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°The investigation of thermal behaviors and subsequent changes in the conformational order of lipids and liposomes is of importance in understanding various phenomena such as the formation and fusion of vesicles, trans-membrane diffusion and membrane interactions with drugs and proteins. In this work, the thermal behavior of a suite of newly developed self-forming synthetic non-phospholipid (PEGylated) lipids and its nanovesicles in buffer suspensions were investigated by variable-temperature thin-layered Fourier Transform Infrared (FTIR) transmission spectroscopy. The temperature-induced infrared spectra of such lipids composed of 1,2-dimyristoyl-rac-glycerol-3-dodecaethylene glycol (GDM-12) and 1,2-distearoyl-rac-glycerol-3-triicosaethylene glycol (GDS-23) were acquired by using FTIR spectrometer in conjunction with a custom built temperature-controlled demountable liquid cell. In contrast to conventional phospholipids, these novel lipids form liposomes spontaneously upon hydration, without the supply of external activation energy. It was found that the thermal stability of the PEGylated lipids defer greatly depending upon the acyl chain-lengths as well as number of associated head group units. Particularly, GDM-12 (saturated 14 hydrocarbon chains) shows one sharp order-disorder transition with temperature increasing from 3 to 5 °C. Similarly, GDS-23 (saturated 18 hydrocarbon chains) exhibits comparatively broad order-disorder transition profiles between temperature 17 and 22 °C. However, the phase transition temperature becomes significantly higher for lipid nanovesicles formed in aqueous suspensions. The results obtained in this study may find applications in various areas including the development of lipid based substance and drug delivery systems.

Lipids and liposomes have remained an active research topic for several decades due to their significance as membrane model. Several vibrational spectroscopic techniques have been developed and employed to study the properties of lipids and liposomes. In this study, near-infrared (NIR) spectroscopy has been used to analyze a suite of synthesized PEGylated lipids trademarked as QuSomesTM. The three amphiphiles used in this study, differ in their apolar hydrophobic chain length and contain various units of polar polyethylene glycol (PEG) head groups. In contrast to conventional phospholipids, this new kind of lipids forms liposomes spontaneously upon hydration, without the supply of external activation energy. Whilst the NIR spectra of QuSomesTM show a common pattern, differences in the spectra are observed which enable the lipids to be distinguished. NIR absorption spectra of these new artificial lipids have been recorded in the spectral range of 4800-9000 cm-1 (~2100-1100 nm) by using a new miniaturized spectrometer based on micro-optical-electro-mechanical systems (MOEMS) technology. In particular, we have established specific band structures as "molecular fingerprints" corresponding to overtones and combinations vibrational modes involving mainly C-H and O-H functional groups for sample analysis of QuSomesTM. Moreover, we have demonstrated that the nanovesicles formed by such lipids in polar solvents show high stability and obey Beer's law at low concentration. The results reported in this study may find applications in various field including the development of lipids based drug delivery systems.

The study of phase transitions in lipids is important to understand various phenomena such as conformational order, trans-membrane diffusion, vesicle formation and fusion as well as drug-and protein-membrane interactions. Several techniques, including Raman spectroscopy, have previously been employed to investigate the phase behaviour of lipids. In this work, temperature-controlled Raman microscopy has been used to detect and analyze the phase transitions in two newly developed synthetic PEGylated lipids trademarked as QuSomes™ and its nanovesicles in phosphate buffered saline (PBS) suspension. The amphiphiles considered in this study differ in their hydrophobic chain length and contain different units of polyethylene glycol (PEG) hydrophilic head groups. Raman spectra of these new artificial lipids and its nanovesicles have been recorded in the spectral range of 500-3100 cm -1 by using a temperature-controlled sample holder attached to a Raman microscope. The gel to liquid-crystalline phase transitions of the sample lipids, composed of pure 1,2-dimyristoyl-rac-glycerol-3-dodecaethylene glycol (GDM-12) and 1,2-distearoyl-rac-glycerol-3-triicosaethylene glycol (GDS-23), have been detected by examining the changes in Raman spectra of the lipids caused by temperature variation. In the liquid phase both of the studied lipids spontaneously form liposomes (nanovesicles) upon hydration. In this study, we have demonstrated the efficacy of the temperature-controlled Raman microscope system to reveal the main phase transition temperature (Tm) profiles of our sample lipids and its nanovesicles in PBS suspension. The phase changes are detected by plotting peak intensity ratios in the C-H stretching region (~I2935/I2883) versus temperature. These ratios correlate with lateral or inter-chain interactions as well as intra-molecular interactions. In particular, we have found that phase transitions occur at a temperature of approximately 5.2 o C and 21.2 o C for pure GDM-12 and GDS-23, respectively. However, the phase transition temperature becomes significantly higher for lipid nanovesicles formed in aqueous suspensions. Such information about these PEG coated lipids might find applications in various studies including the development of lipid based novel substances and drug delivery systems.

