G. Sliaužys, G. Juška, K. Genevičius, J. Smått, M. Lindén, R. Österbacka
In this paper the influence of TiO2/polymer (RR-P3HT) interface to photo generated charge carriers separation and recombination have been studied. The quantum efficiency and charge carrier recombination were studied in heterojunctions of TiO2 (prepared with porous or flat interface) and spin coated RR-P3HT polymer film using time of flight (TOF) and double injection (DoI) transient methods. From the shape of the TOF transients it was determined that the charge carrier generation is taking place in the vicinity of the TiO2/P3HT interface. Samples with porous TiO2 films show better charge carrier separation, but the deep trapping of charge carriers at the interface appear. The charge carrier recombination is trimolecular (Auger type recombination) with the similar values of recombination coefficients in both types of samples.
{"title":"TiO2-PHT interface influence to charge carrier photo generation and recombination","authors":"G. Sliaužys, G. Juška, K. Genevičius, J. Smått, M. Lindén, R. Österbacka","doi":"10.1117/12.815634","DOIUrl":"https://doi.org/10.1117/12.815634","url":null,"abstract":"In this paper the influence of TiO2/polymer (RR-P3HT) interface to photo generated charge carriers separation and recombination have been studied. The quantum efficiency and charge carrier recombination were studied in heterojunctions of TiO2 (prepared with porous or flat interface) and spin coated RR-P3HT polymer film using time of flight (TOF) and double injection (DoI) transient methods. From the shape of the TOF transients it was determined that the charge carrier generation is taking place in the vicinity of the TiO2/P3HT interface. Samples with porous TiO2 films show better charge carrier separation, but the deep trapping of charge carriers at the interface appear. The charge carrier recombination is trimolecular (Auger type recombination) with the similar values of recombination coefficients in both types of samples.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115093040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Ašmontas, J. Gradauskas, V. Kazlauskaitė, A. Sužiedėlis, E. Sirmulis, M. Vingelis
We present experimental study of photoresponse in small area GaAs/AlGaAs heterojunction planar detector induced by nanosecond CO2 laser pulses. This device revealed itself as a fast IR sensor operating at room temperature. Hot carrier effects are proposed to be responsible for the photoresponse formation.
{"title":"GaAs/AlGaAs heterojunction as a fast detector of infrared laser pulses","authors":"S. Ašmontas, J. Gradauskas, V. Kazlauskaitė, A. Sužiedėlis, E. Sirmulis, M. Vingelis","doi":"10.1117/12.815954","DOIUrl":"https://doi.org/10.1117/12.815954","url":null,"abstract":"We present experimental study of photoresponse in small area GaAs/AlGaAs heterojunction planar detector induced by nanosecond CO2 laser pulses. This device revealed itself as a fast IR sensor operating at room temperature. Hot carrier effects are proposed to be responsible for the photoresponse formation.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126489386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In routine eye examination the visual acuity usually is determined using standard charts with black letters on a white background, however contrast and colour are important characteristics of visual perception. The purpose of research was to study the perception of isoluminant coloured stimuli in the cases of true and simulated amlyopia. We estimated difference in visual acuity with isoluminant coloured stimuli comparing to that for high contrast black-white stimuli for true amblyopia and simulated amblyopia. Tests were generated on computer screen. Visual acuity was detected using different charts in two ways: standard achromatic stimuli (black symbols on a white background) and isoluminant coloured stimuli (white symbols on a yellow background, grey symbols on blue, green or red background). Thus isoluminant tests had colour contrast only but had no luminance contrast. Visual acuity evaluated with the standard method and colour tests were studied for subjects with good visual acuity, if necessary using the best vision correction. The same was performed for subjects with defocused eye and with true amblyopia. Defocus was realized with optical lenses placed in front of the normal eye. The obtained results applying the isoluminant colour charts revealed worsening of the visual acuity comparing with the visual acuity estimated with a standard high contrast method (black symbols on a white background).
