Guenter Steinmeyer

• Professor
• Professor at Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy

Due to their controllable optical path length and flexible adjustment of optical nonlinearity, multipass cells (MPCs) have emerged as an effective platform for investigations of strong-field nonlinear optics with few-cycle pulses. Prior compression schemes frequently employed hollow core fibers. Propagation in these fibers is effectively single tra...

The past two decades have seen rapid development of optical atomic clocks with fractional performance at 10⁻¹⁸ level or even below. Dissemination of optical atomic clocks into microwave domain and their intercomparisons using optical frequency combs as clockwork requires precise measurements of their carrier-envelope offset frequencies (fceo). To t...

Spectrally broad laser radiation from continuous wave (cw) lasers can exhibit second-order autocorrelation traces virtually indistinguishable from those of mode-locked lasers. Consequently, based only on autocorrelations, one might erroneously conclude that a cw laser is mode-locked. This pitfall in interpretation can be avoided by carefully charac...

Optical frequency combs have revolutionized frequency metrology and spectroscopic measurements, enabling the most precise measurements of all physical quantities. However, precision frequency metrology heavily relies on mode‐locked laser combs, which are only directly available for a few selected near‐infrared wavelength ranges. Recently, a strong...

Spectrally broad laser radiation from continuous wave (cw) lasers can exhibit second-order autocorrelation traces virtually indistinguishable from those of mode-locked lasers. Consequently, based only on autocorrelations, one might erroneously conclude that a cw laser is mode-locked. Such misinterpretations can be avoided by carefully characterizin...

Spectrally broad laser radiation from continuous wave (cw) lasers can exhibit second-order autocorrelation traces virtually indistinguishable from those of mode-locked lasers. Consequently, based only on autocorrelations, one might erroneously conclude that a cw laser is mode-locked. Such misinterpretations can be avoided by carefully characterizin...

Recent years have seen a resurgence of interest in multimode fibers due to their intriguing physics and applications, with spatial beam self-cleaning (BSC) having received special attention. In BSC light condenses into the fundamental fiber mode at elevated intensities. Despite extensive efforts utilizing optical thermodynamics to explain such coun...

We present a compact nonlinear compression scheme for the generation of millijoule few-cycle pulses beyond 4 µm wavelength. For this purpose 95 fs pulses at 5 µm from a 1 kHz midwave-IR optical parametric chirped pulse amplifier (OPCPA) are spectrally broadened due to a self-phase modulation in ZnSe. The subsequent compression in a bulk material yi...

We present the results of the photoluminescence behavior reflecting Cr ²⁺ → Fe ²⁺ excitation transfer in co-doped ZnSe:Cr ²⁺ Fe ²⁺ . This transfer can be seen as a possible promising pump mechanism to create short pulse lasers for the 3- to 6- µ m wavelengths that can be excited using inexpensive 2- µ m pump light sources. In addition to the kineti...

Cr2+ - and Fe2+ -doped ZnSe crystals are laser materials with phonon-broadened absorption and emission spectra, which provide broadband laser gain in the 2- to 5-μm wavelength range. While Cr2+:ZnSe can be directly pumped with high-power Er, Ho, or Tm lasers, no such possibility exists for Fe2+:ZnSe. To this end, electronic excitation transfer betw...

Diffraction wavefront errors of large-scale Treacy compressors may induce complex spatio-temporal couplings (CSTCs) in chirped pulse amplification and degrade the quality of the pulsed beam in both near and far fields. This problem is particularly pronounced in petawatt laser facilities that require tiled compressor gratings. Here, to the best of o...

We discuss the origin of residual carrier-envelope phase jitters in passively stabilized laser systems, comparing measured data at 9 different laser systems with a theoretical model. These considerations strongly suggest the Gordon-Haus jitter of the primary oscillator as the reason for the often observed excessive CEP jitters of these systems.

Multipass cells (MPCs) recently emerged as a new femtosecond pulse compression technique for lasers with high pulse energy. While most of the work focused on the compression of near-infrared laser systems so far, we address the case of holmium-based gain materials, which offer an enormous potential in terms of pulse energy, yet can only host a very...

Exploiting a plasmonic resonance, near-perfect grating structures have been reported, with a regularity that exceeds typical commercially available diffraction gratings. Plasmonics can help to produce optical gratings with surprisingly high regularity and writing speed, surpassing mechanically ruled gratings in both aspects.

