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Optical spectroscopic techniques are critical for quantifying and characterizing diverse chemical compounds, from small molecules to macromolecules. Their versatility and cost-effectiveness have led to widespread use in fields such as medical diagnostics, industrial quality control, environmental monitoring, and chemical analysis. However, UV-vis spectrophotometry and fluorescence spectroscopy face significant challenges due to the complexity of light-matter interactions. These interactions often occur simultaneously and at overlapping wavelengths, complicating the accurate separation and quantification of absorption, scattering, and emission, particularly in complex samples. A fundamental issue with conventional UV-vis spectrophotometry is the interference from light scattering in turbid samples. Both scattering and absorption contribute to overall light extinction, and conventional instruments cannot quantitatively separate these two components. To address this, we developed an integrating-sphere-assisted resonance synchronous (ISARS) spectroscopy method using readily available spectrofluorometers equipped with integrating-sphere accessories. After calibration, this method can reliably decouple UV-vis extinction into its scattering and absorption spectra, allowing for accurate measurement of each component in complex samples. We also explored the effects of self-absorption, known as the inner-filter effect (IFE), on solution samples. The traditional model for IFE correction often fails, even in simple cases. To solve this, we derived a first-principles model to link the fluorescence measured by a spectrofluorometer with the UV-vis absorbance recorded by a conventional spectrophotometer. We applied this model with total photoluminescence spectroscopy to examine temperature effects on photoluminescent materials. In doing so, we could quantify quantum yield changes under different stimuli using a conventional spectrofluorometer for the first time. Finally, building on the insights from these studies, we developed a new instrument to address limitations in commercial instrumentation. The custom instrument integrates a thermoelectric-cooled CCD that can reach -90°C, significantly improving sensitivity and reducing noise. The advantages of this high-quality, low-temperature CCD are substantial, greatly enhancing the versatility, speed, and wavelength range of detection, not only refining current optical spectroscopic techniques but also enabling the development of new methodologies, thanks to its ability to acquire multiple spectra simultaneously, addressing many of the limitations of traditional instruments and paving the way for the development of new, customizable methodologies.

Optical scattering measurement devices are used to measure light reflection and light scattering from materials, to obtain data of the surface and bulk properties of materials. The measurement data are often used in research and development projects where material requirements are important, also for quality control in manufacturing processes, in different optical simulations and can be used for photorealistic rendering. In this master thesis project conducted at AFRY, a multifunctional team will develop an optical scattering measurement device that aims to collect data more accurately than current devices on the market. This thesis will focus on the mechanical design of the device which consists of the stability and movement of the components, the environment of the measurements and material selection with a focus on performance and sustainability. The optical model that will act as a basis for the development will be a gonioreflectometer consisting of a material sample, sample holder, light source, detector and an environment in which the measurements are conducted. Some of the physical, cognitive and emotional needs of the intended user are efficient use, low risk of misuse, reliable and high precision. A thorough requirement specification was made as a framework for the concept generation. The selected concept provides the movement of the optical components with an angular step enabling the desired optical scattering measurement. The selected stepper motor and gear ratio provides the flexibility of the movement, making it easy for the user to change angular steps of the optical components, enabling both fine and rough measurements. A separating screen was chosen for both concepts in order to avoid light contamination between measurements and the material sample holder resembles a frame that allows for mounting the material sample outside of the device. The mechanical system has a high stability and the material black anodized aluminum further contributes to the sturdiness of the construction. A physical prototype was created to validate the movement, since the movement of the detector and light source will be similar, only the detector movement was prototyped. The prototype showed that the movement of the detector worked in the desired way, hence the construction of the movement is approved. The scope was delimited in consensus with the project members and supervisors due to the time frame, hence there is future work on the device that should be accounted for. In conclusion, the purpose of the project was fulfilled after delimiting the goals and a conceptual solution was created that fulfilled the requirements of the project. / Optiska mätinstrument används för att mäta ljusreflektion och ljusspridning från material, för att erhålla data om materialets yt- och bulkegenskaper. Mätdata används ofta i forsknings- och utvecklingsprojekt där materialkrav är viktiga, även för kvalitetskontroll i tillverkningsprocesser, i olika optiska simuleringar och kan användas för fotorealistisk rendering. I detta examensarbete, genomfört på AFRY, kommer ett multifunktionellt team att utveckla en optisk spridningsmätningsenhet som syftar till att samla in data mer noggrant. Denna avhandling kommer att fokusera på den mekaniska designen av enheten som består av stabiliteten och rörelsen av komponenterna, mätmiljön och materialval med fokus på prestanda och hållbarhet. Den optiska modellen som kommer att ligga till grund för utvecklingen kommer att vara en gonioreflektometer bestående av ett materialprov, provhållare, ljuskälla, detektor och en miljö där mätningarna genomförs. Några av de fysiska, kognitiva och emotionella behoven hos den avsedda användaren är effektiv användning, låg risk för felanvändning, pålitlighet och hög precision. En noggrann kravspecifikation gjordes som en ram för konceptgenereringen. Det valda konceptet möjliggör rörelse av de optiska komponenterna med ett vinkelsteg som tillåter den önskade optiska spridningsmätningen. Den valda stegmotorn och utväxlingen ger flexibilitet i rörelsen, detta bidrar till att det är enkelt för användaren att ändra vinkelstegen för de optiska komponenterna, vilket tillåter både fina och grova mätningar. En avskiljningsskärm valdes för att undvika ljuskontaminering mellan mätningarna och materialprovhållaren liknar en ram där materialprovet monteras utanför enheten. Det mekaniska systemet har en hög stabilitet och materialet svart anodiserad aluminium bidrar till konstruktionens robusthet. En fysisk prototyp skapades för att validera rörelsen, eftersom rörelsen av detektorn och ljuskällan kommer att vara liknande, återskapades endast detektorns rörelse. Prototypen visade att detektorns rörelse fungerade på önskat sätt, därmed godkänns konstruktionen av rörelsen. Projektets mål avgränsades i samförstånd med projektmedlemmarna och handledarna på grund av tidsramen, därmed finns det framtida arbete för mätinstrumentet som bör beaktas. Sammanfattningsvis uppfylldes projektets syfte efter att målen avgränsats och en konceptuell lösning skapades som uppfyllde projektets krav.