Rainer Erdmann - Academia.edu (original) (raw)

Papers by Rainer Erdmann

Single Molecule Spectroscopy and Superresolution Imaging V, 2012

ABSTRACT STimulated Emission Depletion (STED) microscopy enables imaging of biological samples co... more ABSTRACT STimulated Emission Depletion (STED) microscopy enables imaging of biological samples combining significantly improved optical resolution with all benefits of confocal microscopy. Especially, by combining multi-channel image acquisition with high spatial resolution opens up a new understanding of co-localization experiments on nanoscales. Such a microscope provides new insights in various fields of biology, such as cell and membrane biology, neurobiology and physiology. We present new developments and a variety of biological examples for STED microscopy, showing structural details on scales well below 70nm and give an overview of possible field of applications, mainly focused on live cell imaging.

We present the technical integration of state-of-the-art picosecond diode laser sources and data ... more We present the technical integration of state-of-the-art picosecond diode laser sources and data acquisition electronics in conventional laser scanning microscopes. This offers users of laser scanning microscopes an easy upgrade path towards time-resolved measurements. Our setup uses picosecond diode lasers from 375 nm, 405 nm, 440 nm and 470 nm for fluorescence excitation which are coupled in through a sole

Proceedings of SPIE - The International Society for Optical Engineering

ABSTRACT

Genetically encoded labelling by fluorescent pro- teins has opened the possibility to observe pro... more Genetically encoded labelling by fluorescent pro- teins has opened the possibility to observe protein distribution and localisation by fluorescence mi- croscopy. A direct visualisation of these nanometre sized molecules is, however, not possible due to the Abbe limit of diffraction (about 200 nm in confocal microscopes). As an alternative, indirect methods such as Förster Resonance Energy Transfer (FRET) studies can

Optical Components and Materials VI, 2009

In this paper, we compare two amplifier technologies, an ytterbium-doped fiber, and a semiconduct... more In this paper, we compare two amplifier technologies, an ytterbium-doped fiber, and a semiconductor taper, regarding their suitability to amplify sub-100 ps pulses. With both setups, we obtain amplification of the pulse energy by more than 10 dB. However, suppression of self-lasing in the pulse intervals is critical, particularly in the case of the semiconductor amplifier which has a very short upper state lifetime.

Fiber Lasers X: Technology, Systems, and Applications, 2013

ABSTRACT An freely triggerable picosecond visible supercontinuum laser source is presented that a... more ABSTRACT An freely triggerable picosecond visible supercontinuum laser source is presented that allows for a uniform spectral profile and equivalent pulse characteristics over variable repetition rates from 1 to 40MHz. The system features PM Yb3+-doped fiber amplification of a picosecond gain-switched seed diode at 1062 nm. The pump power in the multi-stage amplifier is actively adjusted by a microcontroller for a consistent peak power of the amplified signal in the full range of repetition rates. The length of the PCF is scaled to deliver a homogeneous spectrum and minimized distortion of the temporal pulse shape.

Proceedings of SPIE, 2010

State of the art confocal microscopes offer diffraction limited (or even better) spatial resoluti... more State of the art confocal microscopes offer diffraction limited (or even better) spatial resolution, highest (single molecule) sensitivity and ps-fluorescence lifetime measurement accuracy. For developers, manufacturers, as well as users of confocal microscopes it is mandatory to assign values to these qualities. In particular for users, it is often not easy to ascertain that the instrument is properly aligned as a large number of factors influence resolution or sensitivity. Therefore, we aspire to design a set of performance standards to be deployed on a day-to-day fashion in order to check the instruments characteristics. The main quantities such performance standard must address are: Spatial resolution, Sensitivity, Fluorescence lifetime
To facilitate the deployment and thus promote wide range adoption in day-to-day performance testing the corresponding standards have to be ready made, easy to handle and to store. The measurement procedures necessary should be available on as many different setups as possible and the procedures involved in their deployment should be as easy as possible. To this end, we developed two performance standards to accomplish the mentioned goals: Resolution reference, Combined molecular brightness and fluorescence lifetime reference. The first one is based on sub-resolution sized Tetra-Speck (TM) fluorescent beads or alternatively on single molecules on a glass surface to image and to determine quantitatively the confocal volume, while the latter is a liquid sample containing fluorescent dyes of different concentrations and spectral properties. Both samples are sealed in order to ease their use and prolong their storage life. Currently long-term tests are performed to ascertain durability and road capabilities.