We present the first experimental study of self-forming synthetic lipids, trademarked as QuSomes TM , using Raman spectroscopy in the spectral range of 500 to 3100 cm -1 . Raman spectra of these new artificial lipids composed of 1,2- dimyristoyl- rac -glycerol-3-dodecaethylene glycol (GDM-12) and 1,2-dioleoyl- rac -glycerol-3-dodecaethylene glycol (GDO-12) have been obtained in pure form and in aqueous suspensions with Phosphate Buffered Saline (PBS) by using an inverted confocal laser-tweezers-Raman-microscopy system. This spectrometer works with an 80 mW diode-pumped solid-state laser, operating at a wavelength of 785 nm in the TEM 00 mode. The laser is used both for optical trapping and Raman excitation. The two amphiphiles considered in this study, differ in their hydrophobic chain length and contain similar units of hydrophilic polyethylene glycol (PEG) head groups. Such synthetic PEG coated lipids exist in liquid form at room temperature and spontaneously form liposomes (nano type vesicles) upon hydration. In this work, we have focused on the band assignments for the spectra of single QuSomes TM nano particles in pure form and in aqueous media acquired by means of Raman spectroscopy. In particular, we have found that the most prominent peaks in the studied spectral region are dominated by vibrational modes arising from C-C and C-H bonds. Furthermore, we have noticed that some of the distinct peaks observed below 1800 cm -1 in pure sample are preserved in aqueous environment. These retained intense bands are located at 1449, 1128, 1079, and 1065 cm -1 . This effect might be due to the strong chain-chain interactions, because the chains have to orient themselves and become tightly packed in the vesicles wall rather than adopt random orientations in bulk. This technique has proven to be an excellent tool to establish the fingerprint region revealing the molecular structure and conformation of QuSomes TM particles. The Raman spectroscopic data of these novel lipids and its vesicles formed in suspensions confirm high stability and are therefore considered as potential candidate for varieties of future applications including lipid based novel substances and drug delivery systems.

Near Infrared (NIR) spectroscopy has developed to an important and useful analysis method over the past years. The existence of compact, portable devices offers a lot of applications possibilities, even in harsh environments. Compact devices, mostly based on detector arrays, are quite costly caused by the expensive Indium Gallium Arsenide (InGaAs) detector arrays. By using MOEMS the set-up can be realised much more efficiently. With an adapted optical set-up detector arrays can be replaced by single element detectors. We have realised a new miniaturised spectrometer based on a scanning micro mirror. The mirror is combined with a diffraction grating and other optical components. It periodically disperses the polychromatic radiation into its spectral components. The radiation is measured by an InGaAs-single element detector, which can be thermoelectrically cooled depending on the application. The radiation coupling is possible either directly or by using fiber optics. It allows an easy attachment of substance samples for reflectance measurements as well as attenuated total reflection (ATR) probes, cuvette holders and flow cells. Lowest noise preamplifiers enable high-precise measurements over a wide dynamic range. With a spectral range of 1000 - 2100 nm and a spectral resolution of approx. 15 nm the device is able to fulfill various requirements. Applications for food stuff industry; clinical chemistry and identification of polymers were tested and will be discussed. Furthermore we will show the advanced optical and mechanical design. In addition advanced performance issues and reliability test results of the device will be reviewed.

In this work we have studied the generation of Extreme Ultraviolet (EUV) light by a novel Compact Electron Cyclotron Resonance Ion Source (CECRIS). The EUV emission diagnostics of the ECR plasma was accomplished by means of a 1.5 m Grazing Incidence Monochromator which was operated in a wavelength range of 4-90 nm under the condition of medium to high resolution to discriminate between spectra arising from different Xe q+ (q = 1-10) charge states. One of the major accomplishments of this study is assignment of numerous new optical transitions for Xenon in the 10-80 nm range under absolute conditions to create a database for further investigations. High resolution spectra were recorded confirming fair contributions from highly excited Xe 10+ and Xe 9+ ionic states. Major outcome of this work is that the Xe 10+ ion emission with λ = 13.4 nm may occurs with such a simplified and compact ECR source. The EUV emission of this particular line is of great interest for lithography applications.

Technological reasons stimulated enormous interest in the spectral range between 10 nm and 15 nm. One of the most important, apart from the potential to be applied in the microlithography, was the existence of the high-efficiency, spectrally highly selective (narrow-band) reflective multi-layer (ML) optics in this spectral range. Applying these optics to plasma based XUV (extreme ultra violett) sources the debris from the plasma is a serious problem. For transmissive multi-layer optics we have additionally the low figures of merit. For example, the best beam splitters have an efficiency of about 30% (energy in both parts of the splitted beam). This type of element is crucial for efficient single-shot interferometry being the main application using table-top soft x-ray lasers. We applied capillary optical elements, to our knowledge for the first time, to XUV radiation at 13.9 nm. These optical elements help overcome the limits discussed above or at least remarkably reduce the existing difficulties. A capillary beam splitter and a focussing capillary were applied to an incoherent XUV radiation source. For the beam splitter we measured a throughput of about 80%. With the focussing capillary we obtained a spot size of 27 μm (FWHM) with a gain (intensity in the focal spot compared to the intensity behind a pinhole of the focal spot size) of 600. Advantages and disadvantages of these optics in the discussed spectral range are analyzed.

