Analysis of a 3D printed chip from different quantum dot nanocomposites capable of multiple wavelength photoluminescent emission has been presented. The optical analysis of the result includes the minimization of photoluminescence scattering in arbitrary directions from the chip via structural modifications to the chip design. Other challenges include unwanted transmission of the Quantum Dots UV excitation via photopolymer chip base, contaminating the specimen on the chip. Comments on the feasibility of using this chip as a cheap alternative for narrow-spectrum, multi-wavelength light source for spectrometric analysis of photosensitive samples, have been made, especially with respect to the lifetime and stability of photo luminescence.
The importance of additive manufacturing for optical components and systems is steadily increasing. Conventional 3D printing processes such as multi-jet modeling or stereo lithography were initially used to realize passive optical components. The advantage is that with the help of additive manufacturing optical components can be realized with a complex structure. The challenge is thereby the surface quality of the components produced. Due to the process-related layer structure, steps occur on curved surfaces. Another disadvantage of the layer structure is that it acts on the one hand like a diffraction grating and on the other hand, it contributes to the volume scattering of the light. These disadvantages are attempted to be compensated by adapted printing or post-processing methods. Irrespective of this, the 3D printing of passive optical components has a wide variety of application fields, especially in the field of illumination.
The next step in the additive manufacturing of optical components is now to achieve a higher functionalization of the components, thus turning form passive to active optics, meaning that besides shaping of light rays the component can emit light on its own. Specifically, this means that the printed materials are mixed with other materials to allow additional light emission.
In this talk, the potential of additive manufacturing of passive optical components is introduced by examples. The main part of the talk then focuses on the active 3D printed optical components. For this purpose, we present two different concepts. On the one hand, the integration of optically active quantum dots (for example, CdSe / ZnS nanoparticles) in 3D printing materials. These nanoparticles emit a defined wavelength when excited by UV light. It would be desirable now that not only quantum dots of a certain size / type are printed in an optical component, but also that locally a material mix of different quantum dots can be realized. Thus, a single optical component can emit spatially resolved different wavelengths. In order to do so, we rebuilt a standard stereolithography printer so that we can use different materials in x, y plane and z direction. In this way, we realized an optically active analysis chip for biological samples.
The second concept is 3D printing of a random laser. For this purpose, we mixed nanoparticles (Nd-YAG particles) and Rhodamin as an active material into the 3Dprinting polymer. We show different forms of optically active components printed with this material. In order to prove the effect of random lasing, we pumped the samples with pulsed laser light (10Hz Nd-YAG laser, 532nm) and measured the emitted laser radiation.
Finally, we give a brief presentation of the development of an additive manufacturing platform based on robots. The aim of the platform is to enable additive manufacturing with 6 degrees of freedom. In the development of the platform, we take the requirements for printing of optical components into account.
Additive Manufacturing (AM) is full of opportunities when it comes to fabrication of optical elements whether it be manufacturing complex design systems or precise fabrication of micro structures. In addition, there exists the possibility of introducing optical properties of interest (e.g. photoluminescence) or altering already existing properties (e.g. refractive index) of elements, with the corresponding alteration of raw materials used for fabrication. This possibility is being explored in our research group, to produce optical elements that can be ‘activated’ with respect to a specific property. Our current focus is on the introduction of narrow spectrum photo-luminescence of different wavelengths emitted simultaneously from a single 3D sample. Previously, we demonstrated the use of a photopolymer matrix embedded with quantum dots capable of emission in a specific wavelength, as the raw material to fabricate monolithic samples using DLP based 3D printing system. In this paper, we present the first 3D printed model that includes four different quantum dots in different spatial locations within the sample (printed with multiple quantum dot mixtures), capable of generating photoluminescence simultaneously in four different wavelengths in response to ultra violet excitation. Analysis was done to investigate the effect of nanocomposite mixture variations, printing, and photoluminescence from the samples, in terms of wavelength and emission intensity. The nanocomposites used for manufacturing the prototype were synthesized with a unique hydrophobic resin matrix (ORMOCER®) embedded with quantum dot nanoparticles.
