Nanostructuring Borosilicate Glass With Near-Field Enhanced Energy Using a Femtosecond Laser Pulse

2006 ◽  
Vol 129 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Alex Heltzel ◽  
Arvind Battula ◽  
J. R. Howell ◽  
Shaochen Chen
Keyword(s):  
Laser Pulse ◽  
Femtosecond Laser ◽  
Borosilicate Glass ◽  
Substrate Surface ◽  
Near Field ◽  
Planck Equation ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Avalanche Ionization ◽  
Avalanche Process

A model based on the evolution of electron density derived from the Fokker-Planck equation has been built to describe ablation of dielectrics during femtosecond laser pulses. The model is verified against an experimental investigation of borosilicate glass with a 200fs laser pulse centered at 780nm wavelength in a range of laser energies. The ablation mechanisms in dielectrics include multi-photon ionization (MPI) and avalanche ionization. MPI dominates the ionization process during the first stages of the laser pulse, contributing seed electrons which supply avalanche ionization. The avalanche process initiates and becomes responsible for the majority of free-electron generation. The overall material removal is shown to be highly dependent upon the optical response of the dielectric as plasma is formed. The ablation model is employed to predict the response of borosilicate glass to an enhanced electromagnetic field due to the presence of microspheres on the substrate surface. It is shown that the diffraction limit can be broken, creating nanoscale surface modification. An experimental study accompanies the model, with AFM and SEM characterizations that are consistent with the predicted surface modifications.

scholarly journals Graphene Oxide-Based Silico-Phosphate Composite Films for Optical Limiting of Ultrashort Near-Infrared Laser Pulses

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1638 ◽  
Author(s):  
Adrian Petris ◽  
Ileana Cristina Vasiliu ◽  
Petronela Gheorghe ◽  
Ana Maria Iordache ◽  
Laura Ionel ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Femtosecond Laser ◽  
Near Infrared ◽  
Substrate Surface ◽  
Sol Gel ◽  
Composite Films ◽  
Laser Pulses ◽  
Optical Limiting ◽  
Femtosecond Laser Pulses ◽  
Glassy Matrix

The development of graphene-based materials for optical limiting functionality is an active field of research. Optical limiting for femtosecond laser pulses in the infrared-B (IR-B) (1.4–3 μm) spectral domain has been investigated to a lesser extent than that for nanosecond, picosecond and femtosecond laser pulses at wavelengths up to 1.1 μm. Novel nonlinear optical materials, glassy graphene oxide (GO)-based silico-phosphate composites, were prepared, for the first time to our knowledge, by a convenient and low cost sol-gel method, as described in the paper, using tetraethyl orthosilicate (TEOS), H3PO4 and GO/reduced GO (rGO) as precursors. The characterisation of the GO/rGO silico-phosphate composite films was performed by spectroscopy (Fourier-transform infrared (FTIR), Ultraviolet–Visible-Near Infrared (UV-VIS-NIR) and Raman) and microscopy (atomic force microscopy (AFM) and scanning electron microscopy (SEM)) techniques. H3PO4 was found to reduce the rGO dispersed in the precursor’s solution with the formation of vertically agglomerated rGO sheets, uniformly distributed on the substrate surface. The capability of these novel graphene oxide-based materials for the optical limiting of femtosecond laser pulses at 1550 nm wavelength was demonstrated by intensity-scan experiments. The GO or rGO presence in the film, their concentrations, the composite films glassy matrix, and the film substrate influence the optical limiting performance of these novel materials and are discussed accordingly.

