Reduced arterial elasticity due to surgical skeletonization is ameliorated by abluminal PEG hydrogel.

Arteries for bypass grafting are harvested either with neighboring tissue attached or as skeletonized vessels that are free of surrounding tissue. There are significant benefits to skeletonization, but reports suggest that skeletonized vessels may develop structural defects and are at risk for atherosclerosis. We investigated the specific short-term effects of skeletonization on carotid artery biomechanics and microanatomy in a rabbit model.

Temperature dependence of Ti:Sapphire fluorescence spectra for the design of cryogenic cooled Ti:Sapphire CPA laser.

The fluorescence spectra of titanium doped sapphire (Ti:Sapphire) crystals were measured for temperature ranging from 300K to 77K. The resulting gain cross-section line shapes were calculated and used in a three-dimensional amplification model to illustrate the importance of the precise knowledge of these fluorescence spectra for the design of cryogenic cooled Ti:Sapphire based chirped-pulse laser amplifiers.

Quantitative semi-automated analysis of morphogenesis with single-cell resolution in complex embryos.

A quantitative understanding of tissue morphogenesis requires description of the movements of individual cells in space and over time. In transparent embryos, such as C. elegans, fluorescently labeled nuclei can be imaged in three-dimensional time-lapse (4D) movies and automatically tracked through early cleavage divisions up to ~350 nuclei.

Rapid three-dimensional isotropic imaging of living cells using Bessel beam plane illumination.

A key challenge when imaging living cells is how to noninvasively extract the most spatiotemporal information possible. Unlike popular wide-field and confocal methods, plane-illumination microscopy limits excitation to the information-rich vicinity of the focal plane, providing effective optical sectioning and high speed while minimizing out-of-focus background and premature photobleaching. Here we used scanned Bessel beams in conjunction with structured illumination and/or two-photon excitation to create thinner light sheets (<0.

Spatiotemporal dynamics of cross-polarized wave generation.

We use time-domain spatially and spectrally resolved interferometry to investigate cross-polarized wave (XPW) generation in barium fluoride. We find that the XPW pulse is square root of 3 smaller than the input in the spatiotemporal domain, regardless of input chirp. Additionally, we calculate a temporally dependent focal length resulting from the nonlinear interaction and discuss its implications.

Measurement of pump-induced transient lensing in a cryogenically-cooled high average power Ti:sapphire amplifier.

The transient thermal lensing in a liquid-nitrogren cooled kilohertz multipass amplifier is quantitatively measured with spatially-resolved Fourier transform spectral interferometry. A pump-probe arrangement allows the observation of a polarization-dependent non-thermal component following the fluorescence timescale: additional cooling would not suppress this residual lensing. We also observe a time-dependent thermal component that has a timescale sufficiently fast to indicate that there is cooling between shots even at a repetition rate of 1 kHz.

Characterization of coupled nonlinear spatiospectral phase following an ultrafast self-focusing interaction.

We use collinear spatially resolved spectral interferometery to characterize the nonlinear phase changes experienced by an intense ultrashort pulse propagating in glass. The measurement yields the spectrally dependent wavefront, allowing us to measure the spatial and chromatic aberrations of the nonlinearly induced lens. For these conditions, we find that while the shape of the spatial wavefront follows the beam profile as expected, the spectral dependence of the lensing power is determined by the self-phase modulation.

Ultra-high intensity- 300-TW laser at 0.1 Hz repetition rate.

We demonstrate the highest intensity - 300 TW laser by developing booster amplifying stage to the 50-TW-Ti:sapphire laser (HERCULES). To our knowledge this is the first multi-100TW-scale laser at 0.1 Hz repetition rate.

Characterization of a High Efficiency, Ultrashort Pulse Shaper Incorporating a Reflective 4096-Element Spatial Light Modulator.

We demonstrate pulse shaping via arbitrary phase modulation with a reflective, 1×4096 element, liquid crystal spatial light modulator (SLM). The unique construction of this device provides a very high efficiency when the device is used for phase modulation only in a prism based pulse shaper, namely 85%. We also present a single shot characterization of the SLM in the spatial domain and a single shot characterization of the pulse shaper in the spectral domain.

Simultaneous imaging of multiple focal planes using a two-photon scanning microscope.

Despite all the advances in nonlinear microscopy, all existing instruments are constrained to obtain images of one focal plane at a time. In this Letter we demonstrate a two-photon absorption fluorescence scanning microscope capable of imaging two focal planes simultaneously. This is accomplished by temporally demultiplexing the signal coming from two focal volumes at different sample depths.

Complete characterization of a spatiotemporal pulse shaper with two-dimensional Fourier transform spectral interferometry.

Spatiotemporal pulse shaping is characterized with two-dimensional Fourier transform spectral interferometry. A deformable-mirror-based bidimensional pulse shaper is used to create simple spatiotemporal structures on a femtosecond pulse, structures that are directly calculated from the measured spatiospectral phases and intensities.

Simultaneous visualization of spatial and chromatic aberrations by two-dimensional Fourier transform spectral interferometry.

We demonstrate the use of a simple tool to simultaneously visualize and characterize chromatic and spherical aberrations that are present in multiphoton microscopy. Using two-dimensional Fourier transform spectral interferometry, we measured these aberrations, deducing in a single shot spatiotemporal effects in high-numerical-aperture objectives.

Adaptive correction of a tightly focused, high-intensity laser beam by use of a third-harmonic signal generated at an interface.

By using the third-harmonic signal generated at an air-dielectric interface, we demonstrate a novel way of correcting wavefront aberrations induced by high-numerical-aperture optics. The third harmonic is used as the input physical parameter of a genetic algorithm working in closed loop with a 37-actuator deformable mirror. This method is simple and reliable and can be used to correct aberrations of tightly focused beams, a regime where other methods have limitations.

Generation and characterization of the highest laser intensities (10(22) W/cm2).

We generated a record peak intensity of 0.7 x 10(22) W/cm2 by focusing a 45-TW laser beam with an f/0.6 off-axis paraboloid.

Experimental evidence of 25-fs laser pulse distortion in singlet beam expanders.

We report the measurement of spatiotemporal distortions of an ultrashort pulse in singlet beam expanders. With a simple second-order autocorrelator the temporal broadening of the pulse from 23 to 40 fs, due to propagation time difference (PTD), is determined. The delay due to PTD between different parts of the beam is also measured.