scholarly journals NV– diamond laser

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alexander Savvin ◽  
Alexander Dormidonov ◽  
Evgeniya Smetanina ◽  
Vladimir Mitrokhin ◽  
Evgeniy Lipatov ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Optically Pumped ◽  
Power Laser ◽  
Central Wavelength ◽  
Pump Probe ◽  
Diamond Sample ◽  
Spectrum Width ◽  
20 Nm ◽  
First Time ◽  
532 Nm

AbstractFor the first time, lasing at NV− centers in an optically pumped diamond sample is achieved. A nanosecond train of 150-ps 532-nm laser pulses was used to pump the sample. The lasing pulses have central wavelength at 720 nm with a spectrum width of 20 nm, 1-ns duration and total energy around 10 nJ. In a pump-probe scheme, we investigate lasing conditions and gain saturation due to NV− ionization and NV0 concentration growth under high-power laser pulse pumping of diamond crystal.

Nonlinear Optical Properties of Modified Carbocyanines

1997 ◽  
Vol 479 ◽  
Author(s):  
Nansheng Tang ◽  
Weijie Su ◽  
Thomas M. Cooper ◽  
Daniel G. McLean ◽  
Donna M. Brandelik ◽  
...  
Keyword(s):  
Cross Sections ◽  
Excited State Absorption ◽  
Laser Pulses ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Pump Probe ◽  
Chirped Pulses ◽  
Molecular Hyperpolarizability ◽  
Meso Position ◽  
532 Nm

AbstractWe studied the optical nonlinearities of modified 3,3′-diethylthiadicarbocyanine iodides (X-DTDCI) in dimethyl sulfoxide (DMSO) solutions (X = H, Cl, Br at meso position) by a pump-probe technique with crossed polarized chirped laser pulses at room temperature. Reverse-saturable-absorption (RSA) with monoexponential lifetimes is observed at 532 nm in all the samples studied. We determined the effective excited-state absorption cross-sections and their lifetimes for all the samples investigated and found that they clearly correlate to the substituent X at the meso position. Empowered by the chirped pulses, a much faster nonlinearity with a decay time of ˜3.1 ps that is much shorter than the laser pulses used, is unveiled in Cl-DTDCI. We expressed both the absorptive and the refractive part of this fast nonlinearity as the equivalent molecular hyperpolarizability γ1212 and found γ1212 = (8.1 + i9.8) × 10−32erg−1.

scholarly journals Достижение субпикосекундного временного разрешения при исследовании процессов анизотропной релаксации биологических молекул

2020 ◽  
Vol 46 (4) ◽  
pp. 7
Author(s):  
И.А. Горбунова ◽  
М.Э. Сасин ◽  
О.С. Васютинский
Keyword(s):  
Energy Transfer ◽  
Excited State ◽  
Excited States ◽  
Rotational Diffusion ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Polyatomic Molecules ◽  
Biological Molecules ◽  
Pump Probe ◽  
First Time

A novel pump-probe method has been developed to study anisotropic relaxation and energy transfer in excited states of polyatomic molecules excited by femtosecond laser pulses. The method was used to study the rotational diffusion of NADH with a temporal resolution of about 0.6 ps. For the first time, absorption from the excited state of biological molecules pumped by laser pulses with energies of 1 nJ was detected

scholarly journals Laser-induced thermal grating spectroscopy based on femtosecond laser multi-photon absorption

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maria Ruchkina ◽  
Dina Hot ◽  
Pengji Ding ◽  
Ali Hosseinnia ◽  
Per-Erik Bengtsson ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Laser Pulses ◽  
Photon Absorption ◽  
Gas Flows ◽  
Single Shot ◽  
Photon Excitation ◽  
Fs Laser ◽  
Thermal Grating ◽  
Grating Spectroscopy ◽  
First Time