Far-field and near-field material processing with. femtosecond laser pulses

1999 ◽  
Vol 69 (7) ◽  
pp. S7-S11 ◽  
Author(s):  
F. Korte ◽  
S. Nolte ◽  
B.N. Chichkov ◽  
T. Bauer ◽  
G. Kamlage ◽  
...  
Keyword(s):  
Material Processing ◽  
Femtosecond Laser ◽  
Near Field ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Far Field

Nanometer Material Processing Using NSOM-delivered Femtosecond Laser Pulses

2004 ◽  
Vol 850 ◽  
Author(s):  
Chen-Hsiung Cheng ◽  
Ming Li
Keyword(s):  
Substrate Surface ◽  
Near Field ◽  
Laser Pulses ◽  
Optical Microscope ◽  
Femtosecond Laser Pulses ◽  
Surface Topology ◽  
Field Range ◽  
Field Coupling ◽  
Nanometer Material ◽  
And Performance

ABSTRACTNanometer-scale surface topology modification has been demonstrated using NSOM (near-field scanning optical microscope) delivered femto-second pulses. The ablation laser has a pulse width of 150 femto-second and wavelength of 387-nm. The laser pulses are coupled into the free end of a multimode optical fiber that a nanometer-size NSOM probe was fabricated on the other end with small orifice. The transmitted laser pulses from the probe orifice illuminates and machines the substrate surface when the probe is in near-field range of the substrate surface. The produced feature on Silicon surface is as least 200-nm deep with hole diameter around 200-nm. Near-field coupling of the laser has the potential to achieve ablation of feature size less than diffraction limit. Using NSOM delivery method also allows us to take advantage of nanometer metrology in precision surface ablation or other type of preformed surface modification. The ability of monitoring surface topology of substrate in real time enables us to accomplish the in-situ surface processing. We have demonstrated the technique of drilling 200-nm air holes on a pre-formed 600-nm wide wave guide. This method can be used to fabricate one-dimensional photonic crystal on a waveguide in ambient environment. The experiment design and performance evaluation will be discussed.

scholarly journals Towards optimization of femtosecond laser pulse nanostructuring of targets for high-intensity laser experiments in vacuum

2021 ◽  
Vol 127 (7) ◽  
Author(s):  
A. Andreev ◽  
J. Imgrunt ◽  
V. Braun ◽  
I. Dittmar ◽  
U. Teubner
Keyword(s):  
Laser Pulse ◽  
Femtosecond Laser ◽  
High Intensity ◽  
Extreme Ultraviolet ◽  
Theoretical Models ◽  
Laser Pulses ◽  
High Energy ◽  
Femtosecond Laser Pulses ◽  
Laser Development ◽  
Laser Experiments

AbstractThe interaction of intense femtosecond laser pulses with solid targets is a topic that has attracted a large amount of interest in science and applications. For many of the related experiments a large energy deposition or absorption as well as an efficient coupling to extreme ultraviolet (XUV), X-ray photon generation, and/or high energy particles is important. Here, much progress has been made in laser development and in experimental schemes, etc. However, regarding the improvement of the target itself, namely its geometry and surface, only limited improvements have been reported. The present paper investigates the formation of laser-induced periodic surface structures (LIPSS or ripples) on polished thick copper targets by femtosecond Ti:sapphire laser pulses. In particular, the dependence of the ripple period and ripple height has been investigated for different fluences and as a function of the number of laser shots on the same surface position. The experimental results and the formation of ripple mechanisms on metal surfaces in vacuum by femtosecond laser pulses have been analysed and the parameters of the experimentally observed “gratings” interpreted on base of theoretical models. The results have been specifically related to improve high-intensity femtosecond-laser matter interaction experiments with the goal of an enhanced particle emission (photons and high energy electrons and protons, respectively). In those experiments the presently investigated nanostructures could be generated easily in situ by multiple pre-pulses irradiated prior to a subsequent much more intense main laser pulse.

Nonlinear spectroscopy in the near-field: time resolved spectroscopy and subwavelength resolution non-invasive imaging

Nanophotonics ◽  
2014 ◽  
Vol 3 (1-2) ◽  
pp. 61-73 ◽  
Author(s):  
Mahesh Namboodiri ◽  
Tahirzeb Khan ◽  
Khadga Karki ◽  
Mehdi Mohammad Kazemi ◽  
Sidhant Bom ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Near Field ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Nonlinear Spectroscopy ◽  
Spectroscopic Techniques ◽  
Time Resolved ◽  
Spatially Resolved ◽  
First Results ◽  
Wavelength Resolution

