The authors have developed a highly synchronized picosecond mode-locked laser system. A balanced cross-correlator using two-photon detectors was employed to observe femtosecond order timing jitter between two picosecond lasers ( 1.26 fs with 150 Hz bandwidth and 7.14 fs with 1 kHz bandwidth), and a signal from the correlator was used as a feedback control signal to reduce the timing jitter. The timing jitter between the two lasers was reduced to 8 fs through a low-pass filter with 150 Hz bandwidth.
"Precise time-synchronization of excitations, events is very important in experimental research in many disciplines including high-energy physics, photosynthesis research, chemical relaxation time measurements, technical applications of timeto-digital conversion and many more  . "
[Show abstract][Hide abstract] ABSTRACT: Recently we have shown a system developed to precisely control the laser
pulse timing of excimer lasers . The electronic circuit based on an embedded
microcontroller and utilized the natural jitter noise of the laser pulse
generation to improve the long term regulation of the delay of the laser
related to an external trigger pulse. Based on our results we have developed an
improved system that uses additional, programmable time delay units to tune the
noise source to further enhance performance and allows reduction of complexity
in the same time. A mixed-signal microcontroller generates a randomly dithered
delay of the pulse generation moment to enhance the resolution and also runs a
dedicated algorithm to optimize regulation. The compact, flexible hardware
supports further enhancements; the signal processing algorithm can be replaced
even by in-system reprogramming. Optimized processing and the relaxed hardware
requirements may also support low-power operation, wireless communication,
therefore the application possibilities may be extended to many other
[Show abstract][Hide abstract] ABSTRACT: We realized realtime molecular imaging with low excitation laser intensity using a multi-focus excitation CARS (coherent anti-Stokes Raman scattering) microscope. We demonstrated realtime CARS images of polystyrene beads and lipid vesicles. Time series CARS images of the polystyrene beads in water was obtained with the frame rate of 30 fps. The three dimensional lipids vesicle which consists of 50 slices was observed within 7 s (100 ms/image).
Proceedings of SPIE - The International Society for Optical Engineering 02/2009; DOI:10.1117/12.808699 · 0.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We demonstrated high-speed imaging of the distribution of DPPC (dipalmitoylphosphatidylcholine), d62-DPPC (deuterated DPPC), and DOPC (dioleoylphosphatidylcholine) lipids in a lipid vesicle with a multi-focus excitation CARS (coherent anti-Stokes Raman scattering) microscope using a microlens array scanner. By the multi-focus excitation, the dwell time is increased in proportion to the number of focal spots compared with a single beam scanning, and high-speed and high-quality CARS imaging is possible without increasing the peak power of each spot. We demonstrated the selectively visualization of DPPC and d62-DPPC lipid vesicles, in which the vesicles contain a type of lipid, by observing at 2840 cm-1 and 2090 cm-1. We also visualized the DOPC and DPPC lipids distribution in a lipid mixture vesicle observed at 1440 cm-1 and 1655 cm-1. The image acquisition time of 10 s/image at each Raman shift was realized. The signal ratio of 1440 cm-1 and 1655 cm-1 was locally intense on the lipid vesicle. It must be because the gel phase domain of DPPC lipids was exists in the DOPC lipids which were liquid-crystalline phase at room temperature.
Proceedings of SPIE - The International Society for Optical Engineering 02/2009; DOI:10.1117/12.808679 · 0.20 Impact Factor
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