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Full-Text Articles in Physical Sciences and Mathematics
Monte Carlo Simulation Of The Spatial Resolution And Depth Sensitivity Of Two-Dimensional Optical Imaging Of The Brain, Peifang Tian, Anna Devor, Sara Sakadžić, Anders Dale, David Boas
Monte Carlo Simulation Of The Spatial Resolution And Depth Sensitivity Of Two-Dimensional Optical Imaging Of The Brain, Peifang Tian, Anna Devor, Sara Sakadžić, Anders Dale, David Boas
Peifang Tian
Absorption or fluorescence-based two-dimensional (2-D) optical imaging is widely employed in functional brain imaging. The image is a weighted sum of the real signal from the tissue at different depths. This weighting function is defined as “depth sensitivity.” Characterizing depth sensitivity and spatial resolution is important to better interpret the functional imaging data. However, due to light scattering and absorption in biological tissues, our knowledge of these is incomplete. We use Monte Carlo simulations to carry out a systematic study of spatial resolution and depth sensitivity for 2-D optical imaging methods with configurations typically encountered in functional brain imaging. We …
Deep Tissue Imaging Approaches By Direct Capture Of Two-Photon Absorptionmacro To Nano, T. Ye, W. Wagner, Peifang Tian, G. Yurtsever, M. Fischer, W. Wagner
Deep Tissue Imaging Approaches By Direct Capture Of Two-Photon Absorptionmacro To Nano, T. Ye, W. Wagner, Peifang Tian, G. Yurtsever, M. Fischer, W. Wagner
Peifang Tian
No abstract provided.
Rapid Two-Dimensional Optical Spectroscopy Through Acousto-Optic Pulse Shaping, W. Wagner, Peifang Tian, L. Chunqiang, J. Semmlow, Warren Warren
Rapid Two-Dimensional Optical Spectroscopy Through Acousto-Optic Pulse Shaping, W. Wagner, Peifang Tian, L. Chunqiang, J. Semmlow, Warren Warren
Peifang Tian
No abstract provided.
Femtosecond Phase-Coherent Two-Dimensional Spectroscopy, Peifang Tian, Dorine Keusters, Yoshifumi Suzaki, Warren S. Warren
Femtosecond Phase-Coherent Two-Dimensional Spectroscopy, Peifang Tian, Dorine Keusters, Yoshifumi Suzaki, Warren S. Warren
Peifang Tian
Femtosecond phase-coherent two-dimensional (2D) spectroscopy has been experimentally demonstrated as the direct optical analog of 2D nuclear magnetic resonance. An acousto-optic pulse shaper created a collinear three-pulse sequence with well-controlled and variable interpulse delays and phases, which interacted with a model atomic system of rubidium vapor. The desired nonlinear polarization was selected by phase cycling (coadding experimental results obtained with different interpulse phases). This method may enhance our ability to probe the femtosecond structural dynamics of macromolecules.
Ultrafast Two-Photon Free Induction Decay, D. Keusters, Peifang Tian, W. Warren
Ultrafast Two-Photon Free Induction Decay, D. Keusters, Peifang Tian, W. Warren
Peifang Tian
No abstract provided.
Femtosecond Pulse Shaping Approaches To Multiphoton Imaging., W. Warren, W. Wagner, Peifang Tian, T. Ye
Femtosecond Pulse Shaping Approaches To Multiphoton Imaging., W. Warren, W. Wagner, Peifang Tian, T. Ye
Peifang Tian
No abstract provided.
Ultrafast Measurement Of Two-Photon Absorption By Loss Modulation, Peifang Tian, Warren Warren
Ultrafast Measurement Of Two-Photon Absorption By Loss Modulation, Peifang Tian, Warren Warren
Peifang Tian
We demonstrate a direct and sensitive technique for measuring two-photon absorption (TPA).An intensity- modulated femtosecond laser beam passes through a sample exhibiting TPA.A TPA signal at twice the modulation frequency is then generated and subsequently measured by a lock-in amplifier. The absolute TPA cross section of Rhodamine 6G at 800nm is found to be 15.32.010 -50 cm 4 s / photon and agrees well with previously published results obtained with much higher intensity [J.Chem.Phys. 112, 9201 (2000)]. Our method may be especially useful in measuring nonlinear absorptions of nonfluorescent materials.
Direct And Sensitive Measurement Of Two-Photon Absorption Cross Sections, Peifang Tian, D. Keusters, Warren Warren
Direct And Sensitive Measurement Of Two-Photon Absorption Cross Sections, Peifang Tian, D. Keusters, Warren Warren
Peifang Tian
Summary form only given. We present a direct method to detect weak two-photon absorption (TPA) signals. As a proof of principle, we have measured the TPA cross section δ for rhodamine 6G (R6G) in methanol and obtained a value which agrees with other results. The technique may be very useful in biomedical imaging.
Femtosecond Polarization Detection Using High-Speed Pulse Shaping, D. Keusters, Peifang Tian, W. Warren
Femtosecond Polarization Detection Using High-Speed Pulse Shaping, D. Keusters, Peifang Tian, W. Warren
Peifang Tian
This book presents the latest advances in ultrafast science, including ultrafast laser and measurement technology as well as studies of ultrafast phenomena. Pico- and femtosecond processes relevant in physics, chemistry, biology and engineering are presented. Ultrafast technology has had a profound impact in a wide range of applications, among them imaging, material diagnostics and transformation and high-speed optoelectronics. This book summarizes the results presented at the 12th Ultrafast Phenomena Conference and reviews the state of the art of this important and rapidly advancing field.
