A 50 PW, 10 fs ultrahigh-peak-power laser has been conceptually designed. The system is based onoptical parametric chirped pulse amplifi cation. A 250 J DPSSL and a fl ash-lamp-pumped kJ laser, and ...abroadband OPCPA chain with partially deuterated KDP（pDKDP）crystals are designed as newrepeatable pump sources and a few-cycle pulse amplifier, respectively. The pDKDP has beensuccessfully grown at several different deuteration ratios. A broadband grating with high diffractioneffi ciency in the compressor is under designing.
Lasers as production tools offer several advantages, which are especially relevant for the production of solar cells. The contact-less and localized nature of the energy deposition allows new ...processes, such as laser selective emitter doping, laser ablation of dielectric coatings and via drilling for back contact cell concepts. A highly critical factor is the correct selection of laser parameters and thus laser sources in a manner that adapts the laser process to the requirements of the material, the process nature and the solar cell properties. In this paper the influence of the pulse duration in the range from hundreds of femtoseconds to ten picoseconds on the selective ablation of silicon nitride from multi-crytsalline solar cells is investigated. For this process it is critical to avoid damage to the sensitive emitter and ultra-short laser sources have the potential to enable this process.
High-Energy-Density Plasma Optics NAKATSUTSUMI, Motoaki
The Review of Laser Engineering,
2013, Letnik:
41, Številka:
1
Journal Article
Recenzirano
Odprti dostop
High-energy-density plasmas generated by intense-laser pulses allow the control of light, throughprocesses such as reflection, focusing, amplification and frequency conversion. Many of ...theseapplications have been recently demonstrated. These plasma-based optical devices are compact,functional and do not suffer from conventional optical damage. The present status, remaining issues, andfuture perspectives of these so-called plasma-photonic devices for high-fi eld science and high-energydensityscience will be discussed.
We propose a novel technique that has the potential to realize interrogation of surface plasmon resonance (SPR) sensors at very high speed. In contrast to the incoherent light source used in the ...traditional wavelength interrogation schemes, a broadband coherent laser generating short optical pulses at a high repetition rate is used along with a highly dispersive optical element. The dispersion causes strong broadening of the optical pulses, and the temporal pulse shape could exactly resemble the spectral distribution of the pulses due to the induced linear chirp. Therefore, by measuring the changes in the pulse shapes with a single high-speed photodetector, the spectral response of the SPR sensor can be obtained for each input pulse and the interrogation speed could reach the repetition rate of the pulse train. This could enable SPR measurements at the speed of tens of MHz or higher, which is well beyond that of other current SPR interrogation techniques. We experimentally demonstrate that, by measuring the variations in the pulse shapes of the chirped pulses, sensitive SPR measurements can be made. Implementing this scheme with a femtosecond fiber laser and other fiber optic components also show the potential to realize more compact and integrated SPR systems.
Ultrashort pulse laser heating of a germanium nanofilm was simulated using a combined continuum-atomistic method that couples the molecular dynamics and a self-consistent energy model for ultrafast ...laser-semiconductor interaction. Both a single pulse and a pulse burst were considered. To accurately describe laser energy deposition, the transient optical properties were computed based on the Drude formula. It was found that for a single pulse at low fluence (e.g., 0.02 J/cm
2
), the pulse duration had little impact on the lattice temperature response. In contrast, a higher lattice temperature could be obtained for a longer pulse (e.g., 5 ps) at higher fluences (e.g., 0.06 J/cm
2
) due to lower surface reflectivity. A strong thermal stress wave could be induced by the laser heating, with its maximum compression and tension occurring in the front and rear film regions, respectively. The investigations of laser burst heating revealed that a laser burst not only can retain the advantages of ultrashort pulse lasers but can enhance the photon efficiency for material melting as well.
Abstract
Acne vulgaris is adebilitating dermatologic disease, and is conventionally treated by laser therapy using a microring resonator system. An evolving understanding of laser-tissue interactions ...involving Propioni bacterium acneproducing porphyrins, and the development of lasers to target the sebaceous glands, has led to the development of an escalating number of laser light for acne treatment. The results show that the full width at half maximum of the proposed laser pulse of 0.15 nm can be generated using a microring resonator system. The power of the laser is 200 W and the wavelength laser is 1,032 nm, which is proposed as a treatment of acne vulgaris diseases.
We describe new ideas and tools for analysis of ultra-short pulse laser experiments on warm dense matter. The tools include hydrodynamic codes and a new equation of state for expanded matter. The ion ...density of excited states,
G
j
(
E
)
, is used to rapidly evaluate the partition function for many-electron ions which have many excited states. We describe a strategy for determining the dielectric function of expanding warm dense plasmas by analysis of laser experiments. Special attention is given to the remarkable fact that the observed dielectric functions imply an inhibition of free-electron (“Drude”) conductivity, which suggests electron localization or a metal–insulator transition. We give preliminary models for experiments on Sn and Au targets.
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