Christoph Hauri | Paul Scherrer Institute (original) (raw)
Papers by Christoph Hauri
Conference on Lasers and Electro-Optics 2010, 2010
ABSTRACT We demonstrate an ultrastable high-power laser system providing transform-limited 20-to-... more ABSTRACT We demonstrate an ultrastable high-power laser system providing transform-limited 20-to-100 fs pulses at a tunable central wavelength. Subsequent frequency-conversion provides wavelength-tunable second and third harmonic radiation with up to 3.7 mJ.
Optics Express, 2015
Intense ultrashort pulse lasers are used for fs resolution pump-probe experiments more and more a... more Intense ultrashort pulse lasers are used for fs resolution pump-probe experiments more and more at large scale facilities, such as free electron lasers (FEL). Measurement of the arrival time of the laser pulses and stabilization to the machine or other sub-systems on the target, is crucial for high time-resolution measurements. In this work we report on a single shot, spectrally resolved, non-collinear cross-correlator with sub-fs resolution. With a feedback applied we keep the output of the TW class Ti:sapphire amplifier chain in time with the seed oscillator to ~3 fs RMS level for several hours. This is well below the typical pulse duration used at FELs and supports fs resolution pump-probe experiments. Short term jitter and long term timing drift measurements are presented. Applicability to other wavelengths and integration into the timing infrastructure of the FEL are also covered to show the full potential of the device.
New Journal of Physics, 2016
Nature communications, 2015
Photoinduced electron transitions can lead to significant changes of the macroscopic electronic p... more Photoinduced electron transitions can lead to significant changes of the macroscopic electronic properties in semiconductors. This principle is responsible for the detection of light with charge-coupled devices. Their spectral sensitivity is limited by the semiconductor bandgap which has restricted their visualization capabilities to the optical, ultraviolet, and X-ray regimes. The absence of an imaging device in the low frequency terahertz range has severely hampered the advance of terahertz imaging applications in the past. Here we introduce a high-performing imaging concept to the terahertz range. On the basis of a silicon charge-coupled device we visualize 5-13 THz radiation with photon energy under 2% of the sensor's band-gap energy. The unprecedented small pitch and large number of pixels allow the visualization of complex terahertz radiation patterns in real time and with high spatial detail. This advance will have a great impact on a wide range of terahertz imaging disci...
Broadband amplification without gain-narrowing is demonstrated with 12-fs oscillator pulses and w... more Broadband amplification without gain-narrowing is demonstrated with 12-fs oscillator pulses and with ultrabroadband hollow fiber spectra (650-900 nm). This scheme shows excellent capabilities for spectral shaping of few-cycle pulses important for coherent control and attosecond science.
The wavefront of an ultrabroadband (12.8-fs) pulse is shown to be wavelength dependent and varies... more The wavefront of an ultrabroadband (12.8-fs) pulse is shown to be wavelength dependent and varies at least within half a wavelength. Pressure dependent aberrations after a gas-filled capillary vary over one third of a wavelength
Physical Review Letters, 2014
We report on compact and efficient laser-based THz generation in the terahertz frequency gap (1-1... more We report on compact and efficient laser-based THz generation in the terahertz frequency gap (1-10 THz). The radiation is generated by optical rectification of a midinfrared laser in a large-size, partitioned nonlinear organic crystal assembly. This enables up-scaling of presently field-limited tabletop THz sources to GV=m electric and several tesla magnetic field at millijoule pulse energy. In agreement with simulations, the THz beam properties at focus are shown to be not deteriorated by the discontinuity of the emitter surface. The high laser-to-THz energy conversion efficiency exceeds the Manley-Rowe limit and is explained by a cascaded χ ð2Þ process in the organic crystals accompanied by a significant redshift of the pump spectrum. The scheme provides a compact, tabletop THz source for single-cycle transients at field strength equivalent or even higher to linear accelerator and FEL-based THz sources. This opens an avenue toward novel nonlinear THz applications.
