scholarly journals Temperature Determination by Means of Optoacoustic Measurements

2014 ◽  
Vol 1 (2) ◽  
pp. 15
Author(s):  
John Gorman ◽  
Eph Sparrow ◽  
John Abraham
Keyword(s):  
Temperature Measurement ◽  
Test Specimen ◽  
Laser Light ◽  
Sound Field ◽  
Piezoelectric Sensor ◽  
Controlled Environment ◽  
Muscle Sample ◽  
Photoacoustic Effect ◽  
Opposite Trend ◽  
532 Nm

The capabilities of the optoacoustic principle as a means of temperature measurement have been explored by means of experiments. In the experiments, a tissue test specimen, biological muscle sample, was positioned in a precisely temperature-controlled environment and irradiated with 532-nm laser light. The absorbed radiation gave rise to thermal expansion whose induced stresses created a sound field which was detected by a piezoelectric sensor. During the course of the experiments, the temperature of the water bath was systematically varied, with ample time being allowed to enable the test specimen to achieve thermal equilibrium. The temperature variation encompassed both increasing and decreasing protocols. Replicate samples were tested to ensure accuracy. It was found that temperature increases gave rise to decreasing acoustic amplitudes. An opposite trend was observed when the temperature was decreased. This outcome, when compared with the published literature, suggested that accurate use of the photoacoustic effect as a means of temperature measurement requires great care in the setup and execution of the experiment.

Time Resolved Temperature Measurement of Single Gold Structures via Luminescence Thermometry

MRS Advances ◽  
2018 ◽  
Vol 3 (14) ◽  
pp. 747-751 ◽  
Author(s):  
Ali Rafiei Miandashti ◽  
Martin Kordesch ◽  
Hugh H. Richardson
Keyword(s):  
Thermal Conductivity ◽  
Temperature Measurement ◽  
Heat Dissipation ◽  
Time Resolved ◽  
Temperature Decay ◽  
Energy Transitions ◽  
The Absolute ◽  
532 Nm ◽  
Luminescence Thermometry

ABSTRACTHere we report the use of luminescence thermometry to measure the temperature decay from single gold structure into the substrate of AlGaN:Er3+ film. We looked at Er3+ ion photoluminescence upon illumination by modulated 532 nm laser and recorded time-resolved luminescence of 2H11/2 → 4I15/2 and the 4S3/2 → 4I15/2 energy transitions. We calculated the heat generated from gold microdisk and observed the rate of heat dissipation to the environment. We directly calculated the absolute thermal conductivity of 1.7 W/mK for AlGaN: Er3+ film which was in agreement with the literature.

Transparency of the strong shock-compressed diamond for 532 nm laser light

2016 ◽  
Vol 23 (4) ◽  
pp. 043301 ◽  
Author(s):  
Zhiyu Zhang ◽  
Yang Zhao ◽  
Jiamin Yang
Keyword(s):  
Laser Light ◽  
Strong Shock ◽  
532 Nm

Nonlinear Optical Properties of Tetrabenzporphyrins

1994 ◽  
Vol 374 ◽  
Author(s):  
Gary L. Wood ◽  
Andrew G. Mott ◽  
Mary J. Miller ◽  
Masato Nakashima ◽  
Joseph F. Roach
Keyword(s):  
Optical Properties ◽  
Cross Section ◽  
Ground State ◽  
Nonlinear Optical ◽  
Laser Light ◽  
Nonlinear Refraction ◽  
Nonlinear Behavior ◽  
Population Redistribution ◽  
Optical Focusing ◽  
532 Nm

AbstractOptical limiting in a solution of tetrabenzporphyrin (TBP) dissolved in tetrahydrofuran (THF) was measured in an f/5 optical focusing arrangement using 532 nm wavelength laser light with a 9 ns pulse duration. The performance of this solution was compared to a variety of other materials. In order to better understand the nonlinear behavior of this material, apertured and unapertured Z-scans were performed. From these measurements it was determined that the excited-state cross section and its ratio to ground-state cross section were large. The nonlinear refraction of this material is made up of contributions from thermal density change and population redistribution. Limiter performance was modeled in an f/64 limiter. The limiter behavior of a slightly modified compound and an additional solvent were measured.

p-nitrobenzamide substituted phosphorus(V) porphyrins: synthesis and interactions with DNA

2005 ◽  
Vol 09 (07) ◽  
pp. 453-462 ◽  
Author(s):  
Mariusz P. Gajewski ◽  
Leszek Czuchajowski
Keyword(s):  
Dna Damage ◽  
Singlet Oxygen ◽  
Sodium Azide ◽  
Dna Cleavage ◽  
Electronic Communication ◽  
Laser Light ◽  
Axial Ligands ◽  
Dna Nicking ◽  
532 Nm

Four new phosphorus(V) porphyrins were designed and synthesized. The compounds were diaxially substituted with 4-nitrobenzamide. The axial ligands were attached to the P(V) center of the porphyrins through methylene linkers of different lengths. DNA titrations showed the expected porphyrin binding. When exposed to 532 nm laser light, which corresponds to the porphyrin Q band, the photosensitizers induced DNA nicking. Inhibition of the nicking by sodium azide suggested participation of singlet oxygen in the process. Photoexcitation with 305 nm laser light, which corresponds to absorption of 4-nitrobenzamide, also resulted in DNA damage. Due to the lack of electronic communication between the axial ligands and the porphyrin, the desired pathway of DNA cleavage was chosen by selecting a proper wavelength of the light used for photoexcitation. The activities of the porphyrins in photoinduced DNA nicking were very similar in both experiments: irradiation with 305 and 532 nm light, and were inversely correlated with the length of the linkers.