Fluorescence decay studies of photoexcited porphyrin-triptycene-quinones as biomimetic model syst... more Fluorescence decay studies of photoexcited porphyrin-triptycene-quinones as biomimetic model systems for the primary processes of photosynthesis have been performed. These dyes were chosen on the basis of their rigid structure, high electron transfer (ET) rates and their advantageous absorption properties. The extremely short fluorescence lifetimes caused by an intramolecular ET process favor their use as standards in ps-lifetime measurements. Depending

Advances in Fluorescence Sensing Technology II, 1995

ABSTRACT

Proceedings of SPIE, 2003

We present results from a two channel confocal microscope set-up allowing one to efficiently reco... more We present results from a two channel confocal microscope set-up allowing one to efficiently record two-colour as well as polarization resolved time-correlated single molecule fluorescence data. In addition to their spectral characteristics, single molecules can be distinguished by their fluorescence lifetime and polarization. This provides independent distinctive information and results in enhanced detection sensitivity. The set-up we present uses two picosecond diode lasers (440nm and 635nm) for fluorescence excitation and a piezo scanner for sample movement. A learning scan algorithm permits very fast piezo scanner movement and offers a superior positioning accuracy on single molecules. The time-correlated photon counting system uses Time-Tagged Time-Resolved (TTTR) data acquisition, in which each photon is recorded individually. This method allows for the reconstruction not only fluorescence decay constants of each pixel for the purpose of Fluorescence Lifetime Imaging (FLIM) but also to analyze the fluorescence fluctuation correlation function on a single spot of interest. Cross-correlation between two channels can be used to eliminate detector artifacts. Finally, fluorescence antibunching can also be analyzed. We show results obtained with immobilized and diffusing red and blue excited, fluorescently labelled latex microspheres, as well as from single fluorophore molecules.

Systems and Technologies for Clinical Diagnostics and Drug Discovery, 1998

ABSTRACT Time Correlated Single Photon Counting (TCSPC) is a valuable tool for Single Molecule De... more ABSTRACT Time Correlated Single Photon Counting (TCSPC) is a valuable tool for Single Molecule Detection (SMD). However, existing TCSPC systems did not support continuous data collection and processing as is desirable for applications such as SMD for e.g. DNA-sequencing in a liquid flow. First attempts at using existing instrumentation in this kind of operation mode required additional routing hardware to switch between several memory banks and were not truly continuous. We have designed a hard- and software system to perform continuous real-time TCSPC based upon a modern solid state Time to Digital Converter (TDC). Short dead times of the fully digital TDC design combined with fast Field Programmable Gay Array logic permit a continuous data throughput as high as 3 Mcounts/sec. The histogramming time may be set as short as 100 microsecond(s) . Every histogram or every single fluorescence photon can be real-time tagged at 200 ns resolution in addition to recording its arrival time relative to the excitation pulse. Continuous switching between memory banks permits concurrent histogramming and data read-out. The instrument provides a time resolution of 60 ps and up to 4096 histogram channels. The overall instrument response function in combination with a low cost picosecond diode laser and an inexpensive photomultiplier tube was found to be 180 ps and well sufficient to measure sub-nanosecond fluorescence lifetimes.

Solid State Lasers XIV: Technology and Devices, 2005

Gain-switching of laser diodes might be the most convenient way to generate picosecond laser puls... more Gain-switching of laser diodes might be the most convenient way to generate picosecond laser pulses. The outstanding features of gain-switched laser diodes are a rich choice of wavelength and an easy synchronization to an external trigger source. To broaden the field of applications we pushed the peak power to the 10 W level while maintaining the essential characteristics of the

Conference on Lasers and Electro-Optics 2010, 2010

ABSTRACT Green picosecond pulses with peak powers of more than 4W are generated by second harmoni... more ABSTRACT Green picosecond pulses with peak powers of more than 4W are generated by second harmonic generation in bulk PPLN. These power levels exceed all previous electrically triggerable green picosecond sources by an order of magnitude.

