Current Issue : July - September Volume : 2012 Issue Number : 3 Articles : 5 Articles
We review advances on the experimental study of cavity solitons in VCSELs in the past decade. We emphasize on the design\r\nand fabrication of electrically or optically pumped broad-area VCSELs used for CSs formation and review different experimental\r\nconfigurations. Potential applications of CSs in the field of photonics are discussed, in particular the use of CSs for all-optical\r\nprocessing of information and for VCSELs characterization. Prospects on self-localization studies based on vertical cavity devices\r\ninvolving new physical mechanisms are also given....
Since several years ENEA�s Artificial Vision laboratory is involved in electrooptics systems development. In the last period the efforts\r\nare concentrated on cultural heritage remote diagnosis, trying to develop instruments suitable for multiple purposes concerning\r\nrestoration, cataloguing, and education. Since last five years a new 3D (three-dimensional) laser scanner prototype (RGB-ITR)\r\nbased on three amplitude-modulated monochromatic laser sources mixed together by dichroic filters is under development. Five\r\npieces of information per each sampled point (pixel) are collected by three avalanche photodiodes and dedicated electronics: two\r\ndistances and three target reflectivity signals for each channel, red, green, and blue. The combination of these pieces of information\r\nopens new scenarios for remote colorimetry allowing diagnoses without the use of scaffolds. Results concerning the use of RGBITR\r\nas colorimeter are presented....
We review the recent advances in the development of semiconductor disk lasers (SDLs) producing yellow-orange and mid-IR\r\nradiation. In particular, we focus on presenting the fabrication challenges and characteristics of high-power GaInNAs- and GaSbbased\r\ngain mirrors. These two material systems have recently sparked a new wave of interest in developing SDLs for high-impact\r\napplications in medicine, spectroscopy, or astronomy. The dilute nitride (GaInNAs) gain mirrors enable emission of more than\r\n11Wof output power at a wavelength range of 1180ââ?¬â??1200nm and subsequent intracavity frequency doubling to generate yelloworange\r\nradiation with power exceeding 7W. The GaSb gain mirrors have been used to leverage the advantages offered by SDLs to\r\nthe 2ââ?¬â??3 Ã?µmwavelength range.Most recently, GaSb-based SDLs incorporating semiconductor saturable absorber mirrors were used\r\nto generate optical pulses as short as 384 fs at 2 Ã?µm, the shortest pulses obtained from a semiconductor laser at this wavelength\r\nrange....
We discuss the concept of spin-controlled vertical-cavity surface-emitting lasers (VCSELs) and analyze it with respect to potential\r\nroom-temperature applications in spin-optoelectronic devices. Spin-optoelectronics is based on the optical selection rules as they\r\nprovide a direct connection between the spin polarization of the recombining carriers and the circular polarization of the emitted\r\nphotons. By means of optical excitation and numerical simulations we show that spin-controlled VCSELs promise to have superior\r\nproperties to conventional devices such as threshold reduction, spin control of the emission, or evenmuch faster dynamics. Possible\r\nconcepts for room-temperature electrical spin injection without large external magnetic fields are summarized, and the progress\r\non the field of purely electrically pumped spin-VCSELs is reviewed....
We demonstrate that ultrashort optical pulses propagating in a nonlinear dispersive medium are naturally described through\r\nincorporation of analytic signal for the electric field. To this end a second-order nonlinear wave equation is first simplified using a\r\nunidirectional approximation. Then the analytic signal is introduced, and all nonresonant nonlinear terms are eliminated. The\r\nderived propagation equation accounts for arbitrary dispersion, resonant four-wave mixing processes, weak absorption, and\r\narbitrary pulse duration. The model applies to the complex electric field and is independent of the slowly varying envelope\r\napproximation. Still the derived propagation equation posses universal structure of the generalized nonlinear Schr�¨odinger equation\r\n(NSE). In particular, it can be solved numerically with only small changes of the standard split-step solver or more complicated\r\nspectral algorithms for NSE.We present exemplary numerical solutions describing supercontinuum generation with an ultrashort\r\noptical pulse....
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