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We describe Fourier domain optical coherence tomography equipped with a novel linear-in-wavenumber spectrometer. The presented device linearizes the spectral dispersion of the spectrometer in wavenumber using a specifically designed prism. The spectral linearity in wavenumber makes numerical interpolation into wavenumber unnecessary, reduces computing time, and furthermore results in improvement of the falloff of signal with image range inherent to frequency-domain optical coherence tomography imaging. Experiments demonstrate the improvement of the falloff and agree with the expected results from simulation.

Abstract:We have created a 2.5-mm outer diameter integrated photoacoustic and ultrasonic mini-probe which can be inserted into a standard video endoscope's instrument channel. A small-diameter focused ultrasonic transducer made of PMN-PT provides adequate signal sensitivity, and enables miniaturization of the probe. Additionally, this new endoscopic probe utilizes the same scanning mirror and micromotor-based built-in actuator described in our previous reports; however, the length of the rigid distal section of the new probe has been further reduced to ~35 mm. This paper describes the technical details of the mini-probe and presents experimental results that both quantify the imaging performance and demonstrate its in vivo imaging capability, which suggests that it could work as a mini-probe for certain clinical applications. dual-modality OCT/LIF imaging using a novel VEGF receptor-targeted NIR fluorescent probe in the AOMtreated mouse model," Mol.

This work aims to improve the rheological properties of partially hydrolysed polyacrylamide (HPAM) for enhanced oil recovery by using SiO 2 nanoparticles (NPs).Novel aqueous HAPM based SiO 2 nanocomposites were formulated and their rheological properties were investigated under different salinities, temperature and aging time. The results show that the inclusion of silica NPs improved significantly the viscosity and viscoelastic properties of HPAM especially under high temperature and high salinities. The NP/HPAM hybrid showed an impressive thermal stability at T= 80 ºCafter 12 days, and the viscosity reached ~5 times of that HPAM at 0.8w% NP loading. The FT-IR spectra data confirmed that the formation of hydrogen bond between the carbonyl groups in HPAM and the silanol functionalities on the surface of silica NPs, which attributed to the improved performance. The oscillation test indicated that seeding SiO 2 remarkably facilitated the cross links among polymer molecules and made the hybrids more elastically dominant. For a given HPAM concentration, it was observed that there was acritical NP concentration (CNC)which many indicating the absorption status of SiO 2 NPsonto HPAM, and the salinity also affected the viscosity value.

Abstract. The material properties of the cornea are important determinants of corneal shape and refractive power. Corneal ectatic diseases, such as keratoconus, are characterized by material property abnormalities, are associated with progressive thinning and distortion of the cornea, and represent a leading indication for corneal transplantation. We describe a corneal elastography technique based on optical coherence tomography (OCT) imaging, in which displacement of intracorneal optical features is tracked with a 2-D cross-correlation algorithm as a step toward nondestructive estimation of local and directional corneal material properties. Phantom experiments are performed to measure the effects of image noise and out-of-plane displacement on effectiveness of displacement tracking and demonstrated accuracy within the tolerance of a micromechanical translation stage. Tissue experiments demonstrate the ability to produce 2-D maps of heterogeneous intracorneal displacement with OCT. The ability of a nondestructive optical method to assess tissue under in situ mechanical conditions with physiologic-range stress levels provides a framework for in vivo quantification of 3-D corneal elastic and viscoelastic resistance, including analogs of shear deformation and Poisson's ratio that may be relevant in the early diagnosis of corneal ectatic disease. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).