We will review the recent state-of-the-art of high-power ultrafast disk lasers with a special emphasis on recent achievements in the area of modelocked thin-disk oscillators. These compact high-power modelocked lasers achieve higher average power (up to 350 W) and pulse energy (up to 80 µJ) than any other modelocked oscillator, offer unique possibilities for applications requiring highest pulse energies at Megahertz repetition rate, from compact one-box amplifier-free laser systems. Lasest results show that this is a promising high-power alternative to Ti:Sa amplifiers. We will present the latest technological advances and results as well as new application areas open by progress in the technology, for example for the generation of high-power THz pulses for time-domain spectroscopy.

Clara Saraceno was born in 1983 in Buenos Aires, Argentina. In 2007 she completed a Diploma in Engineering and an MSc at the Institut d’Optique Graduate School, Paris. She completed a PhD in Physics at ETH Zürich in 2012, for which she received among others the EPS-QEOD thesis prize in applied aspects in 2013. From 2013-2014, she worked as a Postdoctoral Fellow at the University of Neuchatel and ETH Zürich, followed by a postdoc position from 2015 – 2016 at ETH Zürich. In 2016, she received a Sofja Kovalevskaja Award of the Alexander von Humboldt Foundation and became Associate Professor of Photonics and Ultrafast Science at the Ruhr University Bochum, Germany. In 2018 she received an ERC Starting Grant and is currently an OSA Ambassador (2019). The current main research topics of her group include high-power ultrafast lasers and Terahertz science and technology.

The development of quantum science and technology has become an international race. High power single frequency lasers at various wavelengths, usually not easy to obtain, are required in laser cooling of atoms, optical standards, precision measurement etc. In this talk, we report our progress in developing high power low noise single frequency Yb, Er, and Raman fiber amplifiers for various specific applications, usually including frequency doubling to visible and ultraviolet regime. As a result, we can produce lasers at virtually any wavelength from 0.25 to 2 micron.

Currently a professor at Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS). He got his Ph.D. degree from the Physics Department of Nankai University in 2000. He spent two postdoctoral research positions at Institute of Physics, CAS, and Institute for Laser Science, University of Electro-communications, Japan. From 2005 to 2009, he was a laser physicist at European Southern Observatory and developed the technology of Raman fiber amplifier based sodium guide star laser. He joined SIOM in 2010 under the support of the 100-talent program of CAS, and is the deputy director of Shanghai Key Laboratory of Solid-state Laser and application. He works on precision fiber lasers and nonlinear fiber optics with important contributions in Raman fiber lasers and sodium guide star lasers. He has published more than 100 papers on referenced journals and edited the first and only reference book on Raman fiber lasers. His contributions have been recognized with awards of Berthold Leibinger Innovation Prize, Excellent Supervisor of CAS, and Contribution Award of Returned Chinese.

A short introduction for the mode-locking and a brief review of recent work on high power femtosecond fiber laser are demonstrated, which shows that few cycle laser pulse can be obtained by optimization of nonlinear process in fiber laser system. Pulse dynamics optimization also bring great impact on the time jitter of the pulse train. These new laser resources provide convenience for novel applications in the fields of high precision fabrication and measurement, experimental quantum physics, functional materials, etc.

Prof. Minglie Hu received the B. Eng. in Opto-electronics and Ph.D in Optic engineering degrees from Tianjin University in 2000 and 2005, respectively. For his PhD thesis, he studied the propagation of femtosecond laser pulses in photonic crystal fibers. After receiving his PhD from Tianjin University, Prof. Hu started to work in the ultrafast laser lab of Tianjin University from associate professor to full professor. Since then Prof. Hu focus on the pulse dynamics in the femtosecond fiber laser and amplifier. Prof. Hu authored or coauthored over 200 peer reviewed publications plus 3 book chapters. Moreover, he holds 23 patents. His current research interests include mode-locking laser oscillators and amplifiers, fiber lasers, linear and nonlinear propagation in photonic crystal fibers, and microstructure optical device.

