We report a compact ultrafast solid-state laser source with a tunable pulse repetition rate from 0.5 - 1.3GHz. The novel cavity design allows to vary the repetition rate by moving two mirrors, without realignment. The Yb:KYW crystal-based SESAM-modelocked laser emits 230fs pulses with 200mW average power around 1040nm.
An all-fiberized dissipative-soliton mode-locked thulium fiber laser operating at 1875 nm was demonstrated. Using an in-house fabricated thulium fiber as thegain medium, the laser provided ultrashort pulses with 12-ps pulse duration and 10.3-nJ pulse energy. The pulses could be compressed to 547 fs using a grating pair compressor.
Nanocrystalline LiYF4:Pr promises exciting design opportunities for composite photonic devices in the visible. Here, we present the spectroscopic properties of monodisperse colloidal LiYF4:Pr nanocrystals. We observed an unexpected yet intense emission with lifetimes comparable to bulk crystals. These results pave the way for applications in quantum optics and biomedicine.
We studied cryogenic laser operation of Tm: YLF using a modular setup pumped by a VBG stabilized diode. At 80K, a maximum output power of 6.50 W corresponding to a slope efficiency of 38% was achieved with excellent beam quality.
We compare a Ho$3+:YAG laser cavity that includes two crossed Porro prisms instead of cavity end mirrors with a conventional mirror resonator. While the Porro resonator shows a slightly lower slope efficiency of 67.4 % than the mirror resonator, it is superior in terms of beam quality and stability.
We studied the continuous-wave laser performance of Yb:Lu2O3 at cryogenic temperatures using a modular laser setup. A maximum output power of 15.23 W was achieved for 120 K corresponding to a slope efficiency of 63%.
High optical quality 3.5-at.% Nd:LGSB crystal with non-congruent melting wasgrown by the Czochralski method. The structural, the linear and nonlinear properties, as well as the laser emission characteristics in the near-infrared spectrum by direct emission and in the green visible range through self-frequency doubling were investigated.
The first subnanosecond pulse duration optical parametric generator (OPG) based on fan-out grating design MgO:PPLN crystal is demonstrated. Fan-out grating OPG enables quickly, widely, and continuously tunable, compact, and effective subnanosecond coherent light source covering near-infrared spectral region (1400 - 4400 nm) with OPG conversion efficiency up to 47 %.
Incongruent melting Pr-doped La0.678Gd0.572Sc2.75(BO3)4 (Pr:LGSB) crystals were grown by the Czochralski method, for the first time to our knowledge. The spectroscopic and nonlinear optical properties of the 2.5 at.% Pr:LGSB crystal shown that it can be a promising self-frequency doubling crystal in the UV range at ~301.5 nm.
We present the manufacturing of side-fused signal-pump combiners with 25/400-µm signal feed-through fibers and >90% pump coupling efficiency. On the basis of CO2-laser restructuring of the used optical fibers, the necessity of splice connection is avoided, which improves the pump coupling efficiency and thus overall laser efficiency.
The slow response time of semiconductor saturable absorbers significantly increases the noise of generated pulse train. We report a substantial improvement of amplitude and phase noise properties in a SESAM mode-locked Er:fiber oscillator via intracavity spectral filtering. We observed a 2.6-fold reduction of integrated timing jitter to 1.71 ps.
We demonstrate a spatially-resolved approach to simulating thin-disk lasers. The model supports exact phase profiles for cavity elements, allowing the impact of experimentally measured non-radially-symmetric aberrations of the thin-disk to be studied. Predicted stability zones, distorted fundamental mode and higher-order mode excitation are in good qualitative agreement with high-power experiments.
Many applications require tunable-wavelength laser radiation, which is provided by optical parametric amplifiers (OPAs) and optical parametric generators (OPGs). We report, to the best of our knowledge, the first dual-crystal LBO subnanosecond OPA system generating widely-tunable radiation in the visible spectrum range from roughly 460 nm to 680 nm.
We present a Mamyshev oscillator setup in which a fiber amplifier is split into two equal parts and placed before the filters. At low repetition rates this setup allows to produce pulses which are less affected by nonlinear distortions.
Methane-air mixtures were ignited in a constant-volume combustion chamber by a diode-pumped, passively Q-switched Nd:YAG/Cr4+:YAG laser with four beams, yielding single pulses or operating in burst mode with two pulses. A discussion of peak pressure, combustion time and of the ignition limits is made for each type of ignition.
Solution-processed nanoplatelets exhibit exciting optical properties which can be exploited for lasing in novel spectral ranges. Here, we incorporate these nanoplatelets in capillary fused silica fibers and investigate their optical properties. These results are the basis for a novel class of solution-processed nano-material fiber lasers.
A passively Q-switch Er:YAP laser, emitting 21.8 ns long (FWHM) pulses with energy 0.54 µJ and repetition rate 41.6 kHz at 2.9 µm is presented. In a free-running regime, the Er:YAP laser reached maximal output mean power of 200 mW with 25.5 % slope efficiency.
Cooling of Pr:YAP crystals close to liquid helium temperature allowed to significantly improve the Pr:YAP laser performances with respect to room temperature, which yielded in Watt-level laser outputs at all studied wavelengths (747 nm, 622 nm, 547 nm, and 493 nm) under 4W InGaN laser diode pumping.
Frequency-doubled 220 fs laser pulses at 515 nm are spectrally broadened and compressed in a multipass cell down to 38 fs using solid and gas as nonlinear media. The efficiency of this process is 90 %. This is the first demonstration of multipass spectral broadening and compression in green.
We present a Tm3+-doped actively Q-switched fiber laser providing pulse energies of 960 µJ with 20.5 kW peak power at a wavelength of 2050 nm and pulse energies of 720 µJ with 6.5 kW peak power at a wavelength of 2090 nm. The laser is ideally suited as a pump source for nonlinear frequency conversion.
We present a picosecond source use to characterise a PCF dispersive properties through Four Wave Mixing. We demonstate that the use of a stochastic pulse train obtain through an Amplified Spontaneous Emission seeder reduce the FWM threshold by several orders of magnitude as compared to a CW seeder.
Here, we report on a sub-30 fs Yb:YAP laser delivering soliton pulses as short as 24 fs at 1085 nm with an average output power of 186 mW and a pulse repetition rate of 87.8 MHz via soft-aperture Kerr-lens mode-locking (KLM).
We present two parallel all-PM-fiber Ytterbium amplifiers seeded by a single oscillator at 78.9 MHz repetition rate. An output power of 5 W is available at 7.5 or 50 ps pulse duration. The femtosecond part delivers 13.5 W output power at a compressed pulse duration below 60 fs.
We developed a high-speed S²-method-based device to monitor the modal content of a beam out of an optical fiber. The device is used to evaluate and optimize a CO2-laser-based fiber end cap manufacturing process.
Measurement of absorption and emission cross sections of the $~$790 nm and $~$1600-1900 nm thulium peaks relevant for high-power operation of cladding-pumped fiber lasers at 2-micrometers is reported. Up to 40% change of the respective peak values were observed while heating the fiber from -15 to 300°C.
The degenerate DROPO was stabilized by using a locking scheme which utilizes monitoring of a “parasitic” sum-frequency generation (SFG) of the signal and pump and together with the phase locked pump laser which can provide high intensities tailored two-color fields and benefit for THz generation.
The power dependence of a Nd:YVO4 laser amplifier beam wavefront was analyzed by Zernike polynomial decomposition. This analysis was performed experimentally and by simulations based on split-step Fourier propagation showing a good agreement. The simulations yield a base for the design of an aberration compensation system.
