Scholars@Duke
Martin Fischer

Martin Fischer

Research Professor in the Department of Chemistry
Chemistry
martin.fischer@duke.edu
Box 90346, Durham, NC 27708-0346
2216 French Science Center, 124 Science Drive, Durham, NC 27708

Selected Publications

Cost-effective, open-source light shutters with Arduino control

Journal Article HardwareX · September 1, 2024 In optical experiments, shutters are devices that open or close a path of light. They are often used to limit the duration of light exposure onto a target or onto a detector to reduce possible light-induced damage. Many commercial shutters are available fo ... Full text Cite

Non-destructive three-dimensional imaging of artificially degraded CdS paints by pump-probe microscopy

Journal Article JPhys Photonics · April 1, 2024 Cadmium sulfide (CdS) pigments have degraded in several well-known artworks, but the influence of pigment properties and environmental conditions on the degradation process have yet to be fully understood. Traditional non-destructive analysis techniques pr ... Full text Cite

Melanin imaging with pump-probe microscopy for diagnosis of metastatic melanoma

Conference CLEO: Applications and Technology, CLEO: A and T 2024 in Proceedings CLEO 2024 - Part of Conference on Lasers and Electro-Optics · January 1, 2024 Melanoma, the most aggressive skin cancer, is responsible for around 10, 000 deaths annually. We are developing a diagnostic biomarker based on femtosecond pump-probe microscopy of melanin, a natural pigment found in most melanoma. ... Cite

Contrast mechanisms in pump-probe microscopy of melanin.

Journal Article Opt Express · August 29, 2022 Pump-probe microscopy of melanin in tumors has been proposed to improve diagnosis of malignant melanoma, based on the hypothesis that aggressive cancers disaggregate melanin structure. However, measured signals of melanin are complex superpositions of mult ... Full text Link to item Cite

Structural, Optical, and Electronic Properties of Two Quaternary Chalcogenide Semiconductors: Ag2SrSiS4 and Ag2SrGeS4.

Journal Article Inorganic chemistry · August 2021 Quaternary chalcogenide materials have long been a source of semiconductors for optoelectronic applications. Recent studies on I2-II-IV-X4 (I = Ag, Cu, Li; II = Ba, Sr, Eu, Pb; IV = Si, Ge, Sn; X = S, Se) materials have shown particul ... Full text Cite

Beyond intensity modulation: new approaches to pump-probe microscopy.

Journal Article Optics letters · March 2021 Pump-probe microscopy is an emerging nonlinear imaging technique based on high repetition rate lasers and fast intensity modulation. Here, we present new methods for pump-probe microscopy that keep the beam intensity constant and instead modulate the inter ... Full text Cite

Low-cost measurement of face mask efficacy for filtering expelled droplets during speech.

Journal Article Sci Adv · September 2020 Featured Publication Mandates for mask use in public during the recent coronavirus disease 2019 (COVID-19) pandemic, worsened by global shortage of commercial supplies, have led to widespread use of homemade masks and mask alternatives. It is assumed that wearing such masks re ... Full text Link to item Cite

Video data from: Low-cost measurement of facemask efficacy for filtering expelled droplets during speech

Dataset · August 5, 2020 Mandates for mask use in public during the recent COVID-19 pandemic, worsened by global shortage of commercial supplies, have led to widespread use of homemade masks and mask alternatives. It is assumed that wearing such masks reduces the likelihood for an ... Full text Cite

Low-cost measurement of facemask efficacy for filtering expelled droplets during speech

Journal Article · June 22, 2020 AbstractMandates for mask use in public during the recent COVID-19 pandemic, worsened by global shortage of commercial supplies, have led to widespread use of homemade masks and mask alternatives. It is assumed that wearing ... Full text Cite

Crossed-beam pump-probe microscopy

Journal Article Optics Express · April 13, 2020 We present a new imaging method for pump-probe microscopy that explores non-collinear excitation. This method (crossed-beam pump-probe microscopy, or CBPM) can significantly improve the axial resolution when imaging through low-NA lenses, providing ... Full text Cite

Visualizing the impact of chloride addition on the microscopic carrier dynamics of MAPbI3 thin films using femtosecond transient absorption microscopy

Journal Article The Journal of Chemical Physics · December 21, 2019 Featured Publication The spatial heterogeneity of carrier dynamics in mixed halide perovskite CH3NH3PbI3−xClx thin films with a range of different chloride additions is mapped using femtosecond transient absorption microscopy (TAM). The comparison of TAM images of fibr ... Full text Cite