Progress on several semiconductor lasers developed in our group will be reviewed. For narrow linewidth thermally tuned multi-channel interference widely tunable lasers, linewidth below ~200 kHz and side-mode suppression-ratio higher than 50 dB across the C-band have been achieved. For two-section high speed directly modulated O-band DFB lasers, 25 Gb/s signal transmission through 10 km fiber from -20 degree C to 80 degree C has been achieved. For 850 nm surface-grating surface emitting lasers, single mode lasing with side mode suppression ratio above 40 dB and threshold current below 10 mA has been achieved.

Prof. Guo received his PhD degree from Institute of Semiconductors, Chinese Academy of Sciences in 2004. Afterwards he joined the school of Physics, Trinity College Dublin Ireland as a research fellow. In 2010 he joined Prof. Coldren’ group as a project scientist in the Electrical and Computer Engineering department of University of California Santa Barbara. In 2014 he joined Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology as a professor and received the support from the 1000 talented youth plan. Now he is mainly working on optoelectronic integrated devices with novel concepts. His group has developed new laser concepts such monolithic widely tunable laser based on multi-channel interference, surface emitting lasers based on surface gratings, DFB lasers with active distributed reflector, etc.

A high energy laser has been used for basic science with laser-induced plasmas for a long time and has generated several kinds of high energy particles (electrons, positrons, neutrons and ions) and high energy radiations. Such high energy sources are attracting much attention to open new industrial and medical applications, such as space debris remove, gamma-ray non-destructive inspection, neutron source/BNCT, ion-beam therapy and so on. In such advanced applications, a repeatable high energy laser is strongly required instead of the conventional single-shot or low rep. rate high energy lasers, including Ti:sapphire laser and OPCPA. And the big laser system size should be miniaturized to be suitable for the new applications.
Developing the repeatable high energy laser, the most significant issue is a thermal problem in the optical devices, especially, a laser amplifier first. A laser material is decided by the required laser characteristics of pulse energy, pulse duration and wavelength. On the other hands, laser amplifier structure and system concept have a high flexibility in designing to suppress the thermal effects. In regard to the amplifier structure, we are focusing on an active mirror amplifier, which has an excellent feature of no wavefront distortion after laser amplification, in addition to excellent power scaling in both pulse energy and repetition rate. Also, a multi-module concept emphasizes the power scaling further. In my talk, our grand plan of the high energy laser facility in fs~ns, based on 100J/100Hz laser technology, will be reported.

1. Doctor of Science, University of Electro-Communications, at Tokyo in 1993, with doctorate thesis of collision with laser cooled and trapped lithium neutral atoms.
2. Assistant Professor of Miyazaki university, at Miyazaki from 1993, discharge-pumped Rare gas exicimer laser in VUV.
3. Researcher Deputy Chief of Japan Atomic Energy Research Institute (JAERI), at Kyoto from 1999, cryogenic laser with Yb-doped material in diode pump.
4. Associate Professor of Osaka university, at Osaka from 2004, kilo-joule, ps laser development (LFEX), Joule-class/100Hz DPSSL with cryogenic ceramic, and ultra-broadband OPCPA.
5. Professor of Osaka university.

Femtosecond fibre lasers have attracted huge technical attention in many applications such as fundamental scientific research, material processing, medicine, and sensing in recent years. One commonly used approach for the implementation of femtosecond fibre lasers is to use a mode-locking technique based on a passive nonlinear optical device, called a “saturable absorber (SA)”. Recently, the saturable absorption properties of MXenes, such as Ti3CTx and Ti3C2Tx, have been extensively investigated and their excellent performance comparable to those of other 2-dimensional (2-D) materials has been well demonstrated. In this presentation we review our recent investigation results on MXene and MAX phases as effective saturable absorption media that can generate femtosecond pulses from fiber lasers.

Ju Han Lee received the B.S. and M.S. degrees in electronics engineering from Seoul National University, Republic of Korea, in 1995 and 1998, respectively. He received a Ph.D. from the ORC at University of Southampton, UK in 2003. He was a senior member of the technical staff in Korea Institute of Science and Technology (KIST) from 2004 to 2007. He was a research fellow at the University of Tokyo, Japan, from September 2004 to October 2005. He was a visiting researcher at the IPAS in University of Adelaide, Australia from 2013 to 2014. Presently, he is Professor at the School of Electrical and Computer Engineering, University of Seoul, Seoul, Republic of Korea. His research interests include ultrafast fiber lasers, nonlinear fiber optics, all-optical signal processing, microwave photonics, and optical communications. He is an author or coauthor of more than 150 international journals and 150 technical conference papers.

