Thermal Lensing in Extended Samples

2002 ◽  
Vol 56 (11) ◽  
pp. 1504-1507 ◽  
Author(s):  
A. O. Marcano ◽  
L. Rodriguez ◽  
N. Melikechi
Keyword(s):  
Low Power ◽  
Thermal Lens ◽  
Continuous Wave ◽  
Thermal Lensing ◽  
Distilled Water ◽  
Pump Probe

We report on a novel pump-probe thermal-lens method for the measurement of absorption in extended samples using nearly collimated continuous wave (CW) and low-power probe and pump beams. We report the measurement of the absorption of a column of distilled water up to 2 meters thick. The method allows the determination of the absorption with sensitivities up to 10−10 W cm−1 in materials with photothermal parameters similar to distilled water.

scholarly journals Continuous wave high-power laser propagation in water is affected by strong thermal lensing and thermal blooming already at short distances

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stefan Reich ◽  
Sebastian Schäffer ◽  
Martin Lueck ◽  
Matthias Wickert ◽  
Jens Osterholz
Keyword(s):  
Refractive Index ◽  
High Power ◽  
Thermal Lens ◽  
Continuous Wave ◽  
Thermal Lensing ◽  
High Input ◽  
Onset Of Convection ◽  
Low Input ◽  
Thermal Blooming ◽  
Fast Development

AbstractWhen laser beams propagate through media with non-vanishing absorption, the media is heated resulting in a change of the refractive index, which can lead to thermal lensing and thermal blooming. However, experimental details about both phenomena for propagations in water are lacking, especially for high-power lasers in the kilowatt range. We show that significant thermal lensing occurs only for high input powers before the onset of convective flow, while for low input powers, no strong thermal lens arises. After the onset of water flow, thermal blooming occurs at low input powers comparable to that known for propagations over kilometres in the air. However, for high input powers a thermal blooming on a qualitatively higher level is shown. By wavefront sensing, the change of refractive index distribution in water is investigated. This clearly shows the fast development of a strong thermal lens for high input powers and the onset of convection. Furthermore, a qualitatively good agreement of the accompanying simulations is observed. It is found that the absorption coefficient is linear with a value of $$\mu ={13.7}\,{\mathrm{m}^{-1}}$$ μ = 13.7 m - 1 at least up to 7.5 kW, i.e. 8 $$\mathrm{kW/cm}^2$$ kW / cm 2 . However, the directed transmission into an aperture is only constant before any thermal lensing of blooming occurs.

Ultratrace Determination of Metals with Dithizone by Thermal Lens Spectrophotometry

1988 ◽  
Vol 42 (2) ◽  
pp. 341-346 ◽  
Author(s):  
G. Ramis Ramos ◽  
M. C. Garcia Alvarez-Coque ◽  
B. W. Smith ◽  
N. Omenetto ◽  
J. D. Winefordner
Keyword(s):  
Carbon Tetrachloride ◽  
Thermal Lens ◽  
Dynamic Range ◽  
Pump Probe ◽  
Pump And Probe ◽  
Relative Standard ◽  
Ion Laser ◽  
Lock In ◽  
Thermal Lens Effect

A pump-probe thermal lens instrument was constructed, evaluated, and applied to the determination of metals after extraction with dithizone in carbon tetrachloride. An argon-ion laser operated at 514.5 nm, with a power of just 22 mW at the cuvette position and chopped at 2 Hz, and a He-Ne laser were used as a pump and probe, respectively. The thermal lens effect was measured by a pinhole-photodiode and a lock-in amplifier. Evaluation of the setup with an iodine solution in carbon tetrachloride gave a minimum detectable absorbance of 5 × 10−6 (S/N = 3), the upper limit of the dynamic range being 5.7 × 10−3. Relative standard deviation was about 3%. Calibration curves and limits of detection for several metal dithizonates were obtained. From extractions of cadmium dithizonate at concentrations lower than 2 ng mL−1, a LOD of 8 pg mL−1, corresponding to an absolute LOD of 4 fg of cadmium in the probe volume, was achieved.

Measurement of Nonlinear Absorption Coefficients of Organic Materials by Mode-Mismatched Z-scan Thermal Lensing Technique

2007 ◽  
Vol 61 (10) ◽  
pp. 1128-1133 ◽  
Author(s):  
M. Guerra ◽  
A. Taouri ◽  
A. O. Marcano ◽  
H. Cabrera ◽  
M. Sylla
Keyword(s):  
Probe Beam ◽  
Thermal Lens ◽  
Nonlinear Absorption ◽  
Pump Beam ◽  
Organic Materials ◽  
Thermal Lensing ◽  
Absorption Coefficients ◽  
Pump Probe ◽  
532 Nm

We evaluate a new pump–probe mode-mismatched thermal lens (TL) scheme for the measurement of nonlinear absorption in nitrobenzene, benzene, and chloroform. In this new scheme the pump beam is focused in the presence of a collimated probe beam. Values of the nonlinear absorption coefficients of the materials studied for the wavelength of 532 nm are reported, and we compare the proposed technique with the well-known open Z-scan method.

Thermal lens determination of fluorescence quantum efficiency of3F4level of Tm3+ions in solids

2005 ◽  
Vol 125 ◽  
pp. 193-196 ◽  
Author(s):  
S. L. Oliveira ◽  
S. M. Lima ◽  
T. Catunda ◽  
H. Vargas ◽  
L. A.O. Nunes ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
Thermal Lens

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.

Optical properties of benzene and derivatives by the single beam thermal lens technique

2017 ◽  
Vol 26 (02) ◽  
pp. 1750025 ◽  
Author(s):  
M. K. Biswas ◽  
P. K. Das ◽  
E. Hoque ◽  
S. M. Sharafuddin ◽  
S. K. Das ◽  
...  
Keyword(s):  
Thermal Lens ◽  
Continuous Wave ◽  
Refractive Index Change ◽  
Optical Nonlinearity ◽  
Index Change ◽  
Single Beam ◽  
Cw Laser ◽  
Ion Laser ◽  
Benzene Toluene ◽  
Long Pulse

The present work studies the optical nonlinearity exhibited by the material (for Continuous Wave (CW) laser or long pulse) due to the change in thermal properties of the material on illumination. Thermal lens (TL) technique has been used to measure the refractive index change due to the formation of TL along with other thermo-optic properties of the material in solution. A CW Ar-ion laser has been used as light source and the laser beam was chopped at 25[Formula: see text]Hz frequency to obtain 12[Formula: see text]ms pulse to observe the formation of the TL within the sample. The [Formula: see text] value have been calculated by the TL technique for Benzene, Toluene and Dimethylaniline (DMA) in toluene and Benzene. The [Formula: see text] value is found to be in the order of 10[Formula: see text] to 10[Formula: see text][Formula: see text]cm2[Formula: see text]W[Formula: see text].

The determination of thermal conductivity coefficients of liquids by a thermal lens technique

1983 ◽  
Vol 77 (2) ◽  
pp. 243-246 ◽  
Author(s):  
R.T. Bailey ◽  
F.R. Cruickshank ◽  
D. Pugh ◽  
S. Guthrie ◽  
A. McLeod ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Lens
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