Abstract:

The advances of femtosecond (fs, 10-15s) laser technology have been so rapid that today sub-10fs pulses can be routinely generated from femtosecond oscillators and sub-30 fs pulses can be routinely obtained from femtosecond amplifiers. Femtosecond tight pulses are characterized by their short duration in temporal domain, broad width in spectral domain, and high peak power in intensity. These features make femtosecond light sources a useful tool in temporal, spectral, and spatial resolved applications in a wide range of fields and subjects. The feature of extremely high peak power with low average power makes femtosecond laser pulses very attractive in applications of light-matter interaction.

Ultra-high temporal and spatial resolutions are desirable in biological studies; these resolutions can be acquired by using femtosecond laser. We shall present our optical manipulation system based on femtosecond laser that functions both as optical tweezers and scalpels. With our system, we have also performed experiments on cell fusion induced by femtosecond laser.

Micromachining with ultrashort laser pulses can offer precise laser induced break down threshold with reduced laser fluence and repeatability. The results are characterized by being free of burrs and little damage. We shall show the advantages of femtosecond pulses in Micro/Nano machining.

Photonic crystal fibers (PCFs) are a new class of single-material optical fibers which usually have wavelength-scale air holes running down the entire fiber length. It has been shown in intensive research activities that many novel properties unimaginable for conventional optical fibers (COFs) appear from the holey structure in PCFs, such as endlessly single mode operation, anomalous dispersion at shorter wavelength than in COFs, small or large mode areas, and high birefringence. PCFs with enhanced nonlinearity and tailorable dispersion are ideally suitable for nonlinear media, as will be exemplified by out experimental results (supercontinuum generation, frequency conversion, and soliton self-frequency shift effects).

Photonic crystal fiber help to control dispersion and nonlinearity in fiber laser systems, enable the creation of new generation PCF femtosecond laser technology with compact and practical high-power laser sources of ultrashort pulses. We shall present our high-power PCF laser amplifier system with 42w in average and 39fs in duration. Using this new technology, we got more than 2w supercontinuum from a single PCF, high-speed clear micromachining in silicon wafer, and high-power teraherez radiation with 4THZ broad band spectrum.

In the past, we are going to discuss the future of the new generation photonic crystal fiber femtosecond laser technology and its applications.