{"title":"The perception of isoluminant coloured stimuli of amblyopic eye and defocused eye","authors":"G. Krumina, M. Ozolinsh, G. Ikaunieks","doi":"10.1117/12.815794","DOIUrl":"https://doi.org/10.1117/12.815794","url":null,"abstract":"In routine eye examination the visual acuity usually is determined using standard charts with black letters on a white background, however contrast and colour are important characteristics of visual perception. The purpose of research was to study the perception of isoluminant coloured stimuli in the cases of true and simulated amlyopia. We estimated difference in visual acuity with isoluminant coloured stimuli comparing to that for high contrast black-white stimuli for true amblyopia and simulated amblyopia. Tests were generated on computer screen. Visual acuity was detected using different charts in two ways: standard achromatic stimuli (black symbols on a white background) and isoluminant coloured stimuli (white symbols on a yellow background, grey symbols on blue, green or red background). Thus isoluminant tests had colour contrast only but had no luminance contrast. Visual acuity evaluated with the standard method and colour tests were studied for subjects with good visual acuity, if necessary using the best vision correction. The same was performed for subjects with defocused eye and with true amblyopia. Defocus was realized with optical lenses placed in front of the normal eye. The obtained results applying the isoluminant colour charts revealed worsening of the visual acuity comparing with the visual acuity estimated with a standard high contrast method (black symbols on a white background).","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134443920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An overview of the new field of Gas in Scattering Media Absorption Spectroscopy (GASMAS) is presented. GASMAS combines narrow-band diode-laser spectroscopy with diffuse media optical propagation. While solids and liquids have broad absorption features, free gas in pores and cavities in the material is characterized by sharp spectral signatures, typically 10,000 times sharper than those of the host material. Many applications in materials science, food packaging, pharmaceutics and medicine have been demonstrated. So far molecular oxygen and water vapour have been studied around 760 and 935 nm, respectively. Liquid water, an important constituent in many natural materials, such as tissue, has a low absorption at such wavelengths, allowing propagation. Polystyrene foam, wood, fruits, food-stuffs, pharmaceutical tablets, and human sinus cavities have been studied. Transport of gas in porous media can readily be studied by first immersing the material in, e.g., pure nitrogen, and then observing the rate at which normal air, containing oxygen, reinvades the material. The conductance of the sinus connective passages can be measured in this way by flushing the nasal cavity with nitrogen. Also other dynamic processes such as drying of materials can be studied. The techniques have also been extended to remote-sensing applications (LIDAR-GASMAS).
{"title":"Gas in scattering media absorption spectroscopy - GASMAS","authors":"S. Svanberg","doi":"10.1117/12.816469","DOIUrl":"https://doi.org/10.1117/12.816469","url":null,"abstract":"An overview of the new field of Gas in Scattering Media Absorption Spectroscopy (GASMAS) is presented. GASMAS combines narrow-band diode-laser spectroscopy with diffuse media optical propagation. While solids and liquids have broad absorption features, free gas in pores and cavities in the material is characterized by sharp spectral signatures, typically 10,000 times sharper than those of the host material. Many applications in materials science, food packaging, pharmaceutics and medicine have been demonstrated. So far molecular oxygen and water vapour have been studied around 760 and 935 nm, respectively. Liquid water, an important constituent in many natural materials, such as tissue, has a low absorption at such wavelengths, allowing propagation. Polystyrene foam, wood, fruits, food-stuffs, pharmaceutical tablets, and human sinus cavities have been studied. Transport of gas in porous media can readily be studied by first immersing the material in, e.g., pure nitrogen, and then observing the rate at which normal air, containing oxygen, reinvades the material. The conductance of the sinus connective passages can be measured in this way by flushing the nasal cavity with nitrogen. Also other dynamic processes such as drying of materials can be studied. The techniques have also been extended to remote-sensing applications (LIDAR-GASMAS).","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131096347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Dimitrocenko, J. Grube, P. Kulis, A. Sarakovskis, M. Spriņģis, I. Tale
AlGaN alloy thin film materials are of high interest for light emitting diodes (LED of the ultraviolet (UV) spectral region. Origin of the deep intrinsic and impurity Si states in the AlxGa1-xN (0 < x < 0.35) epilayer structures grown by metalorganic chemical vapor deposition (MOCVD) technique have been considered. Effects of the lattice mismatch and Si-doping in the heterostructures of epilayers with different alloy composition are investigated using time resolved photoluminescence (PL) of donor - deep acceptor (DA) pairs. It is shown that the undoped AlGaN alloys, grown on a GaN buffer layer, due to the lattice mismatch contain the increased concentration of cation vacancy (Vcation) defects acting as a deep acceptor centers and responsible for PL. Si-doping results in both the additional increase of Vcation concentration and the formation in cation sub lattice of new (VcationSication) deep acceptor complexes. It is shown that by increase of the Al content in the AlGaN alloy the composition disorder of both deep acceptor centers Vcation and (VcationSication) complex appears. The corresponding broad PL bands are resolved in number of subbands. It is stated that deposition of Si-doped AlGaN alloy on undoped GaN results in formation of Si-doped GaN interlayer.
