scholarly journals Transmission Welding of Glass by Femtosecond Laser: Mechanism and Fracture Strength

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
Panjawat Kongsuwan ◽  
Gen Satoh ◽  
Y. Lawrence Yao
Keyword(s):  
Femtosecond Laser ◽  
Numerical Aperture ◽  
Laser Pulses ◽  
Processing Parameters ◽  
Femtosecond Laser Pulses ◽  
Weld Shape ◽  
Spatially Resolved ◽  
Temporal And Spatial Characteristics ◽  
Propagation Properties ◽  
Weld Seams

Femtosecond laser pulses were focused on the interface of two glass specimens. Proper use of optical and laser processing parameters enables transmission welding. The morphology of the weld cross section was studied using differential interference contrast optical microscopy. In addition, a numerical model was developed to predict the absorption volumes of femtosecond laser pulses inside a transparent material. The model takes into account the temporal and spatial characteristics and propagation properties of the laser beam, and the transmission welding widths were subsequently compared with the absorption widths predicted by the model. The model can lead to the achievement of a desirable weld shape through understanding the effects of laser pulse energy and numerical aperture on the shape of the absorption volume. The changes in mechanical properties of the weld seams were studied through spatially resolved nanoindentation, and indentation fracture analysis was used to investigate the strength of the weld seams.

Characterization of Morphology and Mechanical Properties of Glass Interior Irradiated by Femtosecond Laser

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Panjawat Kongsuwan ◽  
Hongliang Wang ◽  
Sinisa Vukelic ◽  
Y. Lawrence Yao
Keyword(s):  
Mechanical Properties ◽  
Femtosecond Laser ◽  
Welding Process ◽  
Laser Pulses ◽  
Structural Rearrangement ◽  
Processing Parameters ◽  
Femtosecond Laser Pulses ◽  
Fused Silica ◽  
Element Analysis ◽  
Spatially Resolved

Femtosecond laser pulses were focused in the interior of a single fused silica piece. Proper use of optical and laser processing parameters generated structural rearrangement of the material through a thermal accumulation mechanism, which could be potentially used for the transmission welding process. The morphology of generated features was studied using differential interference contrast optical microscopy. In addition, the predictive capability of the morphology is developed via a finite element analysis. The change in mechanical properties was studied through employment of spatially resolved nanoindentation. The specimen was sectioned and nanoindents were applied at the cross section to examine mechanical responses of the laser-modified region. Fracture toughness measurements are carried out to investigate the effects of the laser treatment on strength of the glass.

scholarly journals High-Repetition-Rate Femtosecond Laser Processing of Acrylic Intra-Ocular Lenses

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 242 ◽  
Author(s):  
Daniel Sola ◽  
Rafael Cases
Keyword(s):  
Femtosecond Laser ◽  
Repetition Rate ◽  
Laser Processing ◽  
Refractive Index Change ◽  
Laser Pulses ◽  
Processing Parameters ◽  
High Repetition Rate ◽  
Femtosecond Laser Pulses ◽  
Periodic Patterns ◽  
High Repetition

The study of laser processing of acrylic intra-ocular lenses (IOL) by using femtosecond laser pulses delivered at high-repetition rate is presented in this work. An ultra-compact air-cooled femtosecond diode laser (HighQ2-SHG, Spectra-Physics) delivering 250 fs laser pulses at the fixed wavelength of 520 nm with a repetition rate of 63 MHz was used to process the samples. Laser inscription of linear periodic patterns on the surface and inside the acrylic substrates was studied as a function of the processing parameters as well as the optical absorption characteristics of the sample. Scanning Electron Microscopy (SEM) Energy Dispersive X-ray Spectroscopy (EDX), and micro-Raman Spectroscopy were used to evaluate the compositional and microstructural changes induced by the laser radiation in the processed areas. Diffractive characterization was used to assess 1st-order efficiency and the refractive index change.

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.

