We present a novel nano-photonics biosensor concept that offers an ultra-high surface specificity and excellent
suppression of background signals due to the sample fluid on top of the biosensor. In our contribution, we will briefly
discuss the operation principle and fabrication of the biosensor, followed by a more detailed discussion on the
experimentally determined performance parameters. Recent results on detection of fluorescently labeled molecules in a
highly fluorescent background will be shown, and we will give an outlook on real-time detection of bio-molecules such
as proteins and nucleic acids.
Practical EUV sources not only generate the desired EUV radiation at a wavelength of 13.5 nm but also produce debris that severely limits the lifetime of the collecting optics in the lithographic system. In this paper, we address the possibility of reducing the exposure of the collecting optics to debris by using directional gas flows, focusing particularly on mitigation of ballistic microparticles. The purpose of the gas flow is to change the direction of the particles such that they can subsequently be captured by a foil trap.
Two types of gas flows are considered: (i) longitudinal gas flows, i.e. with a flow direction essentially parallel to the velocity of the microparticles, and (ii) transversal gas flows, having a flow direction essentially perpendicular to that of the microparticles. We have conducted contamination experiments using both types of flows in Xe- and Sn-based experimental EUV sources with Ar gas.
The experiments show that directional gas flows suppress microparticles in the same way a buffer gas does unless the flow velocity becomes of the same order as the thermal velocity of the gas (~ 102 m/s). A high-speed longitudinal gas flow is expected to be more efficient in thermalizing the microparticles than a stationary buffer gas; this could however not be confirmed due to experimental constraints. Our experiments with a high-speed transversal gas flow show that submicron debris particles can successfully be suppressed by one order of magnitude. A transversal gas flow combined with a suitable foil trap structure may thus present an effective method for mitigation of microparticles.
Reported are the first calculations and experimental results of the deposition of EUV multilayer coatings that actively suppress the reflectance in the VUV wavelength range. In the undesired 100-200 nm band a factor of five reduction was achieved for one single optical element, while only a minor loss of 4.5% reflectance for λ = 13.5 nm, the operating wavelength of EUVL, was found.
The EUV source is an essential part of an EUV lithography exposure tool. All EUVL sources, and especially Sn-based sources, not only generate the desired radiation at a wavelength of 13.5 nm but also produce debris that limits the lifetime of the collecting optics in the lithographic system. In order to increase the lifetime of these optics we have successfully demonstrated the feasibility of both debris mitigation and cleaning strategies.
In this paper, we show the experimental results for different debris mitigation schemes as performed in cooperation with Philips Extreme UV. We performed our experiments under realistic conditions: samples that closely resemble the optics in the EUV lithography set-up and positioned at realistic distances and orientation to the Sn-based EUV source. Using these schemes we were able to suppress both atomic debris and Sn-particles generated by the Sn-based EUV source with 4-5 orders of magnitude. Based on our experiments, we found a significant improvement in the lifetime of the EUV optics.
In addition to avoiding the contamination of EUV optics, one can also clean the contaminated EUV optics. To do this, we have developed a technology for removing Sn (and C) using atomic hydrogen. We demonstrated Sn removal at a rate >200 nm/hour under a variety of experimental conditions (temperature, pressure).
Our results demonstrate that combining debris mitigation schemes with cleaning schemes could lead to an EUV lithography system with acceptable operational lifetimes.
Integrated optics micoresonators (μ-resonators) are microstructures with dimensions typically in the order of tens of
microns down to a few microns, whose response depends critically on optical wavelength and material properties. Recent experimental studies have shown that they are suitable as refractive index sensors, absorption sensors, and microresonator-assisted single and two-photon fluorescence. The absorption and fluorescence spectra are material-specific properties, that the devices can readily detect by using different excitation wavelengths. Therefore, the devices
are suitable for non-specific agent detection. Due to their inherent small size and the ease of cascading several microresonators, they are suitable building blocks for a sensing array allowing sensing/detection of multiple quantities/agents on a single chip, by e.g., using different chemo-optical transduction layers on top of the
microresonators. Such devices have a chip-area of only a few 100 μm2, making them suitable for sensing ultra-small analyte volumes (which is advantageous for bio-chemical sensing). In this contribution, sensing arrays based on integrated optics microresonators and their prospects for Homeland Security applications are discussed. Several device-concepts based on integrated optics microresonators will be treated. Their performance is analyzed using realistic parameters and experimental results of microresonator devices realized in silicon oxynitride (SiON) technology. The potential integration of theses devices with microelectronics, micro-mechanics and micro total analysis systems is
discussed.
The potential of integrated optical micro cavities (MC) for use in enhanced optical spectroscopy has been studied. The MC devices can sustain high morphological enhancement of optical field due to excitation of high-Q whispering gallery modes. The evanescent near field of the MC can be used to excite spectroscopic signal of molecules pout on top of the MC. Estimation shows that both local excitation field and emitted field can be increased y 2-3 orders of magnitude in the MC on resonance. In total, a gain of 4-8 orders of magnitude in the Raman/fluorescent signal of a molecule near the MC can be expected. In addition, the MC delivers a tunable and measurable enhancement, which is a real benefit in terms of enhanced optical microspectroscopy on-chip. High-Finesse integrated optics cylindrical micro cavities capable of significant field enhancement have been fabricated. Use of various waveguide/MC coupling schemes and design parameters allowed optimization of the devices for the largest intra-cavity power. The result for different micro cavities show prominent enhancement of intra-cavity field correlating with its mode spectrum. The characterization of MC and measurements performed demonstrate feasibility of the MC-based device for optical spectroscopy.
Microsystems are presented in which a SiON based optical waveguiding system is monolithically integrated with photodiodes, which are implemented in the Si substrate. Coupling structures of various type enable to transfer whether (part of) the power of one selected mode or the power of all modi propagating through the waveguide, to the photodiode. Here we focus on coupling structures for use in integrated optical absorption sensor systems, where information can be obtained from both the TE0 and TM0 mode, propagating simultaneously through the waveguide system. The coupling into the photodiodes is achieved by thinning down the thickness of the core layer in the region above the photodiode, which results in a mode specific modewidth expansion of the propagating modi. It will be shown that in asymmetrical layer systems, within a certain interaction length all TM0 power can be absorbed by the Si detector, while the TE0 mode shows only a negligible attenuation. The selectivity of the coupling can be strongly enhanced by implementing an additional substrate layer, having a refractive index in between that of the TE0 and TM0 mode. Both theoretical and experimental results will be presented.
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