AlGaN合金薄膜材料是紫外光谱区发光二极管(LED)的重要材料。探讨了金属有机化学气相沉积(MOCVD)技术生长的AlxGa1-xN (0 < x < 0.35)薄膜结构中深层本征态和杂质态Si的来源。利用时间分辨光致发光技术(PL)研究了不同合金组成的薄膜中晶格失配和硅掺杂对薄膜异质结构的影响。结果表明，由于晶格失配，在GaN缓冲层上生长的未掺杂的AlGaN合金中含有离子空位(v阳离子)缺陷的浓度增加，这些缺陷作为深度受体中心并导致PL。si掺杂导致了v阳离子浓度的额外增加，并且在阳离子亚晶格中形成了新的(vationsication)深度受体配合物。结果表明，随着AlGaN合金中Al含量的增加，深层受体中心Vcation和vationsication复合物的组成均出现紊乱。相应的宽PL波段被分解成若干个子波段。在未掺杂的GaN上沉积掺硅的AlGaN合金，形成掺硅的GaN间层。
{"title":"Formation of deep acceptor centers in AlGaN alloys","authors":"L. Dimitrocenko, J. Grube, P. Kulis, A. Sarakovskis, M. Spriņģis, I. Tale","doi":"10.1117/12.816864","DOIUrl":"https://doi.org/10.1117/12.816864","url":null,"abstract":"AlGaN alloy thin film materials are of high interest for light emitting diodes (LED of the ultraviolet (UV) spectral region. Origin of the deep intrinsic and impurity Si states in the AlxGa1-xN (0 < x < 0.35) epilayer structures grown by metalorganic chemical vapor deposition (MOCVD) technique have been considered. Effects of the lattice mismatch and Si-doping in the heterostructures of epilayers with different alloy composition are investigated using time resolved photoluminescence (PL) of donor - deep acceptor (DA) pairs. It is shown that the undoped AlGaN alloys, grown on a GaN buffer layer, due to the lattice mismatch contain the increased concentration of cation vacancy (Vcation) defects acting as a deep acceptor centers and responsible for PL. Si-doping results in both the additional increase of Vcation concentration and the formation in cation sub lattice of new (VcationSication) deep acceptor complexes. It is shown that by increase of the Al content in the AlGaN alloy the composition disorder of both deep acceptor centers Vcation and (VcationSication) complex appears. The corresponding broad PL bands are resolved in number of subbands. It is stated that deposition of Si-doped AlGaN alloy on undoped GaN results in formation of Si-doped GaN interlayer.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115077019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Yusupov, L. Fedorenko, O. Lytvyn, V. Yukhimchuk
The review of results of submicron surface layers formation is presented under ultraviolet (UV) N2 - laser (λ = 0.337 μm, tp = 5 ns) ablation of silicon target in liquid environment C6H5CH3. The morphological and deformation state of a near-surface Si layer was investigated by polarization modulation spectroscopy (PMS), atom force microscopy (AFM) and Raman spectra methods before and after irradiation. After irradiation AFM data shows the formation of submicron structures with hexagonal-like type of regularity on Si surface, PMS spectra indicates the increasing of refractive index, Raman spectroscopy reveals the broad band in the range 740-800 cm-1. All that facts allow us to assume the possibility of SiC-like layer formation on silicon monocrystal surface by laser stimulated diffusion of carbon atoms from liquid media. The surface morphology and composition of the irradiated surface varies considerable with the number of laser shots.