Probing the Spatial Heterogeneity of Carrier Relaxation Dynamics in CH3NH3PbI3 Perovskite Thin Films with Femtosecond Time‐Resolved Nonlinear Optical Microscopy

Journal Article Advanced Optical Materials · November 2019 AbstractThe spatial heterogeneity of carrier dynamics in polycrystalline metal halide perovskite (MHP) thin films has a strong influence on photovoltaic device performance; however, the underlying cause is not yet clearly u ... Full text Cite

Data from: In vivo pump-probe and multiphoton fluorescence microscopy of melanoma and pigmented lesions in a mouse model

Dataset · July 15, 2019 Featured Publication We demonstrate a multimodal approach that combines a pump--probe with confocal reflectance and multiphoton autofluorescence microscopy. Pump--probe microscopy has been proven to be of great value in analyzing thin tissue sections of pigmented lesions, as i ... Full text Cite

Visualization of vermilion degradation using pump-probe microscopy

Journal Article Science Advances · June 2019 Pump-probe microscopy identifies metacinnabar and metallic mercury as possible degradation product of vermilion (α-HgS). ... Full text Cite

Unraveling the molecular nature of melanin changes in metastatic cancer

Journal Article Journal of Biomedical Optics · April 11, 2019 Full text Cite

Label-Free Imaging of Female Genital Tract Melanocytic Lesions With Pump-Probe Microscopy: A Promising Diagnostic Tool.

Journal Article J Low Genit Tract Dis · April 2017 OBJECTIVES: Melanomas of the female genital tract present a unique clinical challenge. Not only are these lesions in an anatomically sensitive area, but also they tend to be multifocal and have high recurrence rates. Furthermore, several benign melanocytic ... Full text Link to item Cite

Melanin-targeted nonlinear microscopy for label-free molecular diagnosis and staging

Conference Optics InfoBase Conference Papers · April 18, 2016 Nonlinear pump-probe microscopy differentiates cutaneous, vulvar and conjunctival melanomas from less dangerous lesions, and can be used to assess metastatic potential. Applications in vivo (knockout mouse models) and in human biopsy are presented. ... Full text Cite

3D chemical imaging of historic artworks and cultural heritage materials

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · March 13, 2016 Link to item Cite

Invited Review Article: Pump-probe microscopy

Journal Article Review of Scientific Instruments · March 1, 2016 Multiphoton microscopy has rapidly gained popularity in biomedical imaging and materials science because of its ability to provide three-dimensional images at high spatial and temporal resolution even in optically scattering environments. Currently ... Full text Cite

Real-time digital signal processing in multiphoton and time-resolved microscopy

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2016 The use of multiphoton interactions in biological tissue for imaging contrast requires highly sensitive optical measurements. These often involve signal processing and filtering steps between the photodetector and the data acquisition device, such as photo ... Full text Cite

Pump-probe imaging of pigmented cutaneous melanoma primary lesions gives insight into metastatic potential.

Journal Article Biomed Opt Express · September 1, 2015 Metastatic melanoma is associated with a poor prognosis, but no method reliably predicts which melanomas of a given stage will ultimately metastasize and which will not. While sentinel lymph node biopsy (SLNB) has emerged as the most powerful predictor of ... Full text Link to item Cite

Flexible digital signal processing architecture for narrowband and spread-spectrum lock-in detection in multiphoton microscopy and time-resolved spectroscopy

Journal Article Review of Scientific Instruments · March 1, 2015 The lock-in amplifier is a critical component in many different types of experiments, because of its ability to reduce spurious or environmental noise components by restricting detection to a single frequency and phase. One example application is p ... Full text Cite

Ultrafast pump-probe dynamics of iron oxide based earth pigments for applications to ancient pottery manufacture

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2015 We demonstrate that ultrafast pump-probe microscopy provides unique dynamics for natural iron oxide and iron hydroxide earth pigments, despite their chemical similarity. First, we conducted a pump-probe spectroscopy study on heat-treated hematite (the pure ... Full text Cite

Separating higher-order nonlinearities in transient absorption microscopy

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2015 The transient absorption response of melanin is a promising optically-accessible biomarker for distinguishing malignant melanoma from benign pigmented lesions, as demonstrated by earlier experiments on thin sections from biopsied tissue. The technique has ... Full text Cite