Infrared analysis is a well-established tool for measuring composition and purity of various materials in industrial-, medical- and environmental applications. Traditional spectrometers, for example Fourier Transform Infrared (FTIR) Instruments are mainly designed for laboratory use and are generally, too large, heavy, costly and delicate to handle for remote applications. With important advances in the miniaturization, ruggedness and cost efficiency we have designed and created a new type of a micromirror spectrometer that can operate in harsh temperature and vibrating environments This device is ideally suited for environmental monitoring, chemical and biological applications as well as detection of biological warfare agents and sensing in important security locations In order to realize such compact, portable and field-deployable spectrometers we have applied MOEMS technology. Thus our novel dual detector micro mirror system is composed of a scanning micro mirror combined with a diffraction grating and other essential optical components in order to miniaturize the basic modular set-up. Especially it periodically disperses polychromatic radiation into its spectral components, which are measured by a combination of a visible (VIS) and near infrared (NIR) single element detector. By means of integrated preamplifiers high-precise measurements over a wide dynamic wavelength range are possible. In addition the spectrometer, including the radiation source, detectors and electronics can be coupled to a minimum-volume liquid or gas-flow cell. Furthermore a SMA connector as a fiber optical input allows easy attachment of fiber based probes. By utilizing rapid prototyping techniques, where all components are directly integrated, the micro mirror spectrometer is manufactured for the 700-1700 nm spectral range. In this work the advanced optical design and integration of the electronic interface will be reviewed. Furthermore we will demonstrate the performance of the system and present characteristic measurement results. Finally advanced packaging issues and test results of the device will be discussed.

In modern optical diagnostics there is an increasing interest in compact and cost-effective devices, i.e. for the analysis of surfaces, thin films, solids, powders, pastes, gels, liquids and alike. Therefore fast and non-invasive measurements are necessary. For the realization of such devices, micro system technology especially Micro-Opto-Electro-Mechanical System (MOEMS) technology is suitable. Hence two main miniaturized optical analyzer modules employing MOEMS have been developed. They are based on the principle of spectral sensing in the infrared range by means of a scanning micro mirror with an integrated diffraction grating or in combination with a separate grating. Using these configurations it is possible to project a specific wavelength onto an exit slit in front of an infrared detector. The first packaging approach is based on assembled laser-cut stainless steel sheets and optical standard components. During the further development different setups with improved reliability and accuracy have been realized. Due to the requirement of compact dimensions and short optical paths modern methods e.g. rapid prototyping were utilized to optimize packaging and optical setup and therefore the performance of the complete system. In this work the characteristics and the measurement results of different development levels will be reviewed. Furthermore we address issues, challenges and performance optimization of MOEMS packaging with respect to ultra compact micro mirror spectrometers. Finally, the applications and the feasibility of such miniaturized spectrometer systems are discussed.

We report intensive experimental and theoretical data corresponding to helium extreme ultraviolet (EUV) emission in the 30-60 nm wavelengths range for e- + He, H+ + He, and Hn+ + He (n=2-3) collisions with impact velocities from 1.4 to 8.5 a.u. Specifically, the degree of linear polarization associated with HeI (1snp) 1Po levels, n=2-5, (λ=51.7 to 58.4 nm for n=2-5 to n=1 transitions) and HeII (2p) 2Po states (λ=30.4 nm) have been measured at intermediate- to high-energy range using a compact lightweight molybdenum/silicon multilayer mirror polarimeter (MLM). The combination of these polarization measurements with our previous total EUV cross sections has enabled us to determine experimental magnetic substate scattering angle-integrated cross sections σ0 and σ1for ML = 0, ±1, and 1 following excitation of He (1s2) 1S to HeI (1s2p) 1Po levels and ionization-excitation to He+ (2p) 2Po for electron and proton impact at a wide range velocities. The degree of linear polarization and obtained magnetic sublevel cross sections are compared to earlier theoretical calculations together with our recent 23-state R-Matrix, 1st and 2nd Born calculations. Such a detailed comparison may shed more light on the collision processes involved in positively and negatively single charge particle impact in helium. In particular it shows that electron-electron interactions play an important role in the ionization-excitation mechanism. In addition, this comprehensive database possibly will provide a deeper understanding of electron and proton induced jets in solar flare astrophysical investigations.