CLEO: 2014, 2014
ABSTRACT We demonstrate highly efficient Terahertz production and absolute phase control in the h... more ABSTRACT We demonstrate highly efficient Terahertz production and absolute phase control in the hardly accessible THz frequency gap by optical rectification in organic crystals leading to single-cycle field oscillations beyond 150 MV/m and 0.5 Tesla.
2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC, 2013
ABSTRACT form only given. Femtosecond pulses in the short-wavelength infrared spectral range (1-2... more ABSTRACT form only given. Femtosecond pulses in the short-wavelength infrared spectral range (1-2.5 μm) are nowadays available from commercial optical parametric amplifiers (OPA). Further spectral broadening and compression of these pulses potentially leads to table-top, few-cycle pulse laser sources. The full temporal characterization of these sources is important for most applications. In this work, we present a measurement device based on Self-Referenced Spectral Interferometry (SRSI) [1] that uses Cross-Polarized Wave Generation (XPW) [2] as a temporal nonlinear filter. The device is capable of single shot temporal measurement and spectral phase characterization of femtosecond pulses down to a few optical cycles in the 1-2.5 μm spectral range.Figure 1 shows single-shot SRSI measurements of sub-50 fs pulses at 1400 nm (a), 1700 nm (c) and 1950 nm (d) [3]. After nonlinear spectral broadening by filamentation in Xenon and correction of the residual group delay dispersion, 2.5 cycle pulses at 1600 nm have been generated and successfully characterized with our device (Fig. 1, b). As a consistency check, we verified that the XPW spectrum (Fig. 1, dashed blue line) is broader and the FL duration shorter than those of the pulse to be measured (Fig. 1, insets). These results show the excellent capability of the SRSI device to perform accurate single-shot characterization of nearly bandwidth limited pulses over the full 1.2-2.5 μm spectral range. Moreover, the presented setup could be directly used for characterization of broadband pulses in the 1-5 μm spectral range provided that a suitable high-resolution spectrometer is available making it a very simple and yet powerful diagnostic tool.
CLEO:2011 - Laser Applications to Photonic Applications, 2011
ABSTRACT ऀð Abstract: ऀð We ऀð present ऀð efficient ऀð and ऀð broadband ऀð sum ऀð frequency ऀð ge... more ABSTRACT ऀð Abstract: ऀð We ऀð present ऀð efficient ऀð and ऀð broadband ऀð sum ऀð frequency ऀð generation ऀð tenfold ऀð beyond ऀð nonlinear ऀð crystal's ऀð acceptance ऀð bandwidth. ऀð Versatile ऀð shapes, ऀð up ऀð to ऀð 4nm ऀð bandwidth ऀð and ऀð 15% ऀð efficiency ऀð have ऀð been ऀð achieved ऀð for ऀð ps ऀð flattop ऀð UV ऀð pulse ऀð generation . ऀð ऀð ©2010 ऀð Optical ऀð Society ऀð of ऀð America ऀð ऀð OCIS ऀð codes: ऀð 190.0190; ऀð 320.5540. ऀð ऀð
In Terahertz (THz) technology, one of the long-standing challenges has been the formation of inte... more In Terahertz (THz) technology, one of the long-standing challenges has been the formation of intense pulses covering the hard-to-access frequency range of 1-15 THz (so-called THz gap). This frequency band, lying between the electronically (<1 THz) and optically (>15 THz) accessible spectrum hosts a series of important collective modes and molecular fingerprints which cannot be fully accessed by present THz sources. While present high-energy THz sources are limited to 0.1-4 THz the accessibility to the entire THz gap with intense THz pulses would substantially broaden THz applications like live cell imaging at higher-resolution, cancer diagnosis, resonant and non-resonant control over matter and light, strong-field induced catalytic reactions, formation of field-induced transient states and contact-free detection of explosives. Here we present a new, all-in-one solution for producing and tailoring extremely powerful supercontinuum THz pulses with a stable absolute phase and cov...