AbstractThe combination of near-field microscopy along with nonlinear optical spectroscopic techniques is presented here. The scanning near-field imaging technique can be integrated with nonlinear spectroscopic techniques to improve spatial and axial resolution of the images. Additionally, ultrafast dynamics can be probed down to nano-scale dimension. The review shows some examples for this combination, which resulted in an exciton map and vibrational contrast images with sub-wavelength resolution. Results of two-color femtosecond time-resolved pump-probe experiments using scanning near-field optical microscopy (SNOM) on thin films of the organic semiconductor 3,4,9,10 Perylenetetracarboxylic dianhydride (PTCDA) are presented. While nonlinear Raman techniques have been used to obtain highly resolved images in combination with near-field microscopy, the use of femtosecond laser pulses in electronic resonance still constitutes a big challenge. Here, we present our first results on coherent anti-Stokes Raman scattering (fs-CARS) with femtosecond laser pulses detected in the near-field using SNOM. We demonstrate that highly spatially resolved images can be obtained from poly(3-hexylthiophene) (P3HT) nano-structures where the fs-CARS process was in resonance with the P3HT absorption and with characteristic P3HT vibrational modes without destruction of the samples. Sub-diffraction limited lateral resolution is achieved. Especially the height resolution clearly surpasses that obtained with standard microCARS. These results will be the basis for future investigations of mode-selective dynamics in the near-field.

Recording of optical near-field in laser photoelectron microscope by means of two-photon ionization by femtosecond laser pulses

2004 ◽  
Author(s):  
Sergey V. Chekalin ◽  
V. O. Kompanets ◽  
Vladilen S. Letokhov ◽  
Yu A. Matveets ◽  
B. N. Mironov ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Near Field ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Two Photon ◽  
Photon Ionization

scholarly journals Clean source of soft X-ray radiation formed in supersonic Ar gas jets by high-contrast femtosecond laser pulses of relativistic intensity

2020 ◽  
Vol 8 ◽  
Author(s):  
Maria Alkhimova ◽  
Sergey Ryazantsev ◽  
Igor Skobelev ◽  
Alexey Boldarev ◽  
Jie Feng ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Femtosecond Laser ◽  
Argon Plasma ◽  
Plasma Source ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Average Charge ◽  
High Contrast ◽  
X Ray ◽  
Gas Jets

In this work, we optimized a clean, versatile, compact source of soft X-ray radiation $(E_{\text{x}\text{-}\text{ray}}\sim 3~\text{keV})$ with an yield per shot up to $7\times 10^{11}~\text{photons}/\text{shot}$ in a plasma generated by the interaction of high-contrast femtosecond laser pulses of relativistic intensity $(I_{\text{las}}\sim 10^{18}{-}10^{19}~\text{W}/\text{cm}^{2})$ with supersonic argon gas jets. Using high-resolution X-ray spectroscopy approaches, the dependence of main characteristics (temperature, density and ionization composition) and the emission efficiency of the X-ray source on laser pulse parameters and properties of the gas medium was studied. The optimal conditions, when the X-ray photon yield reached a maximum value, have been found when the argon plasma has an electron temperature of $T_{\text{e}}\sim 185~\text{eV}$ , an electron density of $N_{\text{e}}\sim 7\times 10^{20}~\text{cm}^{-3}$ and an average charge of $Z\sim 14$ . In such a plasma, a coefficient of conversion to soft X-ray radiation with energies $E_{\text{x}\text{-}\text{ray}}\sim 3.1\;(\pm 0.2)~\text{keV}$ reaches $8.57\times 10^{-5}$ , and no processes leading to the acceleration of electrons to MeV energies occur. It was found that the efficiency of the X-ray emission of this plasma source is mainly determined by the focusing geometry. We confirmed experimentally that the angular distribution of the X-ray radiation is isotropic, and its intensity linearly depends on the energy of the laser pulse, which was varied in the range of 50–280 mJ. We also found that the yield of X-ray photons can be notably increased by, for example, choosing the optimal laser pulse duration and the inlet pressure of the gas jet.

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