Enhancing Pigmented or Transparent Tissue Imaging with Laser Pulse Shaping

Conference Optics InfoBase Conference Papers · January 1, 2015 Enhanced control over femtosecond lasers (pulse shaping or pulse train modulation) improves contrast in tissue imaging. Pump-probe applications to melanoma diagnosis and cross phase modulation measurement in transparent tissues will be presented. ... Cite

Nonlinear Optical Imaging in Art Conservation and Heritage Science

Conference Optics InfoBase Conference Papers · January 1, 2015 Pump-probe microscopy can extract molecular and structural contrast with high spatial resolution even in thick, scattering samples. We will discuss the technique’s principle and applications for imaging historic paintings and other cultural heritage object ... Cite

Femtosecond pulse train shaping for accurate two-photon excited fluorescence measurements

Conference Optics InfoBase Conference Papers · October 14, 2014 We report a simple measurement method that exploits pulse train shaping to suppress linear contributions to the fluorescence, and allows for extraction of the two-photon absorption cross sections. © 2014 OSA. ... Full text Cite

Femtosecond pump-probe microscopy generates virtual cross-sections in historic artwork

Journal Article Proceedings of the National Academy of Sciences · February 4, 2014 SignificanceWe show that a nonlinear microscopy technique (femtosecond pump-probe microscopy) allows for nondestructive 3D imaging of paintings with molecular and structural contrast. Until now, studying the laye ... Full text Cite

Femtosecond pulse train shaping for accurate two-photon excited fluorescence measurements

Conference Laser Science, LS 2014 · January 1, 2014 We report a simple measurement method that exploits pulse train shaping to suppress linear contributions to the fluorescence, and allows for extraction of the two-photon absorption cross sections. © 2014 OSA. ... Cite

Optical clearing and multiphoton imaging of paraffin-embedded specimens

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · June 12, 2013 New labeling, imaging, or analysis tools could provide new retrospective insights when applied to archived, paraffinembedded samples. Deep-tissue multiphoton microscopy of paraffin-embedded specimens is achieved using optical clearing with mineral oil. We ... Full text Cite

Adapting phasor analysis for nonlinear pump-probe microscopy

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · May 28, 2013 Phasor analysis has become a powerful tool for examining signals in fluorescence life-time microscopy (FLIM), where the analysis provides a fast, robust and intuitive means of separating different fluorescent species and mixtures thereof. In this work we a ... Full text Cite

Shedding new light on old art

Journal Article Physics World · January 1, 2013 Full text Cite

Homodyne near-degenerate four-wave-mixing microscopy for graphene imaging and biomedical applications

Conference 2012 Conference on Lasers and Electro-Optics, CLEO 2012 · December 6, 2012 Homodyne detection of near-degenerate four-wave-mixing with a single laser pulse is used to imaging graphene in biological samples. © 2012 OSA. ... Cite

Nonlinear cross-phase modulation microscopy using spectral shifting

Conference 2012 Conference on Lasers and Electro-Optics, CLEO 2012 · December 6, 2012 Nonlinear phase contrast may be acquired by measuring spectral shifting of an ultrafast pulse due to cross phase modulation. This technique is used to obtain structural details in a pigmented cell from a melanoma biopsy. © 2012 OSA. ... Cite

Pump-probe microscopy of pigments used in historical art

Conference 2012 Conference on Lasers and Electro-Optics, CLEO 2012 · December 6, 2012 We have developed a nonlinear microscopy technique that uses sensitive modulation transfer to extract excited state dynamics with high spatial resolution. Here, we use this technique to characterize several pigments used in historical artwork. © 2012 OSA. ... Cite

Historical pigments revealed by pump-probe microscopy

Conference Laser Science, LS 2012 · December 1, 2012 Nonlinear optical pump-probe microscopy is able to sensitively extract excited state dynamics from historical art pigments. This technique allows three-dimensional imaging and characterization of different pigments, with far reaching applications for conse ... Cite

Phasor analysis for nonlinear pump-probe microscopy

Journal Article Optics Express · July 16, 2012 Full text Cite

Pump-probe imaging of historical pigments used in paintings

Journal Article Optics Letters · April 15, 2012 Full text Cite

Cross-phase modulation imaging

Journal Article Optics Letters · March 1, 2012 Full text Cite

Optimizing shape of femtosecond laser pulses for homodyne detection of nonlinear optical signals

