Rise profile of the thermal lens signal: Contribution of the temperature lens and the population lens

1994 ◽  
Vol 100 (4) ◽  
pp. 2481-2486 ◽  
Author(s):  
Masahide Terazima ◽  
Norobu Hirota
Keyword(s):  
Thermal Lens ◽  
Thermal Lens Signal

Thermal Lens Study of the Absorbance of Silver Colloid Solutions Produced by Photoreduction

1993 ◽  
Vol 47 (12) ◽  
pp. 2126-2128 ◽  
Author(s):  
Zhengming Zhang ◽  
George R. Long
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Thermal Lens ◽  
Colloidal Solution ◽  
Silver Colloid ◽  
Thermal Lens Signal ◽  
Absorption Of Light ◽  
Colloid Formation ◽  
Silver Nitrate Solutions ◽  
Nitrate Solutions

The absorption of light by photolytically generated silver colloid solutions is studied by thermal lens spectrophotometry. It is found that absorbance by silver nitrate solutions at 488 nm is a result of colloid formation. The absorbance is related to the particle size distribution and varies substantially from measurement to measurement even within the same colloidal solution. The shot-to-shot variance of the thermal lens signal is minimized by producing the colloid in a flowing AgNO3 solution, but still varies significantly from solution to solution at equal concentrations.

Enhancement of the thermal lens signal induced by sample matrix absorption of the probe laser beam

2002 ◽  
Vol 41 (27) ◽  
pp. 5814 ◽  
Author(s):  
Victor I. Grishko ◽  
Chieu D. Tran ◽  
Walter W. Duley
Keyword(s):  
Laser Beam ◽  
Thermal Lens ◽  
Probe Laser ◽  
Sample Matrix ◽  
Probe Laser Beam ◽  
Thermal Lens Signal

Obliquely Crossed, Differential Thermal Lens Measurements under Conditions of High Background Absorbance

1989 ◽  
Vol 43 (4) ◽  
pp. 668-674 ◽  
Author(s):  
Steven R. Erskine ◽  
Donald R. Bobbitt
Keyword(s):  
Thermal Lens ◽  
Differential Response ◽  
Intensity Noise ◽  
Experimental Conditions ◽  
High Background ◽  
Pump Source ◽  
Thermal Lens Signal ◽  
Pump And Probe ◽  
Absorbance Changes ◽  
Large Background

A differential thermal lens spectrometer based on the oblique crossing of separate pump and probe beams is described. This arrangement utilizes the differential response of the thermal lens to compensate for the intensity noise in the pump source while maintaining the intrinsic sensitivity of photothermal measurements. Thus, this design is ideally suited for absorbance measurements in the presence of a large background, such as might be encountered in circular dichroism or indirect photometry. The theory describing the thermal lens signal observed with this configuration will be developed and experimentally verified. The experimental conditions mandating differential TL measurements will also be investigated. Absorbance changes of 2 × 10−7 are demonstrated. Application of this arrangement to indirect HPLC detection is also discussed.

Development of a Multiwavelength Thermal Lens Spectrophotometer Based on an Acousto-Optic Tunable Filter as a Polychromator

1994 ◽  
Vol 48 (1) ◽  
pp. 101-106 ◽  
Author(s):  
Chieu D. Tran ◽  
Ricardo J. Furlan ◽  
Jian Lu
Keyword(s):  
Detection Limit ◽  
Thermal Lens ◽  
Laser Light ◽  
Limit Of Detection ◽  
Tunable Filter ◽  
Lanthanide Ions ◽  
Probe Laser ◽  
Excitation Beam ◽  
Thermal Lens Signal ◽  
Rf Signals

Instrumentation development of a novel multiwavelength thermal lens spectrophotometer which has the capability of achieving truly multiwavelength excitation is described. The spectrophotometer is based on a new concept by which the sample is excited by multiwavelength excitation beams simultaneously, not sequentially as in previously reported multiwavelength thermal lens apparatus. This was accomplished by use of the acousto-optic tunable filter (AOTF) as a polychromator. Specifically, four different rf signals were simultaneously applied to the filter to enable it to diffract incident multiline laser light into a beam which contained four different wavelengths. This multiwavelength beam was then used to excite the sample, and the corresponding thermal lens signal was measured by a He-Ne probe laser. Compared with other multiwavelength thermal lens instruments, this all-solid-state thermal lens spectrophotometer has advantages that include its ability to simultaneously analyze multicomponent samples in microsecond times scale, without the need for any prior sample preparation. With this apparatus and with the use of a 12-mW multiwavelength excitation beam, the limit of detection for four-component (lanthanide ions) samples is estimated to be 10−6 cm−1, which is similar to the detection limit obtained for one-component samples with the use of a single-wavelength system.

Thermal Lens Measurements in Liquids on a Submicrosecond Time Scale

1989 ◽  
Vol 43 (3) ◽  
pp. 419-422 ◽  
Author(s):  
Stefan J. Isak ◽  
Stanislaw J. Komorowski ◽  
Clifton N. Merrow ◽  
P. E. Poston ◽  
Edward M. Eyring
Keyword(s):  
Triplet State ◽  
Time Resolution ◽  
Thermal Lens ◽  
Time Scale ◽  
Laser Power ◽  
Reference Sample ◽  
Kinetic Studies ◽  
Time Range ◽  
Accurate Data ◽  
Thermal Lens Signal

The use of the thermal lens method is shown to be quite suitable for kinetic studies of quenching on a submicrosecond time scale. The lower limit of time resolution that can be achieved is determined by the acoustic transit time, τa in the medium. A thermal lens signal with a 100-ns time constant due to the quenched triplet state of benzophenone is readily measured. The thermal lens method is superior to the photoacoustic (PA) method in the breadth of the accessible time range, and in the significantly fewer measurements required to obtain accurate data, including no requirement for a reference sample; it is also less sensitive to geometrical and laser power requirements than is the PA method.

Analysis of surface thermal lens signal in optical coatings with top-hat beam excitation

2008 ◽  
Vol 103 (3) ◽  
pp. 033518 ◽  
Author(s):  
Bincheng Li ◽  
Xiaoxiao Chen ◽  
Yuan Gong
Keyword(s):  
Thermal Lens ◽  
Optical Coatings ◽  
Thermal Lens Signal ◽  
Beam Excitation
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