{"title":"Formation of SiC - like layers on Si surface in contact with C6H5CH3 solution by UV laser irradiation","authors":"M. Yusupov, L. Fedorenko, O. Lytvyn, V. Yukhimchuk","doi":"10.1117/12.815452","DOIUrl":"https://doi.org/10.1117/12.815452","url":null,"abstract":"The review of results of submicron surface layers formation is presented under ultraviolet (UV) N2 - laser (λ = 0.337 μm, tp = 5 ns) ablation of silicon target in liquid environment C6H5CH3. The morphological and deformation state of a near-surface Si layer was investigated by polarization modulation spectroscopy (PMS), atom force microscopy (AFM) and Raman spectra methods before and after irradiation. After irradiation AFM data shows the formation of submicron structures with hexagonal-like type of regularity on Si surface, PMS spectra indicates the increasing of refractive index, Raman spectroscopy reveals the broad band in the range 740-800 cm-1. All that facts allow us to assume the possibility of SiC-like layer formation on silicon monocrystal surface by laser stimulated diffusion of carbon atoms from liquid media. The surface morphology and composition of the irradiated surface varies considerable with the number of laser shots.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117023566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Experimental techniques that exploit pulses of the electromagnetic radiation with characteristic spectra covering the frequency range between few hundreds GHz and few THz and their applications in the characterization of various semiconductor materials are reviewed. The list of material parameters that can be determined by using pulsed THz techniques includes, among other, carrier lifetimes, their energy and momentum relaxation times, inter-valley separation in the conduction band, and nonlinear optical susceptibilities of the material.
{"title":"Characterizing semiconductor materials with terahertz radiation pulses","authors":"A. Krotkus, R. Adomavičius, V. Pačebutas","doi":"10.1117/12.816869","DOIUrl":"https://doi.org/10.1117/12.816869","url":null,"abstract":"Experimental techniques that exploit pulses of the electromagnetic radiation with characteristic spectra covering the frequency range between few hundreds GHz and few THz and their applications in the characterization of various semiconductor materials are reviewed. The list of material parameters that can be determined by using pulsed THz techniques includes, among other, carrier lifetimes, their energy and momentum relaxation times, inter-valley separation in the conduction band, and nonlinear optical susceptibilities of the material.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116486268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Important optical parameter of the eye is intraocular light scattering. Straylight can reduce visual acuity, contrast sensitivity. It is one of the main factors for glare, especially for drivers at night, when there is light source some distance away from the fixation point. There are many factors, which can affect amount of light scattering in the eye. To assess the effect of the color of the straylight source on retinal image quality at different light scattering levels, retinal straylight was measured with and without light scattering occluder. Red, green and blue colors were choosed for straylight source. Psychophysical and electrophysiological methods were used to evaluate light scattering effect on perception on different color stimuli. Results show that straylight values are the greatest for blue color with and without light scattering occluder. In measurements without light scattering occluder ratio of straylight values for red and green color are different between subjects. Using light scattering occluder straylight values for green color are greater than for red color. Optical and anatomical factors which can induce these spectral variations are discussed. Psychophysical and electrophysiological methods showed the similar changes in results with straylight values when light scattering were increased.
{"title":"Factors affecting intraocular light scattering from different color straylight sources","authors":"G. Ikaunieks, M. Ozolinsh","doi":"10.1117/12.815622","DOIUrl":"https://doi.org/10.1117/12.815622","url":null,"abstract":"Important optical parameter of the eye is intraocular light scattering. Straylight can reduce visual acuity, contrast sensitivity. It is one of the main factors for glare, especially for drivers at night, when there is light source some distance away from the fixation point. There are many factors, which can affect amount of light scattering in the eye. To assess the effect of the color of the straylight source on retinal image quality at different light scattering levels, retinal straylight was measured with and without light scattering occluder. Red, green and blue colors were choosed for straylight source. Psychophysical and electrophysiological methods were used to evaluate light scattering effect on perception on different color stimuli. Results show that straylight values are the greatest for blue color with and without light scattering occluder. In measurements without light scattering occluder ratio of straylight values for red and green color are different between subjects. Using light scattering occluder straylight values for green color are greater than for red color. Optical and anatomical factors which can induce these spectral variations are discussed. Psychophysical and electrophysiological methods showed the similar changes in results with straylight values when light scattering were increased.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129190908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Miia Määttälä, J. Lauri, M. Kinnunen, J. Hast, R. Myllylä
Self-mixing interferometry is a promising technique for a variety of measurement applications. Using a laser diode with an external cavity as interferometer, the technique offers several advantages over traditional interferometric configurations. This research used a self-mixing interferometer built in our own laboratory. It is based on a blue emitting GaN laser diode with a wavelength of 405 nm. Light is directed through an optical fiber from which a 1-cm section of cladding has been removed, and a cuvette for holding the sample is fixed around this part. Interference patterns, created in the laser cavity, are acquired with a computer-based data acquisition system and later processed using Matlab software. Since samples with different refractive indices create interference patterns with different phases, even small changes in sample concentrations can be measured. However, coupling light into a single-mode optical fiber is a very challenging task, and the setup is very sensitive to external interference like airflows or vibrations. Experiments with the device showed that, in stability measurements, the standard deviation of the recorded fringe pattern shifts was only 1.7 nm. In sample measurements, the refractive index change in the sample chamber varied from 1.0029 to 1.33, corresponding to a fringe pattern shift of 297±4 nm.
