Search results for "Optical path"
showing 10 items of 22 documents
Behaviour of the phakic iris-claw intraocular lens (Artisan /Verisyse) during accommodation: an optical coherence biometry study.
2007
Purpose To evaluate variations in the position of the phakic iris claw lens (Artisan®, Verisyse®) and the natural crystalline lens during the accommodation process. Methods We measured changes in position of the iris claw lens and the crystalline lens during the accommodation using optical coherence biometry (AC Master®/Carl Zeiss Meditec, Germany) in 17 patients (28 eyes) with a phakic iris claw lens implanted for high myopia and/or myopic astigmatism. Accommodative effort was obtained using an internal optical target within the measuring device. Results There was a forward shift of the phakic iris claw lens with a mean of 70 μm (8–178 μm) of the optical path length (OPL). At the same time…
FT-IR quantitative analysis of solvent mixtures by the constant ratio method
1999
Abstract An analytical methodology to quantify compounds in complex mixtures by FTIR spectroscopy is proposed and the “Constant Ratio Method” (CRM) was developed. The addition of a standard to the sample allows us to establish a constant KMS characteristic of the Analyte/Standard system which can be employed as a quantification factor of the analyte in different samples . In the proposed method the measurements are independent of optical path length. This method has been successfully applied to quantify butylacetate and toluene in binary and tertiary samples and tertiary mixtures. Butylacetate/toluene/nujol have been resolved employing valeronitrile as standard, obtaining values for relativ…
In-line holography of cloud volumes applied to the measurement of raindrops and snowflakes
1998
Abstract The ground-based HODAR (HOlographic Droplet and Aerosol Recording) of the University of Mainz has been operational since 1989 on the Kleiner Feldberg Mountain Observatory near Frankfurt/Main, Germany, in a `small volume' configuration. With this setup an air volume of approximately 1 l can be in situ recorded, which allows it to image all aerosol particles and droplets with diameter larger than 6 μm contained in the sample volume in situ. Recently the beam diameter and optical path length of the inline system have been enlarged such that large cloud volumes (approximately 500 l) can be recorded on single holograms. During the holographic image reconstruction step in the laboratory,…
Implementing the contamination prevention programs in the pesticide industry by infrared spectroscopy.
2014
Abstract An infrared spectroscopy based methodology has been successfully developed to implement contamination prevention programs in the pesticide industry. Sensitivity of the IR procedure, traditionally considered the Achilles Hell of the technique, has been improved by using a transmission cell with an open upper side, an internal volume of 35 µL and an optical pathlength of 0.5 mm, providing detection limits of 32 mg L−1 for folpet and 48 mg L−1 for cymoxanil. The manufacturing of folpet and cymoxanil was employed as an example and the IR methodology was validated for the implementation of contamination prevention programs in the pesticide industry. The swab test and rinsate method were…
Analysis of acousto-optic tunable filter performance for imaging applications
2010
Acousto-optic tunable filters (AOTFs) can be used as spec- tral filters in multispectral imaging applications. Acousto-optic crystals diffract a single wavelength from a broadband light beam, depending on the applied radio frequency signal. However, experimental measurements show that the actual performance is far from the expected behavior. We present an experimental characterization of several commercial off-the- shelf AOTFs for the implementation of multispectral imaging instruments. The diffraction performance of three bare crystals is compared, while a fourth AOTF crystal is mounted on the optical path of a multispectral im- ager to evaluate its performance. The experiments show that t…
Low-K factor of SiO2 layer on Si irradiated by YAG:Nd laser
2007
Abstract The change of optical and electrical properties of SiO2 layer on Si single crystal exposed to YAG:Nd laser radiation has been found experimentally. The second harmonic of YAG:Nd laser was used as a source of light. Before irradiation the SiO2 layer with thickness 0.75 μm had red color in reflecting light due to the interference. After irradiation with the laser with intensity of more than 3.5 MW/cm2 red color changed to yellow. However, samples with thickness 0.21 μm did not change color after irradiation. We explain such peculiarities of optical properties by change of optical path. Capacity (C) measurements of SiO2 layer with thickness 0.21 μm by the method of capacity–voltage ch…
High-Resolution Spectroscopy and Analysis of the ν3 and ν4 Fundamentals of Monoisotopic 70GeF4
2001
The first high-resolution study on germanium tetrafluoride is reported. We used a monoisotopic sample of (70)GeF(4). The FTIR spectra of the two infrared active fundamentals, namely the nu(4) (bending) and nu(3) (stretching) modes, were recorded at a temperature of ca. 210 K and a resolution (1/maximum optical path difference) of 0.0031 and 0.0023 cm(-1), respectively. These spectra were analyzed using the STDS software developed in Dijon. In both cases, we obtained a fit with a root mean square better than 1x10(-3) cm(-1). Both bands show very regular structures with no detectable perturbation. Copyright 2001 Academic Press.
Optical aging behaviour naturally induced on As_2S_3 microstructured optical fibres
2014
The efficiency and the stability of As2S3 microstructured optical fibres (MOFs) are limited by the shift of their optical properties that occurs over time due to a naturally induced aging process. Such sensitivity becomes more crucial for long optical path. Among the variety of fibre designs, the MOFs are developed for promising photonics applications such as supercontinuum generation for example. In the present work, we carried out an extensive aging study on As2S3 chalcogenide MOFs in ambient atmosphere. The evolution of the fibre transmission spectrum has been studied with regards to exposure time. The analysis of the transmission line profile was performed in terms of different spectral…
Colorimetric gas detection by the varying thickness of a thin film of ultrasmall PTSA-coated TiO2 nanoparticles on a Si substrate
2017
Financial support from the Estonian Research Council (IUT2-25, PUT170, PUT1096, PUT748, PUTJD680), the Estonian Centre of Excellence in Research Projects “Advanced materials and high-technology devices for sustainable energetics, sensorics and nanoelectronics” TK141 (2014-2020.4.01.15-0011), “Emerging orders in quantum and nanomaterials” TK134 and the Development Fund of the University of Tartu, are all gratefully acknowledged.
A microscope configuration for nanometer 3-D movement monitoring accuracy.
2011
In this paper we present a new microscopy configuration based upon temporal tracking of a secondary reflected speckle by imaging the speckle through properly defocused optics. The configuration is used to monitor three-dimensional (3-D) spontaneous contraction of rat cardiac muscle cells while achieving nanometer tracking accuracy at a rate of 30 frames per second (fps) without using interferometric recording. Estimation of the change in the optical path of accuracy of 50 nm in the transverse direction and of 200 nm in the axial direction was achieved.