System setup
20/06/2014 14:10-
Our instrument mainly including a femtosecond laser (Tsunami, Spectra-Physics, USA),which has a pulse width of less than 100 fs and a repetition rate of 80 MHz.To overcome the group velocity dispersion of the femtosecond laser through the AOM and the objective, an prism pair was used for optimized pulse width in the wavelength region between 700 to 840 nm. An acousto-optic modulator (AOM) (23080-x-1.06-LTD, Neos, USA) for rapid on/off switching of the laser and pulse selection; and processing of the single photon counting (SPC) signals.Selected experimental parameters such as laser power, scanning rate, imaging, and sample positioning can be adjusted by the use of custom LabVIEW program. In this manner, imaging with nonlinear optical signals (two-photon fluorescence (TPF)/second harmonic generation (SHG)) and 3D microfabrication can be achieved.
- Another illustrates a schematic of the developed high-throughput multiphoton-induced reduction and ablation system . Briefly, the system include a titanium-sapphire (ti-sa) ultrafast amplifier, an ultrafast oscillator as the seed beam of the amplifier, an upright optical microscope, a triple-axis sample positioning stage, an Andor EMCCD camera, a DMD, and a data acquisition (DAQ) card with a field-programmable gate array (FPGA) module. The ultrafast amplifier has a maximum peak power of 400 μJ/pulse and a pulse width of 90 fs at an average power of 4.0 W and a repetition rate of 10 kHz. First, the beam pass through a Michelson-interferometry-based autocorrelator in order to measure the pulse width of the amplifier on the sample surface later, and then oblique incidents on the DMD chip, which generates the designed processing pattern. Following this, the pulsing beam is spatially dispersed via a grating. A set of relay lenses was inserted to lengthen the beam path and also adjust the pattern size incidents on the sample surface. Finally, the dispersed frequencies propagate through the 4f setup to realize temporal focusing excitation.
