Lawrence Livermore National Security, LLC

John Edward Heebner

Jay Walter Dawson

Paul H Pax

Ryan Douglas Muir

Arun K Sridharan

Daniel E Mittelberger

Michael Joseph Messerly

Alexander M Rubenchik

Derrek Reginald Drachenberg

Graham S Allen

Brandon Walter Buckley

James P Armstrong

Vincent J Hernandez

Lars F Voss

Raymond John Beach

Adam M Conway

Jeffrey Devin Bude

Raluca A Negres

Thomas M Spinka

Maurice B Aufderheide

David A Alessi

Scott C Wilks

Steven T Yang

Craig W Siders

Otto L Landen

Michael R Carter

Andrew J Mackinnon

Chrisopher B J Barty

Wade H Williams

Andreas J Kemp

Bedros Afeyan

Methods, systems and devices are described that enable measurement and characterization of complex laser pulses by relying on three interferograms that are measured simultaneously. The described three-phase spectral interferometry (3PSI) can meet the growing demand for optical recorders with long record and 1 ps or finer resolution. An example three-phase interferometric system includes a three-output optical splitter with a first input port to receive the input optical signal, a second input port to receive a reference optical signal with one or more unknown spectral characteristics. The three output ports of the optical splitter produce interferograms that correspond to relative phase shifts of substantially 120 degrees. Detectors are positioned to receive and measure the interferograms, which allows determination of the amplitude and phase of the input optical signal with very high accuracy. The described techniques include may improvements in the alignment, calibration and signal retrieval procedures associated with the 3PSI system.

Three phase spectral interferometry

An apparatus, comprising: Mach-Zehnder modulators (MZMs) numbered MZM #1 to MZM #n that exhibit nonlinearity between an input electrical domain signal and an output optical domain signal; a waveform source for applying a first voltage waveform to a first optical arm of said MZM #1; a laser source configured to direct laser light into the two arms of at least said MZM #1 to produce a first output optical domain signal; the apparatus being provided for utilizing said first output optical signal and the nonlinearities of MZMs numbered MZM #2 to said MZM #n to produce a final output voltage waveform that, compared to said input voltage, comprises at least one of: a shorter rise time, a shorter fall time, an increased signal temporal resolution or small signal dynamic range, an increased vertical resolution for small signals or large signals, a reduced noise on small signals or large signals and an increased bandwidth.

Temporal resolution and fidelity enhancement of arbitrary waveforms

A high-voltage switch, whose operation leverages the speed of electrons to generate the 'on' time of the pulse in combination with the speed of light to generate the “off” time of the pulse, is described. In one example, the high-voltage switch includes a first electrode, a second electrode spaced apart from the first electrode, a region of non-absorbing material occupying a portion of the space between the first and second electrodes and allowing a laser pulse to propagate therethrough without substantial absorption, and a region of absorbing material occupying another portion of the space and producing a charged particle cloud upon receiving the laser pulse. The high-voltage switch remains “on” upon the charged particle cloud reaching an electrode and until it has been collected by the electrode, and where the high-voltage switch remains “off” subsequent to the collection and until another generated charged particle cloud reaches the electrode.

High-power electrically tunable switch

Apparatuses comprising cascaded or series configurations of Mach-Zehnder electrooptic modulators, where the nonlinearities of the cascaded and series configurations of Mach-Zehnder electrooptic modulators increase signal bandwidth and boost signal fidelity in electronic digital to analog converters. The Mach-Zehnder electrooptic modulators are combined with photodiode detectors that are used to convert signals from the optical domain to the electrical domain.

Space-to-time pulse shaping techniques are provided that maintain high fidelity with a practical output coupler, maintain an output resolution that is no longer than the input pulse, and are scalable to long records while maintaining fine resolution.

Space-time induced linearly encoded transcription for temporal optimization (STILETTO)

A method for increasing the MeV hot electron yield and secondary radiation produced by short-pulse laser-target interactions with an appropriately high or low atomic number (Z) target. Secondary radiation, such as MeV x-rays, gamma-rays, protons, ions, neutrons, positrons and electromagnetic radiation in the microwave to sub-mm region, can be used, e.g., for the flash radiography of dense objects.

Burst-mode chirped pulse amplification method

The present invention extends the resolution capability for shaping optical pulses on laser systems from the current state of the art resolution of &#x2dc;250 ps to &#x2dc;1 ps by utilizing a hybrid of EOM and spectral shaping technologies. In one embodiment, a short pulse derived from a mode-locked laser oscillator is dispersed using a dispersive stretcher to about 250 ps, providing a linear mapping of spectrum to time. A typical spectral shaper is used to directly write the desired temporal pattern in the spectral domain to produce a crudely patterned waveform that may also suffer from chirp. The chirp is removed by a process known as difference frequency generation by mixing it with a pulse derived from an equally chirped frequency-doubled pump in an optical parametric amplifier. The pattern is then focused in time, which is accomplished in one embodiment by propagating the pattern through a dispersive element.

