Self-Focusing of Laser Light and Stimulated Scattering Processes in Transparent and Absorbing Liquids: 1. Self-Focusing

1970 ◽  
Vol 25 (12) ◽  
pp. 1868-1879 ◽  
Author(s):  
M. Maier ◽  
O. Rahn ◽  
G. Wendl
Keyword(s):  
Laser Power ◽  
Laser Light ◽  
Beam Diameter ◽  
Incident Laser ◽  
Stimulated Scattering ◽  
Light Pulses ◽  
Incident Laser Power ◽  
Self Focusing ◽  
Stimulated Brillouin ◽  
Good Agreement

Abstract The spatial and temporal development of self-focusing of light pulses is investigated. The beam diameter in CS2 and molten para-di-chlorobenzene decreases with increasing incident laser power to small values in good agreement with theory. The strong influence of beam divergence, non-linearity of refractive index, and absorption on self-focusing action is found to agree well with numerical calculations. It is shown that both backward stimulated Brillouin and Raman scattering terminate the self-focusing process.

scholarly journals Size dependent efficiency of photophoretic swimmers

2015 ◽  
Vol 184 ◽  
pp. 381-391 ◽  
Author(s):  
Andreas P. Bregulla ◽  
Frank Cichos
Keyword(s):  
Particle Size ◽  
Laser Power ◽  
Symmetry Axis ◽  
Particle Surface ◽  
Finite Size ◽  
Optical Power ◽  
Surface Flow ◽  
Incident Laser ◽  
Size Dependent ◽  
Incident Laser Power

We investigate experimentally the efficiency of self-propelled photophoretic swimmers based on metal-coated polymer particles of different sizes. The metal hemisphere absorbs the incident laser power and converts its energy into heat, which dissipates into the environment. A phoretic surface flow arises from the temperature gradient along the particle surface and drives the particle parallel to its symmetry axis. Scaling the particle size from micro to nanometers, the efficiency of converting optical power into motion is expected to rise with the reciprocal size for ideal swimmers. However, due to the finite size of the metal cap, the efficiency of a real swimmer reveals a maximum depending sensitively on the details of the metal cap shape. We compare the experimental results to numerical simulations.

A Novel Multibranched Chromophore Containing Carbazole Moiety for Two-Photon Microfabrication

2012 ◽  
Vol 485 ◽  
pp. 566-569
Author(s):  
Zhi Yuan Hu ◽  
Fu Quan Guo ◽  
Hao Liang ◽  
Bin Guo
Keyword(s):  
Cross Section ◽  
Laser Power ◽  
Photon Absorption ◽  
Structural Motif ◽  
Incident Laser ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Incident Laser Power ◽  
Potential Applications ◽  
Pentaerythritol Triacrylate

A novel multibranched chromophore containing carbazole moiety，4, 4´, 4´´-tris(9-carbazyl-trans-styryl) triphenylamine (TCSTPA)，was synthesized and characterized by 1HNMR and elemental analysis. A larger two-photon absorption (TPA) cross section of the chromophore was obtained as high as 2350 GM compared to that of the traditional linear chromophore when pumped by a femtosecond laser at 800 nm. Microstructure based on TPA induced polymerization with a spatial resolution of submicron was fabricated under much lower incident laser power using TCSTPA as a TPA photoinitiator and a multifunctional resin of pentaerythritol triacrylate (PETA) as a polymerizable monomer. The result indicates potential applications of this kind of chromophores with multibranched structural motif in the fabrication of polymer and functional microdevices.

scholarly journals Study of coexisting stimulated Raman and Brillouin scattering at relativistic laser power

2014 ◽  
Vol 32 (4) ◽  
pp. 657-663 ◽  
Author(s):  
Ashish Vyas ◽  
Ram Kishor Singh ◽  
R.P. Sharma
Keyword(s):  
Refractive Index ◽  
Laser Power ◽  
Stimulated Raman Scattering ◽  
Brillouin Scattering ◽  
Relativistic Mass ◽  
Self Focusing ◽  
Mass Correction ◽  
Stimulated Brillouin ◽  
Pump Depletion ◽  
Stimulated Raman

