Excimer

About: Excimer is a research topic. Over the lifetime, 3725 publications have been published within this topic receiving 75104 citations.

Influence of laser fluence and irradiation timing of F2 laser on ablation properties of fused silica in F2-KrF excimer laser multi-wavelength excitation process

Abstract: A collinear irradiation system of F2 and KrF excimer lasers for high-quality and high-efficiency ablation of hard materials by the F2 and KrF excimer lasers’ multi-wavelength excitation process has been developed. This system achieves well-defined micropatterning of fused silica with little thermal influence and little debris deposition. In addition, the dependence of ablation rate on various conditions such as laser fluence, irradiation timing of each laser beam, and pulse number is examined to investigate the role of the F2 laser in this process. The multi-wavelength excitation effect is strongly affected by the irradiation timing, and an extremely high ablation rate of over 30 nm/pulse is obtained between -10 ns and 10 ns of the delay time of F2 laser irradiation. The KrF excimer laser ablation threshold decreases and its effective absorption coefficient increases with increasing F2 laser fluence. Moreover, the ablation rate shows a linear increase with the logarithm of KrF excimer laser fluence when the F2 laser is simultaneously irradiated, while single KrF excimer laser ablation shows a nonlinear increase. The ablation mechanism is discussed based on these results.

Color‐Change Photoswitching of an Alkynylpyrene Excimer Dye

Abstract: We describe a photoswitchable DNA-based dimeric dye that visibly changes fluorescence from green to blue upon UV irradiation. A novel bis-alkyne-dependent [2+2+2] cycloaddition is proposed as a mechanism for the color change in air. The photoinduced structural switching results in spatial separation of stacked pyrene units, thereby causing selective loss of the excimer emission. We demonstrate and suggest several applications for this novel photoswitch.

Ratiometric Fluorescent Pattern for Sensing Proteins Using Aqueous Polymer-Pyrene/γ-Cyclodextrin Inclusion Complexes

Abstract: A ratiometric, versatile, and selective fluorescent pattern to sense and distinguish proteins on the basis of dissociation of aqueous polymer-pyrene/γ-cyclodextrin (γ-CD) inclusion complexes was developed. First, two kinds of aqueous polymer-pyrene were prepared via atom transfer radical polymerization using pyrene functionalized initiator. Then, the pyrene molecules could be accumulated into γ-CD cavity and form polymer-pyrene/γ-CD complexes, resulting in appearance of excimer emissions. The resultant complexes responded to proteins in two ways: nonmetalloproteins binding to polymer component triggered dissociation of the inclusion complexes, accompanied by alteration of pyrene excimer/monomer emission and ratiometric fluorescent intensity changes; the presence of metalloproteins could quench pyrene excimer/monomer emission because of energy transfer. Moreover, the fluorescent responses of the inclusion complexes to different proteins could be modulated by changing polymer type and chain length, resulting in a tunable selectivity and sensitivity. The proposed fluorescent inclusion complexes could provide a promising platform for sensing proteins.