Advances in Fluorescence Sensing Technology II, 1995

ABSTRACT

CLEO:2011 - Laser Applications to Photonic Applications, 2011

Abstract Yellow-orange picosecond pulses are generated via Sum Frequency Generation of 1529 nm (p... more Abstract Yellow-orange picosecond pulses are generated via Sum Frequency Generation of 1529 nm (pulsed) and 974 nm (cw) radiation in a PPKTP waveguide. The pJ-energy pulses around 595 nm are freely triggerable up to 80 MHz.

Review of Scientific Instruments, 2001

A confocal laser-scanning microscope for ultrasensitive fluorescence lifetime imaging on surfaces... more A confocal laser-scanning microscope for ultrasensitive fluorescence lifetime imaging on surfaces is presented. The system employs a compact electronics for time-correlated single-photon counting ͑TCSPC͒, allowing for measuring fluorescence lifetime with 40 ps time resolution, and for continuously recording photon arrival times with 100 ns time resolution. Additionally developed driver electronics serve for synchronization of scanning and data acquisition, which is significant for achieving high spatial image resolution. The capabilities of the measurement system are demonstrated on imaging single molecules immobilized on glass substrates. Finally, it is shown how the TCSPC capabilities of the system can be used not only for lifetime imaging but also for multichannel measurements.

Proceedings of SPIE, 2012

Depending on the semiconductor material, the luminescence lifetime of semiconductor wafers can va... more Depending on the semiconductor material, the luminescence lifetime of semiconductor wafers can vary over a broad range from microseconds for Si-wafers down to sub-nanoseconds for III/V and II/VI based thin film or organic materials. The lifetime of a given wafer sample depends on the free charge carrier dynamics and can therefore be affected by several parameters. An important example is the influence of bulk or surface defects [1], thus the lifetime is a possible indicator for wafer quality. On dye-sensitized solar cells, lifetime measurements are also useful to characterize the energy transfer process from the sensitizer to the conduction band [2].
We have developed a setup for time-resolved photoluminescence measurements (TRPL) based on pulsed diode lasers and time-correlated single photon counting (TCSPC) with highly sensitive single photon detectors. Depending on the detector type, the instrument response function (IRF) can be as short as 100 ps and the laser pulse rate can be adapted to the luminescence lifetime of the material. The resolvable lifetimes extend from approx. 50 ps up to several hundred microseconds. The electronics can also be integrated into a microscope based setup for imaging with a lateral resolution down to the sub-mu m range [3] as well as testing the lifetime behaviour at different injection levels. We will show measurement results of the system on an GaAsP-based Quantum Well.

Proceedings of SPIE, 2008

We re about the time-resolved confocal fluorescence microscope MicroTime 200, which is completely... more We re about the time-resolved confocal fluorescence microscope MicroTime 200, which is completely based on TTTR format data acquisition and enables to perform very advanced FCS, FRET and FLIM analysis such as Fluorescence Lifetime Correlation Spectroscopy (FLCS) or Two Focus FCS (2fFCS). FLCS is a fundamental improvement of standard FCS overcoming many of its inherent limitations. The basic idea of FLCS is a weighting of the detected photons based on the additional picosecond timing information (TCSPC start-stop time) when using pulsed laser excitation. 2fFCS goes even further, combining Pulsed Interleaved Excitation (PIE) with a time-gated FCS analysis. The basic implementation of 2fFCS uses two synchronized but interleaved pulsed lasers of the same wavelength but of different polarisation to generate two close by excitation foci in a predetermined distance acting as a submicron ruler. In this case it it no longer necessary to have prior knowledge about the size and shape of the confocal volume. Maintaining the information about the photon's origin, the dual focus data allows a precise calculation of absolute diffusion coefficients.

