Viktor I. Balykin

Electromagnetic trapping of cold atoms

This review describes the methods of trapping cold atoms in electromagnetic fields and in the combined electromagnetic and gravity fields. We discuss first the basic types of the dipole radiation forces used for cooling and trapping atoms in the laser fields. We outline next the fundamentals of the laser cooling of atoms and classify the temperature limits for basic laser cooling processes. The main body of the review is devoted to discussion of atom traps based on the dipole radiation forces, dipole magnetic forces, combined dipole radiation–magnetic forces, and the forces combined of the dipole radiation–magnetic and gravity forces. Physical fundamentals of atom traps operating as waveguides and cavities for cold atoms are also considered. The review ends with the applications of cold and trapped atoms in atomic, molecular and optical physics.

Nanolithography based on an atom pinhole camera

In modern experimental physics the pinhole camera is used when the creation of a focusing element (lens) is difficult. We have experimentally realized a method of image construction in atom optics, based on the idea of an optical pinhole camera. With the use of an atom pinhole camera we have built an array of identical arbitrary-shaped atomic nanostructures with the minimum size of an individual nanostructure element down to 30 nm on an Si surface. The possibility of 30 nm lithography by means of atoms, molecules and clusters has been shown.

Single nanohole and photonic crystal: wavelength selective enhanced transmission of light

For the first time we have demonstrated an approach to control transmission of light through a single nanohole with the use of photon crystal microcavity. By use of the approach 28-fold enhanced transmission of light through a single nanohole in Au film has been experimentally demonstrated. The approach has the following advantages: (1) it enables to considerably increase transmission of light through a single nanohole, (2) the increase in transmission is unaffected by the hole diameter, (3) the transmission of nanohole is selective in frequency, the width of the resonance ~λ/90, (4) no auxiliary structures are necessary on the surface of the Au film (extra nanoholes, grooves, etc.).

Reflection of an electron beam by femtosecond light waves

We consider the reflection of electrons by an evanescent wave formed due to the total internal reflection of ultrashort laser pulses from a dielectric-vacuum interface. It is shown that a small value of the cross-section for interaction of electrons with the laser beam can be compensated for by a high intensity of the femtosecond laser pulses. Numerical estimation shows that the duration of the reflected electron pulses may be as short as 100 fs.

Laser controlled atom waveguide as a source of ultracold atoms

This paper considers the channeling of atoms over a hollow tapering waveguide with an evanescent laser light wave formed on its inner surface, the frequency detuning of the wave being positive with respect to the atomic absorption line. Using inelastic reflection of the atoms from the evanescent light wave and tapering waveguide geometry makes it possible to reduce the temperature and increase the phase-space density of the ensemble of atoms being continuously injected into the waveguide from a magneto-optical trap by a factor of 105. It is suggested that the waveguide under consideration should be used to study the specific features of the quantum propagation of atoms over the waveguide and collective phenomena in quantum-mechanical systems of high density (the Bose-Einstein condensate), and also as a bright coherent source of cold atoms.

Increase of the atomic phase density in a hollow laser waveguide

A study is made of the channeling of atoms in a narrowing hollow waveguide carrying on its inner surface a surface wave with positive detuning for the absorption line of an atom. The inelastic reflection of atoms from the surface light wave and the convergent geometry of the waveguide make it possible to decrease the temperature and increase the phase density of an ensemble of atoms introduced continuously into the hollow convergent waveguide from a magnetooptic trap, by a factor of 105. It is suggested that such a waveguide be used to study collective phenomena in quantum-mechanical systems with a high density (Bose-Einstein condensate) and as a high-luminosity coherent source of cold atoms.

Extremely high transmission of light through a nanohole inside a photonic crystal

The transmission of light through single nanoholes with diameters considerably smaller than the wavelength of light (smaller than λ/10) is experimentally studied. The nanoholes were made in a gold film, which is a part of a photonic crystal forming a microcavity with the quality factor Q ≈ 100. A 28-fold increase in the transmission of light through a nanohole inside the microcavity compared to transmission through a nanohole in a gold film is demonstrated. The high spectral selectivity of light transmission through a nanohole is discovered, which is characterized by two features: (i) the transmission maximum is located at the resonance wavelength of the microcavity and (ii) the peak full width at half-maximum is about λ/90.

Zeeman laser cooling of 85Rb atoms in transverse magnetic field

The process of Zeeman laser cooling of 85Rb atoms in a new scheme employing a transverse magnetic field has been experimentally studied. Upon cooling, the average velocity of atoms was 12 m/s at a beam intensity of 7.2×1012 s−1 and an atomic density of 4.7×1010 cm−3.

Pulsed magnetooptic compression of cold atoms

A method is proposed for increasing the density of cold atoms. The method is based on pulsed laser irradiation of the atoms in a nonuniform magnetic field. The interaction conditions under which the velocity of an atom is damped to a value that depends only on the magnitude of the magnetic field and the position of the atom at the moment it is irradiated by the laser field are found. The atom completely loses all memory of its initial coordinates and velocity. In a three-dimensional interaction geometry an irradiated atomic ensemble transforms into an ensemble contracting toward the origin. The basic physical processes accompanying the compression of atoms are studied.

Optics and spectroscopy of individual plasmonic nanostructure

We review the interaction of laser light with a single plasmonic nanostructure. Until recently, the extremely weak optical response of a single nanostructure had only allowed spectroscopic research on ensembles of nanoparticles, where both structural and material parameters vary from one nanoparticle to another and the optical response is therefore averaged over the ensemble. Measurements at the level of a single nanostructure provide an effective tool for investigating the fundamental optical and spectroscopic properties of nanostructures, allowing insight into the mechanisms of elementary physical processes and permitting one to avoid the averaging procedure with the inevitable loss of physical information. The diverse range of linear-interaction optical phenomena occurring in a weak light field is reviewed and nonlinear interaction with high-intensity radiation is discussed.