Cornell University

Other

The University of Arizona

Frank Wise

William Renninger

Logan Wright

Chin Yu Chong

Fatih Omer Ilday

Shian Zhou

Lyuba Kuznetsova

Andy Chong

Walter Fu

Khanh Kieu

Xiang Liu

Dimitre Gueorguiev Ouzounov

Jeffrey Moses

Joel Buckley

Erin Stranford Lamb

Simon Lefrancois

Hyungsik Lim

Qian Liejia

The technology disclosed in this patent document allows mode locking of both selected longitudinal and transverse modes to produce laser pulses. The laser light produced based on such mode locking exhibits a 3-dimensional mode profile based on the locked longitudinal and transverse modes.

Pulsed lasers based on spatiotemporal mode-locking

The technology described in this document can be used to implement an optical device including a seed pump laser to produce pump seed laser pulses at a pump wavelength, a pulse stretcher operable to stretch a pulse duration of the pump seed laser pulses to produce stretched pump seed laser pulses, a pump fiber amplifier including one or more fiber gain media to receive the seed pump laser pulses to produce a pump laser beam of pump laser pulses, a signal laser to produce a signal laser beam at a signal wavelength different from the pump wavelength, an optical module coupled to combine the pump laser beam and the signal laser beam, and a fiber optical parametric amplifier (OPA) to cause a nonlinear parametric interaction in the nonlinear fiber medium to produce an output signal beam, an output idler laser beam at an idler wavelength, and an output pump beam.

Fiber optical parametric chirped-pulse amplification (FOPCPA)

Devices and techniques that use nonlinear optical effects in optical fiber to generate optical pulses via nonlinear optical wave mixing for various applications such as coherent Raman microscopic measurements and optical parametric oscillators. In some implementations, a tunable optical delay path is provided to cause an adjustable delay for synchronizing two optical beams of optical pulses.

Fiber source of synchronized picosecond pulses for coherent Raman microscopy and other applications

This disclosed subject matter allows short pulses with high peak powers to be obtained from seed pulses generated by a gain-switched diode. The gain-switched diode provides a highly stable source for optical systems such as nonlinear microscopy. The disclosed system preserves the ability to generate pulses at arbitrary repetition rates, or even pulses on demand, which can help reduce sample damage in microscopy experiments or control deliberate damage in material processing.

High-energy femtosecond light pulses based on a gain-switched laser diode

Methods, systems, and devices are disclosed for divided-pulse lasers. In one aspect, a pulsed laser is provided to include a laser cavity including an optical amplifier and a plurality of optical dividing elements and configured to direct a laser pulse of linearly polarized light into the plurality of optical dividing elements to divide the light of the laser pulse into a sequence of divided pulses each having a pulse energy being a portion of the energy of the laser pulse before entry of the optical dividing elements, to subsequently direct the divided pulses into the optical amplifier to produce amplified divided pulses. The laser cavity is configured to direct the amplified divided pulses back into the plurality of optical dividing elements for a second time in an opposite direction to recombine the amplified divided pulses into a single laser pulse with greater pulse energy as an output pulse of the laser cavity.

Divided pulse lasers

Implementations and examples of fiber lasers based on fiber laser cavity designs that produce self-similar pulses ('similaritons') to achieve a pulse spectral bandwidth greater than a gain spectral bandwidth based on a spectral broadening fiber segment and a spectral filter to ensure the proper similariton conditions.

Broadband short pulse fiber lasers capable of generating output spectra broader than gain bandwidth

A normal-dispersion fiber laser is operated using parameters in which dissipative solitons exist with remarkably large pulse duration and chirp, along with large pulse energy. A low-repetition-rate oscillator that generates pulses with large and linear chirp can thus replace the standard oscillator, stretcher, pulse-picker and preamplifier in a chirped-pulse fiber amplifier.

Giant-chirp oscillator for use in fiber pulse amplification system

Implementations and examples of mode-locked fiber lasers based on fiber laser cavity designs that produce self-similar pulses ('similaritons') with parabolic pulse profiles with respect to time at the output of the fiber gain media to effectuate the desired mode locking operation. An intra-cavity narrowband optical spectral filter is included in such fiber lasers to ensure the proper similariton conditions.