Arbitrary pulse shaping with picosecond resolution over multiple-nanosecond records

Single-shot transient optical signals are recorded in a time regime of picoseconds to nanosecond. An auxiliary pump beam is crossed through the signal to sample a diagonal 'slice' of space-time, analogous to a rolling shutter. The slice is then imaged onto an ordinary camera, where the recorded spatial trace is a direct representation of the time content of the signal. The pump samples the signal by optically exciting carriers that modify the refractive index in a conventional semiconductor wafer. Through use of birefringent retarders surrounding the wafer, the integrating response of the rapidly excited but persistent carriers is differentiated by probing with two polarization-encoded time-staggered signal replicas that are recombined to interfere destructively.

All optical sampling by slanted light interrogation for cross-correlated encoded recording (slicer)

A system for aerially surveying an area where a plane may have crashed in water and locating pings from the plane's black box using a laser on an aerial platform that produces laser pulses; using a launch telescope to direct the laser pulses to the water producing scattering from the laser pulses and a continuous stream of backscatter; using a receiving telescope to collect the continuous stream of backscatter; using an interferometer operatively connected to the receiving telescope to produce two outputs, wherein one output is the continuous stream of backscatter, and wherein the other output is a delayed replica of the first output; and using a data collection and analysis unit operatively connected to the interferometer to produce a measurement of the sound.

UV laser based stand-off acoustic sensor

Cladding-pumped Raman fiber lasers and amplifiers provide high-efficiency conversion efficiency at high brightness enhancement. Differential loss is applied to both single-pass configurations appropriate for pulsed amplification and laser oscillator configurations applied to high average power cw source generation.

Apparatus and method for enabling quantum-defect-limited conversion efficiency in cladding-pumped Raman fiber lasers

Spatial mode conversion modules are described, with the capability of efficiently transforming a given optical beam profile, at one plane in space into another well-defined optical beam profile at a different plane in space, whose detailed spatial features and symmetry properties can, in general, differ significantly. The modules are comprised of passive, high-efficiency, low-loss diffractive optical elements, combined with Fourier transform optics. Design rules are described that employ phase retrieval techniques and associated algorithms to determine the necessary profiles of the diffractive optical components. System augmentations are described that utilize real-time adaptive optical techniques for enhanced performance as well as power scaling.

Diffractive optical elements for transformation of modes in lasers

An optical source capable of enhanced scaling of pulse energy and brightness utilizes an ensemble of single-aperture fiber lasers as pump sources, with each such fiber laser operating at acceptable pulse energy levels. Beam combining involves stimulated Raman scattering using a Stokes' shifted seed beam, the latter of which is optimized in terms of its temporal and spectral properties. Beams from fiber lasers can thus be combined to attain pulses with peak energies in excess of the fiber laser self-focusing limit of 4 MW while retaining the advantages of a fiber laser system of high average power with good beam quality.

Raman beam combining for laser brightness enhancement

A deterministic methodology is provided for designing optical fibers that support field-flattened, ring-like higher order modes. The effective and group indices of its modes can be tuned by adjusting the widths of the guide's field-flattened layers or the average index of certain groups of layers. The approach outlined here provides a path to designing fibers that simultaneously have large mode areas and large separations between the propagation constants of its modes.

Optical waveguides having flattened high order modes

In one general embodiment, a method for ultrafast optical signal detecting is provided. In operation, a first optical input signal is propagated through a first wave guiding layer of a waveguide. Additionally, a second optical input signal is propagated through a second wave guiding layer of the waveguide. Furthermore, an optical control signal is applied to a top of the waveguide, the optical control signal being oriented diagonally relative to the top of the waveguide such that the application is used to influence at least a portion of the first optical input signal propagating through the first wave guiding layer of the waveguide. In addition, the first and the second optical input signals output from the waveguide are combined. Further, the combined optical signals output from the waveguide are detected. In another general embodiment, a system for ultrafast optical signal recording is provided comprising a waveguide including a plurality of wave guiding layers, an optical control source positioned to propagate an optical control signal towards the waveguide in a diagonal orientation relative to a top of the waveguide, at least one optical input source positioned to input an optical input signal into at least a first and a second wave guiding layer of the waveguide, and a detector for detecting at least one interference pattern output from the waveguide, where at least one of the interference patterns results from a combination of the optical input signals input into the first and the second wave guiding layer. Furthermore, propagation of the optical control signal is used to influence at least a portion of the optical input signal propagating through the first wave guiding layer of the waveguide.

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Livermore, CA, United States of America

John Edward Heebner