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Udgivelsesdato: 2009

Udgivelsesdato: 2009

The authors have investigated the bleaching dynamics that occur in optofluidic dye lasers where the liquid laser dye in a microfluidic channel is locally bleached due to optical pumping. They find that for microfluidic devices, the dye bleaching may be compensated through diffusion of dye molecules alone. By relying on diffusion rather than convection to generate the necessary dye replenishment, their observation potentially allows for a significant simplification of optofluidic dye laser device layouts, omitting the need for cumbersome and costly external fluidic handling or on-chip microfluidic pumping devices. ©2007 American Institute of Physics.

We have investigated the bleaching dynamics that occur in opto-fluidic dye lasers, where the liquid laser dye in a channel is locally bleached due to optical pumping. Our studies suggest that for micro-fluidic devices, the dye bleaching may be compensated through diffusion of dye molecules alone. By relying on diffusion rather than convection to generate the necessary dye replenishment, our observation potentially allows for a significant simplification of opto-fluidic dye laser device layouts, omitting the need for cumbersome and costly external fluidic handling or on-chip micro-fluidic pumping devices.

The authors have investigated the bleaching dynamics that occur in optofluidic dye lasers where the liquid laser dye in a microfluidic channel is locally bleached due to optical pumping. They find that for microfluidic devices, the dye bleaching may be compensated through diffusion of dye molecules alone. By relying on diffusion rather than convection to generate the necessary dye replenishment, their observation potentially allows for a significant simplification of optofluidic dye laser device layouts, omitting the need for cumbersome and costly external fluidic handling or on-chip microfluidic pumping devices. ©2007 American Institute of Physics.

We have investigated the bleaching dynamics that occur in opto-fluidic dye lasers, where the liquid laser dye in a channel is locally bleached due to optical pumping. Our studies suggest that for micro-fluidic devices, the dye bleaching may be compensated through diffusion of dye molecules alone. By relying on diffusion rather than convection to generate the necessary dye replenishment, our observation potentially allows for a significant simplification of opto-fluidic dye laser device layouts, omitting the need for cumbersome and costly external fluidic handling or on-chip micro-fluidic pumping devices.

The authors have investigated the bleaching dynamics that occur in optofluidic dye lasers where the liquid laser dye in a microfluidic channel is locally bleached due to optical pumping. They find that for microfluidic devices, the dye bleaching may be compensated through diffusion of dye molecules alone. By relying on diffusion rather than convection to generate the necessary dye replenishment, their observation potentially allows for a significant simplification of optofluidic dye laser device layouts, omitting the need for cumbersome and costly external fluidic handling or on-chip microfluidic pumping devices. ©2007 American Institute of Physics.

Formålet med dette Ph.D. arbejde har været at udvikle miniaturiserede polymer farvestoflasere, egnet til at blive integreret i mikrochips som også indeholder andre polymerstrukturer – som for eksempel kan findes i ”Laboratorie-på-en-chip” kredsløb. Lasernes funktion skal være at levere lys til meget følsomme sensorformål, og at undgå at skulle opliniere eksterne lyskilder til sensorer på polymerchips. En enkelt type gennemsigtig ”resist” (SU-8) er blevet brugt til at udvikle en række laserresonatorer i polymer. ”Resisten” er blevet formgivet via en række lithografiske teknikker: UV lithografi, elektronstrålelithografi og Röntgenstrålelithografi. Andre polymerer er også blevet formgivet via ”nanoimprint” lithografi for at skabe laserresonatorer. En række lasere, både baseret på et flydende forstærkningsmedium og et faststof forstærkningsrmedium er blevet udviklet. Laserne giver både lys i flere ”modes” og i een enkelt optisk ”mode”. Laserne er baseret på en mængde forskellige optiske egenskaber af polymer tyndfilm og vædsker. De praktiske muligheder for at integrere polymer farvestoflaserne demonstreres ved at integrere en mængde optiske og væske- komponenter på en enkelt chip sammen med en miniaturiseret farvestoflaser., The purpose of this project has been to develop miniaturized polymer dye lasers that can be integrated on microchips containing other polymer ”laboratory on a chip” circuitry. The envisioned function of the polymer dye lasers has been to deliver light for sensing purposes, either for wavelength dependent absorption or for interference based sensing, for example with integrated Mach-Zehnder interferometers. In order to develop this kind of lasers, the project has focused on using a single transparent type of resist (SU-8) that can be patterned via several methods. The methods that have been tried on this resist are UV lithography, electron beam lithography and X-ray lithography. Apart from SU-8, a few alternative polymer types have also been used for forming laser structures via nanoimprint lithography. Throughout the work, several laser resonator types have been fabricated in polymer materials. The resonators range from simple parallel mirror types to first order Bragg grating distributed feedback resonators. Through the optical characterization of the laser type range, the possibilities for forming such miniaturized polymer dye lasers are revealed. Some techniques for modelling micro-optical structures are presented as a suggestion of how to predict the behavior of miniaturized polymer dye lasers and micro-optical structures in general. Both lasers operating in multi-mode and single polarization lasers operating on pre-determined single mode wavelengths are demonstrated. The mode structure of the lasers are controlled by the design of the laser resonators. Integration of a miniaturized polymer dye laser is demonstrated in two examples where the laser delivers light to an absorption cell, which makes it possible to measure the wavelength selective absorption of the fluid in the cell. The findings presented in the thesis forms a basis for selection of laser design for new applications both with respect to integra

