SPIE Letters Virtual Journal

Micro-optical spatial and spectral elements

Pradeep Srinivasan, Yigit O. Yilmaz, Raymond C. Rumpf et al.
Interference filters have a defect layer incorporated within a photonic crystal structure and generate a narrow transmission notch within a wide stop band. In this paper, we propose and demonstrate wavelength-tunable spatial filters by introducing diffractive optical elements in the defect layer. Th ... [SPIE Letters VJ 2009, 019022 (2009)] published Fri Nov 13, 2009.

Combined optical and electrical stimulation of neural tissue in vivo

Austin R. Duke, Jonathan M. Cayce, Jonathan D. Malphrus et al.
Low-intensity, pulsed infrared light provides a novel nerve stimulation modality that avoids the limitations of traditional electrical methods such as necessity of contact, presence of a stimulation artifact, and relatively poor spatial precision. Infrared neural stimulation (INS) is, however, limit ... [SPIE Letters VJ 2009, 017036 (2009)] published Tue Nov 10, 2009.

Physiological fluorescence lifetime imaging microscopy improves Forster resonance energy transfer detection in living cells

Ching-Wei Chang, Mei Wu, Sofia D. Merajver et al.
Accurate, unambiguous detection of molecular interactions in living cells via measurements of Forster (or fluorescence) resonance energy transfer (FRET) events is experimentally challenging. We develop and apply a physiological fluorescence lifetime imaging microscopy (physiological FLIM) system to ... [SPIE Letters VJ 2009, 017035 (2009)] published Thu Nov 5, 2009.

Adaptive quarter-pel motion estimation and motion vector coding algorithm for the H.264/AVC standard

Seung-Won Jung, Chun-Su Park, Le Thanh Ha et al.
We present an adaptive quarter-pel (Qpel) motion estimation (ME) method for H.264/AVC. Instead of applying Qpel ME to all macroblocks (MBs), the proposed method selectively performs Qpel ME in an MB level. In order to reduce the bit rate, we also propose a motion vector (MV) encoding technique that ... [SPIE Letters VJ 2009, 019023 (2009)] published Wed Nov 4, 2009.

Fabrication of silicon optical fiber

Brian Scott, Ke Wang, Vincent Caluori et al.
We experimentally demonstrate the fabrication of silicon optical fibers by using the powder-in-tube technique. The fibers are drawn from a preform utilizing a custom-made fiber drawing system. Silicon optical fibers having cladding diameters in the range of 40 to 240 [mu]m, core diameters in the ... [SPIE Letters VJ 2009, 019021 (2009)] published Fri Oct 30, 2009.

Novel bidirectional optical subassembly with embedded filter, 45-degree angle polished fiber cladding and etched fiber core

Seihyoung Lee, Kwon-Seob Lim, Jong Jin Lee et al.
The optical wavelength-division-multiplex filter for bidirectional optical subassembly (BOSA) is embedded to the fiber core, which results in simplicity of the BOSA module. The fiber cladding is 45-deg angle polished to receive a downstream signal. The core is etched by a femtosecond laser to have a ... [SPIE Letters VJ 2009, 019020 (2009)] published Fri Oct 23, 2009.

High-precision synchronization of video cameras using a single binary light source

Qi Zhao and Yan Qiu Chen
Camera synchronization is necessary for multicamera applications. We propose a simple and yet effective approach termed random on-off light source (ROOLS) to synchronize video sequences. It uses a single light source such as an LED to generate a random binary valued signal that is captured by the vi ... [SPIE Letters VJ 2009, 018005 (2009)] published Tue Oct 20, 2009.

Optical characterization for nearly spherical gold colloidals via their polarization response

Bassam M. Al-Qadi and Toshiharu Saiki
We optically characterized colloidal gold nanoparticles using polarized light scattering which is utilized to investigate both optical anisotropy and aspect ratio of the particle and to observe particle's rotational dynamics. By monitoring time-trace of the polarized scattering from a particle, we c ... [SPIE Letters VJ 2009, 015003 (2009)] published Mon Oct 12, 2009.

Simultaneous, noninvasive observation of elastic scattering, fluorescence and inelastic scattering as a monitor of blood flow and hematocrit in human fingertip capillary beds

Joseph Chaiken, Jerry Goodisman, Bin Deng et al.
We report simultaneous observation of elastic scattering, fluorescence, and inelastic scattering from in vivo near-infrared probing of human skin. Careful control of the mechanical force needed to obtain reliable registration of in vivo tissue with an appropriate optical system allows reproducible o ... [SPIE Letters VJ 2009, 017034 (2009)] published Wed Oct 7, 2009.

Doppler optical microangiography improves the quantification of local fluid flow and shear stress within 3-D porous constructs

Yali Jia, Lin An, and Ruikang K. Wang
Traditional phase-resolved Doppler optical coherence tomography (DOCT) has been reported to have potential for characterizing local fluid flow within a microporous scaffold. In this work, we apply Doppler optical microangiography (DOMAG), a new imaging technique developed by combining optical microa ... [SPIE Letters VJ 2009, 017033 (2009)] published Wed Oct 7, 2009.

Live imaging of rat embryos with Doppler swept-source optical coherence tomography

Irina V. Larina, Kenryo Furushima, Mary E. Dickinson et al.
The rat has long been considered an excellent system to study mammalian embryonic cardiovascular physiology, but has lacked the extensive genetic tools available in the mouse to be able to create single gene mutations. However, the recent establishment of rat embryonic stem cell lines facilitates th ... [SPIE Letters VJ 2009, 017032 (2009)] published Thu Oct 1, 2009.