2008 Conference on Lasers and Electro-Optics, 2008
In our recent experiment we successfully generated forward-directed THz emission by 40-cm-long fi... more In our recent experiment we successfully generated forward-directed THz emission by 40-cm-long filamentation of an intense 0.8 mJ, 30-fs laser pulse in argon at 3 kHz repetition rate. We demonstrated that a specific filament pattern with two sequential focusing-...
2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC, 2013
ABSTRACT Single-cycle THz pulses with electric field strength of MV/cm are required for wide rang... more ABSTRACT Single-cycle THz pulses with electric field strength of MV/cm are required for wide range of applications from physics to biology and medicine [1]. Presently, high fields are still challenging to produce in the THz gap (0.1-10 THz) where important condensed matter resonances are expected (i.e. magnons, phonons, electromagnons). We present our latest results on the generation of 1.5 MV/cm electric field in this frequency range. Broadband THz pulse are achieved by optical rectification (OR) in large organic crystals such as DAST, OH1 and DSTMS [2-4]. These materials present an OR susceptibility one order of magnitude larger than the room-temperature inorganic nonlinear crystals. The THz radiation is phase-matched with IR pump allowing for photon conversion larger than 200% and pulse energy of tens of μJ. The beam can be focused to nearly diffraction-limit for the realization of the highest field. For 0.5 mm thick DSTMS, electric field larger than 1.5 MV/cm is achieved in 350 μm FWHM spot. The electro-optical sampling trace, the corresponding 5-octave spectrum (0.15-5 THz) and the THz focus are shown in Fig. 1. Fields of the 1 MV/cm are obtained also in DAST and OH1. We show that proper dispersive materials can be used to control absolute phase of the THz transient without significant losses.
Conference on Lasers and Electro-Optics 2010, 2010
ABSTRACT We demonstrate an ultrastable high-power laser system providing transform-limited 20-to-... more ABSTRACT We demonstrate an ultrastable high-power laser system providing transform-limited 20-to-100 fs pulses at a tunable central wavelength. Subsequent frequency-conversion provides wavelength-tunable second and third harmonic radiation with up to 3.7 mJ.
Conference on Lasers and Electro-Optics 2010, 2010
ABSTRACT We demonstrate arbitrary shaped UV picosecond pulses with energies up to 50 μJ at 272 nm... more ABSTRACT We demonstrate arbitrary shaped UV picosecond pulses with energies up to 50 μJ at 272 nm. Temporal shaping is performed by a UV AOPDF allowing direct amplitude and spectral phase control.
Optics express, 2014
The accurate measurement of the arrival time of a hard X-ray free electron laser (FEL) pulse with... more The accurate measurement of the arrival time of a hard X-ray free electron laser (FEL) pulse with respect to a laser is of utmost importance for pump-probe experiments proposed or carried out at FEL facilities around the world. This manuscript presents the latest device to meet this challenge, a THz streak camera using Xe gas clusters, capable of pulse arrival time measurements with an estimated accuracy of several femtoseconds. An experiment performed at SACLA demonstrates the performance of the device at photon energies between 5 and 10 keV with variable photon beam parameters.
Advanced Solid-State Lasers Congress, 2013
Demonstration of an acousto-optic filter based infrared spectrometer featuring a 5 cm -1 resoluti... more Demonstration of an acousto-optic filter based infrared spectrometer featuring a 5 cm -1 resolution over more than 2 octaves (1 to 5 µm) is reported.
Scientific Reports, 2015
The intensity of a nonlinear terahertz (THz) source is primarily given by its spectral density. I... more The intensity of a nonlinear terahertz (THz) source is primarily given by its spectral density. In this letter, we introduce triangular Selinium (Se) as a novel THz emitter and show numerically its superior properties to the currently used crystals for intense THz generation. The excellent phase matching enables the applicability of elongated Se crystals which results in very high spectral flatness and broad THz bandwidth (0.5-3.5 THz), high conversion efficiency and THz pulse energy.The spectral THz density produced by optical rectification in Selenium exceeds those from contemporary crystal-based THz sources.