Conference Optics InfoBase Conference Papers · December 1, 2011 Based on homodyne detection of weak nonlinear signals with our spectral reshaping technique, pulse shapes are optimized for fast nonlinear imaging using femtosecond mode-locked lasers. © 2011 OSA. ... Cite

Cross-phase modulation microscopy

Conference Optics InfoBase Conference Papers · December 1, 2011 We report our recently developed spectral re-shaping technique for cross-phase modulation imaging, which extends widely employed phase microscopy to the nonlinear regime. © 2011 OSA. ... Cite

Femtosecond pulse shaping enables nonlinear imaging in highly scattering materials

Conference Optics InfoBase Conference Papers · December 1, 2011 Spectral re-shaping of pulses from a mode-locked femtosecond laser allows detection of two photon absorption and self phase modulation in highly scattering materials, which permits nonlinear tissue imaging with this intrinsic contrast. © 2011 OSA. ... Cite

Controllable ultrabroadband slow light in a warm rubidium vapor

Journal Article Journal of the Optical Society of America B · November 1, 2011 Full text Open Access Cite

Accessing nonlinear phase contrast in biological tissue using femtosecond laser pulse shaping

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · July 25, 2011 Nonlinear imaging takes advantage of the localized nature of the interaction to achieve high spatial resolution, optical sectioning, and deeper penetration in tissue. However, nonlinear contrast (other than fluorescence or harmonic generation) is generally ... Full text Cite

Nonlinear phase contrast imaging in neuronal tissue

Conference Optics InfoBase Conference Papers · 2011 Cite

Optimizing shape of femtosecond laser pulses for homodyne detection of nonlinear optical signals

Conference Optics InfoBase Conference Papers · January 1, 2011 Based on homodyne detection of weak nonlinear signals with our spectral reshaping technique, pulse shapes are optimized for fast nonlinear imaging using femtosecond mode-locked lasers. © 2011 OSA. ... Full text Cite

Nonlinear phase contrast imaging in neuronal tissue

Conference Optics InfoBase Conference Papers · January 1, 2011 We demonstrate nonlinear phase contrast imaging in highly scattering media using rapid femtosecond pulse shaping of mode-locked laser pulses. We will also discuss potential applications of this technique for intrinsic functional neuronal imaging. © 2011 OS ... Full text Cite

Cross-phase modulation microscopy

Conference Optics InfoBase Conference Papers · January 1, 2011 We report our recently developed spectral re-shaping technique for cross-phase modulation imaging, which extends widely employed phase microscopy to the nonlinear regime. © 2011 OSA. ... Full text Cite

Femtosecond pulse shaping enables nonlinear imaging in highly scattering materials

Conference Optics InfoBase Conference Papers · January 1, 2011 Spectral re-shaping of pulses from a mode-locked femtosecond laser allows detection of two photon absorption and self phase modulation in highly scattering materials, which permits nonlinear tissue imaging with this intrinsic contrast. © 2011 OSA. ... Full text Cite

Enhancing coherent anti-stokes Raman scattering background suppression with phase cycled structured femtosecond laser pulses

Conference Optics InfoBase Conference Papers · December 1, 2010 We demonstrate a homodyne coherent anti-Stokes Raman scattering technique based on femtosecond laser pulse shaping (phase-cycling). This technique utilizes a self-generated non-resonant background as a local oscillator to retrieve phase information of the ... Cite

Femtosecond laser pulse shaping improves self-phase modulation measurements in scattering media

Conference Optics InfoBase Conference Papers · December 1, 2010 We demonstrate that our recently developed spectral re-shaping technique improves the accuracy and precision of self-phase modulation measurements in scattering media over the conventional Z-scan method. © 2010 OSA/FiO/LS 2010. ... Cite

Enhancing coherent anti-stokes Raman scattering background suppression with phase cycled structured femtosecond laser pulses

Conference Optics InfoBase Conference Papers · January 1, 2010 We demonstrate a homodyne coherent anti-Stokes Raman scattering technique based on femtosecond laser pulse shaping (phase-cycling). This technique utilizes a self-generated non-resonant background as a local oscillator to retrieve phase information of the ... Full text Cite

Femtosecond laser pulse shaping improves self-phase modulation measurements in scattering media