Radially polarized beam, characterized by spatially axis-symmetrical polarization and doughnut-shaped intensity pattern, shows the feature of tight focusing, and thus has wide applications in laser processing, high-resolution microscopy and so on.
In this study, we presented a continuous-wave mode-locked (CWML) and radially polarized Yb-doped fiber laser. The fiber laser emitted CWML pulse with a maximum output power of 366 mW, a repetition rate of 3.05 MHz and pulse width of 27 ns at the pump power of 1.68 W. By inserting a quarter-wave plate in the laser cavity, the stability of laser, the beam quality and purity of radial polarization were significantly improved.

Jianlang Li is a professor at Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences. His research interests focus on novel fiber and solid-state laser. He developed the first radially polarized fiber laser, and thereafter extended it to the high-power and pulsed operation. He also realized the efficient, high-power and vector solid-state laser in end-pumped microchip laser geometry. In recent years, he developed highly efficient vortex solid-state laser, and invented the maglev and optically-driven rotary disk laser.

A single-cycle 100 petawatt laser pulse is obtained theoretically by dramatically increasing the spectrum, accordingly reducing the pulse duration, of the optical parametric chirped pulse amplification (OPCPA) with a new designed wide-angle non-collinear OPCPA (WNOPCPA). While comparing with two other recent popular methods of the energy-further increased single-beam femtosecond petawatt laser and the spatiotemporally coherent combination of multiple-beam femtosecond petawatt lasers, we believe that the proposed method is another choice for sub-exawatt lasers.

Zhaoyang Li currently is an assistant professor at Institute of Laser Engineering, Osaka University, Japan. He received BS. degree from Beijing Institute of Technology in 2005, MS. degree from the graduate school of China Academy of Engineering Physics in 2008, and PhD. degree from Nanjing University of Science and Technology in 2015. From 2008 to 2016, he was a Research Assistant/Associate at Joint Lab on high power laser & physics and State key Lab of high field laser physics at SIOM. As a core member, he co-developed the Chinese first petawatt laser of SG-II-ps-PW and co-designed the Chinese first 10-PW laser of SULF. Two original techniques he proposed have already been successfully applied in two 10-petawatt-class laser facilities of ELI-Beamlines in Europe and SULF in China. Up to now, he has 24 first-author peer-reviewed papers on Opt. Lett., Opt. Express, etc., 6 first-inventor patents, 6 PI national grant-projects, and several invited talks. He also served as a frequent reviewer for more than 10 optics journals. His recent research interests include the next generation of ultra-intense and high-average-power lasers, optical field measurement and control, nonlinear optics, etc.

As the extending and deeply applications of femtosecond laser pulses in ultrafast spectroscopy, nonlinear optic microscopy, and ultra-intense laser physics etc research fields. Many researches need several femtosecond pulses with different wavelengths or multicolor femtosecond pulses at the same time. Here, we will report the generation of more than 15 multicolor femtosecond pulses at the same time by simply using a thin glass plate through cascaded four-wave mixing process. The generated multicolor femtosecond pulses have high performances in frequency, time, and spatial domain. Then, it is used in the generation of seed pulses with high temporal contrast for PW laser system. Using the generated first-order multicolor femtosecond pulse as sampling pulse, novel four-order cross-correlator for single-shot temporal contrast measurement was proposed with high dynamic range, high fidelity, and high time resolution simultaneously.

Jun Liu received his PhD degree in optics from Shanghai Institute of Optics and Fine Mechanics, CAS, China in 2007. From 2007 to 2011, he worked in the University of Electro-Communications, Tokyo, Japan as a postdoc and then an assistant professor, where he won the fifth “Kondo Award” of Osaka University, Japan in 2011. From Aug. 2011 until now, he is working in the State Key Laboratory of High Field Laser Physics, SIOM, CAS as a professor, where he was selected into the Hundred Talents Program of CAS in 2011 and the Thousand Talents Program of China in 2012. Right now, his research work is focused on femtosecond laser technology and its applications, light sheet microscopy and its applications in photodynamic therapy, and optical imaging through scattering media. He has published more than 70 scientific journal papers, and obtained more than 15 national invent patents.