Optical investigation of diffusion of levofloxacin mesylate in agarose hydrogel

Shuaixia Tan, Hongjun Dai, Juejie Wu et al.
Real-time electronic speckle pattern interferometry method has been applied to study the diffusion behavior of levofloxacin mesylate (MSALVFX) in agarose hydrogel. The results show that the diffusivity of solute decreases with the increase of concentration of agarose and adapts to Kohlrausch's law. ... [SPIE Letters VJ 2009, 017031 (2009)] published Thu Oct 1, 2009.

On the possibility of time-lapse ultrahigh-resolution optical coherence tomography for bladder cancer grading

Zhijia Yuan, Bai Chen, Hugang Ren et al.
It has been recently demonstrated that the cellular details of bladder epithelium embedded in speckle noise can be uncovered with time-lapse ultrahigh-resolution optical coherence tomography (TL-uOCT) by proper time-lapse frame averaging that takes advantage of cellular micromotion in fresh biologic ... [SPIE Letters VJ 2009, 017030 (2009)] published Wed Sep 16, 2009.

Extended in vivo anterior eye-segment imaging with full-range complex spectral domain optical coherence tomography

Johannes Jungwirth, Bernhard Baumann, Michael Pircher et al.
We demonstrate the capability of full-range complex (FRC) spectral domain optical coherence tomography (SD-OCT) to image the anterior eye segment from the cornea to the posterior surface of the lens. With an adapted spectrometer design, we developed a SD-OCT system with an extended normal (single ha ... [SPIE Letters VJ 2009, 017029 (2009)] published Tue Sep 8, 2009.

Motion vector memory reduction scheme for scalable motion estimation

Jinha Choi and Jaeseok Kim
We propose a motion vector memory reduction scheme for the H.264 spatial scalable motion estimation. The spatial scalable prediction of H.264 scalable video coding requires a significant amount of motion vector bits from the previous layer motion prediction. This motion vector causes the Internal me ... [SPIE Letters VJ 2009, 019019 (2009)] published Wed Sep 2, 2009.

Multimodal biometric authentication based on the fusion of finger vein and finger geometry

Byung Jun Kang and Kang Ryoung Park
We propose a new multimodal biometric recognition based on the fusion of finger vein and finger geometry. This research shows three novelties compared to previous works. First, this is the first approach to combine the finger vein and finger geometry information at the same time. Second, the propose ... [SPIE Letters VJ 2009, 019018 (2009)] published Wed Sep 2, 2009.

Complementary optical and nuclear imaging of caspase-3 activity using combined activatable and radio-labeled multimodality molecular probe

Hyeran Lee, Walter J. Akers, Philip P. Cheney et al.
Based on the capability of modulating fluorescence intensity by specific molecular events, we report a new multimodal optical-nuclear molecular probe with complementary reporting strategies. The molecular probe (LS498) consists of tetraazacyclododecanetetraacetic acid (DOTA) for chelating a radionuc ... [SPIE Letters VJ 2009, 017028 (2009)] published Tue Aug 25, 2009.

Label-free imaging by stimulated parametric emission microscopy reveals a difference in hemoglobin distribution between live and fixed erythrocytes

Hieu M. Dang, Gen Omura, Toshiyuki Umano et al.
We demonstrate that stimulated parametric emission (SPE) microscopy enables label-free, 3-D visualization of internal hemoglobin distribution of live mouse and chicken erythrocytes with high sensitivity. Change in hemoglobin distribution in chicken erythrocytes before and after ethanol fixation is c ... [SPIE Letters VJ 2009, 017027 (2009)] published Tue Aug 25, 2009.

Potential of optical microangiography to monitor cerebral blood perfusion and vascular plasticity following traumatic brain injury in mice in vivo

Yali Jia, Nabil Alkayed, and Ruikang K. Wang
Optical microanglography (OMAG) is a recently developed imaging modality capable of volumetric imaging of dynamic blood perfusion, down to capillary level resolution, with an imaging depth up to 2.00 mm beneath the tissue surface. We report the use of OMAG to monitor the cerebral blood flow (CBF) o ... [SPIE Letters VJ 2009, 017026 (2009)] published Tue Aug 25, 2009.

Functional transcranial brain imaging by optical-resolution photoacoustic microscopy

Song Hu, Konstantin Maslov, Vassiliy Tsytsarev et al.
Optical-resolution photoacoustic microscopy (OR-PAM) is applied to functional brain imaging in living mice. A near-diffraction-limited bright-field optical illumination is employed to achieve micrometer lateral resolution, and a dual-wavelength measurement is utilized to extract the blood oxygenatio ... [SPIE Letters VJ 2009, 017024 (2009)] published Tue Aug 18, 2009.

Simultaneous photoacoustic imaging technique using an acoustic imaging lens

Xian Chen, Zhilie Tang, Yongheng He et al.
A simultaneous photoacoustic (PA) tomography imaging technique in multilayer samples was developed. Instead of using the PA image reconstruction methods on the basis of complex algorithms, obtaining a two-dimensional PA image in real time is available by using an acoustic lens that has the ability o ... [SPIE Letters VJ 2009, 017019 (2009)] published Tue Aug 18, 2009.