scholarly journals Fabrication of 50-nm period gratings on GaN in air through plasmonic near-field ablation induced by ultraviolet femtosecond laser pulses

2016 ◽  
Vol 24 (5) ◽  
pp. 4648 ◽  
Author(s):  
Godai Miyaji ◽  
Kenzo Miyazaki
Keyword(s):  
Femtosecond Laser ◽  
Near Field ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses

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

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 Scanning near-field optical coherent anti-Stokes Raman microscopy (SNOM-CARS) with femtosecond laser pulses in vibrational and electronic resonance

2013 ◽  
Vol 21 (1) ◽  
pp. 918 ◽  
Author(s):  
Mahesh Namboodiri ◽  
Tahir Zeb Khan ◽  
Sidhant Bom ◽  
Günter Flachenecker ◽  
Arnulf Materny
Keyword(s):  
Femtosecond Laser ◽  
Near Field ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Raman Microscopy ◽  
Anti Stokes ◽  
Electronic Resonance

scholarly journals Interaction of Tungsten tips with Laguerre-Gaussian beams

2021 ◽  
Vol 255 ◽  
pp. 11003
Author(s):  
Abhisek Sinha ◽  
Debobrata Rajak ◽  
Shilpa Rani ◽  
Ram Gopal ◽  
Vandana Sharma
Keyword(s):  
Femtosecond Laser ◽  
Near Field ◽  
Energy Levels ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Gaussian Beams ◽  
Good Source ◽  
Laser Modes ◽  
The Difference ◽  
Electron Pulses

Interaction of femtosecond laser pulses with metallic tips have been studied extensively and they have proved to be a very good source of ultrashort electron pulses. We present our study of interaction of Laguerre-Gaussian (LG) laser modes with Tungsten tips. We report a change in the order of the interaction for LG beams and the difference in the order of interaction is attributed to ponderomotive shifts in the energy levels corresponding to the enhanced near field intensity supported by numerical simulations.

scholarly journals Fabrication of Periodic Nanostructures on Silicon Suboxide Films with Plasmonic Near-Field Ablation Induced by Low-Fluence Femtosecond Laser Pulses

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1495
Author(s):  
Tatsuyoshi Takaya ◽  
Godai Miyaji ◽  
Issei Takahashi ◽  
Lukas Janos Richter ◽  
Jürgen Ihlemann
Keyword(s):  
Optical Absorption ◽  
Femtosecond Laser ◽  
Absorption Coefficient ◽  
Silicon Oxide ◽  
Near Field ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Fused Silica ◽  
Optical Absorption Coefficient ◽  
Silicon Suboxide

Silicon suboxide (SiOx, x ≈ 1) is a substoichiometric silicon oxide with a large refractive index and optical absorption coefficient that oxidizes to silica (SiO2) by annealing in air at ~1000 °C. We demonstrate that nanostructures with a groove period of 200–330 nm can be formed in air on a silicon suboxide film with 800 nm, 100 fs, and 10 Hz laser pulses at a fluence an order of magnitude lower than that needed for glass materials such as fused silica and borosilicate glass. Experimental results show that high-density electrons can be produced with low-fluence femtosecond laser pulses, and plasmonic near-fields are subsequently excited to create nanostructures on the surface because silicon suboxide has a larger optical absorption coefficient than glass. Calculations using a model target reproduce the observed groove periods well and explain the mechanism of the nanostructure formation.

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

1999 ◽  
Vol 69 (S1) ◽  
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

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.

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