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We generated 106-fs, 4.1-nJ pulses at 778 nm from a single green diode-pumped multipass-cavity Kerr-lens mode-locked Ti3+:sapphire laser. To our knowledge, these represent the highest pulse energies generated directly with a diode-pumped Ti3+:sapphire laser., NA

Date of Conference: 31 July-4 August 2017 Conference Name: 12th Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2017 We report a single-mode, 42 MHz, 3.5-W average power chirped pulse amplification fiber laser system operating at 1560 nm. The laser system comprises a dispersion-managed mode-locked oscillator and twoamplifier stages. The output pulses are compressed to 180 fs by using two diffraction gratings.

We report the first demonstration of femtosecond pulse generation from a Cr:LiSAF laser mode-locked with a monolayer graphene saturable absorber. Nearly transform-limited 72-fs pulses were generated at 850 nm with only two 135-mW pump diodes.

Cataloged from PDF version of article. We report on the development of a ultrafast fiber laser-microscope system for femtosecond photodisruption of biological targets. A mode-locked Yb-fiber laser oscillator generates few-nJ pulses at 32.7 MHz repetition rate, amplified up to similar to 125 nJ at 1030 nm. Following dechirping in a grating compressor, similar to 240 fs-long pulses are delivered to the sample through a diffraction-limited microscope, which allows real-time imaging and control. The laser can generate arbitrary pulse patterns, formed by two acousto-optic modulators (AOM) controlled by a custom-developed field-programmable gate array (FPGA) controller. This capability opens the route to fine optimization of the ablation processes and management of thermal effects. Sample position, exposure time and imaging are all computerized. The capability of the system to perform femtosecond photodisruption is demonstrated through experiments on tissue and individual cells. (c) 2012 Optical Society of America

The majority of the applications of ultrashort laser pulses require a control of its spectral bandwidth. In this paper we show the capability of volume phase holographic gratings recorded in photopolymerizable glasses for spectral pulse reshaping of ultrashort laser pulses originated in an Amplified Ti: Sapphire laser system and its second harmonic. Gratings with high laser induce damage threshold (LIDT) allowing wide spectral bandwidth operability satisfy these demands. We have performed LIDT testing in the photopolymerizable glass showing that the sample remains unaltered after more than 10 million pulses with 0,75 TW/cm2 at 1 KHz repetition rate. Furthermore, it has been developed a theoretical model, as an extension of the Kogelnik's theory, providing key gratings design for bandwidth operability. The main features of the diffracted beams are in agreement with the model, showing that non-linear effects are negligible in this material up to the fluence threshold for laser induced damage. The high versatility of the grating design along with the excellent LIDT indicates that this material is a promising candidate for ultrashort laser pulses manipulations. © 2010 Optical Society of America.

Cataloged from PDF version of article. We propose and demonstrate the use of short pulsed fiber lasers in surface texturing using MHz-repetition-rate, microjoule- and sub-microjoule-energy pulses. Texturing of titanium-based (Ti6Al4V) dental implant surfaces is achieved using femtosecond, picosecond and (for comparison) nanosecond pulses with the aim of controlling attachment of human cells onto the surface. Femtosecond and picosecond pulses yield similar results in the creation of micron-scale textures with greatly reduced or no thermal heat effects, whereas nanosecond pulses result in strong thermal effects. Various surface textures are created with excellent uniformity and repeatability on a desired portion of the surface. The effects of the surface texturing on the attachment and proliferation of cells are characterized under cell culture conditions. Our data indicate that picosecond-pulsed laser modification can be utilized effectively in low-cost laser surface engineering of medical implants, where different areas on the surface can be made cell-attachment friendly or hostile through the use of different patterns. (C) 2011 Optical Society of America

We report on the generation of high-average-power and high-peak-power ultrashort pulses from a mode-locked fiber laser operating in the all-normal-dispersion regime. As gain medium, a large-mode-area ytterbium-doped large-pitch photonic-crystal fiber is used. The self-starting fiber laser delivers 27 W of average power at 50:57 MHz repetition rate, resulting in 534 nJ of pulse energy. The laser produces positively chirped 2 ps output pulses, which are compressed down to sub-100 fs, leading to pulse peak powers as high as 3:2 MW. © 2011 Optical Society of America.