There are more intrinsic technological challenges for the very long wave infrared (≥14μm) quantum cascade lasers (QCLs). First, for photon energies larger than the reststrahlen band, population inversion is more difficult to attain as the upper state lifetime decreases with the emitted photon energy, due to a higher LO phonon scattering rate. Second, the nonradiative injection carrier leakage into the lower laser level increases.Third, the lower state lfetime remains practically unchanged and leads to low voltage efficiency. In this research, we presents a new design of active region for high-performance very long wave infrared QCLs. Guaranteed by efficient electron injection to the upper laser level and fast electron extraction through miniband from the lower laser level, high performance has been obtained at emission wavelength above 15μm.
The QCL structure was grown on a n-doped (Si, 2×1017 cm-3) InP substrate wafer by solid-source molecular beam epitaxy (MBE). The doping level in the active region was empirically adjusted so that roll over current density of was approximately equal to 3kA/cm2. The complete structure include 4 μm lower InP cladding layer (Si, 3×1016 cm-3), 300 nm thick n-In0.53Ga0.47As layer (Si, 4×1016 cm-3), 55 stages of the active/injector region, 300 nm thick n-In0.53Ga0.47As layer (Si, 4×1016 cm-3), 5 μm upper cladding layer (Si, 3×1016 cm-3), 150 nm gradually doped layer (changing from 1×1017 to 3×1017 cm-3) and 800 nm highly doped cladding layer (Si, 5×1018 cm-3). The double channel waveguides with an average ridge width of 40 μm were fabricated by photolithography and wet chemical etching. After etching, a 450-nm thick SiO2 layer was deposited by plasma enhanced chemical vapor deposition (PECVD) for electrical insulation. A 200 nm thick Ti/Au layer was deposited by e-beam evaporation to realize the electrical contact. In order to reduce thermal resistance, an additional 5 µm thick Au layer was subsequently electroplated. With thinning and annealing, the wafer was then cleaved into 4 mm long laser bars and mounted epilayer side down on the copper heat sink with indium solder.

Junqi Liu is currently a Professor at the Institute of Semiconductors, Chinese Academy of Sciences. He is also a Post Professor in Materials Physics and Chemistry in College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences. He received his degree in Materials Science and Technology and his PhD degree from University of Chinese Academy of Sciences and joined the faculty of the Institute of Semiconductors, Chinese Academy of Sciences in 2007. In recent years, his research has focused on quantum cascade lasers and published more than 130 related papers and 40 invention patents.

We report a compact all-fiber laser system mode-locked by Nano-materials such as nanotube and graphene. The proposed laser can deliver the multiple wavelengths and the central wavelengths are tunable. Nanomaterial-based mode-locking fiber laser emits the dissipative solitons with higher pulse energy. These results may provide helpful theoretical and experimental fundamentals for the in-depth study of new high-energy pulses, and bring the new understandings about nonlinear phenomenon of ultra-short high-energy pulses under extreme conditions.

Prof. Liu received the PhD degree in 2000. Successfully, He had engaged in the post-doctoral research in Tsinghua University and Seoul National University from 2000 to 2004. From May 2004 to Oct. 2005, He was a Scientist in Agency for Science, Technology and Research, Singapore. From Apr. 2007 to Jun. 2007 and from Nov. 2007 to Oct. 2008, He was a visiting scholar and research professor in the Chinese University of Hong Kong and Gwangju Institute of Science and Technology (GIST), respectively. From Mar. 2012 to Sep. 2012, He was a senior visiting scholar in the University of Cambridge. He has authored or coauthored papers more than 150. He was honored to the National Science Fund for Distinguished Young Scholars.

Pulse contrast is a crucial parameter of high peak-power lasers since the prepulse noise may disturb laser–plasma interactions. Pulse-contrast requirement increases with laser intensity, but the practical pulse contrast degrades with amplification. How to enhance the pulse contrast remains a challenge for high peak-power laser. In this report, I will introduce our attempts for solving the pulse-contrast challenge, including the generation mechanisms of noise, the single-shot characterization of pulse contrast and the in-band noise filtering. These works show the potential of tackling pulse-contrast challenge in the spatiotemporal 2D domain.

