Articles

One of the main drawbacks of Fourier domain optical coherence tomography (FDOCT) is the limited measurement depth range. Phase shifting techniques allow reconstructing the complex sample signal resulting in a doubled depth range. In current complex FDOCT realizations the phase shift is introduced via a reference path length modulation, which causes chromatic phase errors especially … Read more

Ultrashort pulsed laser material processing is a new micromachining method that is gaining interest. Its capability of submicrometer machining has been proved. To obtain high speed and highly flexible beam steering, a two-axis acousto-optic deflector is employed. However, dispersion associated with acoustic-optic interaction will cause serious spatial deformation on the writing spot. The compensation for … Read more

We propose and experimentally demonstrate an acousto-optic cylindrical lens with a very fast (400-kHz) focal scanning. The lens is realized by use of two adjacent acousto-optic scanners with counterpropagating acoustic waves that have the same frequency modulation but a p phase difference. This scheme completely suppresses the lateral scan but adds the linear chirp of … Read more

We have developed confocal multicolor single-molecule spectroscopy with optimized detection sensitivity on three spectrally distinct channels for the study of biomolecular interactions and FRET between more than two molecules. Using programmable acousto-optical devices as beamsplitter and excitation filter, we overcome some of the limitations of conventional multichroic beamsplitters and implement rapid alternation between three laser … Read more

We present a new instrument, based on a low-frame-rate 8Hz CCD camera used in a heterodyne opticalmixing configuration, that can create wide-field laser Doppler maps. As an illustration, we show results obtained in a mouse brain, in vivo, showing the Doppler signature of blood flow. The instrument is based on a frequency-shifting digital holography scheme. … Read more

Les lasers dits Q-switchés occupent une large place dans la famille des lasers impulsionnels. Cette technique de génération d’impulsions permet en effet d’obtenir de fortes puissances crêtes, indispensables dans de nombreuses applications, en particulier industrielles. Les dispositifs utilisés, appelés Q-switches, sont des dispositifs intra-cavité qui peuvent être électro-optiques, acousto-optiques ou à absorbants saturables.

The critical issue of all fluorescence microscopes is the efficient use of the fluorophores, i.e., to detect as many photons from the excited fluorophores as possible, as well as to excite only the f luorophores that are in focus. This issue is addressed in EMBL’s implementation of a light sheet based microscope single plane illumination … Read more

Experimental realizations of cold 85Rb atom interferometers in Wuhan are reviewed in this paper. The application of atom interferometers in local gravity measurement are reported. The resolutions of gravity measurement are 2.0 × 10−7g for1sand4.5 × 10−9g for 1,888 s. The absolute g value was derived with a difference of 1.6 × 10−7g compared to … Read more

the understanding of brain computations requires methods that read out neural activity on different spatial and temporal scales. Following signal propagation and integration across a neuron and recording the concerted activity of hundreds of neurons pose distinct challenges, and the design of imaging systems has been mostly focused on tackling one of the two operations. … Read more