Author
Jianping Zhou
Bio: Jianping Zhou is an academic researcher from Washington State University. The author has contributed to research in topics: Laser & Ti:sapphire laser. The author has an hindex of 7, co-authored 10 publications receiving 961 citations.
Papers
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TL;DR: By optimizing the intracavity dispersion compensation in a self-mode-locked Ti:sapphire laser, pulses of 10.95-fs duration are generated, which are shorter than has been possible with any other type of laser material to date.
Abstract: By optimizing the intracavity dispersion compensation in a self-mode-locked Ti:sapphire laser, we have generated pulses of 10.95-fs duration. Dispersion within the laser cavity is reduced by use of a short 4.5-mm highly doped Ti:sapphire crystal and fused-silica prisms. The output from the laser has an average power of as much as 500 mW, with a wavelength centered at 780 nm and a bandwidth of 62 nm. Our results demonstrate that the exceptionally broad bandwidth of Ti:sapphire can be utilized to generate pulses that, to our knowledge, are shorter than has been possible with any other type of laser material to date.
403 citations
TL;DR: By operating near the zero second- and third-order dispersion point in a self-mode-locked Ti:sapphire laser the authors can generate sub-10-fs pulses and demonstrate that the pulse is shortest near the middle of the laser crystal, in one direction of propagation.
Abstract: We demonstrate that by operating near the zero second- and third-order dispersion point in a self-mode-locked Ti:sapphire laser we can generate sub-10-fs pulses. Our numerical simulations show that the pulse duration is limited by fourth-order dispersion and that shorter pulses will be possible if this can be reduced. Also, by inserting a pellicle in various positions in a Ti:sapphire cavity, we have measured the intracavity pulse duration and chirp of the circulating pulse in the laser. Our results demonstrate that the pulse is shortest near the middle of the laser crystal, in one direction of propagation. In the other direction of propagation, the pulse is positively chirped and several times longer.
214 citations
TL;DR: A laser system that generates multiterrawatt transform-limited pulses, with good beam quality and low amplified-spontaneous-emission levels, at a duration near the theoretical limit imposed by gain narrowing in Ti:sapphire is reported.
Abstract: We report the generation of 26-fs-duration pulses, with an energy of 60 mJ, from a simple multipass Ti:sapphire amplifier system. The peak power of our amplified pulses is 2 TW, and the repetition rate is 10 Hz. Our amplifier design consists of two highly doped multipass amplifiers and is simple and compact. We use an all-reflective, low-groove-density grating stretcher and compressor, combined with a relatively short material path length in the amplifier. This design allows us to minimize higher-order dispersion. The result is a laser system that generates multiterrawatt transform-limited pulses, with good beam quality and low amplified-spontaneous-emission levels, at a duration near the theoretical limit imposed by gain narrowing in Ti:sapphire.
114 citations
TL;DR: This work analyzes the performance of a Ti:sapphire self-mode-locked laser with near-zero second- and third-order dispersion and concludes that it is possible to generate pulses much shorter than 10 fs if fourth- order dispersion is further reduced.
Abstract: We analyze the performance of a Ti:sapphire self-mode-locked laser with near-zero second- and third-order dispersion. Our simulations show that, in the presence of fourth-order dispersion, solitary laser pulses can be supported within a wide parameter range, close to the experimental values of these parameters. We also conclude that it is possible to generate pulses much shorter than 10 fs if fourth-order dispersion is further reduced.
102 citations
TL;DR: A broadband, low-dispersion chirped-pulse stretcher-and-amplifier design was used for propagation and amplification of the ultrashort pulses, permitting us to generate near-transform-limited amplified pulses at a duration near the theoretical limit imposed by gain narrowing in Ti:sapphire.
Abstract: We have demonstrated the generation of 21 ± 2 fs duration pulses, with an energy of 0.5 mJ, a bandwidth of 44 nm, and a repetition rate of 10 Hz, using a chirped-pulse amplification scheme in Ti:sapphire. We use 11-fs, 5-nJ pulses from a Ti:sapphire oscillator as the input for an eight-pass Ti:sapphire amplifier. A broadband, low-dispersion chirped-pulse stretcher-and-amplifier design was used for propagation and amplification of the ultrashort pulses. By the addition of a prism pair to the stretcher, both the second- and third-order dispersions are minimized, permitting us to generate near-transform-limited amplified pulses at a duration near the theoretical limit imposed by gain narrowing in Ti:sapphire.
86 citations
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TL;DR: In this article, the authors present the landmarks of the 30-odd-year evolution of ultrashort-pulse laser physics and technology culminating in the generation of intense few-cycle light pulses and discuss the impact of these pulses on high-field physics.