Formålet med dette Ph.D. arbejde har været at udvikle miniaturiserede polymer farvestoflasere, egnet til at blive integreret i mikrochips som også indeholder andre polymerstrukturer – som for eksempel kan findes i ”Laboratorie-på-en-chip” kredsløb. Lasernes funktion skal være at levere lys til meget følsomme sensorformål, og at undgå at skulle opliniere eksterne lyskilder til sensorer på polymerchips. En enkelt type gennemsigtig ”resist” (SU-8) er blevet brugt til at udvikle en række laserresonatorer i polymer. ”Resisten” er blevet formgivet via en række lithografiske teknikker: UV lithografi, elektronstrålelithografi og Röntgenstrålelithografi. Andre polymerer er også blevet formgivet via ”nanoimprint” lithografi for at skabe laserresonatorer. En række lasere, både baseret på et flydende forstærkningsmedium og et faststof forstærkningsrmedium er blevet udviklet. Laserne giver både lys i flere ”modes” og i een enkelt optisk ”mode”. Laserne er baseret på en mængde forskellige optiske egenskaber af polymer tyndfilm og vædsker. De praktiske muligheder for at integrere polymer farvestoflaserne demonstreres ved at integrere en mængde optiske og væske- komponenter på en enkelt chip sammen med en miniaturiseret farvestoflaser., The purpose of this project has been to develop miniaturized polymer dye lasers that can be integrated on microchips containing other polymer ”laboratory on a chip” circuitry. The envisioned function of the polymer dye lasers has been to deliver light for sensing purposes, either for wavelength dependent absorption or for interference based sensing, for example with integrated Mach-Zehnder interferometers. In order to develop this kind of lasers, the project has focused on using a single transparent type of resist (SU-8) that can be patterned via several methods. The methods that have been tried on this resist are UV lithography, electron beam lithography and X-ray lithography. Apart from SU-8, a few alternative polymer types have also been used for forming laser structures via nanoimprint lithography. Throughout the work, several laser resonator types have been fabricated in polymer materials. The resonators range from simple parallel mirror types to first order Bragg grating distributed feedback resonators. Through the optical characterization of the laser type range, the possibilities for forming such miniaturized polymer dye lasers are revealed. Some techniques for modelling micro-optical structures are presented as a suggestion of how to predict the behavior of miniaturized polymer dye lasers and micro-optical structures in general. Both lasers operating in multi-mode and single polarization lasers operating on pre-determined single mode wavelengths are demonstrated. The mode structure of the lasers are controlled by the design of the laser resonators. Integration of a miniaturized polymer dye laser is demonstrated in two examples where the laser delivers light to an absorption cell, which makes it possible to measure the wavelength selective absorption of the fluid in the cell. The findings presented in the thesis forms a basis for selection of laser design for new applications both with respect to integra

We demonstrate real-time tunability of a chip-based liquid light source enabled by microfluidic mixing. The mixer and light source are fabricated in SU-8 which is suitable for integration in SU-8-based laboratory-on-a-chip microsystems. The tunability of the light source is achieved by changing the concentration of rhodamine 6G dye inside two integrated vertical resonators, since both the refractive index and the gain profile are influenced by the dye concentration. The effect on the refractive index and the gain profile of rhodamine 6G in ethanol is investigated and the continuous tuning of the laser output wavelength is demonstrated using an ethanolic rhodamine 6G solution of 2×10–2 mol/l mixed with pure ethanol. This yields rhodamine 6G concentrations from 5×10–3 to 1.5×10–2 mol/l inside the laser resonators and a wavelength change of 10 nm with a response time of 110 s. ©2006 American Institute of Physics

We present the first observation, to our knowledge, of lasing from a levitated, dye droplet. The levitated droplets are created by computer controlled pico-liter dispensing into one of the nodes of a standing ultrasonic wave (100 kHz), where the droplet is trapped. The free hanging droplet forms a high quality optical resonator. Our 750 nL lasing droplets consist of Rhodamine 6G dissolved in ethylene glycol, at a concentration of 0.02 M. The droplets are optically pumped at 532 nm light from a pulsed, frequency doubled Nd:YAG laser, and the dye laser emission is analyzed by a fixed grating spectrometer. With this setup we have achieved reproducible lasing spectra in the visible wavelength range from 610 nm to 650 nm. The levitated droplet technique has previously successfully been applied for a variety of bio-analytical applications at single cell level. In combination with the lasing droplets, the capability of this high precision setup has potential applications within highly sensitive intra-cavity absorbance detection. © 2006 Optical Society of America

We demonstrate wavelength tuning of a micro-fluidic dye ring laser. Wavelength tunability is obtained by controlling the liquid dye concentration. The device performance is modelled by FEM simulations supporting a ray-tracing view.