Biomedical Optics and 3-D Imaging, 2010

ABSTRACT

Single Molecule Spectroscopy and Superresolution Imaging V, 2012

ABSTRACT STimulated Emission Depletion (STED) microscopy enables imaging of biological samples co... more ABSTRACT STimulated Emission Depletion (STED) microscopy enables imaging of biological samples combining significantly improved optical resolution with all benefits of confocal microscopy. Especially, by combining multi-channel image acquisition with high spatial resolution opens up a new understanding of co-localization experiments on nanoscales. Such a microscope provides new insights in various fields of biology, such as cell and membrane biology, neurobiology and physiology. We present new developments and a variety of biological examples for STED microscopy, showing structural details on scales well below 70nm and give an overview of possible field of applications, mainly focused on live cell imaging.

We present the technical integration of state-of-the-art picosecond diode laser sources and data ... more We present the technical integration of state-of-the-art picosecond diode laser sources and data acquisition electronics in conventional laser scanning microscopes. This offers users of laser scanning microscopes an easy upgrade path towards time-resolved measurements. Our setup uses picosecond diode lasers from 375 nm, 405 nm, 440 nm and 470 nm for fluorescence excitation which are coupled in through a sole

Proceedings of SPIE - The International Society for Optical Engineering

ABSTRACT

Genetically encoded labelling by fluorescent pro- teins has opened the possibility to observe pro... more Genetically encoded labelling by fluorescent pro- teins has opened the possibility to observe protein distribution and localisation by fluorescence mi- croscopy. A direct visualisation of these nanometre sized molecules is, however, not possible due to the Abbe limit of diffraction (about 200 nm in confocal microscopes). As an alternative, indirect methods such as Förster Resonance Energy Transfer (FRET) studies can

Optical Components and Materials VI, 2009

In this paper, we compare two amplifier technologies, an ytterbium-doped fiber, and a semiconduct... more In this paper, we compare two amplifier technologies, an ytterbium-doped fiber, and a semiconductor taper, regarding their suitability to amplify sub-100 ps pulses. With both setups, we obtain amplification of the pulse energy by more than 10 dB. However, suppression of self-lasing in the pulse intervals is critical, particularly in the case of the semiconductor amplifier which has a very short upper state lifetime.

Fiber Lasers X: Technology, Systems, and Applications, 2013

ABSTRACT An freely triggerable picosecond visible supercontinuum laser source is presented that a... more ABSTRACT An freely triggerable picosecond visible supercontinuum laser source is presented that allows for a uniform spectral profile and equivalent pulse characteristics over variable repetition rates from 1 to 40MHz. The system features PM Yb3+-doped fiber amplification of a picosecond gain-switched seed diode at 1062 nm. The pump power in the multi-stage amplifier is actively adjusted by a microcontroller for a consistent peak power of the amplified signal in the full range of repetition rates. The length of the PCF is scaled to deliver a homogeneous spectrum and minimized distortion of the temporal pulse shape.

Proceedings of SPIE, 2010

State of the art confocal microscopes offer diffraction limited (or even better) spatial resoluti... more State of the art confocal microscopes offer diffraction limited (or even better) spatial resolution, highest (single molecule) sensitivity and ps-fluorescence lifetime measurement accuracy. For developers, manufacturers, as well as users of confocal microscopes it is mandatory to assign values to these qualities. In particular for users, it is often not easy to ascertain that the instrument is properly aligned as a large number of factors influence resolution or sensitivity. Therefore, we aspire to design a set of performance standards to be deployed on a day-to-day fashion in order to check the instruments characteristics. The main quantities such performance standard must address are: Spatial resolution, Sensitivity, Fluorescence lifetime
To facilitate the deployment and thus promote wide range adoption in day-to-day performance testing the corresponding standards have to be ready made, easy to handle and to store. The measurement procedures necessary should be available on as many different setups as possible and the procedures involved in their deployment should be as easy as possible. To this end, we developed two performance standards to accomplish the mentioned goals: Resolution reference, Combined molecular brightness and fluorescence lifetime reference. The first one is based on sub-resolution sized Tetra-Speck (TM) fluorescent beads or alternatively on single molecules on a glass surface to image and to determine quantitatively the confocal volume, while the latter is a liquid sample containing fluorescent dyes of different concentrations and spectral properties. Both samples are sealed in order to ease their use and prolong their storage life. Currently long-term tests are performed to ascertain durability and road capabilities.

