ABSTRACT
We report ultrafast green pulse generation from a Yb-doped fiber laser system with gain-narrowing compensation. The chirped-pulse amplification system outputs repetitive 3 MHz pulses with an energy of 35 nJ and a reconstructed pulse duration of 41 fs.
ABSTRACT
We demonstrate long-term stable passive synchronization between two-color Ti:sapphire (master) and Yb-doped fiber (slave) mode-locked lasers in the master-slave configuration. Active temperature stabilization suppresses the repetition fluctuation of the slave laser, and with the aid of temperature stabilization in combination with simple repetition locking of the master laser, long-term stable synchronization as long as 6 h was realized. The repetition rates of both lasers are locked in submillihertz precision. A timing jitter of 0.75 fs was obtained at a detection bandwidth of 350 kHz.
ABSTRACT
We report long-term stable passive synchronization of a femtosecond Yb-doped fiber chirped-pulse amplifier (CPA) with a mode-locked Ti:sapphire laser for pump-seed synchronization of an optical parametric chirped-pulse amplification (OPCPA) system. The fiber CPA system delivers pulses with a wavelength of 1035 nm, energy of 50 µJ, and duration of 690 fs at a repetition rate of 0.4 MHz. The seed fiber oscillator is passively synchronized with a mode-locked Ti:sapphire laser by injection of the Ti:sapphire laser pulses into the cavity of the fiber oscillator. The second harmonic (SH) output with a wavelength of 518 nm, energy of 18 µJ, and duration of 1.2 ps was prepared for the OPCPA pump. The measured timing jitter between the pump (fiber SH) and the seed (Ti:sapphire) was 42 ± 14 fs, while the jitter between two oscillator outputs was 1.4 ± 0.5 fs. The robust synchronization technique allows long-term stable operation over 8 h.
Subject(s)
Amplifiers, Electronic , Fiber Optic Technology/instrumentation , Lasers, Solid-State , Signal Processing, Computer-Assisted/instrumentation , Aluminum Oxide/chemistry , Equipment Design , Equipment Failure Analysis , Titanium/chemistry , Ytterbium/chemistryABSTRACT
We demonstrate 1W average-power ultraviolet (UV) femtosecond (fs) ultrashort pulse generation at a wavelength of 259 nm and a repetition rate as high as 100 MHz by quadrupling a fs ytterbium-fiber laser. A cavity-enhanced design is employed for efficient frequency doubling to the UV region. The optical-to-optical efficiency of UV output to the pump diode is 2.6%.
Subject(s)
Ultraviolet Rays , Ytterbium , Lasers, Solid-State , Time FactorsABSTRACT
For characterization of Fourier-synthesized optical waveforms of femtosecond multicolor phase-coherent pulses, we report relative-phase measurements among Fourier components from optically phase-locked two-color mode-locked lasers. The interference of two simultaneous second-order frequency-mixing processes in a common nonlinear crystal was utilized. The relative phases among three-color components with a frequency ratio of 2omega:3omega:4omega were measured by observing the interference fringes of two simultaneous frequency-mixing outputs. The inner field structure of the synthesized waveforms can be determined except for the ambiguity of its temporal shift with respect to the synthesized envelope, which corresponds to the carrier-envelope phase slip of one of the source lasers.
ABSTRACT
An ultrashort-pulse, mode-locked ytterbium-doped fiber laser has been developed. The group-delay dispersion was compensated with a grating pair inside the cavity. A broad spectrum from 1000-nm to 1120-nm was obtained without intracavity compensation of third-order dispersion. A 0.7-nJ pulse as short as 28.3 fs was obtained with a repetition rate of 80 MHz. To our knowledge, this is the shortest pulse reported from an Yb fiber laser oscillator.
Subject(s)
Lasers , Optics and Photonics , Oscillometry/methods , Ytterbium/chemistry , Algorithms , Equipment Design , Interferometry/methodsABSTRACT
Ultra-thin semiconductor crystals were investigated as nonlinear materials for second-harmonic generation. Nonlinear susceptibilities of sub-micrometer- thick ZnO, GaN, and AlN crystals were measured, and these crystals were used for sub-10-fs pulse measurement by a fringe-resolved autocorrelation method. We found that a one-cycle pulse could be characterized by using these ultra-thin-film crystals.
ABSTRACT
The pulse timing of a mode-locked Er-doped fiber laser was stabilized to a reference pulse train from a Cr:forsterite mode-locked laser by all-optical passive synchronization scheme. The reference pulses were injected into a ring cavity of the fiber laser by using a 1.3-1.5 mum wavelength-division multiplexer. The spectral shift induced by cross-phase modulation between copropagating two-color pulses realizes self-synchronization due to intracavity group-delay dispersion. The rms integration of timing jitter between the fiber laser pulse and the reference pulse was 3.7 fs in a Fourier frequency range from 1 Hz to 100 kHz.
ABSTRACT
An optical-phase stabilization technique was utilized to reduce the timing jitter between passively synchronized Ti:sapphire and Cr:forsterite two-color mode-locked lasers. The suppression of cavity-length fluctuation by stabilizing pulse-to-pulse slips of relative carrier-envelope phase allowed timing-jitter reduction by a factor of 1.7, resulting in an rms value of 123 attoseconds (as) in a frequency range from 10 mHz to 1 MHz.
ABSTRACT
Long-term optical phase-coherent two-color femtosecond pulses were generated by use of passively timing-synchronized Ti:sapphire and Cr:forsterite lasers. The relative carrier-envelope phase relation was fixed by an active feedback loop. The accumulated phase noise from 10 mHz to 1 MHz of the locked beat note was 0.43 rad, showing tight phase locking. The optical frequency fluctuation between two femtosecond combs was submillihertz, with a 1 s averaged counter measurement over 3400 s, leading to a long-term femtosecond frequency-comb connection.
ABSTRACT
We have demonstrated a reduction of the timing jitter between passively synchronized Ti:sapphire and Cr:forsterite mode-locked lasers into a 100-attosecond (as) regime by suppressing slow fluctuations with the use of active slow-bandwidth extracavity feedback. This active-passive hybrid synchronization scheme permits the achievement of timing jitters of 98 +/- 18 as at a bandwidth of 100 kHz and of 126 +/- 20 as at a bandwidth of 1 MHz for as long as 100 s.
ABSTRACT
We have successfully observed two-photon above-threshold ionization in rare gas atoms (Ar, Xe, and He) by the fifth harmonic (25 eV photon energy) of a KrF laser. Use of the energy-resolved photoelectron counting system together with our laser, providing strong 25 eV radiation at 40-100 Hz, enabled us to detect the very weak single-color two-photon above-threshold ionization signals. Experimental data are in good agreement with our theoretical calculations newly developed along the line of multichannel quantum defect theory.
