Sökning: "Near-infrared absorption"

Visar resultat 1 - 5 av 61 avhandlingar innehållade orden Near-infrared absorption.

  1. 1. Mid- and near-infrared NICE-OHMS : techniques for ultra-sensitive detection of molecules in gas phase

    Författare :Thomas Hausmaninger; Ove Axner; Kyle Crabtree; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; spectrometry; NICE-OHMS; trace gas detection; acetylene; methane; isotopologues; near-infrared; mid-infrared; shot-noise; optical parametric oscillator; teknisk fysik med inriktningen mikrosystemteknik; engineering science with specialization in microsystems technology;

    Sammanfattning : Noise-immune cavity-enhanced optical heterodyne molecular spectrometry (NICE-OHMS) is a technique for ultra-sensitive detection of molecular absorption and dispersion. For highest performance, the technique combines cavity enhancement (CE) with frequency modulation (FM); while the former increases the effective interaction length between the light and the analyte by several orders of magnitudes, the latter removes the in-coupling of 1/f noise and makes the signals background free. LÄS MER

  2. 2. Measurement of trace components in aqueous solutions with near and mid infrared Fourier transform spectroscopy

    Författare :Peter Snoer Jensen; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Near-infrared; Temperature dependency; Dual-beam; Optical null; Optimal pathlength Haemodialysis liquid; Urea; Glucose; Phosphate; Atom- och molekylärfysik; Atomic and molecular physics; Infrared; Water absorption; Fourier transform spectroscopy; Fysicumarkivet A:2003:Snoer Jensen;

    Sammanfattning : This thesis treats various aspects of the measurement of trace components in aqueous solutions with Fourier transform infrared spectroscopy. This technique has several applications from such diverse fields as dairy industry and biomedical optics. LÄS MER

  3. 3. Damage mechanisms for near-infrared radiation induced cataract

    Författare :Zhaohua Yu; Per Söderberg; Konstantin Galichanin; Masami Kojima; Uppsala universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; infrared radiation; photochemical; thermal; forward light scattering; lens; cataract; temperature; Arrhenius equation; heat diffusion;

    Sammanfattning : Purpose: 1) To estimate the threshold dose and the time evolution for cataract induction by near infrared radiation (IRR) in seconds exposure time domain; 2) to determine the ocular temperature development during the threshold exposure; 3) to investigate if near IRR induces cumulative lens damage considering irradiance exposure time reciprocity; 4) to experimentally estimate the temperature in the lens indirectly from the measurement of temperature-induced light scattering increase.Methods: Before exposure, 6-weeks-old albino rats were anesthetized and the pupils of both eyes were dilated. LÄS MER

  4. 4. Synthesis of Conjugated Polymers and Small Molecules for Organic Light-Emitting Devices and Photodetectors

    Författare :Petri Henrik Murto; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; solution processing; conjugated polymers; fluorescence; near-infrared; light-emitting electrochemical cell; organic photodetector; organic light-emitting diode;

    Sammanfattning : Production cost and environmental impact are the two major concerns that are related to the conventional optoelectronic devices. It is desirable for the modern semiconductors that they are free of toxic/costly metals, they can be processed with low-cost solution-based methods, and their optical, electronic, and mechanical properties can be easily tuned depending on the target application. LÄS MER

  5. 5. Elements of AlGaN-Based Light Emitters

    Författare :Martin Stattin; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; graphene; vertical cavity surface emitting laser; deep-ultraviolet; III-nitride; near-infrared; light emitting diode; visible; AlGaN; quantum cascade laser;

    Sammanfattning : The III-nitrides have enabled a range of optoelectronic devices and associated applications of great industrial and societal importance. However, the full potential of the III-nitrides remains to be explored. LÄS MER