AbstractThis paper presents a model to study the stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) simultaneously at relativistic laser power. At high intensity, the relativistic mass correction for the plasma electrons becomes significant and the plasma refractive index gets modified which leads to the relativistic self-focusing of the pump beam. This filamentation process affects the scattering processes (SRS and SBS) and at the same time the pump filamentation process also gets modified in the presence of the coexisting SRS and SBS due to the pump depletion. We have also demonstrated that the pump depletion and relativistic filamentation affects the back-reflectivity of scattered beams (SRS and SBS) significantly, for the coexistence case.

scholarly journals Nonlinear Optical Characteristics of Crystal VioletDye Doped Polystyrene Films by Using Z-Scan Technique

2017 ◽  
Vol 27 (5) ◽  
pp. 83 ◽  
Author(s):  
Mahasin F. Hadi ◽  
Eman Mohi Alwaan ◽  
Wafaa Hameed Abass
Keyword(s):  
Nonlinear Optical ◽  
Laser Light ◽  
Nonlinear Refraction ◽  
Closed Aperture ◽  
Experimental Conditions ◽  
Light Pulses ◽  
Reverse Saturation Absorption ◽  
Self Focusing ◽  
Saturation Absorption ◽  
Doping Ratio

Z-scan technique was employed to study the nonlinear optical properties (nonlinear refractive index and nonlinear absorption coefficient) for crystal violet doped polystyrene films as a function of doping ratio in chloroform solvent. Samples exhibits in closed aperture Z-scan positive nonlinear refraction (self-focusing). While in the open aperture Z-scan gives reverse saturation absorption (RSA) (positive absorption) for all film with different doping ratio making samples candidates for optical limiting devices for protection of sensors and eyes from energetic laser light pulses under the experimental conditions.

scholarly journals Photostability of Uranine via Crossed-Beam Thermal Lens Technique

2007 ◽  
Vol 2007 ◽  
pp. 1-5
Author(s):  
M. Zein El-Din ◽  
K. Elsayed ◽  
S. M. Al-Sherbini ◽  
M. A. Harith
Keyword(s):  
Thermal Lens ◽  
Laser Power ◽  
Modulation Frequency ◽  
Wavelength Modulation ◽  
Incident Laser ◽  
Diagnostic Aid ◽  
Sample Concentration ◽  
Incident Laser Power ◽  
Experimental Parameters ◽  
Photochemical Quantum Yield

Uranine is a diagnostic aid in ophthalmology and is used as an immunohistological stain. A photostability study on this important compound using a crossed-beam thermal lens (TL) technique was carried out. The study is based on the photodegradation (PD) behavior and rate regarding some experimental parameters such as the incident laser power, wavelength, modulation frequency, and sample concentration. The effects of such parameters on the TL signal and PD rate are discussed in details. It has been found that the PD rate is proportional to the power of the pumping laser and the concentration of the sample within the investigated range. However, the modulation frequency is found not to influence the PD rate. The photochemical quantum yield has been measured using potassium ferrioxalate actinometry and it was found to be very low.

Effect of incident laser power and incorporating polariton effects in GaN microrods

2019 ◽  
Vol 209 ◽  
pp. 328-332
Author(s):  
Poulami Ghosh ◽  
Dapeng Yu ◽  
Mingyuan Huang
Keyword(s):  
Laser Power ◽  
Incident Laser ◽  
Incident Laser Power

scholarly journals Plasmon-driven surface catalytic reaction of 4-ethynylaniline in a liquid environment

RSC Advances ◽  
2018 ◽  
Vol 8 (37) ◽  
pp. 20499-20504
Author(s):  
Yu Liu ◽  
Caiqing Ma ◽  
Yanqiu Yang ◽  
Yuanchun Zhao ◽  
Shiwei Wu ◽  
...  
Keyword(s):  
Exposure Time ◽  
Catalytic Reaction ◽  
Laser Power ◽  
Incident Laser ◽  
Interesting Phenomenon ◽  
Liquid Environment ◽  
Incident Laser Power ◽  
Raman Intensities

The mechanism of Ag NP induced dimerization of PEAN was investigated by using SERS spectra. A very interesting phenomenon was discovered, that is where the relative Raman intensities of b2 modes increased either with increasing incident laser power or exposure time.

Sign in / Sign up

Export Citation Format

Share Document