The goal of this study is to test the feasibility of using noise factor/eigenvector bands as general clinical analytical tools for diagnoses. We developed a new technique, Noise Band Factor Cluster Analysis (NBFCA), to diagnose benign tumors via their Fourier transform IR fiber optic evanescent wave spectral data for the first time. The middle IR region of human normal skin tissue and benign and melanoma tumors, were analyzed using this new diagnostic technique. Our results are not in full-agreement with pathological classifications hence there is a possibility that our approaches could complement or improve these traditional classification schemes. Moreover, the use of NBFCA make it much easier to delineate class boundaries hence this method provides results with much higher certainty.

Chemical Factor Analysis (CFA) algorithms were applied to transform complex Fourier transform infrared fiberoptical evanescent wave (FTIR-FEW) normal and malignant skin tissue spectra into factor spaces for analysis and classification. The factor space approach classified melanoma beyond prior pathological classifications related to specific biochemical alterations to health states in cluster diagrams allowing diagnosis with more biochemical specificity, resolving biochemical component spectra and employing health state eigenvector angular configurations as disease state sensors. This study demonstrated a wealth of new information from in vivo FTIR-FEW spectral tissue data, without extensive a priori information or clinically invasive procedures. In particular, we employed a variety of methods used in CFA to select the rank of spectroscopic data sets of normal benign and cancerous skin tissue. We used the Malinowski indicator function (IND), significance level and F-Tests to rank our data matrices. Normal skin tissue, melanoma and benign tumors were modeled by four, two and seven principal abstract factors, respectively. We also showed that the spectrum of the first eigenvalue was equivalent to the mean spectrum. The graphical depiction of angular disparities between the first abstract factors can be adopted as a new way to characterize and diagnose melanoma cancer.

We present here comprehensive experimental data corresponding to helium extreme ultraviolet emission (EUV) for the 300-600A wavelength range in e- + He, H+ + He, and Hnn+ + He (n=2-3) collisions with impact velocities ranging from 1.4 to 6.9 a.u. The degree of linear polarization associated with HeI (1snp) 1Po -> (1s2) 1S decays for n-2-5 ((lambda) =510 to 584A) and HeII (2p) 2Po -> (1s) 2S transitions ((lambda) =304A), have been measured at intermediate and higher energies. These measurements have been conducted using a compact lightweight molybdenum/silicon multilayer mirror (MLM) spetropolarimeter. These experimental results are compared with our most advanced theoretical calculations using the close coupling method and several many body perturbation approaches. In this study, the degree of linear polarization will be discussed as a function of the projectile charge to elucidate few body excitation and ionization-excitation processes. Specifically, more sophisticated calculations including second Born approximation with full off-energy terms for the HeII (2p) 2Po sublevels have been used. The excellent agreement with our HeII Lyman-(alpha) data clearly demonstrates that off-energy terms in two-electron atomic interaction have very prominent effects. Our comprehensive experimental and theoretical database is also of great importance for the understanding of solar physics phenomena. Such results can be used as a new diagnostic tool for clarifying the role of electron and proton beams in solar flares.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The field of microtechnology is an important industrial and scientific resource for the 21st century. There is a great interest in spectroscopic sensors in the near and middle infrared (NIR-MIR) wavelength regions (1 - 2.5 micrometers ; 2.5 - 4.5 micrometers ; 4 - 6 micrometers ). The potential for cheap and small devices for nondestructive, remote sensing techniques at a molecular level has stimulated the design and development of more compact analyzer systems. Therefore we will try to build analyzers using micro optical components such as micromirrors and embossed micro gratings optimized for the above mentioned spectral ranges. Potentially, infrared sensors can be used for rapid nondestructive diagnostics of surfaces, liquids, gases, polymers and complex biological systems including proteins, blood, cells and cellular debris as well as body tissue. Furthermore, NIR-MIR microsensing spectroscopy will be utilized to monitor the chemical composition of petrochemical products like gasoline and diesel. In addition, miniature analyzers will be used for rapid measuring of food, in particular oil, starch and meat. In this paper we will present an overview of several new approaches for subsurface and surface sensing technologies based on the integration of optical micro devices, the most promising sensors for biomedical, environmental and industrial applications, data processing and evaluation algorithms for classification of the results. Both scientific and industrial applications will be discussed.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A detailed investigation of excitation of He (1s2) 1S to He (1snp) 1P degree(s) (n equals 2 - 5) states and ionization-excitation of He (1s2) 1S to He (2p) 2P degree(s) and He (3p) 2P degree(s) states in e- + He and H+ + He collision systems is presented for a wide range of projectile velocities (2.2 a.u. < v < 6.9 a.u.). Specifically new experimental data are presented on measurements of the degree of linear polarization for excitation and excitation-ionization of He following proton impact in the extreme ultraviolet (EUV) wavelengths. These measurements have been performed using a characterized molybdenum/silicon multilayer mirror polarimeter (MLM) whose polarization characteristics have been optimized for EUV emission of He and He+. Furthermore, the proton experimental results are compared with theoretical polarization data using the first Born approximation and recent atomic orbital close coupling (AOCC) calculations for the excitation process. A comprehensive comparison of experimental data for negatively and positively charged projectiles at equal impact velocities is also given in order to elucidate differences in the collision mechanisms of two electron targets. It is important to note that these results are relevant for astrophysical diagnostics such as solar flares.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

