Collagen crosslinking-induced corneal morphological changes: a three-dimensional light sheet Microscopy-based evaluation.

Stiffness-related eye diseases such as keratoconus require comprehensive visualization of the complex morphological matrix changes. The aim of this study was to use three-dimensional (3D) light sheet fluorescence microscopy (LSFM) to analyze unlabeled corneal tissue samples, qualitatively visualizing changes in corneal stiffness. Isolated porcine corneal tissue samples were treated with either NaCl or 0.

Ultrabroadband two-beam coherent anti-Stokes Raman scattering and spontaneous Raman spectroscopy of organic fluids: A comparative study.

Spontaneous Raman spectroscopy is a well-established diagnostic tool, allowing for the identification of all Raman active species with a single measurement. Yet, it may suffer from low-signal intensity and fluorescent background. In contrast, coherent anti-Stokes Raman scattering (CARS) offers laser-like signals, but the traditional approach lacks the multiplex capability of spontaneous Raman spectroscopy.

Tunable picosecond optical parametric amplifier pumped by 1 ps pulses at 1 µm for coherent anti-Stokes Raman scattering.

We report an optical parametric amplifier (OPA), providing a maximum pulse energy of ∼200 µJ at 700-950 nm and a pulse duration of ∼1 ps. The OPA is driven by a ∼1 ps pulse with ∼2.5 mJ energy at 1 kHz, provided by a commercial thin-disk based laser.

Lasing of 2+ induced by filamentation in air as a probe for femtosecond coherent anti-Stokes Raman scattering.

We investigated ultrashort pulse filamentation and lasing action of 2+ for pump-probe experiments in gases. Using femtosecond coherent anti-Stokes Raman scattering, the white-light supercontinuum generated in the filament was used to excite ro-vibrational Raman transitions in air, and . We show that the lasing pulse acts as a probe for the excited levels by detecting the corresponding anti-Stokes Raman spectroscopy signals.

Atomic-resolution mapping of transcription factor-DNA interactions by femtosecond laser crosslinking and mass spectrometry.

Transcription factors (TFs) regulate target genes by specific interactions with DNA sequences. Detecting and understanding these interactions at the molecular level is of fundamental importance in biological and clinical contexts. Crosslinking mass spectrometry is a powerful tool to assist the structure prediction of protein complexes but has been limited to the study of protein-protein and protein-RNA interactions.

CARS-imaging guidance for fs-laser ablation precision surgery.

Due to ageing populations the number of tumors is increasing worldwide. Successful surgical treatment requires complete resection of tumors to reduce recurrence rates. To reach this goal, novel methods combining in vivo tumor and tumor margin detection with low invasive precision surgical tools are needed.

A feasibility study on femtosecond laser thrombolysis.

Objective: In this feasibility study, we investigate possible femtosecond laser thrombolysis.

Background Data: Because of low pulse energies, femtosecond laser surgery inherently minimizes side effects on the surrounding tissue. Moreover, current femtosecond laser sources as well as fiber technology allow consideration of catheter-based treatments.

An in vitro study on focusing fs-laser pulses into ocular media for ophthalmic surgery.

Background And Objective: To investigate femtosecond (fs)-laser patterns within ocular media for ophthalmic surgery.

Methods: Vitreous and crystalline lens tissue from porcine eyes were treated with 2-dimensional fs-laser patterns and inspected under the optical microscope. Time resolved pump-probe experiments were conducted on vitreous tissue and gelatin, which should act as a model for crystalline lens tissue.

Optical side-effects of fs-laser treatment in refractive surgery investigated by means of a model eye.

Optical side-effects of fs-laser treatment in refractive surgery are investigated by means of a model eye. We show that rainbow glare is the predominant perturbation, which can be avoided by randomly distributing laser spots within the lens. For corneal applications such as fs-LASIK, even a regular grid with spot-to-spot distances of ~3 µm is sufficient to minimize rainbow glare perception.

Pig lenses in a lens stretcher: implications for presbyopia treatment.

Purpose: To investigate porcine lenses in a lens stretcher with regard to presbyopia corrective procedures.

Methods: A lens stretching device was designed, which allows to simultaneously determine all relevant geometrical and optical parameters at each stretch position. The setup was used to compare the optical and geometrical lens properties of young slaughter pigs (n = 5) with older sows (n = 7).

Analysis of optical side-effects of fs-laser therapy in human presbyopic lens simulated with modified contact lenses.

Background: In a single-blinded study, optical side-effects of a potential femtosecond (fs)-laser therapy in presbyopic human lenses were tested. Simulation of this therapy was carried out by applying fs-laser patterns into standard contact lenses (CL).

Methods: In the first part of the study, the influence of the numerical aperture on optical side-effects was investigated by comparing a typical fs-LASIK configuration to a fs-presbyopia treatment (n = 11).

Femtosecond laser treatment of the crystalline lens: a 1-year study of possible cataractogenesis in minipigs.

Background: To investigate the long-term stability and possible cataractogenesis after femtosecond laser treatment of the crystalline lens.

Methods: The crystalline lenses of ten Göttingen minipigs® underwent femtosecond laser treatment. During a subsequent 1-year follow-up, the pigs were monitored by means of slit-lamp examination of the anterior segment and Scheimpflug imaging of the lens.

Electric events synchronized with laser filaments in thunderclouds.

We investigated the possibility to trigger real-scale lightning using ionized filaments generated by ultrashort laser pulses in the atmosphere. Under conditions of high electric field during two thunderstorms, we observed a statistically significant number of electric events synchronized with the laser pulses, at the location of the filaments. This observation suggests that corona discharges may have been triggered by filaments.