Jingui Ma received his Ph.D. in Optics at Fudan University, Shanghai, China, in 2014. From 2014-2016, he is a Postdoctoral Researcher in Shanghai Jiao Tong University, where he is now a distinguished associate researcher in School of Physics and Astronomy. He has published over 40 peer-reviewed papers and owned 13 technical patents (including 7 US patents). His Research interests include nonlinear optics, ultrafast measurements, intense lasers and mid-infrared lasers.

Mode-locked lasers emitting ultrashort pulses in the 2-micron spectral range at high (100-MHz) repetition rates offer unique opportunities for time-resolved molecular spectroscopy and are interesting as pump/seed sources for parametric frequency down-conversion and as seeders of ultrafast regenerative laser amplifiers.
Passively mode-locked lasers based on Tm3+- and Ho3+-doped bulk solid-state materials have been under development for about a decade. In 2009 we demonstrated the first steady-state operation of such a Tm:KLu(WO4)2 laser using a single-walled carbon nanotube (SWCNT) saturable absorber (SA) generating 10-ps pulses at 1950 nm. In 2012 it produced for the first time femtosecond (140-fs) pulses at 2037 nm. More recently, the study of numerous active media with different SAs resulted in the generation of sub-100-fs (sub-10-optical-cycle) pulses. Materials with broad and smooth spectral gain profile were selected, naturally emitting above 2-micron to avoid water vapor absorption/dispersion effects, including anisotropic materials, strong crystal-field distortion in hosts that do not contain rare-earths, crystals with structural or compositional (i.e. mixed compounds) disorder that exhibit inhomogeneous line broadening, mixed laser ceramics, and Tm,Ho-codoping of ordered and disordered crystals and ceramics.
A broad absorption band in semiconducting SWCNTs spans from 1.6 to 2.1-micron whereas the absorption of graphene extends into the mid-IR and scales for multilayers, increasing the modulation depth. Compared to GaSb-based semiconductor SA mirrors (SESAMs), the carbon nanostructures exhibit broader spectral response and can be fabricated by simpler and inexpensive techniques. Chirped mirrors were implemented for group-velocity dispersion compensation, to generate the shortest pulses, down to 55-fs at 2048 nm.

1978 – 1983 M.Sc. Degree in Nuclear and Elementary Particle Physics, Sofia University, Diploma work on laser Raman spectroscopy.
1983 - 1984 Institute for CO2 lasers: Full modelling of pulsed CO2 lasers.
1984 - 1988 Ph.D. Thesis: Dept. of Nonlinear Optics, Friedrich-Schiller-University, Jena: Experimental and theoretical studies of passively mode-locked dye lasers.
1988 - 1991 Assistant Professor, Dept. Quantum Electron., Sofia University, Teaching: Experimental Laser Physics and Principles of Quantum Electronics.
1991 – 1992 Guest Scientist (DAAD fellowship), Dept. of Physics, University of Regensburg: Coherent self-locking and passively mode-locked dye lasers.
since 1992 Department A3 of the Max Born Institute, Senior Research Associate

High power lasers with wavelengths around 3 μm have many potential applications, for example, in laser processing for materials which have low absorption at the near-infrared and the visible wavelength range, and in dentistry and surgery because the absorption coefficient of biological tissue containing water is very high at around 3 μm. Recently, output power and efficiency of Er-doped fluoride-glass fiber lasers with a wavelength of 2.8 μm have been significantly improved. Here, we review briefly the high-power 2.8 μm Er-doped fiber lasers and their application of laser processing and infrared solid-state lasers.

Shigeki Tokita is an associate professor of the Institute of Laser Engineering (ILE), Osaka University. After receiving his Dr. Eng. from the Osaka University in 2006, he was an assistant professor at the Institute for Chemical Research, Kyoto University in 2006–2013. His research interests are in high-power fiber lasers and laser-plasma interactions. He conducts research in efficient high-average-power Yb-doped lasers, Er-doped mid-infrared fiber lasers, control of energetic electron beam produced by ultrahigh-intensity laser pulses and strong terahertz wave generation by laser-plasma interactions.

