scholarly journals Ultra-fast photoluminescence in fused silica surface flaws susceptible to laser damage

2011 ◽  
Vol 1365 ◽  
Author(s):  
Ted A. Laurence ◽  
Jeff D. Bude ◽  
Nan Shen
Keyword(s):  
Band Gap ◽  
Single Photon ◽  
High Sensitivity ◽  
Laser Pulses ◽  
Fused Silica ◽  
Photon Absorption ◽  
Defect States ◽  
Surface Flaws ◽  
Defect Densities ◽  
High Defect Densities

ABSTRACTUsing high-sensitivity confocal time-resolved photoluminescence (PL) techniques, we found an ultrafast PL (40 ps-5 ns) from impurity-free surface flaws on fused silica. This PL is excited by the single-photon absorption of sub-band gap light. Regions which exhibit this PL are strongly absorptive well below the band gap, as evidenced by a propensity to damage with 3.5 eV nanosecond-scale laser pulses. Very high defect densities are needed to explain the damage thresholds observed. For such high defect densities, significant interactions between defects may strongly affect the temporal characteristics of the emission of electronic excitations. We propose that the distribution in lifetimes observed is not simply due to a large variety of defect states, but due to a variety of energy transfer interactions between defect states.

LASER-INDUCED MULTIPHOTON PHOTOCONDUCTIVITY IN DIRECT AND INDIRECT BAND GAP CRYSTALS USING Z-SCAN TECHNIQUE

2009 ◽  
Vol 23 (23) ◽  
pp. 2783-2789 ◽  
Author(s):  
ARUN GAUR ◽  
D. K. SHARMA ◽  
K. S. SINGH ◽  
NAGESHWAR SINGH
Keyword(s):  
Absorption Coefficient ◽  
Band Gap ◽  
Laser Pulses ◽  
Beam Waist ◽  
Photon Absorption ◽  
Nanosecond Laser ◽  
Direct Band Gap ◽  
Direct Band ◽  
Nanosecond Laser Pulses ◽  
Indirect Band Gap

Nanosecond laser pulses have employed the photoconductive Z-scan technique. Photoconductivity traces measured by moving the sample across the laser beam waist were used for measuring two and three-photon absorption processes. The value of the three-photon absorption coefficient β3=9.6×10-10 cm 3/ GW 2 in the case of direct, and 8.96×10-12 cm 3/ GW 2 and 5.0×10-12 cm 3/ GW 2 in the case of indirect band gap crystals have been estimated from a comparison of traces measured by exciting the sample with the first and second harmonics of Nd : YAG laser. The low value of β3 in the case of indirect band gap crystals compared to direct band gap crystals is attributed to phonon-assisted transitions.

scholarly journals Методика измерения сечений многофотонного поглощения лазерных импульсов в газах с помощью спектрофона

2021 ◽  
Vol 129 (8) ◽  
pp. 1002
Author(s):  
А.Н. Куряк ◽  
Б.А. Тихомиров
Keyword(s):  
Molecular Oxygen ◽  
Cross Section ◽  
Time Resolution ◽  
Single Photon ◽  
Laser Pulses ◽  
Photon Absorption ◽  
Multiphoton Absorption ◽  
Nanosecond Pulses ◽  
Measure Cross Section

A technique to measure cross section of multiphoton absorption of laser pulses in gases using photoacoustic detector with time resolution of signals (a spectrophone) has been developed. The efficiency of the technique was tested on the example of single-photon and three-photon absorption of nanosecond pulses of quasimonochomatic radiation with a wavelength of 266 nm by molecular oxygen.

Theoretical study on saturable absorption using Gaussian vortex beam z-scan

2019 ◽  
Vol 28 (04) ◽  
pp. 1950038
Author(s):  
A. Srinivasa Rao
Keyword(s):  
Gaussian Beam ◽  
Saturable Absorber ◽  
Single Photon ◽  
Laser Pulses ◽  
Photon Absorption ◽  
Saturable Absorption ◽  
Vortex Beam ◽  
Potential Applications ◽  
Level Model ◽  
Beam Parameters

The study of nonlinear absorption has potential applications as saturable absorption and optical limiting character in scientific and engineering technology. In this work, we report on the Gaussian vortex beam z-scan to study the saturable absorption in the two-level model. For a given material and laser beam parameters, even though vortex beam shows less saturable absorption nature than the conventional Gaussian beam but not much appreciated. The open aperture z-scan peak is narrower for Gaussian vortex beam as compared with Gaussian beam. Also, in the presence of pico- and femto-second laser pulses, the central dark core of Gaussian vortex beam can provide a stable and accurate z-scan profile with avoiding thermal and other nonlinear optical effects at the beam waist of z-scan in the saturable absorber characterization. With including above mentioned points, we have shown how the Gaussian vortex z-scan is superior to the conventional Gaussian beam z-scan for saturable absorber characterization. Though discussed for single-photon absorption, it may extend to multi-photon absorption.

