Fast two-photon in vivo imaging with three-dimensional random-access scanning in large tissue volumes
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…
Interference and crosstalk in double optical tweezers using a single laser source
Experimental studies of single molecule mechanics require high force sensitivity and low drift, which can be achieved with optical tweezers. We built an optical tweezer setup for force measurements in…
Ultrafast random-access scanning in two-photon microscopy using acousto-optic deflectors
Two-photon scanning microscopy (TPSM) is a powerful tool for imaging deep inside living tissues with sub-cellular resolution. The temporal resolution of TPSM is however strongly limited by the galvanometric mirrors…
Frequency-domain wide-field laser Doppler in vivo imaging
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…
Quantum Dot Photon Statistics
We present an instrument for performing correlation spectroscopy on single fluorescent particles while tracking their Brownian motion in three dimensions using real-time feedback. By tracking CdSe/ZnS quantum dots in water…
High-speed in vivo calcium imaging reveals neuronal network activity with near-millisecond precision
two-photon calcium imaging of neuronal populations enables optical recording of spiking activity in living animals, but standard laser scanners are too slow to accurately determine spike times. here we report…
Millijoule pulse energy Q-switched short-length fiber laser
We report on a Q-switched short-length fiber laser producing 100 W of average output power at 100 kHz repetition rate and pulse durations as short as 17 ns.Upto2mJof energy and…
Double-pass acousto-optic modulator system
A practical problem that arises when using acousto-optic modulators sAOMsd to scan the laser frequency is the dependence of the beam diffraction angle on the modulation frequency. Alignment problems with…
Optical phase Shifting in AOM
A novel optical phase-shifting method based on a well-known acousto-optic interaction is proposed. By using a pair of acousto-optic modulators (AOMs) and properly aligning them, we construct an optical phase…
Multicolor Single-Molecule Spectroscopy with Alternating Laser Excitation for the Investigation of Interactions and Dynamics
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…
Optical recording of electrical activity in intact
One of the main challenges in understanding the central nervous system is to measure the network dynamics of neuronal assemblies, while preserving the computational role of individual neurons. However, this…
Pulse Shortening and scaling of passively mode-locked feedback-stabilised Nd:KWG laser
We show that by incorporating negative feedback stabilisation to allow on increasing the modulation depth of the saturable absorber in a diode-pumped mode-locked Nd:KGd(WO4)2 laser leads to significant pulse shortening.
Video-rate computational heterodyne holography
We present a versatile computational image rendering software of optically-acquired holograms. The reported software can process 4 Megapixel 8-bit raw frames from a sensor array acquired at a sustained rate…
Holographic imaging of surface acoustic waves
We report on an experimental demonstration of surface acoustic waves monitoring on a thin metal plate with heterodyne optical holography. Narrowband imaging of local optical pathlength modulation is achieved with…
Non-destructive testing of composite plates by holographic vibrometry
Wereport on a wide-field optical monitoring method for revealing local delaminations in sandwichtype composite plates at video-rate by holographic vibrometry. Non-contact measurements of low frequency flexural waves is performed with…
Holographic laser Doppler imaging of microvascular blood
We report on local superficial blood flow monitoring in biological tissue from laser Doppler holographic imaging. In time-averaging recording conditions, holography acts as a narrowband bandpass f ilter, which, combined…
Holographic laser Doppler imaging of pulsatile blood flow
“We report on wide-field imaging of pulsatile motion induced by blood flow using heterodyne holographic interferometry on the thumb of a healthy volunteer, in real-time. Optical Doppler images were measured…
Singular value demodulation of phase-shifted holograms
“We report on phase-shifted holographic interferogram demodulation by singular value decomposition. Numerical processing of optically-acquired interferograms over several modulation periods was performed in two steps : 1- rendering of off-axis…
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