Beam Cleanup by Stimulated Rayleigh-Wing Scattering of a Bessel Pump Beam

1996 ◽  
Author(s):  
S. Klewitz ◽  
S. Herrninghaus
Keyword(s):  
Pump Beam

Pump-Probe Measurements Using Silicon Nanocrystal Waveguides

2003 ◽  
Vol 770 ◽  
Author(s):  
Nathanael Smith ◽  
Max J. Lederer ◽  
Marek Samoc ◽  
Barry Luther-Davies ◽  
Robert G. Elliman
Keyword(s):  
Probe Beam ◽  
Time Resolution ◽  
Pump Beam ◽  
Silicon Nanocrystals ◽  
Continuous Wave ◽  
Optical Gain ◽  
Optical Pump ◽  
Time Resolved ◽  
Pump Probe ◽  
Probe Measurements

AbstractOptical pump-probe measurements were performed on planar slab waveguides containing silicon nanocrystals in an attempt to measure optical gain from photo-excited silicon nanocrystals. Two experiments were performed, one with a continuous-wave probe beam and a pulsed pump beam, giving a time resolution of approximately 25 ns, and the other with a pulsed pump and probe beam, giving a time resolution of approximately 10 ps. In both cases the intensity of the probe beam was found to be attenuated by the pump beam, with the attenuation increasing monotonically with increasing pump power. Time-resolved measurements using the first experimental arrangement showed that the probe signal recovered its initial intensity on a time scale of 45-70 μs, a value comparable to the exciton lifetime in Si nanocrystals. These data are shown to be consistent with an induced absorption process such as confined carrier absorption. No evidence for optical gain was observed.

Ultra-Broadband Optical Parametric Chirped-Pulse Amplification with a Diverged Pump Beam

2007 ◽  
Vol 35 (9) ◽  
pp. 596-598
Author(s):  
Kanade OGAWA ◽  
Yutaka AKAHANE ◽  
Tetsuo HARIMOTO ◽  
Makoto AOYAMA ◽  
Koichi TSUJI ◽  
...  
Keyword(s):  
Pump Beam ◽  
Chirped Pulse ◽  
Pulse Amplification ◽  
Optical Parametric ◽  
Chirped Pulse Amplification

scholarly journals A Quantitative Method for In-Situ Pump-Beam Metrology in Ultrafast Electron Microscopy

2021 ◽  
Vol 27 (S1) ◽  
pp. 3416-3418
Author(s):  
Jialiang Chen ◽  
Chris Leighton ◽  
David Flannigan
Keyword(s):  
Electron Microscopy ◽  
Pump Beam ◽  
Quantitative Method

scholarly journals End-pumped Nd:YVO_4 laser with reduced thermal lensing via the use of a ring-shaped pump beam

2017 ◽  
Vol 42 (15) ◽  
pp. 2910 ◽  
Author(s):  
Di Lin ◽  
W. Andrew Clarkson
Keyword(s):  
Pump Beam ◽  
Thermal Lensing

Ce : LiSrAlF6 laser performance with antisolarant pump beam

1996 ◽  
Vol 69 (2) ◽  
pp. 85-94 ◽  
Author(s):  
A.J. Bayramian ◽  
C.D. Marshall ◽  
J.H. Wu ◽  
J.A. Speth ◽  
S.A. Payne ◽  
...  
Keyword(s):  
Pump Beam ◽  
Laser Performance

Mapping Thickness Dependent Thermal Conductivity of GaN

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
Elbara Ziade ◽  
Jia Yang ◽  
Gordie Brummer ◽  
Denis Nothern ◽  
Theodore Moustaks ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Pump Beam ◽  
Continuous Wave ◽  
High Electron Mobility Transistors ◽  
Heat Diffusion ◽  
Phase Lag ◽  
High Electron ◽  
Heat Diffusion Equation ◽  
Phase Images ◽  
Gan Film

Frequency domain thermoreflectance (FDTR) is used to create quantitative maps of thermal conductivity and thickness for a thinning gallium nitride (GaN) film on silicon carbide (SiC). GaN was grown by molecular beam epitaxy on a 4H-SiC substrate with a gradient in the film thickness found near the edge of the chip. The sample was then coated with a 5 nm nickel adhesion layer and a 85 nm gold transducer layer for the FDTR measurement. A piezo stage raster scans the sample to create phase images at different frequencies. For each pixel, a periodically modulated continuous-wave laser (the red pump beam) is focused to a Gaussian spot, less than 2 um in diameter, to locally heat the sample, while a second beam (the green probe beam) monitors the surface temperature through a proportional change in the reflectivity of gold. The pump beam is modulated simultaneously at six frequencies and the thermal conductivity and thickness of the GaN film are extracted by minimizing the error between the measured probe phase lag at each frequency and an analytical solution to the heat diffusion equation in a multilayer stack of materials. A scanning electron microscope image verifies the thinning GaN. We mark the imaged area with a red box. A schematic of the GaN sample in our measurement system is shown in the top right corner, along with the two fitting properties highlighted with a red box. We show the six phase images and the two obtained property maps: thickness and thermal conductivity of the GaN. Our results indicate a thickness dependent thermal conductivity of GaN, which has implications of thermal management in GaN-based high electron mobility transistors.

Optically induced birefringence in dye-doped blue phase liquid crystals

2019 ◽  
Vol 46 (6) ◽  
pp. 913-919
Author(s):  
Lin ◽  
Kuo ◽  
Huang ◽  
Wu ◽  
Lin ◽  
...  
Keyword(s):  
Refractive Index ◽  
Liquid Crystal ◽  
Pump Beam ◽  
Pump Intensity ◽  
Photoinduced Change ◽  
Methyl Red ◽  
Sem Images ◽  
Photoinduced Birefringence ◽  
Phase Liquid ◽  
Blue Phase

This paper investigates the photoinduced change of refractive index in dye (methyl red, MR)-doped blue phase (DDBP) cells by illumination of a pump beam. Through excitation of light irradiation with proper photon energy, MR can transform from trans-state to cis-state and successively diffuse and anisotropically adsorb on the inner glass substrate of the DDBP cell along the direction perpendicular to the polarisation of the pump beam. The adsorbed MR molecules can effectively rotate the orientation of the liquid crystal (LC) molecules and thereby modulate the effective refractive index of the DDBP cell. The SEM images of the adsorbed regions of the illuminated DDBP samples were also taken for discussing the relation between the pump intensity and the photoinduced birefringence.

Efficient Cherenkov-Type Phase-Matched Widely Tunable Terahertz-Wave Generation via an Optimized Pump Beam Shape

2009 ◽  
Vol 2 ◽  
pp. 032302 ◽  
Author(s):  
Takayuki Shibuya ◽  
Toshihiro Tsutsui ◽  
Koji Suizu ◽  
Takuya Akiba ◽  
Kodo Kawase
Keyword(s):  
Pump Beam ◽  
Terahertz Wave ◽  
Wave Generation ◽  
Beam Shape ◽  
Type Phase
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