There is tremendous technological needs for compact and efficient pulsed lasers operating in the mid-infrared range. While recent advances in mid-infrared gain platforms (including QCLs and mid-infrared rare earth doped fibers) are exciting, the lack of a capable optical switching device in the MIR has significantly limited the field. Following great efforts in low-dimensional materials, such as graphene and carbon nanotubes, we have recently identified a new class of quantum material –Topological Dirac Semimetal- which show promise for mid-infrared optical switching devices. The material shows good absorption as well as excellent tunability in key optical characteristics in the MIR, and can be fabricated into SESAM devices that greatly facilitates mass processing.

Prof. Fengqiu Wang obtained his B.S. in Electronic Engineering from Peking University and then a PhD from Cambridge University. He joined Nanjing University in 2013 and has since focused on the investigation of light-matter interaction in emerging low-dimensional materials. In particular, emphasis is placed on exploiting effects with relevance to applied photonics, where disruptive or better-performing devices can be developed. Examples include ultrafast optical switching devices with unprecedented bandwidth and tunability; 2D heterostructure devices operating across multiple spectral ranges, providing functionalities such as photo-detection, light-wave modulation, as well optical information processing. Dr. Wang has published over 100 papers and contributed 30 oral presentations at international conferences. His publications have drawn a total citation of >6000. He is program committee member for CLEO, CLEO-pacific rim, and ACP. He was awarded youth-1000-talent fellowship (2013) and Distinguished Young Scholars of Jiangsu Province (2017) and is principal investigator of two NSFC projects and work package chair for one State Key Project of Research and Development.

Gravitational wave detection is a new window to observational cosmology. Gravitational waves have been directly observed for fifteen times by the Advanced Laser Interferometer Gravitational-wave Observatory (Advanced LIGO) until recently. The next generation of gravitational wave detection will need a 2µm single frequency fiber laser as laser source to reduce thermal noise and high frequency quantum noise of the detection. What’s more, the noise of the 2µm single frequency fiber laser is a main noise source of the detection system. On the aim to be used for next generation of gravitational wave detection we demonstrate a low-noise narrow-linewidth single frequency fiber laser at 2µm, which consist a pair of homemade fiber bragg grating (FBG) and a segment commercial thulium-doped silica fiber. By optimizing the pumping scheme, cavity designing, and temperature controlling, we have realized the output of 2µm single frequency fiber laser with lower relative intensity noise (RIN) and narrower linewidth. Even after three-stage fiber amplification, the power is amplified to hundred watts, the RIN and linewidth don’t increase significantly.

Wang Pu graduated from the physics department of Shandong University with a bachelor's degree in 1986. In 2000, he graduated from Macquarie University in Australia with a PhD in laser physics from the Center for Lasers & Applications. He joined Institute of Laser Engineering of Beijing University of Technology in Nov. 2009。 His main research interests are novel high power ultrafast fiber lasers, fiber amplifiers, novel nanosecond pulsed fiber lasers, novel fiber-based optical devices and high peak power based nonlinear frequency conversion and so on. He has published more than 60 journal papers.

In this talk, we will introduce single and multiple vortex beam generation from laser and the applications in free-space communications.
By laser inscribing of cavity mirror, we can generate order-tunable vortex beam from laser. We built the numerical relationship between vortex topological charge and inscribed hole radius, which provides a design criterion for intracavity vortex laser generation. With the method, we realized intracavity vortex beam generation up to 288th-order. The generated vortex beam from laser is stable with propagation.
Furthermore, we demonstrated multiple vortex beam generation from laser by laser inscribing of cavity mirror. Numerical simulation shows that one can control multiple vortex modes to simultaneously oscillate in the laser. The multiple vortex laser could be self-mode-locked and generated high-repetition-rate picosecond pulses.
Finally, we demonstrate free-space communications with the multiple vortex laser, showing the potential of multiple vortex laser for spatial and temporal encoding.

Guoqiang Xie is a professor at the School of Physics and Astronomy of Shanghai Jiao Tong University. His current research interests include mid-infrared ultrashort and intense laser, vortex laser.