Conference Optics InfoBase Conference Papers · January 1, 2010 We demonstrate that our recently developed spectral re-shaping technique improves the accuracy and precision of self-phase modulation measurements in scattering media over the conventional Z-scan method. © 2010 OSA/FiO/LS 2010. ... Full text Cite

Experiments on quantum transport of ultra-cold atoms in optical potentials

Chapter · December 1, 2009 In this chapter, we describe our experiments with ultra cold atoms in optical potentials and show how we can address fundamental issues of time in quantum mechanics. The high degree of experimental control and the conceptual simplicity are the main advanta ... Full text Cite

Enhancing two-color absorption, self-phase modulation and raman microscopy signatures in tissue with femtosecond laser pulse shaping

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · June 1, 2009 Nonlinear microscopies (most commonly, two-photon fluorescence, second harmonic generation, and coherent anti-Stokes Raman scattering (CARS)) have had notable successes in imaging a variety of endogenous and exogenous targets in recent years. These methods ... Full text Cite

Tissue imaging with shaped femtosecond laser pulses

Conference Optics InfoBase Conference Papers · January 1, 2009 Rapid laser pulse shaping permit detection of novel molecular signatures such as self- and cross-phase modulation or nonlinear absorption. These effects are used to discriminate between different melanins in tissue and to monitor neuronal activation. © 200 ... Cite

New nonlinear signatures in spectroscopy and imaging

Conference Conference on Quantum Electronics and Laser Science (QELS) - Technical Digest Series · September 15, 2008 Ultrafast laser pulse shaping makes it possible to observe nonlinear signatures, such as self phase modulation and sum frequency absorption, at safe laser powers for tissue. Neuronal activation and melanoma diagnosis are two early targets. © 2008 Optical S ... Full text Cite

Early changes of lung function and structure in an elastase model of emphysema—a hyperpolarized3He MRI study

Journal Article Journal of Applied Physiology · March 2008 Early changes of lung function and structure were studied in the presence of an elastase-induced model of emphysema in 35 Sprague-Dawley rats at mild (5 U/100 g) and moderate (10 U/100 g) severities. Lung ventilation was measured on a regional basi ... Full text Cite

Self-phase modulation signatures of neuronal activity

Journal Article Optics Letters · February 1, 2008 Full text Cite

Accessing nonlinear contrast in imaging using rapid pulse shaping techniques

Conference Optics InfoBase Conference Papers · January 1, 2008 We have designed an interferometric acousto-optic pulse shaper capable of shaping individual pulses differently from a mode-locked laser. The design enables the measurement of weak nonlinear optical signals at megahertz (MHz) rates for imaging applications ... Cite

Femtosecond laser pulse shaping for molecular imaging in biological tissue

Conference Optics InfoBase Conference Papers · January 1, 2008 Recently developed ultrafast laser pulse shaping technology allows highsensitivity measurements of nonlinear optical effects in highly scattering media. We present applications of these techniques to extract intrinsic structural, metabolic and functional c ... Cite

Intrinsic nonlinear optical signatures of neuronal activity

Conference Optics InfoBase Conference Papers · January 1, 2008 Using novel femtosecond laser pulse shaping techniques and a virtually background-free detection strategy we demonstrate strong self-phase modulation signatures of neuronal activity in hippocampal brain slices without the use of exogenous contrast agents. ... Cite

Intrinsic nonlinear optical signatures of neuronal activity

Conference Optics InfoBase Conference Papers · January 1, 2008 Using novel femtosecond laser pulse shaping techniques and a virtually background-free detection strategy we demonstrate strong self-phase modulation signatures of neuronal activity in hippocampal brain slices without the use of exogenous contrast agents. ... Full text Cite

Femtosecond laser pulse shaping for molecular imaging in biological tissue

Conference Optics InfoBase Conference Papers · January 1, 2008 Recently developed ultrafast laser pulse shaping technology allows highsensitivity measurements of nonlinear optical effects in highly scattering media. We present applications of these techniques to extract intrinsic structural, metabolic and functional c ... Full text Cite

Accessing nonlinear contrast in imaging using rapid pulse shaping techniques

Conference Optics InfoBase Conference Papers · January 1, 2008 We have designed an interferometric acousto-optic pulse shaper capable of shaping individual pulses differently from a mode-locked laser. The design enables the measurement of weak nonlinear optical signals at megahertz (MHz) rates for imaging applications ... Full text Cite