The transfer of electronic excitations from Cr²⁺ to Fe²⁺ ions in co-doped epitaxially grown ZnSe is studied by time-resolved photoluminescence (PL) spectroscopy with unprecedented sub-10 ns time resolution. Upon excitation of Cr²⁺ ions by a picosecond pulse at 2.05 µm wavelength, PL from Fe²⁺ ions displays a delayed onset and a retarded decay in co...

Efficient all-optical switching is a challenging task as photons are bosons and cannot immediately interact with each other. Consequently, one has to resort to nonlinear optical interactions, with the Kerr gate being the classical example. However, the latter requires strong pulses to switch weaker ones. Numerous approaches have been investigated t...

The synchronization of spatial modes in the formation of multimode solitons can be considered as the transverse analog of mode locking. In this process, the inherent Kerr nonlinearity in the fiber core binds different spatial fiber modes together. However, compared to their temporal counterparts, the binding mechanism in multimode solitons is rathe...

A completely analytical approach is presented that provides deep insight into the pulse formation processes in a hollow fiber compressor by disentangling spatial soliton dynamics.

Multimode nonlinear optics is used to overcome a long-standing limitation of fiber optics, tightly phase locking several spatial modes and enabling the coherent transport of a wave packet through a multimode fiber. A similar problem is encountered in the temporal compression of multimillijoule pulses to few-cycle duration in hollow gas-filled fiber...

Using a discrete mode approach we investigate the intermodal dynamics in a frequency comb with nonlinear coupling due to four-wave mixing. In the presence of sufficient saturable absorption, phase space collapses into a single state, and all modes tightly lock with identical phase. In case of a purely reactive nonlinearity, a less constrained locki...

Handbook of Laser Technology and Applications

Multimode nonlinear optics offers to overcome a long-standing limitation of fiber optics, tightly phase locking several spatial modes and enabling the coherent transport of a wavepacket through a multimode fiber. A similar problem is encountered in the temporal compression of multi-mJ pulses to few-cycle duration in hollow gas-filled fibers. Scalin...

Mathematica code to compute the nonlinear refractive index of noble gases

A pulse-shaper-based method for spectral phase measurement and compression with milliradian precision is proposed and tested experimentally. Measurements of chirp and third-order dispersion are performed and compared to theoretical predictions. The single-digit milliradian accuracy is benchmarked by a group velocity dispersion measurement of fused...

The theoretical framework of the Haus master equation of passive mode-locking is revisited. Reformulating the equation in the frequency domain as coupled ordinary differential equations, the complete set of fundamental soliton solutions is surveyed. For large values of anomalous dispersion, this leads to the well known bell-shaped solutions origina...

The situation of self-compression and concomitant supercontinuum generation in a multipass cell is analyzed in numerical simulations. This study focuses on multipass cells that contain a dielectric slab as nonlinear medium and overcompensate the dispersion of the slab with intracavity dispersive coatings. A 2D+1 unidirectional pulse propagation equ...

The past 30 years have seen spectacular progress in the development of techniques for measuring the complete temporal field, and even the complete spatiotemporal field, of ultrashort laser pulses. The challenge has been to measure a pulse without the use of a shorter event or an independent known reference pulse, neither of which is typically avail...

Controlling the carrier envelope phase (CEP) in mode-locked lasers over practically long timescales is crucial for real-world applications in ultrafast optics and precision metrology. We present a hybrid solution that combines a feed-forward technique to stabilize the phase offset in fast timescales and a feedback technique that addresses slowly va...

Efficient all-optical switching is a challenging task as photons are bosons and cannot immediately interact with each other. Consequently, one has to resort to nonlinear optical interactions, with the Kerr gate being the classical example. However, the latter requires strong pulses to switch weaker ones. Numerous approaches have been investigated t...

Spectral coherence is an important prerequisite for many applications of femtosecond supercontinua, including precision frequency metrology, attosecond science, and high-field physics. These applications often critically depend on measurement of the carrier-envelope phase via $f{-}{2}f$ interferometry. As mode-locked laser sources cannot directly p...

Controlling the carrier envelope phase (CEP) in mode-locked and associated laser systems over practically long timescales is crucial for real-world applications in ultrafast optics and precision metrology. We present a hybrid solution that combines a feed-forward (FF) technique to stabilize the phase offset in fast timescales and a feedback (FB) te...

We experimentally demonstrate how the optical Doppler effect can be exploited to modulate the carrier-envelope frequency of a mode-locked laser without causing detrimental side-effects and without any intervention into the laser.

Amplified spontaneous emission (ASE) causes fluctuations of pulse energy, of the optical phase and of the timing of the pulse intensity envelope in a mode-locked laser or frequency comb. Starting from the assumption of one ASE photon per longitudinal laser mode and roundtrip, we rederive analytic equations for the three fundamental types of quantum...

