Frank W Wise

• Cornell University

This publisher’s note contains a correction to Opt. Lett. 49, 5787 (2024)10.1364/OL.539381.

Soliton formation and soliton self-frequency shift are investigated in a hollow-core fiber filled with N2 gas. With 10-µJ and 80-fs input pulses at 1030 nm, solitons with greater than 500-nJ energy and duration less than 100 fs can be generated between 1090 and 1310 nm. With peak powers above 5 MW, we expect that these pulses will be useful for app...

Three-photon fluorescence microscopy (3PM) has driven rapid progress in deep-tissue imaging beyond the depth limit of two-photon microscopy, with impacts in neuroscience, immunology, and cancer biology. Three-photon excitation places a premium on ultrashort pulses with high peak power in the 1300- and 1700-nm wavelength bands, which allow deepest i...

Noise can play an important role in nonlinear pulse propagation. It is not only the origin of fluctuations in supercontinuum but can also determine the generated signal amplitude and phase, as seen in phenomena such as noise-seeded four-wave mixing and spontaneous Raman scattering. Current models rely on input-pulse shot noise and Raman Langevin te...

Pulse compression based on periodic layered Kerr media has been demonstrated as an effective technique for femtosecond pulses with energies around 100 µJ or more. We report such a compressor designed for pulses in the 10-µJ range, which is valuable for many applications. Pulses from a fiber chirped-pulse amplifier are compressed from 300 fs to as s...

An exciting recent development for deep-tissue imaging with cellular resolution is three-photon fluorescence microscopy (3PM) with excitation at long wavelengths (1300 and 1700 nm). In the last few years, long-wavelength 3PM has driven rapid progress in deep-tissue imaging beyond the depth limit of two-photon microscopy, with impacts in neuroscienc...

Electrocatalytically active titanium oxynitride (TiNO) thin films were fabricated on commercially available titanium metal plates using a pulsed laser deposition (PLD) method for energy storage applications. The elemental composition and nature of bonding were analyzed using x-ray photoelectron spectroscopy (XPS) to reveal the reacting species and...

Raman scattering has found renewed interest owing to the development of gas-filled hollow-core fibers, which constitute a unique platform for exploration of novel ultrafast nonlinear phenomena beyond conventional solid-core-fiber and free-space systems. Much progress has been made through models for particular interaction regimes, which are delinea...

We present an experimental technique for customizing the spatio-spectral speckled intensity statistics of ultra-short optical pulses at the output of a a disordered multimode fiber by controlling the spatial profile of the input light.

We show that regenerative amplification enables a femtosecond fiber amplifier with an unprecedented combination of features: single-mode operation ( M ² ≤ 1.3) despite multimode (100 μm ) fiber, high-gain (> 55 dB), and high pulse energy (> 50 μ J).

We study the evolution of 300-fs pulses at 1030 nm in anti-resonant fiber hollow-core fiber filled with N 2 in the anomalous-dispersion regime. Experimental results are compared to numerical simulations.

We present a two-color and two-pulse approach to femtosecond pulse generation at long-wave-infrared wavelengths in H 2 -filled hollow-core fiber. The technique numerically produces 88-fs pulses at 12 µm with 48 % quantum efficiency.

We present a theory of Raman scattering in gas-filled hollow-core fiber, connecting different temporal regimes. The theory provides new insights into Raman gain and Raman-induced index changes, and strategies on frequency conversion.

The peak power performance of ultrafast fiber lasers scales with fiber mode area, but large fibers host multiple modes that are difficult to control. We demonstrate a technique for single-mode operation of highly multimode fiber based on regenerative amplification. This results in a short-pulse fiber source with, to our knowledge, an unprecedented...

Speckle patterns are used in a broad range of applications including microscopy, imaging, and light–matter interactions. Tailoring speckles’ statistics can dramatically enhance their performance in applications. We present an experimental technique for customizing the spatio-spectral speckled intensity statistics of optical pulses at the output of...

The nonlinear propagation of picosecond or femtosecond optical pulses in multimode fiber amplifiers underlies a variety of intriguing physical phenomena as well as the potential for scaling sources of ultrashort pulses to higher powers. However, existing theoretical models of ultrashort-pulse amplification do not include some critical processes, an...

We report the generation of multimode solitons in step-index fibers. The solitons are superpositions of 5–10 temporally aligned transverse modes, they exhibit speckled beam profiles, and the spatio-spectral variation across the soliton can be complex. A greater understanding of multimode solitons should create a foundation for further research into...