Self-phase modulation and two-photon absorption imaging of cells and active neurons

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · September 3, 2007 Even though multi-photon fluorescence microscopy offers higher resolution and better penetration depth than traditional fluorescence microscopy, its use is restricted to the detection of molecules that fluoresce. Two-photon absorption (TPA) imaging can pro ... Full text Cite

Novel nonlinear contrast improves deep-tissue microscopy

Journal Article Laser Focus World · June 1, 2007 Femtosecond laser pulse and pulse-train shaping allow detection of new nonlinear effects, with modest powers, making new biomarkers accessible and permitting deeper tissue imaging than conventional microscopy. The most developed of these technique create l ... Cite

Imaging melanin by two-photon absorption microscopy

Conference Proceedings of SPIE - The International Society for Optical Engineering · May 8, 2006 Multiphoton excitation fluorescence microscopy has proven to be a powerful method for non-invasive, in vivo, thick tissue imaging with molecular specificity. However, many important endogenous biomolecules do not fluoresce (NAD) or fluoresce with low effic ... Full text Cite

Deep tissue imaging with shaped femtosecond laser pulses

Conference Optics InfoBase Conference Papers · January 1, 2006 Two-photon absorption and self phase modulation can be detected deep in tissue with modest laser powers, using shaped femtosecond pulses. This permit microscopic-resolution images of biologically important targets. © 2006 Optical Society of America. ... Cite

Imaging physiological parameters with hyperpolarized gas MRI

Journal Article Progress in Nuclear Magnetic Resonance Spectroscopy · December 15, 2005 Full text Cite

Hyperpolarized 3He MRI in Asthma

Journal Article Academic Radiology · November 2005 Full text Cite

Quantitative assessment of emphysema using hyperpolarized 3He magnetic resonance imaging.

Journal Article Magn Reson Med · June 2005 In this experiment, Sprague-Dawley rats with elastase-induced emphysema were imaged using hyperpolarized (3)He MRI. Regional fractional ventilation r, the fraction of gas replaced with a single tidal breath, was calculated from a series of images in a wash ... Full text Link to item Cite

Two-photon absorption and self-phase modulation measurements with shaped femtosecond laser pulses

Conference 2005 Conference on Lasers and Electro-Optics, CLEO · January 1, 2005 We demonstrate experimentally that phase sensitive detection of spectral hole refilling can yield information about self-phase modulation and two-photon absorption coefficients. © 2005 Optical Society of America. ... Full text Cite

Hyperpolarized helium-3 MR imaging of pulmonary function.

Journal Article Radiol Clin North Am · January 2005 Recent advances in HP MR imaging contrast agents have led to novel tests of pulmonary function. Many of these tests show promise in the clinical arena. ... Full text Link to item Cite

Two-photon absorption microscopy of tissue

Conference Optics InfoBase Conference Papers · January 1, 2005 Two-photon absorption microscopy (TPAM) has been demonstrated to be able to image melanin with high sensitivity. TPAM opens up a wide range of nonfluorescent molecular targets. © 2005 Optical Society of America. ... Cite

Two-photon absorption imaging with shaped femtosecond laser pulses

Conference Springer Series in Chemical Physics · December 1, 2004 Femtosecond laser pulse shaping permits background-free detection of two-photon absorption, which tends to refill spectral holes. This opens up new spectroscopic windows for monitoring tissue characteristics. ... Cite

Deep tissue imaging approaches by direct capture of two-photon absorption

Conference 2004 2nd IEEE International Symposium on Biomedical Imaging: Macro to Nano · December 1, 2004 Multiphoton imaging with fluorescence detection has proven to be a powerful method for moderately deep tissue imaging (less than 1 mm) with molecular specificity. However, many important endogenous biomolecules do not fluoresce (NAD) or with low efficiency ... Cite

Single-acquisition sequence for the measurement of oxygen partial pressure by hyperpolarized gas MRI.

Journal Article Magn Reson Med · October 2004 Magnetic resonance imaging (MRI) with hyperpolarized 3-helium gas (HP 3He) offers the possibility of studying functional lung parameters such as the alveolar oxygen concentration and oxygen depletion rate. Until now, a double-acquisition technique has been ... Full text Link to item Cite

A small animal model of regional alveolar ventilation using HP 3He MRI1.