On-Line Monitoring of Chlorosilane Streams by Raman Spectroscopy

1998 ◽  
Vol 52 (1) ◽  
pp. 42-46 ◽  
Author(s):  
Elmer D. Lipp ◽  
Ronda L. Grosse
Keyword(s):  
Raman Spectroscopy ◽  
Laser Light ◽  
Maintenance Costs ◽  
Distillation Columns ◽  
Corrosive Liquid ◽  
Fiberoptic Probe ◽  
Sampling Intervals ◽  
On Line ◽  
Compositional Changes ◽  
532 Nm

On-line Raman spectroscopy was used to monitor the composition of methylchlorosilane streams from distillation columns. A spectrometer was assembled that used 532 nm laser light and a fiberoptic probe that could be inserted into corrosive liquid streams. The spectral regions below 800 cm−1 and near 2250 cm−1 contained strong, distinctive bands that were used to identify and quantitate the species of interest. On-line spectra were recorded at 5 min sampling intervals. Several instances were found where large changes in the composition of the columns were observed. Detection limits of 1000 ppm were generally achievable, and, in favorable circumstances, compositional changes of 100 ppm could be detected. Raman spectroscopy gave much better time resolution than current gas chromatography (GC) monitoring and is also projected to have lower capital and maintenance costs.

scholarly journals Sub-lethal effects of exposing the human melanoma cell line Skmel−23 to 532 nm laser light

1997 ◽  
Vol 72 (6) ◽  
pp. 1104-1112 ◽  
Author(s):  
Ning Wen Zhu ◽  
John Kenealy ◽  
Andrew Burd ◽  
Terry Gradidge ◽  
Robert Warr ◽  
...  
Keyword(s):  
Cell Line ◽  
Melanoma Cell ◽  
Melanoma Cell Line ◽  
Laser Light ◽  
Human Melanoma ◽  
Human Melanoma Cell Line ◽  
Human Melanoma Cell ◽  
Lethal Effects ◽  
532 Nm

scholarly journals POTENSI LASER (light amplification by stimulated emission of radiation) SEBAGAI PENDETEKSI BAKTERI (Studi awal detektor makanan halal)

2019 ◽  
Vol 3 (1) ◽  
pp. 1
Author(s):  
Hadi Kurnia Wan
Keyword(s):  
Laser Light ◽  
Stimulated Emission ◽  
Light Amplification ◽  
532 Nm

Penelitian untuk mengetahui keberadaan mikroorganisme pada sebuah benda merupakan kebutuhan yang sangat penting dilakukan. Bakteri Escericia coli sebagai mikroorganisme patogen banyak ditemukan didalam feses hewan. Penggunaan laser untuk mendeteksi keberadaan bakteri memberikan hasil yang cukup signifikan. Dengan panjang gelombang 532 nm dan 650 nm spektrum spekel bisa ditangkap oleh kamera CMOS 30 fps 12 mp dengan baik, sehingga dihasilkan intensitas kontras yang berbeda. Titik Sampel yang ada bakteri memeiliki nilai kontras yang lebih kecil dibandingkan denghan titik sampel yang tidak ada bakterinya.  Pengukuran intensitas dilakukan dengan menggunakan sofware Matlab 7 dengan arah penyinaran Vertikal dan sudut kamera 450

scholarly journals Photoacoustic tomography of fingerprint and underlying vasculature for improved biometric identification

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wenhan Zheng ◽  
Diana Lee ◽  
Jun Xia
Keyword(s):  
Linear Array ◽  
High Spatial Resolution ◽  
3D Image ◽  
Photoacoustic Effect ◽  
Acoustic Coupling ◽  
Sensing System ◽  
Dry Coupling ◽  
Vascular Structures ◽  
Ultrasound System ◽  
532 Nm

AbstractCapitalizing on the photoacoustic effect, we developed a new fingerprint sensing system that can reveal both fingerprints and underlying vascular structures at a high spatial resolution. Our system is built on a 15 MHz linear transducer array, a research ultrasound system, and a 532-nm pulsed laser. A 3D image was obtained by scanning the linear array over the fingertip. The acquired fingerprint images strongly agreed with the images acquired from ultrasound. Additional experiments were also conducted to investigate the effect of acoustic coupling. We discovered that high-quality fingerprint and vessel images can be acquired from both wet and dry fingers using our photoacoustic system. The reduced subdermal features in dry coupling can be enhanced through post-processing. Compared to existing fingerprint scanners, the photoacoustic approach provides a higher quality 3D image of the fingerprint, as well as unique subdermal vasculature structures, making the system almost impossible to counterfeit.

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