Fluorescence decay studies of photoexcited porphyrin-triptycene-quinones as biomimetic model syst... more Fluorescence decay studies of photoexcited porphyrin-triptycene-quinones as biomimetic model systems for the primary processes of photosynthesis have been performed. These dyes were chosen on the basis of their rigid structure, high electron transfer (ET) rates and their advantageous absorption properties. The extremely short fluorescence lifetimes caused by an intramolecular ET process favor their use as standards in ps-lifetime measurements. Depending

Advances in Fluorescence Sensing Technology II, 1995

ABSTRACT

Proceedings of SPIE, 2003

We present results from a two channel confocal microscope set-up allowing one to efficiently reco... more We present results from a two channel confocal microscope set-up allowing one to efficiently record two-colour as well as polarization resolved time-correlated single molecule fluorescence data. In addition to their spectral characteristics, single molecules can be distinguished by their fluorescence lifetime and polarization. This provides independent distinctive information and results in enhanced detection sensitivity. The set-up we present uses two picosecond diode lasers (440nm and 635nm) for fluorescence excitation and a piezo scanner for sample movement. A learning scan algorithm permits very fast piezo scanner movement and offers a superior positioning accuracy on single molecules. The time-correlated photon counting system uses Time-Tagged Time-Resolved (TTTR) data acquisition, in which each photon is recorded individually. This method allows for the reconstruction not only fluorescence decay constants of each pixel for the purpose of Fluorescence Lifetime Imaging (FLIM) but also to analyze the fluorescence fluctuation correlation function on a single spot of interest. Cross-correlation between two channels can be used to eliminate detector artifacts. Finally, fluorescence antibunching can also be analyzed. We show results obtained with immobilized and diffusing red and blue excited, fluorescently labelled latex microspheres, as well as from single fluorophore molecules.

Systems and Technologies for Clinical Diagnostics and Drug Discovery, 1998

ABSTRACT Time Correlated Single Photon Counting (TCSPC) is a valuable tool for Single Molecule De... more ABSTRACT Time Correlated Single Photon Counting (TCSPC) is a valuable tool for Single Molecule Detection (SMD). However, existing TCSPC systems did not support continuous data collection and processing as is desirable for applications such as SMD for e.g. DNA-sequencing in a liquid flow. First attempts at using existing instrumentation in this kind of operation mode required additional routing hardware to switch between several memory banks and were not truly continuous. We have designed a hard- and software system to perform continuous real-time TCSPC based upon a modern solid state Time to Digital Converter (TDC). Short dead times of the fully digital TDC design combined with fast Field Programmable Gay Array logic permit a continuous data throughput as high as 3 Mcounts/sec. The histogramming time may be set as short as 100 microsecond(s) . Every histogram or every single fluorescence photon can be real-time tagged at 200 ns resolution in addition to recording its arrival time relative to the excitation pulse. Continuous switching between memory banks permits concurrent histogramming and data read-out. The instrument provides a time resolution of 60 ps and up to 4096 histogram channels. The overall instrument response function in combination with a low cost picosecond diode laser and an inexpensive photomultiplier tube was found to be 180 ps and well sufficient to measure sub-nanosecond fluorescence lifetimes.

Solid State Lasers XIV: Technology and Devices, 2005

Gain-switching of laser diodes might be the most convenient way to generate picosecond laser puls... more Gain-switching of laser diodes might be the most convenient way to generate picosecond laser pulses. The outstanding features of gain-switched laser diodes are a rich choice of wavelength and an easy synchronization to an external trigger source. To broaden the field of applications we pushed the peak power to the 10 W level while maintaining the essential characteristics of the

Conference on Lasers and Electro-Optics 2010, 2010

ABSTRACT Green picosecond pulses with peak powers of more than 4W are generated by second harmoni... more ABSTRACT Green picosecond pulses with peak powers of more than 4W are generated by second harmonic generation in bulk PPLN. These power levels exceed all previous electrically triggerable green picosecond sources by an order of magnitude.