Efficient mode-locking in a Tm:KY(WO4)(2) laser is demonstrated by using InGaAsSb quantum-well SESAMs. Self-starting ultrashort pulse generation was realized in the 1979-2074 nm spectral region. Maximum average output power up to 411 mW was produced around 1986 nm with the corresponding pulse duration and repetition rate of 549 fs and 105 MHz respectively. Optimised pulse durations of 386 fs were produced with an average power of 235 mW at 2029 nm. (C) 2011 Optical Society of America Publisher PDF

We report the generation of high-energy high-peak power pulses in an all-normal dispersion fiber laser featuring large-mode-area photonic crystal fibers. The self-starting chirped-pulse fiber oscillator delivers 11 W of average power at 15:5 MHz repetition rate, resulting in 710 nJ of pulse energy. The output pulses are dechirped outside the cavity from 7 ps to nearly transform-limited duration of 300 fs, leading to pulse peak powers as high as 1:9 MW. Numerical simulations reveal that pulse shaping is dominated by the amplitude modulation and spectral filtering provided by a resonant semiconductor saturable absorber. © 2010 Optical Society of America.

We report large-aperture volume holographic chirped Bragg reflector recorded in a photopolymer material. It permits to realize compact optical pulse stretchers (230-ps) for femtoseconds lasers.

Circular craters with diameters of 500 nm are fabricated on the surface of fused silica by femtosecond ultraviolet-infrared (UV-IR) pulse trains with 0.8 nJ UV pulse energy. UV damage thresholds at different IR energies and UV-IR delays are measured. Diameters and depths of the ablated craters can be modified by adding the IR pulse and varying the UV-IR delays. These results demonstrate the feasibility of nanomachining using short wavelength lasers with pulse energy far below normal damage thresholds.

A room temperature, multipass-cavity, femtosecond Cr4+:forsterite laser was modelocked with a single-layer graphene saturable absorber on a YAG substrate. The resonator produced nearly transform-limited 92 fs pulses near 1250 nm with 53 kW of peak power. © OSA 2013.

Date of Conference: 16–21 May 2010 Conference name: Conference on Lasers and Electro-Optics 2010 Controlled modification of implant surfaces using femtosecond, picosecond and nanosecond pulses from home-built all-fiber-integrated lasers is demonstrated. Picosecond and femtosecond pulses offer superior control over the surface texture. Increasing cell attachment to surface is discussed. ©2010 Optical Society of America.

Multiphoton fluorescence microscopy based on femtosecond laser scanning is a powerful technique for three dimensional optical sectioning in life sciences. The method is based on the simultaneous absorption of two or three photons in the focal volume of a high NA microscope objective. The same setup is suited for nanodissection of living cells and subcellular structures. A very small lateral extent of the modified focal volume is required to minimize collateral damage in the vicinity of the laser focus and to improve long-term cell viability. By using high NA microscope objectives and laser pulse energies close to the ablation threshold, the lateral extent of the modified material is limited to less than 1 µm. This diffraction limited resolution can be further improved by techniques generally referred to as superresolution. These are achieved by controlling the phase of the laser beam with a diffractive filter placed at the exit pupil of an optical system. We integrated this technique into nanosurgery of cells, which we demonstrate here for the first time.

Date of Conference: 10-15 May 2015 Conference name: 2015 Conference on Lasers and Electro-Optics (CLEO) This paper investigates a new field for application of femtosecond laser-induced periodic surface structures (LIPSS). We designed an innovative solution to reduce coefficient of friction of mechanical parts by using the nonlinear laser lithography technique (NLL). © 2015 OSA.