4. Survey of Novel Multiphoton Active Materials 1257 4.1. Multiphoton Absorbing Systems 1257 4.2. Organic Molecules 1257 4.3. Organic Liquids and Liquid Crystals 1259 4.4. Conjugated Polymers 1259 4.4.1. Polydiacetylenes 1261 4.4.2. Polyphenylenevinylenes (PPVs) 1261 4.4.3. Polythiophenes 1263 4.4.4. Other Conjugated Polymers 1265 4.4.5. Dendrimers 1265 4.4.6. Hyperbranched Polymers 1267 4.5. Fullerenes 1267 4.6. Coordination and Organometallic Compounds 1271 4.6.1. Metal Dithiolenes 1271 4.6.2. Pyridine-Based Multidentate Ligands 1272 4.6.3. Other Transition-Metal Complexes 1273 4.6.4. Lanthanide Complexes 1275 4.6.5. Ferrocene Derivatives 1275 4.6.6. Alkynylruthenium Complexes 1279 4.6.7. Platinum Acetylides 1279 4.7. Porphyrins and Metallophophyrins 1279 4.8. Nanoparticles 1281 4.9. Biomolecules and Derivatives 1282 5. Nonlinear Optical Characterizations of Multiphoton Active Materials 1282

Multiphoton Absorbing Materials : Molecular Designs, Characterizations, and Applications

We review recent developments in the physics of ultracold atomic and molecular gases in optical lattices. Such systems are nearly perfect realisations of various kinds of Hubbard models, and as such may very well serve to mimic condensed matter phenomena. We show how these systems may be employed as quantum simulators to answer some challenging open questions of condensed matter, and even high energy physics. After a short presentation of the models and the methods of treatment of such systems, we discuss in detail, which challenges of condensed matter physics can be addressed with (i) disordered ultracold lattice gases, (ii) frustrated ultracold gases, (iii) spinor lattice gases, (iv) lattice gases in “artificial” magnetic fields, and, last but not least, (v) quantum information processing in lattice gases. For completeness, also some recent progress related to the above topics with trapped cold gases will be discussed. Motto: There are more things in heaven and earth, Horatio, Than are dreamt of in your...

/pdf/ultracold-atomic-gases-in-optical-lattices-mimicking-tfesylj4h7.pdf

Ultracold atomic gases in optical lattices: mimicking condensed matter physics and beyond

https://link.aps.org/pdf/10.1103/RevModPhys.70.721

Nobel Lecture: Laser cooling and trapping of neutral atoms

Publisher Summary This chapter discusses optical dipole traps for neutral atoms Methods for storage and trapping of charged and neutral particles have very often served as the experimental key to great scientific advances, covering physics in the vast energy range from elementary particles to ultracold atomic quantum matter It describes the basic physics of dipole trapping in fardetuned light, the typical experimental techniques and procedures, and the different trap types currently available, along with their specific features In the experiments discussed, optical dipole traps have already shown great promise for a variety of different applications Of particular importance is the trapping of atoms in the absolute internal ground state, which cannot be trapped magnetically In this state, inelastic binary collisions are completely suppressed for energetic reasons In this respect, an ultracold cesium gas represents a particularly interesting situation, because Bose–Einstein condensation seems attainable only for the absolute ground state Therefore, an optical trap may be the only way to realize a quantum-degenerate gas of Cs atoms Further, optical dipole traps can be seen as storage devices at the low end of the presently explorable energy scale Future experiments exploiting the particular advantages of these traps can reveal interesting new phenomena

Optical Dipole Traps for Neutral Atoms

Squeezed states of the electromagnetic field have been generated by nondegenerate four-wave mixing due to Na atoms in an optical cavity. The optical noise in the cavity, comprised of primarily vacuum fluctuations and a small component of spontaneous emission from the pumped Na atoms, is amplified in one quadrature of the optical field and deamplified in the other quadrature. These quadrature components are measured with a balanced homodyne detector. The total noise level in the deamplified quadrature drops below the vacuum noise level.

Observation of squeezed states generated by four-wave mixing in an optical cavity

The spatial distribution and the dynamics of Cs atoms in a 1D optical molasses are probed by measuring the absorption (or amplification) spectrum of a weak laser beam. Narrow (35--50 kHz) Raman lines give access for the first time to the frequency and to the damping of the atom's oscillation in the potential wells associated with light shifts. A narrower (8 kHz) Rayleigh resonance demonstrates the existence of a large-scale spatial order of the atoms, presenting some analogy with an antiferromagnetic medium.

Dynamics and spatial order of cold cesium atoms in a periodic optical potential.

Observation of instabilities due to mirrorless four-wave mixing oscillation in sodium

A spatial instability is observed when a laser beam at 795 nm is transmitted through a rubidium cell with single plane feedback mirror. The emitted beams have patterns looking like flowers. The dependence of the number of petals in the pattern with the distance between the cell and the mirror is studied and interpreted using an expansion of the instability in Laguerre-Gauss modes. This experiment shows the influence of the saturation of the nonlinearity in the pattern selection.

Flowerlike patterns generated by a laser beam transmitted through a rubidium cell with single feedback mirror.

We report on the first expeimental observation of recoil-induced resonances. These resonances, which can be considered as the atomic analog of the grain mechanism of the free-electron laser, are observed on the transmission spectrum of a probe beam making a small angle with a one-dimensional lin\ensuremath{\perp}lin cesium optical molasses. They are interpreted either as stimulated Raman transitions between differently populated velocity groups (the internal atomic state being unchanged), or as stimulated Rayleigh resonances originating from a bunching of the atomic density. Their shape provides information about the transverse velocity distribution of the atoms.

Recoil-induced resonances in cesium: An atomic analog to the free-electron laser.

Cold cesium atoms in a magneto-optical trap are probed by an additional weak laser beam. Resonances having a subnatural linewidth are observed on the probe beam absorption when the probe frequency is scanned about the trapping beam frequency. These resonances are interpreted in terms of stimulated Raman processes. They provide information on the internal as well as external states of the atoms in the trap.

https://iopscience.iop.org/article/10.1209/0295-5075/15/2/007/pdf

G. Grynberg

Papers

Dynamics and spatial order of cold cesium atoms in a periodic optical potential.

Observation of instabilities due to mirrorless four-wave mixing oscillation in sodium

Flowerlike patterns generated by a laser beam transmitted through a rubidium cell with single feedback mirror.

Recoil-induced resonances in cesium: An atomic analog to the free-electron laser.

Raman Spectroscopy of Cesium Atoms in a Laser Trap