The coherent artifact hinders accurate inversion of pulse measurements. Here we demonstrate a FROG algorithm to accurately retrieve not only the average pulse shape but also the artifact itself, providing access to the underlying coherence properties.

A new mode-locking mechanism is discussed that solely relies on four-wave mixing and does not require a saturable absorber. This mechanism explains a number of previously reported peculiar findings of self-modelocking and comb formation.

Self-mode-locking of semiconductor lasers has been frequently reported, defying all known solutions of the Haus Master Equation approach. Here we show that four-wave mixing all by itself suffices to mode-lock a laser.

We present carrier-envelope phase stabilization of an Er:Yb:glass laser at 1.55 pm via the feed-forward method with 2.9 as (1 Hz - 3 MHz) timing jitter and continuous stabilization over 24 hours.

We demonstrate a novel algorithm for pulse recovery from FROG traces contaminated with coherent artifacts. It separately retrieves the fields corresponding to the coherent artifact and the average features of unstable pulses from a single trace.

Controlling the CEP in mode-locked lasers over long timescales is crucial for real-world applications. We present a hybrid stabilization system in an Er: Yb:glass mode-locked laser with 75 hours of stabilization and IPN below 14 mrad.

Controlling the CEP in mode-locked lasers over long timescales is crucial for real-world applications. We present a hybrid stabilization system in an Er:Yb:glass mode-locked laser with 75 hours of stabilization and IPN below 14 mrad.

Pulse train instabilities have often given rise to confusion and misinterpretation in ultrafast pulse characterization measurements. Most prominently known as the coherent artifact, a partially mode-locked laser with a non-periodic waveform may still produce an autocorrelation that has often been misinterpreted as indication of a coherent pulse tra...

Few-cycle pulsed laser technology highlights the need for control and stabilization of the carrier-envelope phase (CEP) for applications requiring shot-to-shot timing and phase consistency. This general requirement has been achieved successfully in a number of free–space and fiber lasers via feedback and feed-forward (FF) methods. Expanding on exis...

We investigate the influence of the optical Doppler effect on the carrier-envelope frequency (CEF) of a mode-locked pulse train. The laser pulses are Doppler-shifted in frequency during reflection off a periodically moving mirror that is driven by an electro-dynamical exciter inside an interferometer. Depending on the relative movement of the mirro...

Pulse train instabilities have often given rise to confusion in misinterpretation in ultrafast pulse characterization measurements. Most prominently known as the coherent artifact, a partially mode-locked laser with non-periodic waveform may still produce an autocorrelation that has often been misinterpreted as indication for a coherent pulse train...

Few-cycle pulsed laser technology highlights the need for control and stabilization of the carrier-envelope phase (CEP) for applications requiring shot-to-shot timing and phase consistency. This general requirement has been achieved successfully in a number of free space and fiber lasers via feedback and feed-forward methods. Expanding upon existin...

Established characterization methods for repetitive pulse trains tend to fail in the presence of degraded coherence properties. Partial coherence is present in several pulse generation schemes but is not yet properly addressed in many pulse characterization techniques. Full coherence is a common assumption in most techniques, and failing to detect...

The papers in this special section focus on ultrafast science and technology. This field has seen a big highlight, since the Nobel prize in physics for 2018 was announced in high intensity lasers. The application space integrates state-of-the-art photonics techniques coming from the areas of quantum electronics, lasers, fiber optics and electro-opt...

When confronted with a pulse train whose intensity and/or phase versus time varies from pulse to pulse, multi-shot pulse-measurement techniques usually exhibit a coherent artifact (CA), which substantially complicates the interpretation of the measurement. In frequency-resolved optical gating (FROG), such instabilities are indicated by discrepancie...

A recent publication on arXiv:1905.00668 suggests that the phase relationship within a frequency comb can be reconstructed from a heterodyne measurement using a reference comb. In principle, following this approach, such retrieval of optical phases appears possible, but should give rise to a temporally constant signal. Instead, arXiv:1905.00668 pro...

Introduction of optical gain into the infrared arm of f-to-2 f interferometers is demonstrated to improve signal-to-noise ratios by > 20 dB. This opens a perspective for CEP stabilization of unstabilizable lasers.

Obtaining the temporal shape of an ultrashort laser pulse using the method of dispersion scan entails solving a nonlinear inverse problem, a challenging prospect on its own, yet still aggravated when the pulse shape being measured is temporally varying from pulse to pulse. For this purpose, we use a Differential Evolution (DE) algorithm enhanced by...