The development of additive manufacturing methods has enlarged rapidly in recent years. Thereby the work mainly focuses on the realization of mechanical components. But the additive manufacturing technology offers a high potential in the field of optics as well. Due to new design possibilities, completely new solutions are possible. Thus elements with virtually any geometry can be realized, which is often difficult with conventional fabrication methods.
Depending on the material and thus the manufacturing method used, either transparent optics or reflective optics can be developed with the aid of additive manufacturing. Ultimately, the application or the specification decides on the approach. For example, transmissive 3D printed parts exhibit the disadvantage of a significant reduced transmission. Conversely, reflective 3d printed optics often require a greater amount of rework in order to achieve a sufficient optical quality of the surface. Nonetheless there is a high potential in additively manufactured optical components.
Here, we compare metal optics (manufactured using a selective laser melting machine) with polymer optics (realized either by stereolithography or by multijet modling). In addition to the basic properties, the post-processing of the 3D printed optics is discussed. This includes, for example, cleaning and polishing of the surface using lasers or a robot based fluidjet process for metallic optics. In the case of the polymer optics a dip-coating process was developed in order to improve the surface quality.
Our aim is to integrate the additive manufactured optics into optical systems. Therefore we will present different examples in order to point out new possibilities and new solutions enabled by 3D printing of the parts. In this context, the development of 3D printed reflective and transmissive adaptive optics will be discussed as well.
Finally we will give an insight into our current developments. On the one hand the development of a robot based additive manufacturing platform will be discussed. The aim of this platform is to realize optimized 3D printed optical components, which is not possible with standard additive manufacturing machines. On the other hand, the functionalization of 3D printed optics will be discussed. Thereby functionalization can take place on the surface or in the volume of the 3D printed part. Based on the stereolithography method, a monolithic optical component was 3D-printed, showing light emission at different defined wavelengths due to UV excited quantum dots inside the 3D-printed optics.
Additive Manufacturing (AM) has the potential to become a powerful tool in the realization of complex optical components. The primary advantage that meets the eye, is that fabrication of geometrically complicated optical structures is made easier in AM as compared to the conventional fabrication methods (using molds for instance). But this is not the only degree of freedom that AM has to offer. With the multitude of materials suitable for AM in the market, it is possible to introduce functionality into the components one step before fabrication: by altering the raw material. A passive example would be to use materials with varying properties together, in a single manufacturing step, constructing samples with localized refractive indices for instance. An active approach is to blend in materials with distinct properties into the photopolymer resin and manufacturing with this composite material. Our research is currently focused in this direction, with the desired optical property to be introduced being Photoluminescence. Formation of nanocomposite mixtures to produce samples is the current approach. With this endeavor, new sensor systems can be realized, which may be used to measure the absorption spectra of biological samples. Thereby the sample compartment, the optics and the spectral light source (different quantum dots) are 3D-printed in one run. This component can be individually adapted to the biological sample with respect to wavelength, optical and mechanical properties.
Here we would like to present our work on the additive manufacturing of an active optical component. Based on the stereolithography method, a monolithic optical component was 3D-printed, showing light emission at different defined wavelengths due to UV excited quantum dots inside the 3D-printed optics.
In recent years, additive manufacturing methods became more and more prominent. Thereby, these techniques are mainly used in order to realize mechanical components. But the additive manufacturing technology offers a high potential in the field of optics as well. Owing to new design possibilities, completely new solutions are possible. We report on the realization of complex freeform optics using standard 3D printers. We briefly point out the characteristics of 3D printing and its influence on the optical properties. Additionally we address the needed rework of 3D printed optical components. Therefore we apply two different methods - a robot-based fluid jet polishing and a coating method. The advantage of a 3D printed optic lies in its shape complexity. Thus different complex shaped optical elements are discussed. They are used for either metrology tasks or illumination tasks.