摘要
We introduce an extremely simple and highly stable system for stimulated Raman scattering(SRS)microscopy.An 8-W,450-fs Yb:KGW bulk oscillator with 41 MHz repetition rate pumps an optical parametric amplifier,which is seeded by a cw tunable external cavity diode laser.The output radiation is frequency doubled in a long PPLN crystal and generates 1.5-ps long narrowband pump pulses that are tunable between 760 and 820 nm with 450 mW average power.Part of the oscillator output is sent through an etalon and creates Stokes pulses with 100 mW average power and 1.7 ps duration.We demonstrate SRS microscopy at a 30-μs pixel dwell time with high chemical contrast,signal-to-noise ratio in excess of 45 and no need for balanced detection,thanks to the favorable noise properties of the bulk solid-state system.Cw seeding intrinsically ensures low spectral drift.We discuss its application to chemical contrast microscopy of freshly prepared plant tissue sections at different vibrational bands.
基金
support by the Carl Zeiss foundation and the Projekthaus NanoBioMater at the University of Stuttgart
ERC(ComplexPlas)
EU-COST(MP1302)
the EU Graphene Flagship(contract no.CNECT-ICT-604391)
BW-Stiftung,Deutsche Forschungsgemeinschaft,BMBF
Fondazione Cariplo through the 2012-0904 project.