A rotating optical ring-shape lattice is generated by overlapping a pair of 20 Hz, 800 nm chirped pulses with a Michelson interferometer (MI). Its rotating rate can be up to ten trillion radians per second (Trad/s), which can be flexibly tuned with a mirror in the MI. Besides, its fold rotational symmetry structure is also changeable by controlling the difference from the topological charges of the pulse pair. Experimentally, we have successfully got a two-petal lattice with a tunable rotating speed of 7.9 Trad/s or 14 Trad/s, which is confirmed by our single-shot ultrafast frame imager basing on non-collinear optical parametric amplification with its frame rate up to 15 Tfps. This work is available at relativistic, even ultra-relativistic intensity by using an ultrashort but ultra-intense laser system operating at low repetition rate, so it may be interesting for laser plasma-based accelerators, the strong terahertz radiations and celestial phenomena.

Shixiang Xu, born in 1965, completed his PhD in 1998 from Shanghai Institute of Optics and Fine Mechanics, China. In 2006, he was awarded Shanghai Pujiang talent Fund. His current position is a professor of Shenzhen University, and his research interests include ultrashort pulse laser, ultrafast imaging and terahertz optics. Now, he also serves as a member of Laser Professional Committee of Chinese Optical Society, and one of the Councils of Guangdong Optical Society of China. Up to date, he has published more than 110 papers in peer-reviewed journals and authorized more than 25 patents.

High-performance infrared diode lasers offer exceptional properties which are exploited in many applications fields such as medicine and material processing, as well as the pumping sources for fiber lasers. We fully studied the fabrications of F-P cavity edge-emitting lasers (FP laser) and optically pumped infrared disk lasers (SDL), both of which were grown on Te-doped (001) oriented GaSb substrate by molecular beam epitaxy. The FP laser with InGaSb/AlGaAsSb double-quantum-well in the core area shows the peak power conversation efficiency more than 26% and efficiency higher than 16% at 1W. The maximum output power of the 2-mm-long, 100-μm-wide single emitter reaches to more than 1.6W at 7A and a 19-emitter bar with the maximum efficiency higher than 20% show 16W at 70A. The SDL chips were optically pumped by a fiber coupled commercial laser diode emitting at 1470 nm and an intra-cavity SiC heat spreader was attached to the chip for effective thermal management. Continuous-wave output power of over 1W operating at room temperature is achieved at 2.03 μm and as the effective region temperature increases, the envelope of multimode spectrum shifts to longer wavelengths as the pump power increases, thus increasing the output power. The M2 factors along the horizontal axis and vertical axis for the SDL are 1.30 and 1.66, showing a great beam quality.

Zhang Yu, associate researcher, The State Key Laboratory of Superlattice and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences. Mainly engaged in the epitaxy growth of antimony semiconductor lasers and the micro-fabrication of devices. His research was focused on high power GaSb-based diode laser, bars and high performance DFB, DBR single-mode lasers.

Pulse combination in space and time domain is one of the solutions for both high pulse energy and high repetition rate. Pulse combination in time domain (also called “pulse stacking) stacks the energy from a train of pulses in one pulse. Not only the polarization, but also the phase of the individual pulses has to be controlled for sequential pulse combination. Our group has developed coherent pulse combination system based on our 1GHz repetition rate fiber laser. By phase control and delay compensation, we have stacked four pulses together. More pulse stacking is possible and is in progress. The talk will introduce the progress, difficulties and perspective.

Prof. Zhigang Zhang received his PhD degree in Physics from Monash University, Australia, in 1992. He joined the Institute of Research and Innovation Japan, the Electrotechnical Labs in 1992 and 1996 respectively. In 1999, joined Tianjin University as a “Cheung Kong Scholar”. In 2005, he moved to Peking University as a full professor at the Department of Electronics, Peking University.
His has published more than 120 journal papers in peer reviewed international journals and a book “Femtosecond laser technology”. His current research interest is femtosecond fiber laser frequency combs, low noise microwave extraction from combs, coherent pulse stacking beam combination and femtosecond laser micromachining.
Prof. Zhigang Zhang is a Fellow of Optical Society of America

Vacuum ultraviolet (VUV) beam sources (λ= 100–200 nm, i.e., hυ= 6.20–12.40 eV) are indispensable for laser-based angle-resolved photo-emission spectroscopy (ARPES). Results on 10-MHz femtosecond enhancement cavity based, and 1-MHz single pass configuration based high harmonic generation will be introduced. Combined with ARPES, electron signal has been detected. Further consideration on how to improve the system performance will also be presented.

