Control of the bipolarization emission of an Yb:YAG laser by the orientation of the pump polarization.

We show that the polarized pumping can be used to control the relative powers of two linear, orthogonally polarized, eigenstates in a Yb:YAG laser. The experimental observations are in full agreement with a two-mode rate-equation model, highlighting the roles of both the gain anisotropy and the cross-saturation parameters, whose values are found to be =0.08 and β = 0.

Switchable Two-Dimensional Waveguiding Abilities of Luminescent Hybrid Nanocomposites for Active Solar Concentrators.

Passing from fossil energy sources to renewable ones, meanwhile answering the increasing world energy demand, will require innovative and low-cost technologies. Smart photovoltaic windows could fulfill our needs in this matter. Their transparency can be controlled to manage solar energy and regulate interior temperature and illumination.

Class-A operation of an optically-pumped 1.6 µm-emitting quantum dash-based vertical-external-cavity surface-emitting laser on InP.

A continuous-wave 1.6 µm-emitting InAs Quantum Dash-based Optically-Pumped Vertical-External-Cavity Surface-Emitting Laser on InP is demonstrated. The laser emits in the L-band with a stable linear polarization.

Free-space active polarimetric imager operating at 1.55 μm by orthogonality breaking sensing.

We report the design and optimization of an active polarimetric imaging demonstrator operating at 1.55 μm that is based on the orthogonality breaking technique. It relies on the use of a fibered dual-frequency dual-polarization source raster scanned over the scene.

Iron Alkynyl Helicenes: Redox-Triggered Chiroptical Tuning in the IR and Near-IR Spectral Regions and Suitable for Telecommunications Applications.

The combination of a bis-alkynyl-helicene moiety with two iron centers leads to novel electroactive species displaying unprecedented redox-triggered chiroptical switching. Upon oxidation, strong changes of vibrational modes (either local or extended coupled modes) are detected by vibrational circular dichroism and Raman optical activity. Remarkably, the sign of the optical rotation at 1.

Buffer reservoir approach for cancellation of laser resonant noises.

The introduction of a buffer reservoir mechanism with optimized time-constants and cross sections in a laser system enables breaking any resonant exchange between the population inversion and photon population over an extremely wide bandwidth. The associated noise cancellation, including the excess noise at relaxation oscillations and spontaneous-signal beating, is experimentally evidenced up to 16 GHz in an Er,Yb laser comprising a GaAs two-photon absorber. Such approach is shown to preserve the laser linewidth quality and is advantageously implemented for optical distribution of frequency references.

GHz bandwidth noise eater hybrid optical amplifier: design guidelines.

This Letter describes the design of an optical amplifier system optimized to reduce the relative intensity noise (RIN) of the input signal, and discloses its performance in terms of intensity noise reduction and bandwidth, without phase noise degradation. This polarization-maintaining amplifier is composed of an erbium-doped fiber amplifier (EDFA) cascaded with a semiconductor optical amplifier (SOA). The EDFA is sized to feed the SOA with a constant power corresponding to the optimal saturation level for noise reduction, through coherent population oscillations.

Dual frequency laser with two continuously and widely tunable frequencies for optical referencing of GHz to THz beatnotes.

A dual-frequency 1.55 µm laser for CW low noise microwave, millimeter and sub millimeter wave synthesis is demonstrated, where frequency stabilization is possible on each wavelength independently. The solid state Er:Yb laser output power is 7 mW.

Experimental demonstration of a dual-frequency laser free from antiphase noise.

A reduction of more than 20 dB of the intensity noise at the antiphase relaxation oscillation frequency is experimentally demonstrated in a two-polarization dual-frequency solid-state laser without any optical or electronic feedback loop. Such behavior is inherently obtained by aligning the two orthogonally polarized oscillating modes with the crystallographic axes of a (100)-cut neodymium-doped yttrium aluminum garnet active medium. The antiphase noise level is shown to increase as soon as one departs from this peculiar configuration, evidencing the predominant role of the nonlinear coupling constant.