Conference on Lasers and Electro-Optics 2010, 2010
ABSTRACT We demonstrate an ultrastable high-power laser system providing transform-limited 20-to-... more ABSTRACT We demonstrate an ultrastable high-power laser system providing transform-limited 20-to-100 fs pulses at a tunable central wavelength. Subsequent frequency-conversion provides wavelength-tunable second and third harmonic radiation with up to 3.7 mJ.
Optics Express, 2015
Intense ultrashort pulse lasers are used for fs resolution pump-probe experiments more and more a... more Intense ultrashort pulse lasers are used for fs resolution pump-probe experiments more and more at large scale facilities, such as free electron lasers (FEL). Measurement of the arrival time of the laser pulses and stabilization to the machine or other sub-systems on the target, is crucial for high time-resolution measurements. In this work we report on a single shot, spectrally resolved, non-collinear cross-correlator with sub-fs resolution. With a feedback applied we keep the output of the TW class Ti:sapphire amplifier chain in time with the seed oscillator to ~3 fs RMS level for several hours. This is well below the typical pulse duration used at FELs and supports fs resolution pump-probe experiments. Short term jitter and long term timing drift measurements are presented. Applicability to other wavelengths and integration into the timing infrastructure of the FEL are also covered to show the full potential of the device.
New Journal of Physics, 2016
Nature communications, 2015
Photoinduced electron transitions can lead to significant changes of the macroscopic electronic p... more Photoinduced electron transitions can lead to significant changes of the macroscopic electronic properties in semiconductors. This principle is responsible for the detection of light with charge-coupled devices. Their spectral sensitivity is limited by the semiconductor bandgap which has restricted their visualization capabilities to the optical, ultraviolet, and X-ray regimes. The absence of an imaging device in the low frequency terahertz range has severely hampered the advance of terahertz imaging applications in the past. Here we introduce a high-performing imaging concept to the terahertz range. On the basis of a silicon charge-coupled device we visualize 5-13 THz radiation with photon energy under 2% of the sensor's band-gap energy. The unprecedented small pitch and large number of pixels allow the visualization of complex terahertz radiation patterns in real time and with high spatial detail. This advance will have a great impact on a wide range of terahertz imaging disci...
Broadband amplification without gain-narrowing is demonstrated with 12-fs oscillator pulses and w... more Broadband amplification without gain-narrowing is demonstrated with 12-fs oscillator pulses and with ultrabroadband hollow fiber spectra (650-900 nm). This scheme shows excellent capabilities for spectral shaping of few-cycle pulses important for coherent control and attosecond science.
The wavefront of an ultrabroadband (12.8-fs) pulse is shown to be wavelength dependent and varies... more The wavefront of an ultrabroadband (12.8-fs) pulse is shown to be wavelength dependent and varies at least within half a wavelength. Pressure dependent aberrations after a gas-filled capillary vary over one third of a wavelength
Physical Review Letters, 2014
We report on compact and efficient laser-based THz generation in the terahertz frequency gap (1-1... more We report on compact and efficient laser-based THz generation in the terahertz frequency gap (1-10 THz). The radiation is generated by optical rectification of a midinfrared laser in a large-size, partitioned nonlinear organic crystal assembly. This enables up-scaling of presently field-limited tabletop THz sources to GV=m electric and several tesla magnetic field at millijoule pulse energy. In agreement with simulations, the THz beam properties at focus are shown to be not deteriorated by the discontinuity of the emitter surface. The high laser-to-THz energy conversion efficiency exceeds the Manley-Rowe limit and is explained by a cascaded χ ð2Þ process in the organic crystals accompanied by a significant redshift of the pump spectrum. The scheme provides a compact, tabletop THz source for single-cycle transients at field strength equivalent or even higher to linear accelerator and FEL-based THz sources. This opens an avenue toward novel nonlinear THz applications.
