Physics of shock waves and high-temperature hydrodynamic phenomena - Ya.B. Zeldovich and Yu.P. Raizer (translated from the Russian and then edited by Wallace D. Hayes and Ronald F. Probstein); Dover Publications, New York, 2002, 944 pp., $34.

In the past years, laser ablation synthesis in solution (LASiS) emerged as a reliable alternative to traditional chemical reduction methods for obtaining noble metal nanoparticles (NMNp). LASiS is a “green” technique for the synthesis of stable NMNp in water or in organic solvents, which does not need stabilizing molecules or other chemicals. The so obtained NMNp are highly available for further functionalization or can be used wherever unprotected metal nanoparticles are desired. Surface functionalization of NMNp can be monitored in real time by UV-visible spectroscopy of the plasmon resonance. However LASiS has some limitations in the size control of NMNp, which can be overcome by “chemical free” laser treatments of NMNp. In this paper we provide an overview of LASiS, size manipulation by laser irradiation and functionalization of NMNp, with special care in pointing out some of the main issues about this research area.

Laser ablation synthesis in solution and size manipulation of noble metal nanoparticles

By L I Sedov London: Cleaver-Hume Press Ltd Pp xvi + 363 Price 105s This is really two separate books within the same pair of covers First of all Chapters 1-3, some 145 pages, are devoted to the discussion of similarity and dimensional, methods and their application to a variety of problems in mechanics and fluid mechanics

http://iopscience.iop.org/article/10.1088/0031-9112/11/6/008/pdf

Similarity and Dimensional Methods in Mechanics

The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation (LA) with electrospray ionization (ESI).

Laser ablation electrospray ionization (LAESI) for atmospheric pressure, in vivo, and imaging mass spectrometry

Femtosecond-laser micromachining (also known as inscription or writing) has been developed as one of the most efficient techniques for direct three-dimensional microfabrication of transparent optical materials. In integrated photonics, by using direct writing of femtosecond/ultrafast laser pulses, optical waveguides can be produced in a wide variety of optical materials. With diverse parameters, the formed waveguides may possess different configurations. This paper focuses on crystalline dielectric materials, and is a review of the state-of-the-art in the fabrication, characterization and applications of femtosecond-laser micromachined waveguiding structures in optical crystals and ceramics. A brief outlook is presented by focusing on a few potential spotlights.

Optical waveguides in crystalline dielectric materials produced by femtosecond-laser micromachining

Part 1: Basic Physics and Simulations Numerical simulation of the expansion into vacuum of a crystal heated by an ultrashort laser pulse- Fast electronic transport and Coulomb explosion in materials irradiated with ultrashort laser pulses- New methods for laser cleaning of nanoparticles- Plume dynamics- New aspects of laser-induced ionization of wide band-gap solids- Part 2: Ultrafast Interactions Three-dimensional material processing with femtosecond lasers- Ultrafast optical measurements of shocked materials- Time and space-resolved spectroscopy- Physical chemistry of ultrafast laser interactions with solids- Femtosecond plasma-mediated nanosurgery of cells and tissues- Part 3: Material Processing Designed polymers for ablation- Fabrication of waveguides by laser deposition- Pulsed laser deposition for functional optical films- Laser forward transfer of electronic and power generating materials- Part 4: Laser-matter interaction in novel regimes Development of inertial fusion energy by lasers- Laser space propulsion- Laser propulsion thrusters for space transportation- Laser propulsion- Nano-structuring using pulsed laser radiation- Soft laser desorption ionization - MALDI, DIOS and nanostructures- Materials modification with intense extreme ultraviolet pulses from a compact laser- Laser restoration of painted artworks

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Laser Ablation and its Applications