MCT-detectors are the most sensitive detectors used for spectroscopic applications in the middle infrared (MIR) fingerprint region of spectra (5-15 micrometers ), but their exploitation requires Liquid Nitrogen (LN) cooling in specialized optical dewars and precise optical alignment systems. Polycrystalline Infrared (PIR) fibers from solid solutions of AgCl/AgBr are transparent in the spectral range of 4-18 micrometers and have been coupled with pigtailed MCT detectors. The combination of such more advanced MCT detectors with PIR-fibers' flexibility enables remote spectroscopy of chemical reaction processes in situ or biomedical diagnostics in vivo at distances up to 20 meters from Fourier Transform Infrared (FTIR), Tunable Diode Laser (TDL) or optical filter spectrometers. The main advantage of these multichannel MCT/PIR detectors for spectroscopy and multispectral sensing is that there is no need for costly and bulky optics and time consuming alignment procedures of the MCT detector and the dewar in relation to the IR sources used. In this study, PIR-fiber pigtailed 2 and 4 channel MCT-detectors are described for different spectroscopic applications where the fibers are assembled in a bundle for remote spectroscopy and for multispectral analysis of specific targets and characteristic wavelengths.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

An advanced infrared interferometric method using fiber optics has been developed for biomedical, environmental and industrial applications. The fiberoptic Evanescent Wave Fourier Transform Infrared (FEW-FTIR) spectroscopy method has been applied to diagnostics of numerous materials including living tissue without sample preparation. This highly sensitive diagnostics tool can conduct surface and subsurface analysis at the molecular level on such diverse materials as human tissue and body fluids, plants, soil, rocks, chemicals, oil, paper and polymers nondestructively, noninvasively in vivo. Operating in the attenuated total reflection regime in the middle-infrared range, the FEW-FTIR technique provides direct contact between the fiber probe and any surface. Our fiber optical spectroscopic device is compact, portable for any application and operates up to a distance of three meters with extremely low loss and nontoxic fibers. This method allows the detection of functional chemical groups and bonds directly from a surface by soft touching of a surface for 15 sec. Applications of this method include (1) early diagnostics of precancerous conditions and other diseases, (2) sun, laser radiation and the influence of other environmental factors (water, pollution and weather), (3) quality control during manufacturing processes, in process analysis.

Development of Polycrystalline Infrared (PIR-) fibers extruded from solid solutions of AgCl/AgBr has opened a new horizon of molecular spectroscopy applications in 4 - 18 micron range of spectra. PIR-fiber cables and probes could be coupled with a variety of Fourier Transform Infrared spectrometer and Tunable Diode Lasers (TDL), including pig tailing of Mercury Cadmium Tellurium (MCT) detectors. Using these techniques no sample preparation is necessary for PIR- fiber probes to measure reflection and absorption spectra, in situ, in vivo, in real time and even multiplexed. Such PIR-fiber probes have been used for evanescent absorption spectroscopy of malignant tissue and skin surface diagnostics in-vivo, glucose detection in blood as well as crude oil composition analysis, for organic pollution and nuclear waste monitoring. A review of various PIR-fiber applications in medicine, industry and environment control is presented. The synergy of PIR-fibers flexibility with a super high resolution of TDL spectrometers with (Delta) v equals 10-4 cm-1, provides the unique tool for gas analysis, specifically when PIR-fibers are coupled as pigtails with MCT-detectors, and Pb-salt lasers. Design of multichannel PIR-fiber tailed TDL spectrometer could be used as a portable device for multispectral gas analysis at 1 ppb level of detectivity for various applications in medicine and biotechnology.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