Mode-locked fiber laser based on narrowband optical spectral filtering and amplifier similaritons

To avoid harmful nonlinear effects in the amplification of short optical pulses, an initial pulse is divided into a sequence of lower-energy temporally spaced pulses that are otherwise identical to the original pulse. The low-intensity pulses are amplified and then recombined to create a final amplified output pulse.

Divided-pulse amplification of short pulses

A modelocked fiber laser is designed to have strong pulse-shaping based on spectral filtering of a highly-chirped pulse in the laser cavity. The laser generates femtosecond pulses without a dispersive delay line or anomalous dispersion in the cavity.

All-normal-dispersion femtosecond fiber laser

A saturable absorber (SA) is constructed using a fiber taper embedded in a carbon nanotube/polymer composite. A fiber taper is made by heating and pulling a small part of standard optical fiber. At the taper's waist light is guided by the glass-air interface, with an evanescent field protruding out of the taper. Carbon nanotubes mixed with an appropriate polymer host material are then wrapped around the fiber taper to interact with the evanescent field. Saturable absorption is possible due to the unique optical properties of the carbon nanotubes. The device can be used in mode-locked lasers where it initiates and stabilizes the pulses circulating around the laser cavity. The SA can be used in various laser cavities, and can enable different pulse evolutions such as solitons, self-similar pulses and dissipative solitons. Other applications include but are not limited to optical switching, pulse cleanup and pulse compression.

Saturable absorber using a fiber taper embedded in a nanostructure/polymer composite and lasers using the same

A chirped-pulse fiber amplification method and system operates with large nonlinear phase shifts (as large as &#x2dc;20&#x3c0; or more). In this regime, the pulse spectrum is modified by strong self-phase modulation and gain shaping. With large-enough nonlinear phase shift, substantial spectral broadening occurs. The amplified spectrum can therefore be much broader than the spectrum that is obtained with small nonlinear phase shifts. The broader spectrum enables the formation of a shorter pulse, and the bandwidth generated in nonlinear chirped-pulse amplification can in fact be exploited to generate shorter pulses. Ultimately, this allows the generation of pulses shorter than the gain-narrowing limit of a fiber amplifier.

Nonlinear chirped pulse fiber amplifier with pulse compression

A pulse compressor for compressing many-cycle femtosecond-duration high-energy pulses to near-single-cycle durations uses a single quadratic nonlinear crystal. A pulsed laser beam is controlled and its passage is aligned through the quadratic nonlinear crystal such that the detrimental effects of group-velocity mismatch are avoided, while still allowing enough nonlinear phase accumulation for compression to near-single-cycle pulse durations. To do so, the perturbation to nonlinear Schr&#xf6;dinger-type soliton compression due to group-velocity mismatch is minimized which requires that the soliton order must not exceed an optimal value set by the amount of group-velocity mismatch.

Quadratic nonlinearity-based high-energy pulse compressor for generating few-cycle pulses

A short-pulse fiber amplifier system () is designed so that nonlinear phase shifts and third-order dispersion are purposely introduced that compensate each other. In particular, the nonlinear phase shift accumulated in the amplifier is compensated by the third-order dispersion of the combination of a fiber stretcher () and a grating compressor (). In the presence of third-order dispersion, an optimal nonlinear phase shift reduces the pulse duration, and enhances the peak power and pulse contrast compared to the pulse produced in linear propagation.

Chirped pulse fiber amplifier

A laser producing high energy ultrashort laser pulses comprises a normal dispersion segment, a gain segment, an anomalous dispersion segment with negligible nonlinearity and an effective saturable absorber arranged to form a laser cavity. Each segment is optically interconnected so that a laser pulse will propagate self-similarly therein. (A pulse that propagates in a self-similar manner is sometimes referred to as a 'similariton.') With this laser the limitations of prior art laser oscillators are avoided. Also provided are means for pumping the gain medium in the laser cavity, and means for extracting laser pulses from the laser cavity. The laser cavity is preferably a ring cavity. Preferably the laser is configured to achieve unidirectional circulation of laser pulses therein. This configuration is scalable to much higher pulse energy than lasers based on soliton-like pulse shaping.

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Ithaca, NY, United States of America

Frank Wise