We report on a multi-mJ 2.1 μm optical parametric chirped-pulse amplification (OPCPA) system operating at 1 kHz repetition rate, pumped by picosecond cryogenic Yb:YAG laser, and the demonstration of soft x-ray high-harmonic generation (HHG) with flux ∼2×10(8) photon/s/1% bandwidth 160 eV in Ar. The pump laser amplifies pulses up to 56 mJ delivers compressed 42 mJ, 17 ps OPCPA system. In three-stage chain, we have obtained 2.6 output energies 40 fs good beam quality. Finally, show cut-off...

The broadband parasitic amplification in a diode-seeded nanosecond ytterbium-doped fiber laser amplifier system is numerically and experimentally investigated. originated from weak pulsed signal associated with the 1064-nm seed diode laser. Although average power of pulse less than 5% total power, significant transient spike observed during amplification. In agreement simulation, nonlinear effects caused by limits scaling peak preamplifiers. With utilization narrow bandwidth filter to...

We experimentally and numerically investigate the spectral temporal structure of mid-infrared (mid-IR) filaments in bulk dielectrics with normal anomalous group velocity dispersion (GVD) pumped by a 2.1 μm optical parametric chirped-pulse amplifier (OPCPA). The formation stable robust several microjoules pulse energy is observed. demonstrate supercontinuum that spans more than three octaves from ZnS GVD regime self-compression mid-IR to sub-two-cycle duration CaF2 regime. experimental...

We report the generation of coherent water-window soft x-ray harmonics in a neon-filled semi-infinite gas cell driven by femtosecond multi-mJ mid-infrared optical parametric chirped-pulse amplification (OPCPA) system at 1 kHz repetition rate. The cutoff energy was extended to ∼450 eV with 2.1 μm driver wavelength and photon flux photons/s/1% bandwidth obtained 350 eV. A comparable observed nitrogen K-edge 410 This is first demonstration harmonic up from OPCPA system. Finally, this suitable...

By using a laser-induced transient density ramp, we demonstrate self-injection of electrons in self-modulated laser-wakefield accelerator with spatial localization. The number injected reaches 1.7 x 10(8). ramp is produced by prepulse propagating transversely to drill depression channel via ionization and expansion. same mechanism injection comparable efficiency also demonstrated transverse plasma waveguide driven Coulomb explosion.

A tomographic diagnosis method was developed to systematically resolve the injection and acceleration processes of a monoenergetic electron beam in laser-wakefield accelerator. It found that all electrons are injected at same location plasma column accelerated from 5 55 MeV energy 200 microm distance. This is direct measurement real gradient accelerator, experimental data consistent with model transverse wave breaking loading for injection.

We report on a diode-pumped, hybrid Yb-doped chirped-pulse amplification (CPA) laser system with compact pulse stretcher and compressor, consisting of fiber preamplifiers, room-temperature Yb:KYW regenerative amplifier (RGA), cryogenic Yb:YAG multi-pass amplifiers. The RGA provides relatively broad bandwidth thereby long duration to mitigate B-integral in the CPA chain. ~1030-nm pulses are amplified up 70 mJ at 1-kHz repetition rate, currently limited by available optics apertures, then...

We demonstrate a 0.56-GW, 1-kHz, 4.2-ps, 2.74-mJ deep-ultraviolet (DUV) laser at ∼257.7 nm with beam propagation factor (M2) of ∼2.54 from frequency-quadrupled cryogenic multi-stage Yb-doped chirped-pulse amplifier. The frequency quadrupling is achieved using LiB3O5 and β-BaB2O4 crystals for near-infrared (NIR)-to-green green-to-DUV conversion, respectively. An overall NIR-to-DUV efficiency ∼10% has been achieved, which currently limited by the thermal-induced phase mismatching DUV-induced...

We present our recent progress on the development of a mid-infrared (mid-IR), multi-mJ, kHz optical parametric chirped-pulse amplification (OPCPA) system, pumped by homebuilt picosecond cryogenic Yb:YAG amplifier, and its application to soft x-ray high-order harmonic generation. The laser operating at 1 repetition rate delivers 42 mJ, 17 ps, 1.03 μm pulses pump OPCPA system. Efficient second fourth generations from system are demonstrated, which provide pumping capability for various...

Production of a monoenergetic electron bunch in self-injected laser-wakefield accelerator is investigated with tomographic method which resolves the injection and acceleration processes. It found that all electrons are injected at same location plasma column then accelerated an gradient exceeding $2\phantom{\rule{0.3em}{0ex}}\mathrm{GeV}∕\mathrm{cm}$. The position shifts pump-pulse focus, no significant deceleration observed for after it reaches maximum energy. results consistent model...