CLEO: 2014, 2014
ABSTRACT We demonstrate highly efficient Terahertz production and absolute phase control in the h... more ABSTRACT We demonstrate highly efficient Terahertz production and absolute phase control in the hardly accessible THz frequency gap by optical rectification in organic crystals leading to single-cycle field oscillations beyond 150 MV/m and 0.5 Tesla.
2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC, 2013
ABSTRACT form only given. Femtosecond pulses in the short-wavelength infrared spectral range (1-2... more ABSTRACT form only given. Femtosecond pulses in the short-wavelength infrared spectral range (1-2.5 μm) are nowadays available from commercial optical parametric amplifiers (OPA). Further spectral broadening and compression of these pulses potentially leads to table-top, few-cycle pulse laser sources. The full temporal characterization of these sources is important for most applications. In this work, we present a measurement device based on Self-Referenced Spectral Interferometry (SRSI) [1] that uses Cross-Polarized Wave Generation (XPW) [2] as a temporal nonlinear filter. The device is capable of single shot temporal measurement and spectral phase characterization of femtosecond pulses down to a few optical cycles in the 1-2.5 μm spectral range.Figure 1 shows single-shot SRSI measurements of sub-50 fs pulses at 1400 nm (a), 1700 nm (c) and 1950 nm (d) [3]. After nonlinear spectral broadening by filamentation in Xenon and correction of the residual group delay dispersion, 2.5 cycle pulses at 1600 nm have been generated and successfully characterized with our device (Fig. 1, b). As a consistency check, we verified that the XPW spectrum (Fig. 1, dashed blue line) is broader and the FL duration shorter than those of the pulse to be measured (Fig. 1, insets). These results show the excellent capability of the SRSI device to perform accurate single-shot characterization of nearly bandwidth limited pulses over the full 1.2-2.5 μm spectral range. Moreover, the presented setup could be directly used for characterization of broadband pulses in the 1-5 μm spectral range provided that a suitable high-resolution spectrometer is available making it a very simple and yet powerful diagnostic tool.
CLEO:2011 - Laser Applications to Photonic Applications, 2011
ABSTRACT ऀð Abstract: ऀð We ऀð present ऀð efficient ऀð and ऀð broadband ऀð sum ऀð frequency ऀð ge... more ABSTRACT ऀð Abstract: ऀð We ऀð present ऀð efficient ऀð and ऀð broadband ऀð sum ऀð frequency ऀð generation ऀð tenfold ऀð beyond ऀð nonlinear ऀð crystal's ऀð acceptance ऀð bandwidth. ऀð Versatile ऀð shapes, ऀð up ऀð to ऀð 4nm ऀð bandwidth ऀð and ऀð 15% ऀð efficiency ऀð have ऀð been ऀð achieved ऀð for ऀð ps ऀð flattop ऀð UV ऀð pulse ऀð generation . ऀð ऀð ©2010 ऀð Optical ऀð Society ऀð of ऀð America ऀð ऀð OCIS ऀð codes: ऀð 190.0190; ऀð 320.5540. ऀð ऀð
In Terahertz (THz) technology, one of the long-standing challenges has been the formation of inte... more In Terahertz (THz) technology, one of the long-standing challenges has been the formation of intense pulses covering the hard-to-access frequency range of 1-15 THz (so-called THz gap). This frequency band, lying between the electronically (<1 THz) and optically (>15 THz) accessible spectrum hosts a series of important collective modes and molecular fingerprints which cannot be fully accessed by present THz sources. While present high-energy THz sources are limited to 0.1-4 THz the accessibility to the entire THz gap with intense THz pulses would substantially broaden THz applications like live cell imaging at higher-resolution, cancer diagnosis, resonant and non-resonant control over matter and light, strong-field induced catalytic reactions, formation of field-induced transient states and contact-free detection of explosives. Here we present a new, all-in-one solution for producing and tailoring extremely powerful supercontinuum THz pulses with a stable absolute phase and cov...