Speckle patterns are used in a broad range of applications including microscopy, imaging, and light-matter interactions. Tailoring speckles' statistics can dramatically enhance their performance in applications. We present an experimental technique for customizing the spatio-spectral speckled intensity statistics of optical pulses at the output of...

Spatiotemporal sculpturing of light pulse with ultimately sophisticated structures represents a major goal of the everlasting pursue of ultra-fast information transmission and processing as well as ultra-intense energy concentration and extraction. It also holds the key to unlock new extraordinary fundamental physical effects. Traditionally, spatio...

The nonlinear propagation of picosecond or femtosecond optical pulses in multimode fiber amplifiers underlies a variety of intriguing physical phenomena as well as the potential for scaling sources of ultrashort pulses to higher powers. However, existing theoretical models of ultrashort-pulse amplification do not include some critical processes, an...

The nonlinear propagation of picosecond or femtosecond optical pulses in multimode fiber amplifiers underlies a variety of intriguing physical phenomena as well as the potential for scaling sources of ultrashort pulses to higher powers. However, existing theoretical models of ultrashort-pulse amplification do not include some critical processes, an...

Citation: Sarkar, K.; Jordan, M.; Kebede, A.; Kriske, S.; Wise, F.; Kumar, D. Enhanced Magnetic Cooling through Tailoring the Size-Dependent Magnetocaloric Effect of Iron Nanoparticles Embedded in Titanium Nitride Thin Films. Magnetochemistry 2023, 9, 188. Abstract: The magnetocaloric effect (MCE) in iron (Fe) nanoparticles incorporated within a ti...

We report the generation of multimode solitons in step-index fiber. The solitons are superpositions of 5-10 temporally-aligned transverse modes, they exhibit speckled beam profiles, and the spatio-spectral variation across the soliton can be complex. Greater understanding of multimode solitons should create a foundation for further research into co...

Nonlinear optical microscopy (NOM) has been widely adopted in neural imaging in vivo for its advantages in deep penetration, three‐dimensional resolution, and low phototoxicity, etc. However, it relies on femtosecond laser sources for signal excitation, which are complex and bulky for conventional solid‐state ultrafast lasers. Alternatively, the de...

Kerr beam cleaning is a nonlinear phenomenon in graded-index multimode fiber where power flows toward the fundamental mode, generating bell-shaped output beams. Here we study beam cleaning of femtosecond pulses accompanied by gain in a multimode fiber amplifier. Mode-resolved energy measurements and numerical simulations showed that the amplifier g...

Two-photon excited fluorescence microscopy is a widely-employed imaging technique that enables the noninvasive study of biological specimens in three dimensions with sub-micrometer resolution. Here, we report an assessment of a gain-managed nonlinear (GMN) fiber amplifier for multiphoton microscopy. This recently-developed source delivers 58-nJ and...

Femtosecond long-wave-infrared (LWIR) pulses have found applications in several fields, but their generation is limited to ${{\rm CO}_2}$ lasers and solid-state frequency converters. Waveguide-based Raman red shifting provides another promising solution to efficiently generate LWIR pulses. Here, we numerically study LWIR pulse generation in a hydro...

Epitaxial titanium nitride (TiN) and titanium oxynitride (TiON) thin films have been grown on sapphire substrates using a pulsed laser deposition (PLD) method in high-vacuum conditions (base pressure <3 × 10-6 T). This vacuum contains enough residual oxygen to allow a time-independent gas phase oxidation of the ablated species as well as a time-dep...

We study beam cleaning of femtosecond pulses induced by gain in a Graded-Index Multimode Fiber Amplifier. Mode-resolved energy measurements show that beam cleaning results in high fundamental mode content (~ 50% of the pulse energy).

Spatiotemporal sculpturing of light pulse with ultimately sophisticated structures represents the holy grail of the human everlasting pursue of ultrafast information transmission and processing as well as ultra-intense energy concentration and extraction. It also holds the key to unlock new extraordinary fundamental physical effects. Traditionally,...

Linear multimode optical systems have enabled clean experimental observations and the applications of numerous phenomena that continually extend the boundaries of wave physics. The infrastructure that has enabled these studies facilitates the study of an even richer world of nonlinear multimode optical systems. Multimode nonlinear optical physics i...