A two-dimensional simulation was employed to study the melt/air and melt/solid interface shapes of miniature molten zone formed in a laser-heated pedestal growth (LHPG) system. Using non-orthogonal body-fitting grid system with control-volume finite-difference method, shape can be determined both efficiently accurately. During stable growth, dependence molten-zone length on heating CO 2 laser is examined detail under maximum minimum allowed powers various speeds. The effect gravity also...

An electron-beam-fabricated subwavelength grating coupler for direct side coupling of light emission from a high-power laser diode array (LDA) was studied theoretically and implemented experimentally. A gold-embedded silica-based design employed to minimize the thermal expansion caused by accumulated heat absorption metal part coupler. In addition, with consideration backward diffraction loss groove wall nonverticality fabrication distortion, pitch width were optimized highest efficiency....

Heat transfer and fluid flow in a laser-heated pedestal growth (LHPG) system are analyzed near the deformed interfaces. The global thermal distributions of crystal fiber, melt, source rod described by their temperature axial gradient over length ∼10 mm. Compared with bulk several centimeters diameter, natural convection is 6 orders magnitude smaller owing to melt volume; therefore, conduction rather than determines distribution molten zone. Moreover, thermocapillary mass-transfer becomes...

This study evaluated the effectiveness of near-infrared laser-excited gold nanorods as active target to selectively kill cancer cells. The key parameters laser and sample be measured include absorption coefficient, fluence irradiation time, temperature profiles. optimal operation for surface volume heating was achieved by a novel pulsed-train technique using an auto-controlled on-off time meet desired temperatures. is increasing function time. For fixed influence, GNRs solution with smaller...

We report on the development of a 2.74-mJ, ~4.2 ps, ~258 nm deep-ultraviolet (DUV) source at 1 kHz based frequency quadrupling ~32 mJ, 8.4 ~1030 near-infrared (NIR) laser pulses with an excellent beam profile, generated from diode-pumped, ultrafast hybrid Yb-doped chirped-pulse amplification system. have used two-stage second harmonic generation scheme LBO (NIR-to-green) and BBO crystals (green-to-DUV), respectively, to achieve fourth-harmonic (FHG). The NIR-to-DUV conversion efficiency ~10%...

Grating couplers for side coupling of the light from a high-power laser diode array (LDA) into inner cladding double-clad fiber were studied theoretically and implemented experimentally. In experiments, two types grating designed fabricated: gold-coated surface relief coupler gold-embedded silica coupler. A suitable design heat dissipation each was employed to minimize thermal expansion due accumulated absorption by metal part The experimental results show that is superior gold coupler,...

A sub-wavelength gold-embedded silica binary grating for side coupling light emission from a 976-nm high-power laser diode array into the 400-μm-diameter inner cladding of double-clad fiber was demonstrated with near 50% overall efficiency.

A nonlinear theory for the optical properties of gold nanorods is presented. The refractive index sensitivity associated surface plasmon resonance calculated to be 100-1000 nm/RIU aspect ratio range 1-10. According Gan's theory, figure merit, defined by divided FWHM value extinction coefficient, 1.0-12.0, which has a maximum at optimum 3.5-4.5 depending on surrounding medium.

We demonstrate more than 3-octave supercontinuum for the first time from ZnS in normal dispersion regime and self-compression of mid-IR pulse to sub-2-cycle CaF2 anomalous regime.

The time-dependent coupled rate equations based on the multi-channel treatment has been applied to study influences of amplified spontaneous emission fiber laser amplifier with experimental verification and practical solutions for suppressing ASE.

Analysis and applications of vision correction via accommodating intraocular lens (AIOL) are presented. By Gaussian optics, analytic formulas for the accommodation rate function (M) two-optics three-optics systems derived compared with exact numerical results. In a single-optics AIOL, typical value M is (0.5-1.5) D/mm, an IOL power (10-20) diopter. For given power, higher achieved in positive-IOL than negative-IOL. dual-optics maximum predicted when front positive-optics moves toward corneal...

High brightness diode pump source is becoming a matter of concern for developing high power fiber laser [1]. It crucial to convert the emission but low array into kind and maintain same level. Complex beam-shaping methods each single emitter was used in past [2,3]. In order increase efficiency compactness, grating coupling mechanism promising way achieve pumping. this paper, we demonstrate through by using coupler.

Phonon scattering processes to κ lat of Ge 0.85 Sb 0.1 W 0.05 Te: Umklapp, boundary, point-defect, stacking faults, resonant scattering, nanoprecipitates & microstructural effects. (b) reduction (inset: ZT enhancement).