Spectral UV losses in 355nm pulsed laser delivery system at low temperatures

Heimann, Jan; Gonschior, C. P.; Klein, Karl-Friedrich; Hillrichs, Georg; Takala, E.

doi:10.1016/j.jnoncrysol.2013.04.042

Cited by 3 publications

(3 citation statements)

References 23 publications

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“…18 Similarly, solarization and thermal cumulative effects are known to become significant for high power UV transmission through the core. 17 , 19 , 28 For our system, the intensity of light can be up to

if transmitting through the core. Therefore, both processes should be considered carefully since they can degrade the fiber transmission and affect the optical performance.…”

Section: Resultsmentioning

confidence: 99%

Dual-modality optical coherence tomography and frequency-domain fluorescence lifetime imaging microscope system for intravascular imaging

et al. 2020

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Significance: Detailed biochemical and morphological imaging of the plaque burdened coronary arteries holds the promise of improved understanding of atherosclerosis plaque development, ultimately leading to better diagnostics and therapies. Aim: Development of a dual-modality intravascular catheter supporting swept-source optical coherence tomography (OCT) and frequency-domain fluorescence lifetime imaging (FD-FLIM) of endogenous fluorophores with UV excitation. Approach: We instituted a refined approach to endoscope development that combines simulation in a commercial ray tracing program, fabrication, and a measurement method for optimizing ball-lens performance. With this approach, we designed and developed a dual-modality catheter endoscope based on a double-clad fiber supporting OCT through the core and fluorescence collection through the first cladding. We varied the relative percent of UV excitation launched into the core and first cladding to explore the potential resolution improvement for FD-FLIM. The developed catheter endoscope was optically characterized, including measurement of spatial resolution and fluorescent lifetimes of standard fluorophores. Finally, the system was demonstrated on fresh ex vivo human coronary arteries. Results: The developed endoscope was shown to have optical performance similar to predictions derived from the simulation approach. The FLIM resolution can be improved by over a factor of 4 by primarily illuminating through the core rather than the first cladding. However, time-dependent solarization losses need to be considered when choosing the relative percentage. We ultimately chose to illuminate with 7% of the power transmitting through the core. The resulting catheter endoscope had 40-μm lateral resolution for OCT and <100 μm lateral resolution for FD-FLIM. Images of ex vivo coronary arteries are consistent with expectations based on histopathology. Conclusions: The results demonstrate that our approach for endoscope simulation produces reliable predictions of endoscope performance. Simulation results guided our development of a multimodal OCT/FD-FLIM catheter imaging system for investigating atherosclerosis in coronary arteries.

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if transmitting through the core. Therefore, both processes should be considered carefully since they can degrade the fiber transmission and affect the optical performance.…”

Section: Resultsmentioning

confidence: 99%

Dual-modality optical coherence tomography and frequency-domain fluorescence lifetime imaging microscope system for intravascular imaging

et al. 2020

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“…For spectral analyses of UV-damage, the treated fibers were tested in the system described above with deuterium-lamp; however, the irradiation time was less than 5 s to avoid further damage or annealing (see [7,19]). …”

Section: Existing Equipments For Uv-damagementioning

confidence: 99%

“…. 1); tests were carried out at room temperature (293 K) and at liquidnitrogen (77 K); more details in [ 7,19] In addition to 355 nm wavelength, the pulsed Nd:YAG lasers with 266 nm (fourth harmonics), are used in the following applications: MALDI-TOF, micro dissection, laser induced fluorescence (LIF), light detection and ranging (LIDAR), micro machining, marking, and basic research in bio-photonics and life science. They are also used as replacement for Nitrogen gas lasers when high reliability and low service cost is a requirement.…”

Section: Introductionmentioning

confidence: 99%

Improvement of optical damage in specialty fiber at 266 nm wavelength

Tobisch

Ohlmeyer

Zimmermann³

et al. 2014

SPIE Proceedings

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Improved multimode UV-fibers with core diameters ranging from 70 to 600 µm diameter have been manufactured based on novel preform modifications and fiber processing techniques. Only E'-centers at 214 nm and NBOHC at 260 nm are generated in these fibers.A new generation of inexpensive laser-systems have entered the market and generated a multitude of new and attractive applications in the bio-life science, chemical and material processing field. However, for example pulsed 355 nm Nd:YAG lasers generate significant UV-damages in commercially available fibers. For lower wavelengths, no results on suitable multi-mode or low-mode fibers with high UV resistance at 266 nm wavelength (pulsed 4 th harmonic Nd:YAG laser) have been published. In this report, double-clad fibers with 70 µm or 100 µm core diameter and a large claddingto-core ratio will be recommended. Laser-induced UV-damages will be compared between these new fiber type and traditional UV fibers with similar core sizes. Finally, experimental results will be cross compared against broadband cw deuterium lamp damage standards.

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UV-fibers: two decades of improvements for new applications

Klein

Khalilov²

2015

SPIE Proceedings

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Multimode UV-fibers with high-OH synthetic silica core and F-doped silica cladding have been available for over 40 years. At the beginning, the spectral UV-range above 250 nm wavelength was commonly used, because the generation of UV-absorbing defect centers prevented reliable light transfer below 250 nm; even light from a low-power broadband deuterium-lamp was sufficient to damage these UV-fibers of the 1 st generation. However, even then, applications in the field of spectroscopy, laser light delivery, sensors and process control were discussed and improvements of fiber quality in this very interesting UVC range required by researchers and industrical end-users. Starting in 1993 with hydrogen-loaded fibers, further modification in preform and fiber manufacturing including additional fiber treatments lead to currently available hydrogen-free UV-fiber (4 th generation) with significantly improved stability in the DUV-region below 250 nm, enabling routine use of optical fibers in this field. In addition to the UV-fiber improvements, some selected UV fiber-optic applications using broadband deuterium-lamps will be discussed. Finally, there is still room for further improvements, especially in combination with newly available pulsed UV light sources, which are low-cost, small sized and highly reliable.

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Spectral UV losses in 355nm pulsed laser delivery system at low temperatures

Cited by 3 publications

References 23 publications

Dual-modality optical coherence tomography and frequency-domain fluorescence lifetime imaging microscope system for intravascular imaging

Dual-modality optical coherence tomography and frequency-domain fluorescence lifetime imaging microscope system for intravascular imaging

Improvement of optical damage in specialty fiber at 266 nm wavelength

UV-fibers: two decades of improvements for new applications

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