Spatiotemporal mode-locking in a laser with anomalous dispersion is investigated. Mode-locked states with varying modal content can be observed, but we find it difficult to observe highly-multimode states. We describe the properties of these mode-locked states and compare them to the results of numerical simulations. Prospects for the generation of...

Spatiotemporal mode-locking in a laser with anomalous dispersion is investigated. Mode-locked states with varying modal content can be observed, but we find it difficult to observe highly multimode states. We describe the properties of these mode-locked states and compare them to the results of numerical simulations. Prospects for the generation of...

The overall goal of photonics research is to understand and control light in new and richer ways to facilitate new and richer applications. Many major developments to this end have relied on nonlinear optical techniques, such as lasing, mode-locking, and parametric downconversion, to enable applications based on the interactions of coherent light w...

Nonlinear multimode optical systems support a host of intriguing effects that are impossible in single-mode settings. Although nonlinearity can provide a rich environment where the chaotic power exchange among thousands of modes can lead to novel behaviours, understanding and harnessing these processes to our advantage is challenging. Over the year...

Recent years have witnessed a resurgence of interest in nonlinear multimode optical systems where a host of intriguing effects have been observed that are impossible in single-mode settings. While nonlinearity can provide a rich environment where the chaotic power exchange among thousands of modes can lead to novel behaviors, at the same time, it p...

Mamyshev oscillators produce high-performance pulses, but technical and practical issues render them unsuitable for widespread use. Here we present a Mamyshev oscillator with several key design features that enable self-starting operation and unprecedented performance and simplicity from an all-fiber laser. The laser generates 110 nJ pulses that co...

We demonstrate an optical parametric chirped-pulse amplifier (OPCPA) that uses birefringence phase matching in a step-index single-mode optical fiber. The OPCPA is pumped with chirped pulses that can be compressed to sub-30-fs duration. The signal (idler) pulses are generated at 905 nm (1270 nm), have 26 nJ (20 nJ) pulse energy, and are compressibl...

We report a study of soliton self-frequency shifting in a hydrogen-filled hollow-core fiber. The combination of hydrogen and short 40-fs input pulses underlies clean and efficient generation of Raman solitons between 1080 and 1600 nm. With 240-nJ input pulses, the Raman soliton energy ranges from 110 to 20 nJ over that wavelength range, and the pul...

Spatiotemporal mode-locking (STML) is demonstrated in a Mamyshev Oscillator. We observe a variety of STML states with different degrees of spatiotemporal coupling. The design allows some control over the multimode output beam profile.

Spatiotemporal mode-locking in a laser with anomalous dispersion is observed. Experimental results are compared to numerical simulation, which show strong temporal breathing.

We present an all-fiber Mamyshev oscillator that generates 40 fs and 80 nJ pulses. The resulting 1.5-MW peak power is 20 times higher than that of prior all-fiber and self-starting lasers.

We present a spatiotemporally mode-locked Mamyshev oscillator. A wide variety of multimode mode-locked states, with varying degrees of spatiotemporal coupling, are observed. We find that some control of the modal content of the output beam is possible through the cavity design. Comparison of simulations with experiments indicates that spatiotempora...

We report a study of soliton self-frequency shifting in hydrogen-filled hollow-core fiber. The combination of hydrogen and short 40-fs input pulses underlies clean and efficient generation of Raman solitons between 1080 and 1600 nm. With 240-nJ input pulses, the Raman soliton energy ranges from 110 to 20 nJ over that wavelength range, and the pulse...

We present a spatiotemporally mode-locked Mamyshev oscillator. A wide variety of multimode mode-locked states, with varying degrees of spatiotemporal coupling, are observed. We find that some control of the modal content of the output beam is possible through the cavity design. Comparison of simulations to experiments indicates that spatiotemporal...

Kerr beam cleaning in graded-index multimode fiber has been investigated in experiments with sub-nanosecond pulses and in experiments with femtosecond pulses at wavelengths where the dispersion is normal. We report a theoretical and experimental study of this effect with femtosecond pulses and anomalous dispersion. In this regime, only weak beam cl...

Advancements in computational capabilities along with the possibility of accessing high power levels have stimulated a reconsideration of multimode fibers. Multimode fibers are nowadays intensely pursued in terms of addressing longstanding issues related to information bandwidth and implementing new classes of high-power laser sources. In addition,...