Journal Article Acad Radiol · October 2004 RATIONALE AND OBJECTIVES: The aim of this study was to establish a standardized procedure for the measurement of regional fractional ventilation in a healthy rat model as a baseline for further studies of pulmonary disorder models. MATERIALS AND METHODS: T ... Full text Link to item Cite

Two-photon absorption imaging and self-phase modulation imaging with shaped laser pulses

Conference Optics InfoBase Conference Papers · January 1, 2004 We present a new method for deep tissue imaging using nonlinear optics. Specific tailored laser pulses permit measurement of two-photon absorption or self-phase modulation with modest near-IR powers (1-10 mW), giving good penetration and molecular specific ... Cite

Two-photon absorption imaging with shaped femtosecond laser pulses

Conference Optics InfoBase Conference Papers · January 1, 2004 Femtosecond laser pulse shaping permits background-free detection of two-photon absorption, which tends to refill spectral holes. This opens up new spectroscopic windows for monitoring tissue characteristics. ... Cite

FEC performance under optical power transient conditions

Journal Article IEEE Photonics Technology Letters · November 2003 Full text Cite

Effect of reflection on un-isolated spot-size-converted 1.3 µm DFB lasers for 2.5 Gbit/s transmission

Conference Optics InfoBase Conference Papers · January 1, 2002 We have fabricated SSC-DFB laser transmitter modules, which give enough output power, and can tolerate strong reflection. They satisfy the SDH/SONET requirements for transmission up to 15 km at 2.5 Gbit/s. Because of the expected low packaging cost, the tr ... Cite

Effect of reflection on un-isolated spot-size-converted 1.3 μm DFB lasers for 2.5 Gbit/s transmission

Conference Conference on Optical Fiber Communication, Technical Digest Series · January 1, 2002 Spot-size-converted 1.3 μm distributed feedback laser transmitter modules for 2.5 Gbit/s transmission, were fabricated. The laser was mounted on a submount, and fiber coupling was done passively. Reflection was defined as the ratio of optical power coming ... Cite

160GB/s single-channel unrepeatered transmission over 200km of non-zero dispersion shifted fiber

Conference European Conference on Optical Communication, ECOC · December 1, 2001 Single-channel 160Gb/s unrepeated transmission over 200km of non-zero dispersion shifted fiber (NZDSF) was reported using distributed Raman amplification. Clock recovery and demultiplexing were realized simultaneously by cascading a tandem electro-absorpti ... Cite

FM spectroscopy in recoil-induced resonances

Journal Article Journal of Optics B: Quantum and Semiclassical Optics · August 1, 2001 Full text Cite

Observation of the Quantum Zeno and Anti-Zeno Effects in an Unstable System

Journal Article Physical Review Letters · July 10, 2001 Full text Cite

Observation of the quantum zeno and anti-zeno effects in an unstable system

Conference Technical Digest - Summaries of Papers Presented at the Quantum Electronics and Laser Science Conference, QELS 2001 · January 1, 2001 We study the motion of ultra-cold atoms in an accelerating optical lattice. We find that the tunneling dynamics are strongly affected by repeated measurement during the non-exponential time, leading to either inhibition (zeno) or enhancement (anti-zeno) of ... Full text Cite

Dynamical Bloch band suppression in an optical lattice

Conference Optics InfoBase Conference Papers · January 1, 1999 Cite

Dynamical Bloch band suppression in an optical lattice

Conference IQEC, International Quantum Electronics Conference Proceedings · January 1, 1999 The first observation of dynamical suppression of Bloch bands due to an AC field is presented. The system consists of laser-cooled atoms in an optical lattice. The neutral sodium atoms in the lowest band of a 1D optical lattice are trapped. The position of ... Cite

Dynamical Bloch Band Suppression in an Optical Lattice

Journal Article Physical Review Letters · December 7, 1998 Full text Cite

Nonexponential decay in atomic tunneling

Conference Technical Digest - European Quantum Electronics Conference · January 1, 1998 A simple model of the band structure with a single (trapped) band separated by a bandgap from a free particle state is used to study short-time deviation from exponential decay in a quantum tunneling experiment. The system consists of ultracold sodium atom ... Cite

Observation of non-exponential decay In quantum tunnelling

Conference Optics InfoBase Conference Papers · January 1, 1997 We report the observation of short-time deviation from exponential decay in tunneling of ultra-cold atoms from an accelerating periodic optical potential. We measure a'flat survival probability followed by a transition to exponential decay. ... Cite