Acoustic shock waves (ASWs) in the frequency range of 30-120 kHz generated during laser-induced breakdown (LIB) ambient air using 7 ns and 30 ps pulse durations are studied. The specific peak amplitudes observed to be different for nanosecond (ns) picosecond (ps) LIB. ASW frequencies ps-LIB lie between 90 120 with one dominant peak, whereas ns-LIB, two peaks 30-70 80-120 observed. These laser intensity dependent. With increasing energy pulses, acoustic move toward audible range. variation...

Evolution of acoustic shock wave (ASW) properties generated during nanosecond (ns) and picosecond (ps) laser-induced breakdown (LIB) atmospheric air at different input intensities is presented. The intensity varied by changing the focal geometry ns ps pulses. ASW pressures are observed to follow dynamic interplay between plasma density recombination species. conversion laser energy has increased from loose tight focusing conditions. central frequencies have moved toward lower side with...

The radio frequency emissions scanned over broad spectral range (30 MHz–1 GHz) from single shot nanosecond (7 ns) and picosecond ps) laser induced breakdown (LIB) of different target materials (atmospheric air, aluminum, copper) are presented. dominant ns-LIB, compared to those the ps-LIB, indicate presence importance atomic molecular clusters in plasma. dynamics pulse-matter interaction properties were found play an important role determining plasma parameters which subsequently determine...

The interaction of two counterpropagating plasmas and shockwaves due to a 7 ns laser induced breakdown (LIB) ambient atmospheric air was studied using the 2D emission shadowgraphic imaging technique. effect separation distance (d) between plasma sources their energy ratio on shockwave evolution is presented. These low density temperature form stagnation layer in zone that showed an interesting dependence input sources. dynamics plumes shock waves are compared with respective single source...

The studies on the effect of input laser intensity, through variation focusing geometry, radio frequency (RF) emissions, over 30–1000 MHz from nanosecond (ns) and picosecond (ps) induced breakdown (LIB) atmospheric air are presented. RF emissions ns ps LIB were observed to be decreasing increasing, respectively, when traversed tight loose conditions. angular radial intensities found consistent with sin2θ/r2 dependence electric dipole radiation. normalized vary incident intensity (Iλ2),...

The interaction and evolution dynamics of two counterpropagating shockwaves generated by collinear laser induced air plasmas equal unequal energies are presented. formation a stagnation layer during the from plasma sources, namely, S1 S2 separated distance 4 mm, were studied over duration 30 μs, using two-dimensional FLASH radiation hydrodynamic code. formed is observed to be “hard” in case energy = S2. While sources with > S1, allow propagation energy. For both cases maximum increase...

Abstract A clear visualization of the physical processes spatially confined ns laser induced atmospheric air plasma within a rectangular glass cavity using optical imaging is presented. The occurrence various starting from early and shock wave expansion dynamics to reflection at boundaries compression due reflected shockwaves studied defocused shadowgraphy self-emission techniques. Experimentally, we evidenced that counter propagating primary interact with expanding generating secondary...

We present the spatial and temporal characterization of copper (Cu) plasma produced by femtosecond laser filaments. The filaments various lengths intensities were generated with aid three different focusing lenses. Further, filamentation induced breakdown spectroscopy (FIBS) measurements carried out for each filament at positions along length filament. spatially characterized estimating temperature electron density. Our investigation has demonstrated that centre is best to obtain a maximum...

Abstract We present results on the dynamics of laser-induced blow-off shockwave generation from rear side 20 µ m thick aluminum and copper foil confined with a glass (BK7) substrate. These foils are irradiated by 10 ns, 532 nm laser pulses energy 25–200 mJ corresponding to intensity range 0.2–10 GW cm −2 . The plasma temperature at glass-foil interface is observed play an important role in coupling foil. From our experiments 1D hydrodynamic simulations, we confirm that moving away focal...

We present the measurements on propagation characteristics of laser generated acoustics shock waves and vibrations inside material targets from laser-metal interaction in real time. Laser pulses (7 ns) second harmonic a Nd: YAG (532 nm) were used to launch compression solid samples. The acoustic carried out using calibrated microphone, while induced within before getting converted into ASW atmosphere measured vibration transducers (piezoelectric accelerometer). arrival time transducer was...

Observation of radio frequency (RF) emissions from laser induced breakdown (LIB) stainless steel (SS304) and the studies on origin these are presented. The emitted frequencies were observed to be in range estimated ion-plasma frequencies, indicating contribution ion-neutral collisional interactions radiation RF plasma. These can extended develop an based tool study plasmas varying electron temperatures densities.

We present an acoustic detection technique to study the interaction of two shock waves emitted by nearby, simultaneous, laser-induced air-breakdown events that resembles phenomenon fluids. A microphone is employed detect wave (ASW) from zone. The experiments were done at various separation distances between plasma sources. incident laser energy sources varied 25 100 mJ in ratios 1:1 1:4. peak sound pressure ASW was compared single and dual sources, showing pressures are higher for source...

The detection and analysis of the radio frequency (RF) waves emitted by nanosecond laser breakdown atmospheric air metal (aluminum copper) targets is presented. emissions from different target materials were observed to be spectral selective with specific dependence on antenna polarization. From produced plasma (LPP) air, RF output was found increasing input energy up certain value, beyond which almost no emission over range used in this study. This effect attributed modification net induced...

Evolution of laser-induced dynamic states matter aimed at controlled release energy from materials with inherent high is discussed. Optical and microwave instrumentation developed addressing the challenge presented.

We present the results on electromagnetic (em) radiation emitted in 70 MHz - 1 GHz frequency range from laser induced breakdown of atmospheric air. Laser pulses (7 ns) second harmonic an Nd:YAG (532 nm) were used to air form plasma. During plasma evolution and expansion, dipole moment is homonuclear molecules nitrogen oxygen (the main components air), which naturally have no permanent electron moments. The RF spectra originating longitudinal oscillation these dipoles was detected using...

The effect of external focusing conditions on the on-axis plasma electron density generated by fs laser filament in air via corroborated acoustic and optical spectral emission profile measurements is presented.

A numerical study of interaction two counter propagating laser induced atmospheric air plasmas separated by a distance 4 mm using FLASH <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> 2D radiation hydrodynamic code is presented. The plasma dynamics and the subsequent shock wave expansion were validated with experimental results show good agreement. Second harmonic pulses from Q-switched Nd:YAG (TITAN-5, 5J, 10 ns, 5 Hz, M/s. Amplitude...

Quasi-static light filaments with variable lengths and properties were generated in the lab, by propagating femtosecond laser pulses ambient air <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> under varying focusing conditions. The temporal dynamics high intensity associated has attracted interest from many research domains xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , thereby demanding a holistic characterization of their...

The influence of confining material on dynamics laser induced plasma and shock waves when confined in lateral direction a rectilinear geometry is presented. Glass, polystyrene aluminum were used as boundaries to confine the air plasma. Experimentally, (SW) are generated via breakdown using second harmonic Nd:YAG pulses 10 ns width for intensity GW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> (200 mJ). reflection wave from boundary...