An innovative spectroscopic diagnostic method has been developed for investigation of different regions of normal human skin tissue, as well as cancerous and precancerous conditions in vivo, ex vivo and in vitro. This new method is a combination of fiber-optical evanescent wave Fourier Transform infrared (FEW-FTIR) spectroscopy and fiber optic techniques using low-loss, highly flexible and nontoxic fiber optical sensors. The FEW-FTIR technique is nondestructive and very sensitive to changes of vibrational spectra in the IR region without heating and staining and thus altering the skin tissue. A special software package was developed for the treatment of the spectra. This package includes a database, programs for data preparation and presentation, and neural networks for classification of disease states. An unsupervised neural competitive learning neural network is implemented for skin cancer diagnosis. In this study, we have investigated and classified skin tissue in the range of 1400 to 1800 cm-1 using these programs. The results of our surface analysis of skin tissue are discussed in terms of molecular structural similarities and differences as well as in terms of different skin states represented by eleven different skin spectra classes.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A molybdenum/silicon (Mo/Si) multilayer mirror (MLM) polarimeter has been constructed and used to analyze the extreme ultraviolet (EUV) emission from excited HEI and HeII states following electron impact on helium for wavelengths ranging from approximately 256 angstrom to 584 angstrom. A ratio of reflectivities for s and p polarized light, Rs/Rp approximately equals 10, and a resolving power of (lambda) /(Delta) (lambda) approximately equals 6 at 304 angstrom were obtained. These characteristics and the use of a VYNS26 spectral filter were sufficient to allow a detailed polarization study of the first two members of the Lyman series of He+ at wavelengths of 304 angstrom (HeII 2p yields 1s) and 256 angstrom (HeII 3p yields 1s) for impact electron energies ranging from threshold to 1500 eV. The MLM has also been used as a single flat surface mirror polarimeter for the analysis of longer wavelength radiation (517 angstrom to 584 angstrom) from the HeI (1snp) 1Po yields (1s2) 1S series of neutral helium with Rs/Rp approximately equals 3. While MLM polarimeters have previously been used for EUV measurements with bright photon sources such as those provided by synchrotron facilities, the results from this work clearly demonstrate the feasibility of such devices with lower intensity electron and ion impact sources. The compact design of the apparatus makes it suitable as a portable measurement and calibration device.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

New experimental results are presented on measurements of the degree of linear polarization for ionization-excitation of He following electron and proton impact on a He gas target. These measurements have been performed using an optically characterized molybdenum/silicon (Mo/Si) multilayer mirror (MLM) polarimeter whose reflection and polarization characteristics have been optimized for the 304 angstrom wavelength region. In particular, the polarization of the photon emission from the decay of HeII (2p) 2P0 yields (1s) 2S with a wavelength of 304 Angstrom (Lyman (alpha) of HeII) has been measured for electron impact energies ranging from threshold to 1500 eV. These results are compared with polarization measurements of HeII Lyman (alpha) following proton impact on He for 187 to 460 keV beam energy corresponding to 2.7 a.u. less than v less than 4.3 a.u. projectile velocities. The integral alignment parameter A0 is also provided for negatively and positively charged particle impact to elucidate similarities and differences in the collision dynamics of two electron targets such as helium. Such results are of importance for astrophysical and laboratory plasma diagnostics.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We report here on ultra-compact diode-pumped single frequency, TEMoo mode Nd:YVO4 lasers at 1064 nm and 1340 nm. The lasers incorporate coupled cavity design operating in single longitudinal mode with a line-width of less than 20 kHz and frequency drift of 50 MHz over 10 minutes. These lasers produce more than 500 mW output at 1064 nm and more than 200 mW output at 1340 nm wavelength and are pumped by a 1.2 W laser diode. In addition, the lasers also feature excellent output stability with a output power variation of less than 1% over 8 hours and less than 0.2% amplitude noise in the 10 Hz to 50 MHz frequency range. The dimensions of the laser head are 3 X 3 X 12 cm and the universal 100 to 240 VAC input power control unit has been dimensions of 5 X 14 X cm. The total power consumption of the laser system is only 12 W. Therefore these ultra-compact, single frequency lasers will have a great potential for analytical instrumentation, Raman spectroscopy, biomedical diagnostics, optical communication as well as space exploration.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A new infrared (IR) interferometric method has been developed in conjunction with low-loss, flexible optical fibers, sensors, and probes. This combination of fiber optical sensors and Fourier Transform (FT) spectrometers can be applied to many fields, including (1) noninvasive medical diagnostics of cancer and other different diseases in vivo, (2) minimally invasive bulk diagnostics of tissue, (3) remote monitoring of tissue, chemical processes, and environment, (4) surface analysis of polymers and other materials, (5) characterization of the quality of food, pharmacological products, cosmetics, paper, and other wood-related products, as well as (6) agricultural, forensic, geological, mining, and archeological field measurements. In particular, our nondestructive, fast, compact, portable, remote and highly sensitive diagnostics tools are very promising for subsurface analysis at the molecular level without sample preparation. For example, this technique is ideal for different types of soft porous foams, rough polymers, and rock surfaces. Such surfaces, as well as living tissue, are very difficult to investigate by traditional FTIR methods. We present here FEW-FTIR spectra of polymers, banana and grapefruit peels, and living tissues detected directly at surfaces. In addition, results on the vibrational spectral analysis of normal and pathological skin tissue in the region of 850 - 4000 cm-1 are discussed.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Fourier transform infrared fiberoptic evanescent wave (FTIR- FEW) spectra, in the middle infrared (MIR) region, of human normal skin tissue, and melanoma and benign tumors were analyzed using chemical factor analysis (CFA). The first step in CFA is to determine the rank of the factor space and in this study several model validation techniques were employed. In particular we compare results obtained from Complete Cross Validation (CCV), Binary Cross Validation (BCV), Fisher variance ratios (F-Tests), Malinowiski indicator function (IND) and significance level (%SL). All methods' results were in agreement expect for F-Tests which differed with the other methods for normal skin tissue and melanoma tumors' rank. Using the two highest ranking eigenvectors for normal skin tissue as a basis set for cluster analysis, normal skin and melanoma tumors' clusters were well separated and localized in the two dimensional factor space. The projection of benign tumors' spectral points in this factor space revealed that some of the benign tumors had already regressed into either cancerous and other abnormal skin states. Furthermore the angular disparity between normal skin tissue and melanoma tumors' eigenvectors was successfully used to discriminate between the two skin states.