The -to- interferometer plays a key role for carrier-envelope phase (CEP) measurement and subsequent stabilization. The CEP measurement typically relies on the application of two optical nonlinearities, namely supercontinuum generation and second-harmonic generation. Then the cascadation of these nonlinearities often leads to signal levels on the o...

We extend the analogy of particle-like behavior of solitons one decisive step further, demonstrating completely Newtonian collisions for unequal solitons, detached from any wave properties. They even act like extended massive objects, exhibiting elastic deformation.

We demonstrate both numerically and experimentally the direct creation of an optical event horizon that arises from the interaction of a solitary optical pulse with a group-velocity matched dispersive wave.

Focusing short CO2 laser pulses into air reveals rich ionization physics that is best explained by solid-state theories and results in centimetre-scale-diameter megafilaments that transport joules of energy.

We demonstrate a dual-beam infrared optical parametric source featuring a noncollinear KTA booster amplifier and straightforward angular dispersion compensation of the idler beam. Through careful beam and pulse characterization, and high-harmonic generation in a crystalline solid, we show that the corrected idler beam is diffraction-limited, astigm...

Few-cycle pulse characterization methods face a serious challenge in providing sufficient signal-to-noise ratios together with superior spectral fidelity, as imposed by phase-matching conditions and linear dispersion effects. Here we investigate the effect of linear dispersion inside the nonlinear medium inherently present in such arrangements. We...

Mode locking of a 1.34 μm vertical external cavity surface emitting laser is demonstrated using a GaSb-based semiconductor saturable absorber mirror (SESAM). The SESAM includes six AlGaSb quantum wells (QWs) with an absorption edge at . The proposed approach has two key benefits: the QWs can be grown lattice matched, and only a small number of Brag...

Broadband characterization of the carrier-envelope phase (CEP) noise spectral density of free-running mode-locked lasers is essential for advanced low-noise optical frequency comb designs. Here we present a direct method that utilizes an optical heterodyne beat between a pair of repetition-rate-locked mode-locked lasers for CEP noise characterizati...

The near-ultraviolet photoluminescence of ZnO nanorods induced by multiphoton absorption of unamplified Ti:sapphire pulses is investigated. Power dependence measurements have been conducted with an adaptation of the ultrashort pulse characterization method of interferometric frequency-resolved optical gating. These measurements enable the separatio...

We experimentally demonstrate the use of subwavelength optical nanoantennas to assist a direct nanoscale ablation using the ultralow fluence of a Ti:sapphire oscillator through the excitation of surface plasmon waves. The mechanism is attributed to nonthermal transient unbonding and electrostatic ablation, which is triggered by the surface plasmon-...

We characterized 4fs pulses of a high-energy Ti:Sa system under vacuum condition by d-scan arrangements using second harmonic generation and cross-polarized wave generation as nonlinearities. Both methods deliver similar temporal shapes and consistent pulse durations.

The concept of intrapulse coherence is defined for judging a fixed phase relation between different spectral components within a laser pulse. This new criterion plays an important role for passive CEP stabilization of OPA systems.

Frequency doubling of an amplified laser is experimentally demonstrated with electric-field induced second-harmonic generation in air. The method promises application with unattenuated terawatt laser and offers wavelength conversion beyond the ultraviolet limit of nonlinear crystals.

We demonstrate pulse retrieval from dispersion-scan and FROG traces using a genetic algorithm. The algorithm is extremely robust even for complex pulse shapes, resilient to noise, and can reliably compensate for spectral efficiency variations.

The intrapulse coherence is introduced as a measure for judging a fixed phase relation between different spectral components within a laser pulse. This new criterion plays an important role for passive CEP stabilization of OPA systems.

We demonstrate frequency-doubling of an amplified femtosecond laser with electric-field induced second-harmonic generation in air. The method promises application with unattenuated terawatt lasers and offers wavelength conversion beyond the ultraviolet limit of nonlinear crystals.

We present a detailed study of all-optical signal amplification that exploits the extreme sensitivity of supercontinuum generation to input power fluctuations. As useful signal amplification relies on determinism and correlation between input and output signals, the question naturally arises whether such conditions can be maintained in the presence...

Rogue waves are rare but extreme events that appear in a multitude of different physical systems. So far, the definition of rogue events has solely relied on anomalous statistical distributions with an elevated heavy tail. Another hallmark of ocean rogue waves is their surprising appearance, which suggests the unpredictability of rogue waves in gen...