Zhigang Zhao, born in 1984, is professor with school of information science and engineering (ISE), Shandong University (Qingdao Campus). He got his bachelor degree from Shandong University in 2006, Ph.D. from Zhejiang University in 2011. Afterward, he spent one year as postdoc in Technische Universität Berlin, Germany. Since November 2012, he became researcher in the Institute for Solid State Physics (ISSP) in the University of Tokyo, where he developed high power fiber chirped pulse amplifier with average power exceeding 100 W at repetition rate of 1 MHz, mW-level VUV source for ARPES investigation, and high-power UV laser at 258/221/193 nm. His current interests include high power ultrafast laser system, nonlinear frequency conversion, high repetition rate VUV sources generation, and laser processing.

Random distributed feedback fiber lasers have been drawing more and more research interesting due to their research and application potentials in broadband application fields, such as remote sensing, imaging, biotechnology, nonlinear frequency converter as well as new pump source. In this talk, we will review the recent research progress on optical field manipulation in our group. Manipulating the polarization, optical spectrum, spatial mode would be covered as well as power-scaling performance and analysis.

Pu Zhou received Ph.D degree in Optical Engineering from National University of Defense Technology (NUDT), China, and now he is a professor and supervisor for Ph.D student in NUDT. His recent research interests include fundamental investigation on high power fiber laser and beam combining. He is leading or has completed over ten projects funded by National Natural Science Foundation of China and others. As the first author or corresponding author, he has published more than 150 peer-reviewed papers. He is the reviewer of more than 30 peer-reviewed journals and has been recognized as outstanding reviewer of OSA (2017) and CLP (2017, 2018).

Yb solid-state lasers have the potential to generate high power ultrashort femtosecond pulses due to the excellent spectroscopic and thermal properties of the Yb3+-doped laser materials. However, only several tens to hundreds mW average power was achieved from a conventional diode-pumped Kerr-lens mode-locked (KLM) Yb solid-state lasers, which is mainly limited by the pumping diode and the critical laser configuration. In order to scale the average power to watt-lever while maintaining the sub-100 fs pulse duration for various applications, such as seeding the solid-state amplifier, nonlinear frequency conversion and multi-photon microscopy, we have developed two methods to generate high power femtosecond pulses from Yb solid-state lasers via KLM technique. By employing the high beam quality 976 nm fiber laser as the pump source, we have realized stable KLM operation in the Yb:CYA laser, with as high as 4.2 W average power and 148 fs pulse duration. By enhancing the nonlinearity in the cavity and extra-cavity pulse compression, we’ve got 2 W, 36 fs pulses, which is the highest power for sub-40 fs solid-state Yb lasers. Further power scaling is proposed by multimode laser diode (LD) as the pump. By inserting another Kerr medium in the cavity to build a double-confocal cavity, we have achieved 6.2 W, 59 fs pulses from a LD pumped Yb:CYA oscillator, with the single pulse energy of 124 nJ and peak power of 2.1 MW, respectively.

Dr. Zhu received the Ph.D. degree in ultrafast optics from the Institute of Physics, Chinese Academy of Sciences, Beijing, China, in 2008. He was with the Department of Applied Physics, Hokkaido University, Sapporo, Japan, from 2008 to2011, as a Post-Doctoral Fellow. Since 2011, he has been with the School of Physics and Optoelectronic Engineering, Xidian University, Xi’an, China. Currently he is professor and dean of Department of Laser technology. His research interests include novel ultrafast laser technology, nonlinear frequency conversion, and their applications. He has authored and co-authored more than 100 peer-reviewed journals; more than 40 contributed and invited talks at international meetings. He serves as Topical Editor of “Chinese Optics Letters” and “Acta Optica Sinica”, Youth Editorial Board of Chinese Laser Press and “Journal of Applied Optics”.