LASER ablation propulsion (LAP) is a major new electric propulsion concept with a 35-year history. In LAP, an intense
laser beam [pulsed or continuous wave (CW)] strikes a condensedmatter surface (solid or liquid) and produces a jet of vapor or plasma.
Just as in a chemical rocket, thrust is produced by the resulting reaction force on the surface. Spacecraft and other objects can be propelled in this way. In some circumstances, there are advantages for this technique compared with other chemical and electric propulsion schemes. It is difficult to make a performance metric for LAP, because only a few of its applications are beyond the research phase and because it can be applied in widely different circumstances that would require entirely different metrics. These applications range from milliwatt-average-power satellite attitude-correction
thrusters through kilowatt-average-power systems for reentering near-Earth space debris and megawatt-to-gigawatt systems for direct launch to lowEarth orbit (LEO). 
We assume an electric laser rather than a gas-dynamic or
chemical laser driving the ablation, to emphasize the performance as an electric thruster. How is it possible for moderate laser electrical efficiency to givevery high electrical efficiency? Because laser energy can be used to drive an exothermic reaction in the target material controlled by the laser input, and electrical efficiency only measures the ratio of exhaust power to electrical power. This distinction may
seem artificial, but electrical efficiency is a key parameter for space applications, in which electrical power is at a premium.
The laser system involved in LAP may be remote from the
propelled object (on another spacecraft or planet-based), for
example, in laser-induced space-debris reentry or payload launch to low planetary orbit. In other applications (e.g., the laser–plasma microthruster that we will describe), a lightweight laser is part of the propulsion engine onboard the spacecraft.

Review: Laser-Ablation Propulsion

Removing orbital debris with lasers

We developed an entirely new type of orientation thruster for micro- and nanosatellites. The laser plasma thruster is based on the recent commercial availability of diode lasers with sufficient brightness and 100% duty cycle to produce a repetitively pulsed or continuous vapor or plasma jet on a surface in vacuum. A low-voltage semiconductor switch can drive the laser. A lens focuses the laser diode output on the ablation target, producing a miniature jet that provides the thrust. Single-impulse dynamic range is nearly five orders of magnitude, and the minimum impulse bit is 1 nN/s in a 100-„s pulse. Even with diffraction-limited focusing optics, at least 0.5-W optical power is needed to produce thrust from selected ablator materials. Thrust-to-power ratio Cm is 50 to 100„N/W and specific impulse Isp is 200‐500 s with a 1-W laser, depending partially on the illumination mode. Transmission and reflection (R) illumination modes are discussed. R mode gives about 50% better Isp and two times better Cm. Improved results are anticipated from higher laser power in the reflection mode. The prototype engine we are developing is intended to provide lifetime on-orbit steering for a 5-kg satellite, as well as reentering it from low Earth orbit.

/pdf/diode-laser-driven-microthrusters-a-new-departure-for-2rfnr9j8iy.pdf

Diode Laser-Driven Microthrusters: A New Departure for Micropropulsion

The ablation characteristics of various polymers were studied at low and high fluences for an irradiation wavelength of 308 nm. The polymers can be divided into three groups, i.e. polymers containing triazene groups, designed ester groups, and reference polymers, such as polyimide. The polymers containing the photochemically most active group (triazene) exhibit the lowest thresholds of ablation (as low as 25 mJ cm-2) and the highest etch rates (e.g. 250 nm/pulse at 100 mJ cm-2), followed by the designed polyesters and then polyimide. Neither the linear nor the effective absorption coefficients have a clear influence on the ablation characteristics. The different behavior of polyimide might be explained by a pronounced thermal part in the ablation mechanism. The laser-induced decomposition of the designed polymers was studied by nanosecond interferometry and shadowgraphy. The etching of the triazene polymer starts and ends with the laser pulse, indicating photochemical ablation. Shadowgraphy reveals mainly gaseous products and a pronounced shockwave in air. The designed polymers were tested for an application as the polymer fuel in laser plasma thrusters.

Claude R. Phipps

Papers

Laser Ablation and its Applications

Review: Laser-Ablation Propulsion

Removing orbital debris with lasers

Diode Laser-Driven Microthrusters: A New Departure for Micropropulsion

Fundamentals and applications of polymers designed for laser ablation