Serial synchrotron crystallography (SSX) is enabling the efficient use of small crystals for structure–function studies of biomolecules and for drug discovery. An integrated SSX system has been developed comprising ultralow background-scatter sample holders suitable for room and cryogenic temperature crystallographic data collection, a sample-loadi...

Two-photon fluorescence microscopy is a nonlinear imaging modality frequently used in deep-tissue imaging applications. A tunable-wavelength multicolor short-pulse source is usually required to excite fluorophores with a wide range of excitation wavelengths. This need is most typically met by solid-state lasers, which are bulky, expensive, and comp...

Mamyshev oscillators can generate high-power femtosecond pulses, but starting a mode-locked state has remained a major challenge due to the suppression of continuous-wave lasing. Here, we study the starting dynamics of a linear Mamyshev oscillator designed to generate high-power femtosecond pulses while avoiding component damage. Reliable starting...

We review the recent advances in fiber-based sources of ultrashort pulses based on the gain-managed nonlinear regime. We discuss how highly nonlinear pulse evolution can be exploited to overcome typical limits of fiber-based sources.

We present a ring-type Mamyshev oscillator with only one amplification stage. The design allows self-starting via modulation of the pump power, high pulse performance, and is suitable for all-fiber integration.

Unexpected multimode solitary waves can be formed spontaneously in hollow-core fibres, hinting at a vast world of exciting nonlinear optics, with applications for generating few-cycle, ultra-intense pulses.

We start an environmentally-stable linear Mamyshev oscillator with electronically-controlled modulated pump and a moving filter. It delivers a 21-nJ pulse that becomes 65 fs in duration after a compressor. Reliable starting into stable mode-locking is found achievable with a modulated mode-locked state observed only when the modulation frequency is...

We demonstrate numerically and experimentally a gain-managed nonlinear amplifier with a large mode area fiber. The amplifier delivers 1.2 µJ and sub-40 fs pulses with the spectrum spanning from ${\sim}{{1000}}$ to ${\sim}{{1180}}\;{\rm{nm}}$ . We show that longitudinal gain-loss evolution plays an essential role in pulse formation by comparing simu...

We theoretically investigate methods of controlling pulse generation in normal-dispersion fiber optical parametric chirped-pulse amplifiers. We focus on high-energy, ultrashort pulses at wavelengths widely separated from those of the pump, and find that within this regime, a number of simple properties describe the essential phase and gain dynamics...

Mode-locking is a process in which different modes of an optical resonator establish stable synchronization through non-linear interactions. This self-organization underlies light sources that enable many modern scientific applications, such as ultrafast and high-field optics and frequency combs. Despite this, mode-locking has almost exclusively re...

We investigate the starting dynamics of an environmentally-stable linear Mamyshev oscillator that is started by modulation of the pump power. A moving filter is implemented to generate 21-nJ and 65-fs pulses.

We experimentally investigate a recently-proposed thermodynamic theory of highly multimode nonlinear optical systems. Mode-resolved measurements demonstrate thermalization of the distribution via the Kerr nonlinearity in multimode optical fiber.

We demonstrate a synchronously-pumped Raman oscillator that generates a 48 nJ Stokes pulse at 1200 nm and a 43 nJ pulse at 1080 nm, extending the spectral range of conventional ytterbium-doped silica fiber-based ultrafast sources.

We report observation of optical thermalization in ultrashort pulse propagation in the normal dispersion regime. Mode-resolved measurements provide direct evidence of thermalization of mode occupancies via the Kerr nonlinearity in a multimode fiber.

We uncover the mechanisms behind a range of new 3D solitons in multimode lasers using an approach called attractor dissection. Experimental measurements allow us to decompose multimode states containing up to 30 million locked modes.

Beam cleanup in multimode optical fiber is investigated with femtosecond pulses and anomalous dispersion. Beam cleaning is accompanied by dramatic temporal pulse compression.

We demonstrate a gain-managed nonlinear amplifier with large mode area fiber. The amplifier delivers 1.2-µJ and sub-40 fs pulses. We show that longitudinal gain-loss evolution plays an essential role in pulse formation.

Mode-locking is a process in which different modes of an optical resonator establish, through nonlinear interactions, stable synchronization. This self-organization underlies light sources that enable many modern scientific applications, such as ultrafast and high-field optics and frequency combs. Despite this, mode-locking has almost exclusively r...

