an enhanced evanescent wave as a mirror in which to reflect atoms at normal incidence. Sodium atoms are collected in a magneto-optical trap, cooled to -40 p K using polarization gradient cooling and then released to accelerate in the gravity field. The atomic mirror sits 1 M O mm under the trap, and reflects the atomic wave. The reflected atoms are detected in the trap region after their ballistic flight time. We report a large enhancement of the evanescent wave, observed by reflection of atoms dropped from a 10mm hei ht on a large area atomic mirror (10 mm) up until large detunings (10 GHz) using moderate amounts of laser power (500 mW). 'Institut d'Optique Thhorique et Appliqute, B.P. 147, F-91403 d'orsay, France

The effect of stimulated light pressure (SLP) on a beam of Na atoms is investigated theoretically and experimentally. Expressions are derived for the SLP force on two-level atoms in the field of counterpropagating short light pulses of arbitrary area and for the diffusion coefficient for pi-pulses. It is shown that a value of the SLP force that is close to the ideal case of pi-pulses may be achieved in the case of counterpropagating amplitude-modulated waves that is more convenient for experimental study, viz. that of two standing waves of different frequency. The effect of the SLP force in the field of two standing waves on the Na atoms in a beam is studied experimentally.

The possibility of observation of light pressure on molecules has been theoretically investigated. Interaction of a molecule with counterpropagating short pulses has been analyzed. It is found that about 100 hkBAR (hkBAR - photon moment) can be transferred to significant part (about 10%) of molecules even in the case when the repetition time of pulses surpasses that of spontaneous radiation.

A theoretical investigation is made of the force acting on a two-level atom under conditions of saturation in the field of counterpropagating amplitude- and frequency-modulated waves of different intensities, which are in resonance with an atomic transition. It is shown that the resultant induced optical pressure (due to preferential absorption of light of one of the waves and subsequent stimulated emission in the form of the other wave) depends linearly on the correlation function of the amplitude of the field of one of the waves and on the rate of change of the amplitude of the other wave, and also on the correlation function of the phase of one of the waves and the rate of change of the phase of the other wave at the point where the atom is located.

An investigation was made of the emission spectrum of a cw dye laser with an intracavity lens-like absorbing medium. The emission spectrum of the frequency-locked laser was obtained as a function of the oscillator strength of the absorption line and the resonator tuning, and measurements were also made of the selective reduction in the losses near the absorption line (10 – 4–10 – 5 cm – 1). It was confirmed experimentally that the reason for the frequency locking of the laser radiation was a reduction in the diffraction losses in the resonator under the action of the lens-like properties of the absorbing medium.