Abstract
We derive the time-variant second-order statistics of the depth-scan photocurrent in time-domain optical coherence tomography (TD-OCT) systems using polarized thermal light sources and superluminescent diodes (SLDs). Since the asymptotic-joint-probability-distribution function (JPDF) of the photocurrent due to polarized thermal light is Gaussian and the signal-noise-ratio in TD-OCT is typically high (> 80 dB), the JPDF of the depth-scan photocurrent could be approximated as a Gaussian random process that is completely determined by its second-order statistics. We analyze both direct and differential light detection schemes and include the effect of electronic thermal fluctuations. Our results are a necessary prerequisite for future development of statistical image processing techniques for TD-OCT. (c) 2007 Optical Society of America.

Abstract
Femtosecond Titanium: sapphire lasers can deliver high average power broadband spectra in a high quality beam, being therefore an optical source of choice for high-resolution optical coherence tomography (OCT) at high acquisition rates. We present a brief tutorial on the basic physics behind the operation and design of Kerr-lens modelocked lasers, where the high peak powers associated with femtosecond pulses give rise to nonlinear optical effects that play a major role in the laser operation itself and strongly influence the output spectrum. Additional nonlinear devices, in particular photonic crystal fibers (PCFs), can also be directly pumped with the generated femtosecond pulses to further extend the spectral range of the laser output, both in terms of bandwidth and center wavelength. Two specific laser systems employing different technologies for intracavity dispersion compensation (intracavity prisms in one case, and octave-spanning double-chirped mirrors in the other) will be described, and the corresponding advantages for OCT, namely the maximum achievable resolution and the applicability of spectral tuning and shaping techniques, will be briefly discussed.

Abstract
A new variety of nanoparticles showing unique and characteristic optical properties, appeals for its use as contrast agents in medical imaging. Gold nanospheres, nanorods and nanoshells with a silica core are new forms of promising contrast agents which can be tuned to specific absorption or scattering characteristics within the near-infrared (NIR) spectrum ranging from 650 - 1300 nm. They have the ability to be used for both image enhancement and as photosensitive markers due to their well designable scattering and absorption properties. Furthermore, their strong optical absorption permits treatment of malignant cells by photoablation processes, induced when heating them with a matched light source. Differential absorption optical coherence tomography (DA-OCT) allows for the detection and depth resolved concentration measurement of such markers. So far, reports on DA-OCT systems used A-scan based imaging systems to assess depth resolved information about the absorption properties and the concentration of a chemical compound. En-face OCT (B(T) or C(T) scan based) images allow for better depth localization and a depth resolved concentration measurement of the compound under investigation. For this aim, we evaluate the suitability of a multiscan time-domain OCT set-up, compatible with different light sources providing different wavelengths and bandwidths in the NIR, to perform differential absorption OCT measurements, using gold nanorods as the contrast agent.

Abstract
A versatile optical imaging system is presented that provides imaging resolutions down to the micrometer range. The system is built for time domain optical coherence tomography, with versatility in the scanning regime to be employed when scanning samples in the transverse and depth directions, thus generating cross-section images (B-scans) by using either transverse priority or depth priority. The system is targeted for eye fundus imaging but is easily adapted for the imaging of other biological samples, in vivo, by using its non-invasive property.

Abstract
The XENON10 experiment at the Gran Sasso National Laboratory uses a 15 kg xenon dual phase time projection chamber to search for dark matter weakly interacting massive particles (WIMPs). The detector measures simultaneously the scintillation and the ionization produced by radiation in pure liquid xenon to discriminate signal from background down to 4.5 keV nuclear-recoil energy. A blind analysis of 58.6 live days of data, acquired between October 6, 2006, and February 14, 2007, and using a fiducial mass of 5.4 kg, excludes previously unexplored parameter space, setting a new 90% C.L. upper limit for the WIMP-nucleon spin-independent cross section of 8.8x10(-44) cm(2) for a WIMP mass of 100 GeV/c(2), and 4.5x10(-44) cm(2) for a WIMP mass of 30 GeV/c(2). This result further constrains predictions of supersymmetric models.

Abstract
XENON10 is an experiment to directly detect weakly interacting massive particles (WIMPs), which may comprise the bulk of the nonbaryonic dark matter in our Universe. We report new results for spin-dependent WIMP-nucleon interactions with (129)Xe and (131)Xe from 58.6 live days of operation at the Laboratori Nazionali del Gran Sasso. Based on the nonobservation of a WIMP signal in 5.4 kg of fiducial liquid xenon mass, we exclude previously unexplored regions in the theoretically allowed parameter space for neutralinos. We also exclude a heavy Majorana neutrino with a mass in the range of similar to 10 GeV/c(2) -2 TeV/c(2) as a dark matter candidate under standard assumptions for its density and distribution in the galactic halo.