Ultrafast Laser Induced Structural Modification of Fused Silica—Part II: Spatially Resolved and Decomposed Raman Spectral Analysis

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Siniša Vukelić ◽  
Panjawat Kongsuwan ◽  
Sunmin Ryu ◽  
Y. Lawrence Yao
Keyword(s):  
Femtosecond Laser ◽  
Structural Changes ◽  
Volume Fraction ◽  
Random Network ◽  
Target Material ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Fused Silica ◽  
Process Conditions ◽  
Spatially Resolved

Nonlinear absorption of femtosecond laser pulses enables the induction of structural changes in the interior of bulk transparent materials without affecting their surface. In the present study, femtosecond laser pulses were tightly focused within the interior of bulk fused silica specimen. Localized plasma was formed, initiating rearrangement of the random network structure. Cross sections of the induced features were examined via decomposition of spatially resolved Raman spectra and a new method for the quantitative characterization of the structure of amorphous fused silica was developed. The proposed method identifies the volume fraction distribution of ring structures within the continuous random network of the probed volume of the target material and changes of the distribution with laser process conditions. Effects of the different process conditions and the material response to different mechanisms of feature generation were discussed as well.

scholarly journals Temporally focused femtosecond laser pulses for low numerical aperture micromachining through optically transparent materials

2010 ◽  
Vol 18 (17) ◽  
pp. 18086 ◽  
Author(s):  
Dawn N. Vitek ◽  
Daniel E. Adams ◽  
Adrea Johnson ◽  
Philbert S. Tsai ◽  
Sterling Backus ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Numerical Aperture ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Optically Transparent ◽  
Transparent Materials

INTRACELLULAR MANIPULATION BY FEMTOSECOND LASERS: REVIEW

2009 ◽  
Vol 02 (01) ◽  
pp. 1-8 ◽  
Author(s):  
WATARU WATANABE ◽  
SACHIHIIRO MATSUNAGA ◽  
KIICHI FUKUI ◽  
KAZUYOSHI ITOH
Keyword(s):  
Femtosecond Laser ◽  
Femtosecond Lasers ◽  
Numerical Aperture ◽  
Laser Pulses ◽  
Living Cells ◽  
Femtosecond Laser Pulses ◽  
Multiphoton Absorption ◽  
High Numerical Aperture ◽  
Recent Advances

Multiphoton absorption of femtosecond laser pulses focused through an objective with high numerical aperture (NA) can be used to image and manipulate cellular and intracellular objects. This review highlights recent advances in intracellular manipulation, including nanosurgery and labeling in living cells with femtosecond lasers.

Inorganic-organic Hybrid Materials for Real 3-D Sub-νm Lithography

2003 ◽  
Vol 780 ◽  
Author(s):  
R. Houbertz ◽  
J. Schulz ◽  
L. Fröhlich ◽  
G. Domann ◽  
M. Popall ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Sol Gel ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Hybrid Polymer ◽  
Organic Hybrid ◽  
Two Photon ◽  
Applied Technology ◽  
Scale Structures ◽  
Sol Gel Synthesis

AbstractReal 3-D sub-νm lithography was performed with two-photon polymerization (2PP) using inorganic-organic hybrid polymer (ORMOCER®) resins. The hybrid polymers were synthesized by hydrolysis/polycondensation reactions (modified sol-gel synthesis) which allows one to tailor their material properties towards the respective applications, i.e., dielectrics, optics or passivation. Due to their photosensitive organic functionalities, ORMOCER®s can be patterned by conventional photo-lithography as well as by femtosecond laser pulses at 780 nm. This results in polymerized (solid) structures where the non-polymerized parts can be removed by conventional developers.ORMOCER® structures as small as 200 nm or even below were generated by 2PP of the resins using femtosecond laser pulses. It is demonstrated that ORMOCER®s have the potential to be used in components or devices built up by nm-scale structures such as, e.g., photonic crystals. Aspects of the materials in conjunction to the applied technology are discussed.

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