AbstractLaser-induced grating spectroscopy (LIGS) is for the first time explored in a configuration based on the crossing of two focused femtosecond (fs) laser pulses (800-nm wavelength) and a focused continuous-wave (cw) laser beam (532-nm wavelength). A thermal grating was formed by multi-photon absorption of the fs-laser pulses by $$\hbox {N}_{{2}}$$ N 2 with a pulse energy around 700 $$\upmu $$ μ J ($$\sim $$ ∼ 45 TW/$$\hbox {cm}^{2}$$ cm 2 ). The feasibility of this LIGS configuration was investigated for thermometry in heated nitrogen gas flows. The temperature was varied from room temperature up to 750 K, producing strong single-shot LIGS signals. A model based on the solution of the linearized hydrodynamic equations was used to extract temperature information from single-shot experimental data, and the results show excellent agreement with the thermocouple measurements. Furthermore, the fluorescence produced by the fs-laser pulses was investigated. This study indicates an 8-photon absorption pathway for $$\hbox {N}_{{2}}$$ N 2 in order to reach the $$\hbox {B}^{3}\Pi _{g}$$ B 3 Π g state from the ground state, and 8 + 5 photon excitation to reach the $$\hbox {B}^{2}\Sigma _{u}^{+}$$ B 2 Σ u + state of the $$\hbox {N}_{2}^{+}$$ N 2 + ion. At pulse energies higher than 1 mJ, the LIGS signal was disturbed due to the generation of plasma. Additionally, measurements in argon gas and air were performed, where the LIGS signal for argon shows lower intensity compared to air and $$\hbox {N}_{{2}}$$ N 2 .

Characterisation of supersonic gas jets for different nozzle geometries for laser-plasma acceleration experiments at SPARC_LAB

2022 ◽  
Vol 17 (01) ◽  
pp. C01049
Author(s):  
G. Costa ◽  
M.P. Anania ◽  
A. Biagioni ◽  
F.G. Bisesto ◽  
M. Del Franco ◽  
...  
Keyword(s):  
High Power ◽  
Plasma Channel ◽  
Laser Pulses ◽  
Industrial Applications ◽  
Point Of View ◽  
Theoretical Point ◽  
High Power Laser ◽  
Power Laser ◽  
Neutral Gas ◽  
Nozzle Geometries

Abstract Plasma-based technology promises a tremendous reduction in size of accelerators used for research, medical, and industrial applications, making it possible to develop tabletop machines accessible for a broader scientific community. The use of high-power laser pulses on gaseous targets is a promising method for the generation of accelerated electron beams at energies on the GeV scale, in extremely small sizes, typically millimetres. The gaseous target in question can be a collimated supersonic gasjet from a nozzle. In this work, a technique for optimising the so generated plasma channel is presented. In detail, a study on the influence of the nozzle throat shape in relation to the uniformity and density of the generated plasma profile is reported. These considerations are discussed first of all from a theoretical point of view, by means of a stationary one-dimensional mathematical model of the neutral gas, thus exploiting the possibility of comparing the properties of the output flow for different nozzle geometries. This is combined with an experimental approach using interferometric longitudinal density measurements of the plasma channel. The latter is generated by a high-power laser pulse focused on a helium gasjet, in the SPARC_LAB laboratories.

Metal wire cutting by repeated application of low‐power laser pulses

1992 ◽  
Vol 63 (6) ◽  
pp. 3516-3518
Author(s):  
Joseph B. Bernstein ◽  
Simon S. Cohen ◽  
Peter W. Wyatt
Keyword(s):  
Low Power ◽  
Laser Pulses ◽  
Metal Wire ◽  
Repeated Application ◽  
Power Laser ◽  
Wire Cutting

scholarly journals Improvement in the diffraction efficiency of a polymer using an ionic liquid

2018 ◽  
Vol 83 (2) ◽  
pp. 213-220
Author(s):  
Sung Kim ◽  
Pankaj Attri ◽  
In Kim
Keyword(s):  
Diffraction Efficiency ◽  
Information Storage ◽  
Polymer Mixture ◽  
Dihydrogen Phosphate ◽  
Storage Devices ◽  
Dpss Laser ◽  
Photosensitive Polymer ◽  
Diode Pumped ◽  
First Time ◽  
532 Nm