Picosecond Single-Photon and Femtosecond Two-Photon Pulsed Laser Stimulation for IC Characterization and Failure Analysis

2009 ◽  
Author(s):  
V. Pouget ◽  
E. Faraud ◽  
K. Shao ◽  
S. Jonathas ◽  
D. Horain ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Single Photon ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Laser Stimulation ◽  
Two Photon ◽  
Resolution Improvement ◽  
Ultrashort Laser

Abstract This paper presents the use of pulsed laser stimulation with picosecond and femtosecond laser pulses. We first discuss the resolution improvement that can be expected when using ultrashort laser pulses. Two case studies are then presented to illustrate the possibilities of the pulsed laser photoelectric stimulation in picosecond single-photon and femtosecond two-photon modes.

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 .

2D organic-inorganic hybrid perovskite materials for nonlinear optics

Nanophotonics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1787-1810 ◽  
Author(s):  
Xiao Han ◽  
Yongshen Zheng ◽  
Siqian Chai ◽  
Songhua Chen ◽  
Jialiang Xu
Keyword(s):  
Nonlinear Optical ◽  
Second Harmonic ◽  
Low Cost ◽  
Laser Pulses ◽  
Structural Features ◽  
Photon Absorption ◽  
Saturable Absorption ◽  
Research Attention ◽  
Inorganic Hybrid ◽  
Quantum Well Structures

AbstractTwo-dimensional (2D) organic-inorganic hybrid perovskites feature characteristics of inherent quantum-well structures and intriguing optoelectronic properties, and have therefore attracted enormous research attention for their optical applications in light emitting, sensing, modulation, and telecommunication devices. The low-cost and solution-processed fabrications as well as alternative organic spacer cations endue 2D hybrid perovskites with higher tunability in optical and photonic applications. In particular, they demonstrate distinguished nonlinear optical characters such as second-harmonic generation (SHG), two-photon absorption (2PA), and saturable absorption (SA) under the excitation of laser pulses. Here, we discuss the construction of the various sorts of 2D hybrid perovskites with different structural features. We have also highlighted some representative properties and applications of these 2D hybrid perovskites in both linear and nonlinear optical regimes.

scholarly journals Enhanced two-photon absorption in a hollow-core photonic-band-gap fiber

2011 ◽  
Vol 83 (3) ◽  
Author(s):  
Kasturi Saha ◽  
Vivek Venkataraman ◽  
Pablo Londero ◽  
Alexander L. Gaeta
Keyword(s):  
Band Gap ◽  
Photonic Band Gap ◽  
Photon Absorption ◽  
Hollow Core ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Photonic Band

Optical Waveguides Embedded in PCBs - A Real World Application of 3D Structures Written by TPA

2007 ◽  
Vol 1054 ◽  
Author(s):  
Ruth Houbertz ◽  
Herbert Wolter ◽  
Volker Schmidt ◽  
Ladislav Kuna ◽  
Valentin Satzinger ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Optical Waveguides ◽  
High Speed ◽  
Printed Circuit Boards ◽  
Data Transfer ◽  
Laser Pulses ◽  
Photon Absorption ◽  
Optical Data ◽  
Direct Laser ◽  
High Speed Data

ABSTRACTThe integration of optical interconnects in printed circuit boards (PCB) is a rapidly growing field worldwide due to a continuously increasing need for high-speed data transfer. There are any concepts discussed, among which are the integration of optical fibers or the generation of waveguides by UV lithography, embossing, or direct laser writing. The devices presented so far require many different materials and process steps, but particularly also highly-sophisticated assembly steps in order to couple the optoelectronic elements to the generated waveguides. In order to overcome these restrictions, an innovative approach is presented which allows the embedding of optoelectronic components and the generation of optical waveguides in only one optical material. This material is an inorganic-organic hybrid polymer, in which the waveguides are processed by two-photon absorption (TPA) processes, initiated by ultra-short laser pulses. In particular, due to this integration and the possibility ofin situpositioning the optical waveguides with respect to the optoelectronic components by the TPA process, no complex packaging or assembly is necessary. Thus, the number of necessary processing steps is significantly reduced, which also contributes to the saving of resources such as energy or solvents. The material properties and the underlying processes will be discussed with respect to optical data transfer in PCBs.

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