Ultrafast lasers are becoming increasingly widespread in science and industry alike. Fiber-based ultrafast laser sources are especially attractive because of their compactness, alignment-free setups, and potentially low cost. However, confining short pulses within a fiber core leads to high intensities, which drives a host of nonlinear effects. Whi...

Ultrafast lasers are becoming increasingly widespread in science and industry alike. Fiber-based ultrafast laser sources are especially attractive because of their compactness, alignment-free setups, and potentially low costs. However, confining short pulses within a fiber core leads to high intensities, which drive a host of nonlinear effects. Whi...

Multimode optical fibers have recently reemerged as a viable platform for addressing a number of long-standing issues associated with information bandwidth requirements and power-handling capabilities. As shown in recent studies, the complex nature of such heavily multimoded systems can be effectively exploited to observe altogether novel physical...

We investigated the possibility of reaching nanojoule-level pulse energies in a femtosecond erbium-doped fiber Mamyshev oscillator. In experiments, lasers generate stable pulse trains with energy up to 31.3 nJ, which is comparable to the highest achieved by prior ultrafast erbium fiber lasers. The pulse duration after a grating compressor is around...

We provide a systematic analysis of geometric parametric instabilities in nonlinear graded-index multimode fibers. Our approach implicitly accounts for self-focusing effects and considers dispersion processes to all orders. It is shown that the resulting parametric problem takes the form of a Hill's equation that can be systematically addressed usi...

Recent progress in scaling the peak power of femtosecond-pulse fiber oscillators will be reviewed. So-called Mamysehv oscillators achieve peak powers an order of magnitude higher than those of prior fiber lasers.

We propose a new method to generate self-similar parabolic pulses in exponentially tapered multimode fibers. In such broadband amplification-free settings the input pulse can quickly acquire a parabolic profile with a high quality linear chirp.

We present a fiber optical parametric oscillator based on polarization-maintaining, step-index fiber. Using birefringence-induced phase-matching, we convert chirped pulses at 1 μm to nanojoule-scale, femtosecond pulses at 0.8 μm and 1.3 μm.

We outline a theoretical framework to understand the multitude of new mode-locked states possible in multi-transverse mode resonators. Full-3D measurements of mode-locked states comprising roughly 30 million modes agree with theoretical expectations.

We propose a new technique for generating self-similar parabolic pulses in exponentially tapered multimode fibers. In such amplification-free settings, the input pulse evolves into a pulse with a parabolic profile and a high-quality linear chirp.

In most hyperspectral SRS imaging experiments, the SRS spectral range is limited by the total bandwidth of the excitation laser to ~300 cm−1 and spectral resolution of ~20 cm−1. Here we present a novel approach for broadband hsSRS microscopy based on parabolic fiber amplification to provide linearly chirped broadened Stokes pulses. This novel hsSRS...

Hyperspectral stimulated Raman scattering (hsSRS) microscopy has recently emerged as a powerful non-destructive technique for the label-free chemical imaging of biological samples. In most hsSRS imaging experiments, the SRS spectral range is limited by the total bandwidth of the excitation laser to ~300 cm⁻¹ and a spectral resolution of ~25 cm⁻¹. H...

Blue-enhanced, broadband supercontinuum generation in a 50 um core fluorine-doped graded-index multimode fiber is demonstrated by pumping with a 1064 nm picosecond source. Multi-octave supercontinuum spectrum extending from ~400 nm to 2,400 nm is achieved in a relatively short fiber. The measured spectrum and multimode nonlinear properties are comp...

We demonstrate a fiber optical parametric chirped-pulse amplifier pumped in the normally dispersive regime. This approach is readily scalable, offering a route to microjoule-level, femtosecond pulses at new wavelengths. As a first demonstration, we pump with chirped pulses at 1.03 μm and seed with a continuous-wave beam at 0.85 μm, and are able to...

Noise is a fundamental and ubiquitous problem in optics, and only those out of the signal bandwidth can be filtrated away by traditional spectral filters. This paper presents an in‐band noise filtering scheme where the ultrafast signal is controlled by spatio‐spectral coupling such that the signal and its in‐band noise can be separated in the spati...

We demonstrate a fiber oscillator that achieves 3 MW peak power, is easily started, and is environmentally stable. The Mamyshev oscillator delivers 190-nJ pulses that can be compressed externally to 35 fs duration. Accurate numerical modeling of the gain medium provides insight into the behavior and performance of the device.