In this paper, photosensitive materials for information storage devices are presented. The polymers were prepared using surface relief-grating (SRG) fabrication with a diode-pumped solid-state (DPSS) laser of 532 nm, and the diffraction efficiency (DE) of the polymers were assessed with a low-power DPSS laser at 633 nm. However, the diffraction efficiency of the azo-functionalized epoxy-based polymer was low, even after 15 min of exposure. To improve the efficiency and reduce the time it takes for the DE measurements of the photosensitive polymer, the polymer was combined ionic liquids (ILs). Various ILs, i.e., 1-methylimidazolium chloride ([Mim]Cl) from the imidazolium family of ILs and diethylammonium dihydrogen phosphate (DEAP), triethylammonium 4-aminotoluene-3-sulfonic acid (TASA) and tributylmethylammonium methyl sulphate (TBMS) from the ammonium family of ILs, were investigated. For the first time, it was observed that DE dramatically increased the DEAP?polymer mixture in 4 min compared to the polymer (alone) and other polymer?IL mixtures. Therefore, DEAP IL could help improve the efficiency of DE measurements in a shorter time.

scholarly journals Developments of Space Debris Laser Ranging Technology Including the Applications of Picosecond Lasers

2021 ◽  
Vol 11 (21) ◽  
pp. 10080
Author(s):  
Haifeng Zhang ◽  
Mingliang Long ◽  
Huarong Deng ◽  
Shaoyu Cheng ◽  
Zhibo Wu ◽  
...  
Keyword(s):  
Space Debris ◽  
New Technologies ◽  
Pulse Repetition Frequency ◽  
Average Power ◽  
Picosecond Laser ◽  
Laser Ranging ◽  
Telescope Array ◽  
High Pulse ◽  
First Time ◽  
532 Nm

Debris laser ranging (DLR) is receiving considerable attention as an accurate and effective method of determining and predicting the orbits of space debris. This paper reports some technologies of DLR, such as the high pulse repetition frequency (PRF) laser pulse, large-aperture telescope, telescope array, multi-static stations receiving signals. DLR with a picosecond laser at the Shanghai Astronomical Observatory is also presented. A few hundred laps of space debris laser-ranging measurements have been made. A double-pulse picosecond laser with an average power of 4.2 W, a PRF of 1 kHz, and a wavelength of 532 nm has been implemented successfully in DLR, it’s the first time that DLR technology has reached a ranging precision at the sub-decimeter level. In addition, the characteristics of the picosecond-pulse-width laser transmission with the advantages of transmission in laser ranging were analyzed. With a mode of the pulse-burst picosecond laser having high average power, the DLR system has tracked small debris with a radar cross-section (RCS) of 0.91 m2 at a ranging distance up to 1726.8 km, corresponding to an RCS of 0.1 m2 at a distance of 1000 km. These works are expected to provide new technologies to further improve the performance of DLR.

scholarly journals Demonstration of laser pulse amplification by stimulated Brillouin scattering

2014 ◽  
Vol 2 ◽  
Author(s):  
E. Guillaume ◽  
K. Humphrey ◽  
H. Nakamura ◽  
R. M. G. M. Trines ◽  
R. Heathcote ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Plasma Density ◽  
Brillouin Scattering ◽  
Laser System ◽  
Laser Pulses ◽  
Seed Pulse ◽  
Central Wavelength ◽  
Demonstration Experiment ◽  
Stimulated Brillouin ◽  
Underdense Plasma

Abstract The energy transfer by stimulated Brillouin backscatter from a long pump pulse (15 ps) to a short seed pulse (1 ps) has been investigated in a proof-of-principle demonstration experiment. The two pulses were both amplified in different beamlines of a Nd:glass laser system, had a central wavelength of 1054 nm and a spectral bandwidth of 2 nm, and crossed each other in an underdense plasma in a counter-propagating geometry, off-set by $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}10^\circ $ . It is shown that the energy transfer and the wavelength of the generated Brillouin peak depend on the plasma density, the intensity of the laser pulses, and the competition between two-plasmon decay and stimulated Raman scatter instabilities. The highest obtained energy transfer from pump to probe pulse is 2.5%, at a plasma density of $0.17 n_{cr}$ , and this energy transfer increases significantly with plasma density. Therefore, our results suggest that much higher efficiencies can be obtained when higher densities (above $0.25 n_{cr}$ ) are used.

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