Advances in Fluorescence Sensing Technology II, 1995

ABSTRACT

CLEO:2011 - Laser Applications to Photonic Applications, 2011

Abstract Yellow-orange picosecond pulses are generated via Sum Frequency Generation of 1529 nm (p... more Abstract Yellow-orange picosecond pulses are generated via Sum Frequency Generation of 1529 nm (pulsed) and 974 nm (cw) radiation in a PPKTP waveguide. The pJ-energy pulses around 595 nm are freely triggerable up to 80 MHz.

Review of Scientific Instruments, 2001

A confocal laser-scanning microscope for ultrasensitive fluorescence lifetime imaging on surfaces... more A confocal laser-scanning microscope for ultrasensitive fluorescence lifetime imaging on surfaces is presented. The system employs a compact electronics for time-correlated single-photon counting ͑TCSPC͒, allowing for measuring fluorescence lifetime with 40 ps time resolution, and for continuously recording photon arrival times with 100 ns time resolution. Additionally developed driver electronics serve for synchronization of scanning and data acquisition, which is significant for achieving high spatial image resolution. The capabilities of the measurement system are demonstrated on imaging single molecules immobilized on glass substrates. Finally, it is shown how the TCSPC capabilities of the system can be used not only for lifetime imaging but also for multichannel measurements.

Proceedings of SPIE, 2012

Depending on the semiconductor material, the luminescence lifetime of semiconductor wafers can va... more Depending on the semiconductor material, the luminescence lifetime of semiconductor wafers can vary over a broad range from microseconds for Si-wafers down to sub-nanoseconds for III/V and II/VI based thin film or organic materials. The lifetime of a given wafer sample depends on the free charge carrier dynamics and can therefore be affected by several parameters. An important example is the influence of bulk or surface defects [1], thus the lifetime is a possible indicator for wafer quality. On dye-sensitized solar cells, lifetime measurements are also useful to characterize the energy transfer process from the sensitizer to the conduction band [2].
We have developed a setup for time-resolved photoluminescence measurements (TRPL) based on pulsed diode lasers and time-correlated single photon counting (TCSPC) with highly sensitive single photon detectors. Depending on the detector type, the instrument response function (IRF) can be as short as 100 ps and the laser pulse rate can be adapted to the luminescence lifetime of the material. The resolvable lifetimes extend from approx. 50 ps up to several hundred microseconds. The electronics can also be integrated into a microscope based setup for imaging with a lateral resolution down to the sub-mu m range [3] as well as testing the lifetime behaviour at different injection levels. We will show measurement results of the system on an GaAsP-based Quantum Well.

Proceedings of SPIE, 2008

We re about the time-resolved confocal fluorescence microscope MicroTime 200, which is completely... more We re about the time-resolved confocal fluorescence microscope MicroTime 200, which is completely based on TTTR format data acquisition and enables to perform very advanced FCS, FRET and FLIM analysis such as Fluorescence Lifetime Correlation Spectroscopy (FLCS) or Two Focus FCS (2fFCS). FLCS is a fundamental improvement of standard FCS overcoming many of its inherent limitations. The basic idea of FLCS is a weighting of the detected photons based on the additional picosecond timing information (TCSPC start-stop time) when using pulsed laser excitation. 2fFCS goes even further, combining Pulsed Interleaved Excitation (PIE) with a time-gated FCS analysis. The basic implementation of 2fFCS uses two synchronized but interleaved pulsed lasers of the same wavelength but of different polarisation to generate two close by excitation foci in a predetermined distance acting as a submicron ruler. In this case it it no longer necessary to have prior knowledge about the size and shape of the confocal volume. Maintaining the information about the photon's origin, the dual focus data allows a precise calculation of absolute diffusion coefficients.

Biomedical Optics and 3-D Imaging, 2010

ABSTRACT