We report here on a new compact frequency-doubled Nd:YVO 4 laser emitting up to 165 mW of single frequency, TEM 00 mode, 532 nm green laser output. This compact, high efficiency, single frequency laser incorporating a novel coupled cavity technology appears promising for use in holographics and the printing industry. This coupled cavity technology provides for a frequency-doubled laser capable of operating in single longitudinal mode while eliminating many intracavity optical components, such as polarizers, waveplates or etalons. The few intracavity elements include a KTP nonlinear optical crystal employed for intracavity frequency doubling. The reduced component count results in a dramatic reduction in optical losses in the laser cavity and increased efficiency. This laser device produces 165 mW of green laser output power from a 1 W pumping laser diode, illustrating that both power and efficiency are improved using this technology. The reduced components also allow for a more compact laser, with the laser head measuring 3 X 3 X 12 cm, and the power control unit measuring 5 X 13 X 15 cm. This laser also features excellent output stability with power variation less than 1% over 4 hours, and less than 0.5% amplitude noise in the 10 Hz to 560 MHz bandwidth range.

A new powerful and highly sensitive technique for non-invasive biomedical diagnostics in vivo has been developed using Infrared Fiberoptic Evanescent Wave Fourier Transform Spectroscopy (FEW-FTIR). This compact and portable method allows to detect functional chemical groups and bonds via vibrational spectroscopy directly from surfaces including living tissue. Such differences and similarities in molecular structure of tissue and materials can be evaluated online. Operating in the attenuated total reflection (ATR) regime in the middle-infrared (MIR) range, the FEW-FTIR technique provides direct contact between the fiber probe and tissue for non-destructive, non-invasive, fast and remote (few meters) diagnostics and quality control of materials. This method utilizes highly flexible and extremely low loss unclad fibers, for example silver halide fibers. Applications of this method include investigations of normal skin, precancerous and cancerous conditions, monitoring of the process of aging, allergic reactions and radiation damage to the skin. This setup is suitable as well for the detection of the influence of environmental factors (sun, water, pollution, and weather) on skin surfaces. The FEW-FTIR technique is very promising also for fast histological examinations in vitro. In this review, we present recent investigations of skin, breast, lung, stomach, kidney tissues in vivo and ex vivo (during surgery) to define the areas of tumor localization. The main advantages of the FEW-FTIR technique for biomedical, clinical, and environmental applications are discussed.

New applications for the Fiberoptic Evanescent Wave Fourier Transform Infrared (FEW-FTIR) method have beendeveloped for the diagnostics of skin surfaces. Our technique allows for the detection of functional groups in the molecularstructure of skin tissue nonivasively and in vivo. The FEW-FTIR spectroscopic method is direct, nondestructive. and fast.Our optical fibers for the middle infrared (MIR) range are nontoxic, nonhygroscopic, flexible, and characterized by extremelylow losses. This combination of trathtional FTIR spectroscopy and advanced fiber teclmology has enabled us tononinvasively investigate normal and cancerous skin tissue in vivo in the range of 900 to 4000 cm' . We have developed aspecial software package of programs with database for the treatment of spectral data that utilizes wavelet analysis, principalcomponent analysis (PCA), image processing, artificial neural fuzzy logic, and data fusion. These programs provide us withthe ability to make base line corrections, normalize spectra, and determine peak positions from second order derivativespectra. In this study, we investigated normal, precancerous, and cancerous skin tissue in the range 1480 to 1800 cni' usingthese programs. The results of our surface analysis of skin tissue are discussed in terms of spectral parameters, DNA bandassignments, and molecular structural similarities and differences.Keywords: (10) FEW-FTIR Spectroscopy, skin surface, cancer, thtabase, smoothing, denoising, features

