Alignment-free, all-spliced fiber laser source for CARS microscopy based on four-wave-mixing

Abstract

An environmentally-stable low-repetition rate fiber oscillator is developed to produce narrow-bandwidth pulses with several tens of picoseconds duration. Based on this oscillator an alignment-free all-fiber laser for multi-photon microscopy is realized using in-fiber frequency conversion based on four-wave-mixing. Both pump and Stokes pulses for coherent anti-Stokes Raman scattering (CARS) microscopy are readily available from one fiber end, intrinsically overlapped in space and time, which drastically simplifies the experimental handling for the user. The complete laser setup is mounted on a home-built laser scanning microscope with small footprint. High-quality multimodal microscope images of biological tissue are presented probing the CH-stretching resonance of lipids at an anti-Stokes Raman-shift of 2845 cm(-1) and second-harmonic generation of collagen. Due to its simplicity, compactness, maintenance-free operation, and ease-of-use the presented low-cost laser is an ideal source for bio-medical applications outside laser laboratories and in particular inside clinics.

Effect of the laser pulse width on the field evaporation behavior of metals and oxides

“…A fiber-Bragg grating-based filter centered at 1040 nm is included inside the cavity to limit the spectral bandwidth to less than 140 pm [30]. The laser generates nearly transform-limited pulses with 30 ps duration and less than 1 nJ energy, at a repetition rate of 8 MHz.…”

Accumulating advantages, reducing limitations: Multimodal nonlinear imaging in biomedical sciences – The synergy of multiple contrast mechanisms

“…This discrepancy is resolved when using long pulse, i.e., 50 ps, low repetition rate, i.e., 1MHz, fiber lasers utilizing four wave mixing in a photonic crystal fiber for wavelength conversion [61]. Such lasers allows for the first time complete fiber integration [62]. Seeding the FWM process by a low power cw laser allows for fast wavelength tuning and significantly improves the spectral resolution to 1 cm À1 [63].…”

Coherent anti-Stokes Raman scattering for label-free biomedical imaging

“…The same group demonstrates a second laser system which is a highly integrated all fibre system consisting of an Yb ps oscillator, however doesn't allow tuning through different Raman shifts. The fibre needs to be tailored for a specific pump frequency at a specified output (57 …”