{"title":"Fiber-optic biosensor based on self-mixing interferometry","authors":"Miia Määttälä, J. Lauri, M. Kinnunen, J. Hast, R. Myllylä","doi":"10.1117/12.815269","DOIUrl":"https://doi.org/10.1117/12.815269","url":null,"abstract":"Self-mixing interferometry is a promising technique for a variety of measurement applications. Using a laser diode with an external cavity as interferometer, the technique offers several advantages over traditional interferometric configurations. This research used a self-mixing interferometer built in our own laboratory. It is based on a blue emitting GaN laser diode with a wavelength of 405 nm. Light is directed through an optical fiber from which a 1-cm section of cladding has been removed, and a cuvette for holding the sample is fixed around this part. Interference patterns, created in the laser cavity, are acquired with a computer-based data acquisition system and later processed using Matlab software. Since samples with different refractive indices create interference patterns with different phases, even small changes in sample concentrations can be measured. However, coupling light into a single-mode optical fiber is a very challenging task, and the setup is very sensitive to external interference like airflows or vibrations. Experiments with the device showed that, in stability measurements, the standard deviation of the recorded fringe pattern shifts was only 1.7 nm. In sample measurements, the refractive index change in the sample chamber varied from 1.0029 to 1.33, corresponding to a fringe pattern shift of 297±4 nm.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121697221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The laser photoacoustic spectroscopy (LPAS) can be applied analytically to determine the concentration of an analyte in samples and its absorption variation as a function of time. The LPAS has advantages of higher detection sensitivity, pure absorption measurement and much less interference by background scattering in comparison with traditional optical spectroscopy. On the other hand, the apparatus is simpler and more generally useful than that of fluorescent spectroscopy. In this study, we built a photoacoustic setup of a Q-switched Nd:YAG laser excited at the third harmonic wavelength and a wideband piezoelectric transducer clamped to the side of a cuvette. The samples included NADH solutions, mitochondrial suspensions and Intralipid-ink mixtures. The experiment results show that the lowest detectable absorption of the setup is in the order of 10-5 cm-1; the detectable concentration of NADH in a buffer is as low as 1.67 μM. When monitoring mitochondrial suspensions, the minimal concentration that can be detected is lower than 0.1 mg/mL and the absorption variation caused by full reduction of NAD+ to NADH in mitochondria can be detected.
{"title":"Pulsed photoacoustic measurements of suspensions: in case study of mitochnodrial NADH and its phantom","authors":"Zuomin Zhao, J. Hast, R. Myllylä, M. Känsäkoski","doi":"10.1117/12.815279","DOIUrl":"https://doi.org/10.1117/12.815279","url":null,"abstract":"The laser photoacoustic spectroscopy (LPAS) can be applied analytically to determine the concentration of an analyte in samples and its absorption variation as a function of time. The LPAS has advantages of higher detection sensitivity, pure absorption measurement and much less interference by background scattering in comparison with traditional optical spectroscopy. On the other hand, the apparatus is simpler and more generally useful than that of fluorescent spectroscopy. In this study, we built a photoacoustic setup of a Q-switched Nd:YAG laser excited at the third harmonic wavelength and a wideband piezoelectric transducer clamped to the side of a cuvette. The samples included NADH solutions, mitochondrial suspensions and Intralipid-ink mixtures. The experiment results show that the lowest detectable absorption of the setup is in the order of 10-5 cm-1; the detectable concentration of NADH in a buffer is as low as 1.67 μM. When monitoring mitochondrial suspensions, the minimal concentration that can be detected is lower than 0.1 mg/mL and the absorption variation caused by full reduction of NAD+ to NADH in mitochondria can be detected.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"133 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122490783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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