Fiberoptical evanescent wave Fourier transform infrared (FEW- FTIR) spectroscopy has been applied in the middle infrared (MIR) wavelength range (3 to 20 micrometer) to the in vivo diagnostics of normal skin tissue, acupuncture points as well as precancerous and cancerous conditions. The FTIR-FEW technique, using nontoxic unclad fibers, is suitable for noninvasive, sensitive investigations of skin tissue for various dermatological studies of skin caner, aging, laser treatment, cosmetics, skin allergies, etc. This method is direct, nondestructive, and fast (seconds). Our optical fibers are nonhygroscopic, flexible, and characterized by extremely low losses. In this study, we have noninvasively investigated more than 300 cases of normal skin, acupuncture points, precancerous and cancerous tissue in the range of 1400 to 1800 cm-1. The results of our analysis of skin and other tissue are discussed in terms of structural and mathematical similarities and differences on a molecular level. In addition, we have also performed cluster analysis, using principal component scores, to confirm pathological classifications and to discriminate between genders. We have found good agreement with prior pathological classifications for normal skin tissue and melanoma tumors and normal females were distinctly separate from males.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

An innovative spectroscopic diagnostic method has been developed for investigation of different regions of normal human skin tissue. This new method is a combination of Fourier transform infrared fiberoptic evanescent wave (FTIR-FEW) spectroscopy and fiber optic techniques for the middle infrared (MIR) wavelength range (3 to 20 μm). The fiber optical sensors we have used are characterized by low optical losses and high flexibility for remote analysis. Our fiber optical accessories and method allows for direct interaction of the skin tissue with the fiber probe and can be utilized with a diversity of standard commercial Fourier transform spectrometers. The FTIR-FEW technique, using nontoxic unclad fibers in the attenuated total reflection(ATR) regime, is suitable for noninvasive, fast, sensitive investigations of normal skin in vivo for various medical diagnostics applications including studies of acupuncture points. Here we present the first data on infrared spectra of skin tissue in vivo for normal skin and several acupuncture points in the range of 1300 to 1800 cm -1 and 2600 to 4000 cm -1 .

For characterization of skin cancer, an artificial neural network method has been developed to diagnose normal tissue, benign tumor and melanoma. The pattern recognition is based on a three-layer neural network fuzzy learning system. In this study, the input neuron data set is the Fourier transform IR spectrum obtained by a new fiberoptic evanescent wave Fourier transform IR spectroscopy method in the range of 1480 to 1850 cm-1. Ten input features are extracted from the absorbency values in this region. A single hidden layer of neural nodes with sigmoids activation functions clusters the feature space into small subclasses and the output nodes are separated in different nonconvex classes to permit nonlinear discrimination of disease states. The output is classified as three classes: normal tissue, benign tumor and melanoma. The results obtained from the neural network pattern recognition are shown to be consistent with traditional medical diagnosis. Input features have also been extracted from the absorbency spectra using chemical factor analysis. These abstract features or factors are also used in the classification.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

An innovative spectroscopic diagnostic method has been developed of investigation of different regions of normal human skin tissue. This new method is a combination of Fourier transform infrared fiberoptic evanescent wave (FTIR-FEW) spectroscopy and fiber optic technique for the middle infrared (MIR) wavelength range (3 to 20 micrometer). The fiberoptical sensors we have used are characterized by low optical losses and high flexibility for remote analysis. Our new fiber optical accessory can be utilized with a diversity of standard commercial Fourier transform spectrometers. FTIR-FEW, using nontoxic unclad fibers in the attenuated total reflection (ATR) regime, is suitable for noninvasive, fast, sensitive investigations of normal skin in vivo for various medical diagnostics applications including studies of acupuncture points. Our method allows for direct interaction of the skin tissue with the fiber. Here we present the first data on infrared spectra of skin tissue in vivo for several acupuncture points in the range of 1300 to 1800 cm-1 and 2600 to 4000 cm-1.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A new Fourier transform infrared fiberoptic evanescent wave (FTIR-FEW) spectroscopy method has been developed for tissue diagnostics in the middle infrared (MIR) wavelength range (3 to 20 micrometers). Specific novel fiberoptical chemical and biological sensors have been studied and used for spectroscopic diagnostic purposes. These nontoxic and nonhygroscopic fiber sensors are characterized by (1) low optical losses (0.05 to 0.2 dB/m at about 10 micrometer) and (2) high flexibility. Our new fiber optical devices can be utilized with standard commercially available Fourier transform spectrometers including attenuated total reflection (ATR) techniques. They are in particular ideally suited for noninvasive, fast, direct, sensitive investigations of in vivo and ex vivo medical diagnostics applications. Here we present data on IR spectra of skin tissue in vivo for various cases of melanoma and nevus in the range of 1480 - 1800 cm-1. The interpretation of the spectra of healthy and different stages of tumor and cancer skin tissue clearly indicates that this technique can be used for precancer and cancer diagnostics. This technique can be designed for real-time and on-line computer modeling and analysis of tissue changes.