We demonstrate real-time tunability of a chip-based liquid light source enabled by microfluidic mixing. The mixer and light source are fabricated in SU-8 which is suitable for integration in SU-8-based laboratory-on-a-chip microsystems. The tunability of the light source is achieved by changing the concentration of rhodamine 6G dye inside two integrated vertical resonators, since both the refractive index and the gain profile are influenced by the dye concentration. The effect on the refractive index and the gain profile of rhodamine 6G in ethanol is investigated and the continuous tuning of the laser output wavelength is demonstrated using an ethanolic rhodamine 6G solution of 2×10–2 mol/l mixed with pure ethanol. This yields rhodamine 6G concentrations from 5×10–3 to 1.5×10–2 mol/l inside the laser resonators and a wavelength change of 10 nm with a response time of 110 s. ©2006 American Institute of Physics

We present the first observation, to our knowledge, of lasing from a levitated, dye droplet. The levitated droplets are created by computer controlled pico-liter dispensing into one of the nodes of a standing ultrasonic wave (100 kHz), where the droplet is trapped. The free hanging droplet forms a high quality optical resonator. Our 750 nL lasing droplets consist of Rhodamine 6G dissolved in ethylene glycol, at a concentration of 0.02 M. The droplets are optically pumped at 532 nm light from a pulsed, frequency doubled Nd:YAG laser, and the dye laser emission is analyzed by a fixed grating spectrometer. With this setup we have achieved reproducible lasing spectra in the visible wavelength range from 610 nm to 650 nm. The levitated droplet technique has previously successfully been applied for a variety of bio-analytical applications at single cell level. In combination with the lasing droplets, the capability of this high precision setup has potential applications within highly sensitive intra-cavity absorbance detection. © 2006 Optical Society of America

We demonstrate wavelength tuning of a micro-fluidic dye ring laser. Wavelength tunability is obtained by controlling the liquid dye concentration. The device performance is modelled by FEM simulations supporting a ray-tracing view.

We present single-mode solid-state polymer dye lasers fabricated with standard UV lithography. The lasers use a high-order Bragg grating and rely on index-tuning of a photosensitive polymer for waveguiding. The gain medium is Rhodamine 6G.

We present a lab-on-a-chip device featuring a microfluidic dye laser, wave-guides, microfluidic components and photo-detectors integrated on the chip. The microsystem is designed for wavelength selective absorption measurements in the visible range on a fluidic sample, which can be prepared/mixed on-chip. The laser structures, wave-guides and micro-fluidic handling system are defined in a single UV-lithography step on a 10 μm thick SU-8 layer on top of the substrate. The SU-8 structures are sealed by a Borofloat glass lid, using polymethylmethacrylate (PMMA) adhesive bonding.

We present a lab-on-a-chip device featuring a microfluidic dye laser, wave-guides, microfluidic components and photo-detectors integrated on the chip. The microsystem is designed for wavelength selective absorption measurements in the visible range on a fluidic sample, which can be prepared/mixed on-chip. The laser structures, wave-guides and micro-fluidic handling system are defined in a single UV-lithography step on a 10 μm thick SU-8 layer on top of the substrate. The SU-8 structures are sealed by a Borofloat glass lid, using polymethylmethacrylate (PMMA) adhesive bonding.

We demonstrate a single mode distributed feedback liquid dye laser, based on a short 133 'rd order Bragg grating defined in a single polymer layer between two glass substrates.

We present a lab-on-a-chip device featuring a microfluidic dye laser, wave-guides, microfluidic components and photo-detectors integrated on the chip. The microsystem is designed for wavelength selective absorption measurements in the visible range on a fluidic sample, which can be prepared/mixed on-chip. The laser structures, wave-guides and micro-fluidic handling system are defined in a single UV-lithography step on a 10 μm thick SU-8 layer on top of the substrate. The SU-8 structures are sealed by a Borofloat glass lid, using polymethylmethacrylate (PMMA) adhesive bonding.

We demonstrate a single mode distributed feedback liquid dye laser, based on a short 133 'rd order Bragg grating defined in a single polymer layer between two glass substrates.

We demonstrate a single mode distributed feedback liquid dye laser, based on a short 133 'rd order Bragg grating defined in a single polymer layer between two glass substrates.