Generation of UV and blue light by using off-axis pumping for fluorescence lifetime spectroscopy

Abstract

We report on generation of blue light exploiting high-order mode propagation in a microstructured fiber pumped by a Ti:Sapphire close to the zero-dispersion wavelength of the first high-order mode. An new interesting regime was observed with axial offset pump. With 230 mW of incident pump power we generated over 3 mW in the 450-510 nm window achieving 50 μW/nm power density. In a final round of measurements we were able to show generation of a peak at 350 nm. This complex regime has still to be fully investigated but we believe an optimized fiber design will allow to efficiently extend the operation of Ti:Sapphire laser to UV/blue wavelength region

Hyperspectral (fluorescence lifetime) imaging based on a UV-VIS enhanced supercontinuum source using high-order mode propagation

“…Further work will also need to better investigate the optimum interplay of pump wavelength and ZDW wavelength. As previously reported by changing the power level at a fixed wavelength we were able to tune the spectral peaks [12]. However in this case we had enough power to perform measurement by simply slicing the supercontinnum spectrum at a fixed pump power and pump wavelength.…”

“…[12]. The use of a custom made MSF [12,13] allowed us to achieve a regime quite different from the one reported in [8][9][10]. We found that using off-axis pumping and being able to carefully tune the pump wavelength close to first order mode ZDW we can very efficiently generate UV and visible light.…”

“…We also demonstrated the similar peaks in the output spectra were formed in the IR up to 2.5 μm. [12]. The use of a custom made MSF [12,13] allowed us to achieve a regime quite different from the one reported in [8][9][10].…”

“…Since alignment and tuning are easy and very stable, this technique is suitable for real-world measurements. In previous works we discussed the performance of this source exploiting propagation on high-order modes and its applications to fluorescence lifetime measurement [12] and to fluorescence imaging of multi-labeled neuronal rat cells in a confocal laser scanning microscope by simultaneous generation of the three requested wavelengths and and neuronal rat cell imaging [14]. In this paper we present the source and results of its application to hyperspectral FRET-FLIM measurements on amyloid oligomers and fibrils grown from the yeast prion Sup35p [15].…”

Neuronal rat cell imaging using a new UV-extended supercontinuum source

“…We also demonstrated the similar peaks in the output spectra were formed in the IR up to 2.5 μm. [12] In this work we investigate the characteristic of this regime as we tune the pump power and the excitation wavelength approaching around the zero-dispersion wavelength of the first-order mode. We aimed to generate light in the visible range (300 nm -600 nm wavelength interval) for an application to confocal fluorescence microscopy.…”