Imra America, Inc.

Irma America, Inc.

Gregg D Sucha

Donald J Harter

Martin E Fermann

Min Jiang

Almantas Galvanauskas

Michelle L Stock

Mark P Bendett

Anand Hariharan

Jeff Squier

Use of quasi-phase-matched (QPM) materials for parametric chirped pulse amplification (PCPA) substantially reduces the required pump peak power and pump brightness, allowing exploitation of spatially-multimode and long duration pump pulses. It also removes restrictions on pump wavelength and amplification bandwidth. This allows substantial simplification in pump laser design for a high-energy PCPA system and, consequently, the construction of compact diode-pumped sources of high-energy ultrashort optical pulses. Also, this allows elimination of gain-narrowing and phase-distortion limitations on minimum pulse duration, which typically arise in a chirped pulse amplification system. One example of a compact source of high-energy ultrashort pulses is a multimode-core fiber based PCPA system. Limitations on pulse energy due to the limited core size for single-mode fibers are circumvented by using large multimode core. Limitations on pulse duration and beam quality due to multimode core are circumvented by using a PCPA scheme. Additionally, the large core of the multimode fiber facilitates cladding-pumping by inexpensive and high-power multiple-mode laser diodes.

Quasi-phase-matched parametric chirped pulse amplification systems

Methods and apparatuses for performing temporal scanning using ultra-short pulse width lasers in which only minimal (micro-scale) mechanical movement is required, and related methods for obtaining high-accuracy timing calibration, on the order of femtoseconds, are disclosed. A dual laser system is disclosed in which the cavity of one or more of the lasers is dithered using a piezoelectric element. A Fabry-Perot etalon generates a sequence of timing pulses used in conjunction with a laser beam produced by the laser having the dithered laser cavity. A correlator correlates a laser pulse from one of the lasers with the sequence of timing pulses to produce a calibrated time scale. The invention is applicable to applications requiring rapid scanning and time calibration, including metrology, characterization of charge dynamics in semiconductors, electro-optic testing of ultrafast electronic and optoelectronic devices, optical time domain reflectometry, and electro-optic sampling oscilloscopes.

Scanning temporal ultrafast delay and methods and apparatuses therefor

The present invention is directed to methods and apparatuses for performing temporal scanning using ultra-short pulsewidth lasers in which only minimal (micro-scale) mechanical movement is required. The invention also relates to methods for obtaining high-accuracy timing calibration, on the order of femtoseconds. A dual laser system is disclosed in which the cavity of one or more of the lasers is dithered, by using a piezoelectric element. A Fabry-Perot etalon is used to generate a sequence of timing pulses used in conjunction with a laser beam produced by the laser having the dithered laser cavity. A correlator correlates a laser pulse from one of the lasers with the sequence of timing pulses to produce a calibrated time scale. The methods and apparatuses of the present invention are applicable to many applications requiring rapid scanning and time calibration, including, but not limited to metrology, characterization of charge dynamics in semiconductors, electro-optic testing of ultrafast electronic and optoelectronic devices, optical time domain reflectometry, and electro-optic sampling oscilloscopes.

An intracavity resonant Fabry-Perot saturable absorber (R-FPSA) induces modelocking in a laser such as a fiber laser. An optical limiter such as a two photon absorber (TPA) can be used in conjunction with the R-FPSA, so that Q-switching is inhibited, resulting in laser output that is cw modelocked. By using both an R-FPSA and a TPA, the Q-switched modelocked behavior of a fiber laser is observed to evolve into cw modelocking.

Resonant Fabry-Perot semiconductor saturable absorbers and two photon absorption power limiters

Resonant fabry-perot semiconductor saturable absorbers and two photon absorption power limiters

Scanning temporal ultrafast delay methods and apparatuses therefor

An invention is described, which uses terahertz radiation for chemical sensing and gas analysis. Relatively narrow-band THz radiation is generated by impinging an optical pulse train from a short-pulse laser source on a THz emitter. Coherent detection of the resulting THz radiation is accomplished by using a similar optical pulse train to activate the THz sensor. The invention is shown to detect and indicate various concentrations of water vapor in air. Optimal phase biasing conditions give maximum sensitivity to variations in concentration of the species under investigation.

Single-shot differential spectroscopy and spectral-imaging at submillimeter wavelengths

An optical parametric amplifier pumped by ultrashort optical pulses provides time-gated image amplification or time-gated image frequency conversion, resulting in optical sectioning of an object under test and/or background rejection of improperly timed light. An ultrashort laser pulse of one frequency is used to illuminate an object under test. An ultrashort pulse light beam at a signal frequency transmitted through or scattered from the object is optically mixed with an ultrashort laser pulse at a pump frequency in a nonlinear optical medium. This mixing produces an amplified image of a particular optical section of the object at the signal frequency in addition to producing a frequency converted image of the same optical section at an idler frequency. This time-gated amplification can be used in conjunction with a confocal imaging system, or a conventional imaging system. The resolution of optical sectioning is determined by the temporal widths of the signal and pump pulses and by the group velocity walkoff in the nonlinear medium. By illuminating the target with a train of closely spaced ultrashort pulses, an image of multiple sections can be amplified and downconverted within a single laser shot, giving a contour image of the target. The signal light can also be fluorescence from the object, excited by a short laser pulse, either through single-photon or multi-photon absorption. In this case, the signal light is incoherent with respect to the pump light. By using quasi-phase-matched nonlinear optical crystals as the amplifying medium, advantages such as an increased acceptance angle and lower pump thresholds are obtained.

Method and apparatus for optical sectioning and imaging using time-gated parametric image amplification

An apparatus and method for delivery of high peak power pulse through an optical fiber to an optical device includes an ultrashort pulsed laser source which produces ultrashort optical pulses having high peak power. Prior to transmitting the optical pulses through a delivery optical fiber, the pulse width of the optical pulses is stretched, forming chirped optical pulses having a lower peak power. The stretched pulses are transmitted through an optical fiber which delivers the pulse to an optical device requiring ultrashort, high peak power optical pulses. The optical fiber and/or an output unit coupled to the end of the optical fiber introduces a dispersion which compensates for the dispersion introduced by the pulsed laser source and the stretcher, and delivers a recompressed optical pulse to an optical device. The optical fiber delivery system preferably pre-compensates for the dispersion introduced by optical components within the optical device, so that the optical pulses are fully recompressed at a point of interest within the optical device, such as at a specimen or at a detector. The optical fiber delivery system may include a frequency converter either before or after the delivery optical fiber. The frequency converter allows optical pulses having frequencies other than that generated by the laser source to be delivered to the optical device in an efficient manner.

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Manchester, MI, United States of America

Gregg D Sucha