Transparent Stacked Organic Light Emitting Devices. I. Design Principles And Transparent Compound Electrodes, G. Gu, G. Parthasarathy, P. E. Burrows, Peifang Tian, I. G. Hill, A. Kahn, S. R. Forrest
Transparent Stacked Organic Light Emitting Devices. I. Design Principles And Transparent Compound Electrodes, G. Gu, G. Parthasarathy, P. E. Burrows, Peifang Tian, I. G. Hill, A. Kahn, S. R. Forrest
Peifang Tian
Vertical stacking of organic light emitting devices (OLEDs) that emit the three primary colors is a means for achieving full-color flat panel displays. The physics, performance, and applications of stacked OLEDs (SOLEDs) are discussed in this and the following paper (Papers I and II, respectively). In Paper I, we analyze optical microcavity effects that can distort the emission colors of SOLEDs if not properly controlled, and describe design principles to minimize these parasitic effects. We also describe the fabrication and operating characteristics of transparent contacts that are an integral part of SOLEDs. We demonstrate that both metal-containing and metal-free transparent …
Transparent Stacked Organic Light Emitting Devices. Ii. Device Performance And Applications To Displays, G. Gu, G. Parthasarathy, Peifang Tian
Transparent Stacked Organic Light Emitting Devices. Ii. Device Performance And Applications To Displays, G. Gu, G. Parthasarathy, Peifang Tian
Peifang Tian
Vertical stacking of organic light emitting devices (OLEDs) that emit the three primary colors is shown to be a means for achieving efficient and bright full-color displays. In Paper I, we addressed stacked OLED (SOLED) design and fabrication principles to optimize emission colors, operating voltage, and efficiency. Here, we present results on two different (metal-containing and metal-free cathode) SOLED structures that exhibit performance suitable for many full-color display applications. The operating voltages at 10 mA/cm2 (corresponding to video display brightnesses) are 6.8, 8.5, and 12.1 V for the red (R), green (G), and blue (B) elements of the metal-containing SOLED, …
Precise, Scalable Shadow Mask Patterning Of Vacuum-Deposited Organic Light Emitting Devices, Peifang Tian, V. Bulovic, P. Burrows, G. Gu, S. Forrest, T. Zhou
Precise, Scalable Shadow Mask Patterning Of Vacuum-Deposited Organic Light Emitting Devices, Peifang Tian, V. Bulovic, P. Burrows, G. Gu, S. Forrest, T. Zhou
Peifang Tian
We demonstrate a scheme to pattern vacuum-deposited, small molecular weight organic light emitting diodes OLEDs. Both the organic thin films and the metallic electrodes are patterned by shifting the position of a single shadow mask which accompanies the substrate throughout the deposition process. A full color, stacked OLED SOLED has been fabricated using this technique. The substrate movement relative to the mask was manually controlled to a root mean square accuracy of 8 m using a mask translating fixture. The performance of the patterned SOLED is comparable with that of devices fabricated by conventional, low tolerance methods. The limits to …
Photolithographic Patterning Of Vacuum-Deposited Organic Light Emitting Devices, Peifang Tian, P. Burrows, B. Bulovic, S. Forrest
Photolithographic Patterning Of Vacuum-Deposited Organic Light Emitting Devices, Peifang Tian, P. Burrows, B. Bulovic, S. Forrest
Peifang Tian
No abstract provided.
Photolithographic Patterning Of Vacuum-Deposited Organic Light Emitting Devices, Peifang Tian, P. E. Burrows, S. E. Forrest
Photolithographic Patterning Of Vacuum-Deposited Organic Light Emitting Devices, Peifang Tian, P. E. Burrows, S. E. Forrest
Peifang Tian
We demonstrate a photolithographic technique to fabricate vacuum-deposited organic light emitting devices. Photoresist liftoff combined with vertical deposition of the emissive organic materials and the metal cathode, followed by oblique deposition of a metal cap, avoids the use of high processing temperatures and the exposure of the organic materials to chemical degradation. The unpackaged devices show no sign of deterioration in room ambient when compared with conventional devices fabricated using low-resolution, shadow mask patterning. Furthermore, the devices are resistant to rapid degradation when operated in air for extended periods. This work illustrates a potential foundation for the volume production of …
A Surface-Emitting Vacuum-Deposited Organic Light Emitting Device, V. Bulovic, Peifang Tian, P. E. Burrows, M. R. Gokhale, S. R. Forrest, M. E. Thompson
A Surface-Emitting Vacuum-Deposited Organic Light Emitting Device, V. Bulovic, Peifang Tian, P. E. Burrows, M. R. Gokhale, S. R. Forrest, M. E. Thompson
Peifang Tian
We demonstrate a vacuum-deposited organic light emitting device which emits from its top surface through a transparent indium-tin-oxide anode. This device employs a novel protective cap layer which prevents damage to the organic layers during sputter deposition of the anode, while also improving hole injection. Mechanisms of current transport and carrier injection from the contacts are investigated. This device configuration allows for integration of organic light emitting devices with n-channel field effect transistors used in display active matrix backplanes.