Abstract: The rise time of intense radiation determines the maximum field strength atoms can be exposed to before their polarizability dramatically drops due to the detachment of an outer electron. Recent progress in ultrafast optics has allowed the generation of ultraintense light pulses comprising merely a few field oscillation cycles. The arising intensity gradient allows electrons to survive in their bound atomic state up to external field strengths many times higher than the binding Coulomb field and gives rise to ionization rates comparable to the light frequency, resulting in a significant extension of the frontiers of nonlinear optics and (nonrelativistic) high-field physics. Implications include the generation of coherent harmonic radiation up to kiloelectronvolt photon energies and control of the atomic dipole moment on a subfemtosecond $(1{\mathrm{f}\mathrm{s}=10}^{\mathrm{\ensuremath{-}}15}\mathrm{}\mathrm{s})$ time scale. This review presents the landmarks of the 30-odd-year evolution of ultrashort-pulse laser physics and technology culminating in the generation of intense few-cycle light pulses and discusses the impact of these pulses on high-field physics. Particular emphasis is placed on high-order harmonic emission and single subfemtosecond extreme ultraviolet/x-ray pulse generation. These as well as other strong-field processes are governed directly by the electric-field evolution, and hence their full control requires access to the (absolute) phase of the light carrier. We shall discuss routes to its determination and control, which will, for the first time, allow access to the electromagnetic fields in light waves and control of high-field interactions with never-before-achieved precision.
2,547 citations
TL;DR: The carrier-envelope phase of the pulses emitted by a femtosecond mode-locked laser is stabilized by using the powerful tools of frequency-domain laser stabilization to perform absolute optical frequency measurements that were directly referenced to a stable microwave clock.
Abstract: We stabilized the carrier-envelope phase of the pulses emitted by a femtosecond mode-locked laser by using the powerful tools of frequency-domain laser stabilization. We confirmed control of the pulse-to-pulse carrier-envelope phase using temporal cross correlation. This phase stabilization locks the absolute frequencies emitted by the laser, which we used to perform absolute optical frequency measurements that were directly referenced to a stable microwave clock.
2,499 citations
TL;DR: In this article, the field of femtosecond pulse shaping is reviewed, and applications of pulse shaping to optical communications, biomedical optical imaging, high power laser amplifiers, quantum control, and laser-electron beam interactions are reviewed.
Abstract: We review the field of femtosecond pulse shaping, in which Fourier synthesis methods are used to generate nearly arbitrarily shaped ultrafast optical wave forms according to user specification. An emphasis is placed on programmable pulse shaping methods based on the use of spatial light modulators. After outlining the fundamental principles of pulse shaping, we then present a detailed discussion of pulse shaping using several different types of spatial light modulators. Finally, new research directions in pulse shaping, and applications of pulse shaping to optical communications, biomedical optical imaging, high power laser amplifiers, quantum control, and laser-electron beam interactions are reviewed.
2,051 citations
TL;DR: Semiconductor lasers for optical pumping and fast optical saturable absorbers, based on either semiconductor devices or the optical nonlinear Kerr effect, have dramatically improved these lasers and opened up new frontiers for applications with extremely short temporal resolution, extremely high peak optical intensities and extremely fast pulse repetition rates.
Abstract: Ultrafast lasers, which generate optical pulses in the picosecond and femtosecond range, have progressed over the past decade from complicated and specialized laboratory systems to compact, reliable instruments. Semiconductor lasers for optical pumping and fast optical saturable absorbers, based on either semiconductor devices or the optical nonlinear Kerr effect, have dramatically improved these lasers and opened up new frontiers for applications with extremely short temporal resolution (much smaller than 10 fs), extremely high peak optical intensities (greater than 10 TW/cm2) and extremely fast pulse repetition rates (greater than 100 GHz).
1,914 citations
TL;DR: In this paper, the design requirements of SESAM's for stable pulse generation in both the mode-locked and Q-switched regime were reviewed, and the combination of device structure and material parameters provided sufficient design freedom to choose key parameters such as recovery time, saturation intensity, and saturation fluence.
Abstract: Intracavity semiconductor saturable absorber mirrors (SESAM's) offer unique and exciting possibilities for passively pulsed solid-state laser systems, extending from Q-switched pulses in the nanosecond and picosecond regime to mode-locked pulses from 10's of picoseconds to sub-10 fs. This paper reviews the design requirements of SESAM's for stable pulse generation in both the mode-locked and Q-switched regime. The combination of device structure and material parameters for SESAM's provide sufficient design freedom to choose key parameters such as recovery time, saturation intensity, and saturation fluence, in a compact structure with low insertion loss. We have been able to demonstrate, for example, passive modelocking (with no Q-switching) using an intracavity saturable absorber in solid-state lasers with long upper state lifetimes (e.g., 1-/spl mu/m neodymium transitions), Kerr lens modelocking assisted with pulsewidths as short as 6.5 fs from a Ti:sapphire laser-the shortest pulses ever produced directly out of a laser without any external pulse compression, and passive Q-switching with pulses as short as 56 ps-the shortest pulses ever produced directly from a Q-switched solid-state laser. Diode-pumping of such lasers is leading to practical, real-world ultrafast sources, and we will review results on diode-pumped Cr:LiSAF, Nd:glass, Yb:YAG, Nd:YAG, Nd:YLF, Nd:LSB, and Nd:YVO/sub 4/.
1,866 citations