2008 Conference on Lasers and Electro-Optics, 2008
In our recent experiment we successfully generated forward-directed THz emission by 40-cm-long fi... more In our recent experiment we successfully generated forward-directed THz emission by 40-cm-long filamentation of an intense 0.8 mJ, 30-fs laser pulse in argon at 3 kHz repetition rate. We demonstrated that a specific filament pattern with two sequential focusing-...
2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC, 2013
ABSTRACT Single-cycle THz pulses with electric field strength of MV/cm are required for wide rang... more ABSTRACT Single-cycle THz pulses with electric field strength of MV/cm are required for wide range of applications from physics to biology and medicine [1]. Presently, high fields are still challenging to produce in the THz gap (0.1-10 THz) where important condensed matter resonances are expected (i.e. magnons, phonons, electromagnons). We present our latest results on the generation of 1.5 MV/cm electric field in this frequency range. Broadband THz pulse are achieved by optical rectification (OR) in large organic crystals such as DAST, OH1 and DSTMS [2-4]. These materials present an OR susceptibility one order of magnitude larger than the room-temperature inorganic nonlinear crystals. The THz radiation is phase-matched with IR pump allowing for photon conversion larger than 200% and pulse energy of tens of μJ. The beam can be focused to nearly diffraction-limit for the realization of the highest field. For 0.5 mm thick DSTMS, electric field larger than 1.5 MV/cm is achieved in 350 μm FWHM spot. The electro-optical sampling trace, the corresponding 5-octave spectrum (0.15-5 THz) and the THz focus are shown in Fig. 1. Fields of the 1 MV/cm are obtained also in DAST and OH1. We show that proper dispersive materials can be used to control absolute phase of the THz transient without significant losses.
Conference on Lasers and Electro-Optics 2010, 2010
ABSTRACT We demonstrate an ultrastable high-power laser system providing transform-limited 20-to-... more ABSTRACT We demonstrate an ultrastable high-power laser system providing transform-limited 20-to-100 fs pulses at a tunable central wavelength. Subsequent frequency-conversion provides wavelength-tunable second and third harmonic radiation with up to 3.7 mJ.
Conference on Lasers and Electro-Optics 2010, 2010
ABSTRACT We demonstrate arbitrary shaped UV picosecond pulses with energies up to 50 μJ at 272 nm... more ABSTRACT We demonstrate arbitrary shaped UV picosecond pulses with energies up to 50 μJ at 272 nm. Temporal shaping is performed by a UV AOPDF allowing direct amplitude and spectral phase control.
Optics express, 2014
The accurate measurement of the arrival time of a hard X-ray free electron laser (FEL) pulse with... more The accurate measurement of the arrival time of a hard X-ray free electron laser (FEL) pulse with respect to a laser is of utmost importance for pump-probe experiments proposed or carried out at FEL facilities around the world. This manuscript presents the latest device to meet this challenge, a THz streak camera using Xe gas clusters, capable of pulse arrival time measurements with an estimated accuracy of several femtoseconds. An experiment performed at SACLA demonstrates the performance of the device at photon energies between 5 and 10 keV with variable photon beam parameters.
Advanced Solid-State Lasers Congress, 2013
Demonstration of an acousto-optic filter based infrared spectrometer featuring a 5 cm -1 resoluti... more Demonstration of an acousto-optic filter based infrared spectrometer featuring a 5 cm -1 resolution over more than 2 octaves (1 to 5 µm) is reported.
Scientific Reports, 2015
The intensity of a nonlinear terahertz (THz) source is primarily given by its spectral density. I... more The intensity of a nonlinear terahertz (THz) source is primarily given by its spectral density. In this letter, we introduce triangular Selinium (Se) as a novel THz emitter and show numerically its superior properties to the currently used crystals for intense THz generation. The excellent phase matching enables the applicability of elongated Se crystals which results in very high spectral flatness and broad THz bandwidth (0.5-3.5 THz), high conversion efficiency and THz pulse energy.The spectral THz density produced by optical rectification in Selenium exceeds those from contemporary crystal-based THz sources.