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In the development of microfluidic systems, conventional 2D processing technologies are increasingly difficult to meet the requirement of integration of multifunctional components within a microchannel. Recently, two-photon polymerization (TPP) technology has emerged as a novel alternative to fabricate 3D microdevices functionalizing conventional microfluidic chips. Here, the development of TPP microfluidic technology comprising parallel fabrication, holographic patterning method and real-time lithography in a controlled flow is reported. And a series of functional microcomponents containing microfilters, microsorters, microtrap, tunable microlens are fabricated by above methods. The results indicate that the processing of microfluidic devices is simple, timesaving, low cost and programmable designability. The functional microchips are further used in blood cells sorting, biomedical sensing, microparticle purification and trapping with successful test results.

The shape of manufactured microtubes is one of the most important properties in their numerous emerging applications areas, like drug delivery, microfluidics, and cell biology. However, making non-cylindrical microtubes with 3D features in a reproducible and single-step fashion, and meanwhile, with the ability of remote control has remained challenging. In this study, we demonstrate the controlled synthesis of highly curved 3D microtubes by two-photon polymerization with single exposure of structured optical vortices, which is generated by phase modulation with a liquid crystal spatial light modulator (SLM). We exploit the tight focusing property of the optical vortices along the light path to create 3D microtubes. By modulating the topological charge and symmetry of the optical vortices, the size and geometry of fabricated microtubes can be well controlled. Finally, we combine these two ideas with the use of magnetic nanoparticles doped resist to fabricate 3D microtubes with elaborate features and remote controllability. Precise rotation and motion of the microtubes are realized by external magnetic field. With the fabricated functional mocrotubes, elaborate capture, delivery, and realease of microparticles are demonstrated. The technology we introduce is simple, stable and achieves a high production rate to make a wide variety of functional 3D microtubes, which have broad applications in cargo transportation, drug delivery, biosensing, microfluidics, and targeted cell therapy.

This paper reports on the evolution of femtosecond laser indu ced periodic surface structures (LIPSSs) on titanium surface irradiated with different wavelengths. By SEM observations, it is noted that different nanostructures with respective surface features depend highly on the laser wavelength and the laser fluence. The period of LIPSSs formed at the laser fluence just above the ablation threshold is shorter than the laser wavelength, as well as dependence on the incident wavelength. Experiments using wavelength of 600 and 1500 nm, studies are performed in more detail. The period and the depth of the grooves of LIPSSs are increased with the increase of laser fluence at wavelength of 600nm. The created structures on the surface at the laser fluence of 0.42 J/cm 2 would significantly influence the field intensity distribution on the surface. The redistribution of the electric field intensity plays a crucial role in the creation of the HSFLs formed on the ridges of the LI PSSs, and the period decreases to half. Another kind of HSFLs whose orientation is perpendicular to the sidewalls of LIPSSs is created at wavelength of 1500nm. These HSFLs lie at the bottom of the valleys between both the LIPSSs and new formed grooves. As compared with the surface nanostructures formed at wavelength of 600 nm, the formation of identical HSFLs is induced with smaller laser fluence at wavelength of 1500 nm. Keywords : Femtosecond laser pulses, titanium, LSFLs, HSFLs

Two-photon polymerization is a powerful technique in the area of functional micro/nano device fabrication. The greatest limiting factor in widespread use of this technique is the low efficiency because the structure is fabricated by point-by-point scanning. In recent years, computer generated hologram is used for parallel fabrication via multi foci. In this paper, we proposed a new rapid fabrication method which use desirable multi-focus pattern as scanning cell instead of single focus point or foci array to polymerize. We establish a femtosecond laser experimental setup involved in a liquid crystal spatial light modulator. The computer generated hologram pattern on spatial light modulator is used to produce desirable foci array. The position and intensity of each focus in the pattern can be controlled well by optimal design. We use multi foci in a line as scanning cell to fabricate some revolving structure and the Fresnel lens can be expected. This work provides a new method to greatly improve the efficiency of two-photon polymerization production in fabricating revolving structures.

Anthracene derivative is one of the important two photon absorption materials. In this work, novel symmetric-type D-Œ-D anthracene derivative, 2, 6 - di- substituted anthracene chromophore with 4-methylstyrene has been synthesized via Heck reaction. The two-photon absorption (TPA) s uorescence emission property and TPA absorption coefficient are investigated by Sapphire femtosecond laser pulses at the wavelength of 800nm, repetition rate of 1 KHz and pulse width of 120fs, in an attempt to obtain the TPA cross-sections of this compound (1 film =695.8 h 10 –50 cm 4 s/photon). Finally, Three-dimensional (3D) optical data storage experiments are carried out and realized by two-photon absorption with 800nm-fs laser in the compound films. Keywords: Anthracene derivative, Two-photon absorption, 3D optical data storage 1. INTRODUCTION Longer conjugated molecules exhibiting large two-photon absorption (TPA) cross sections ( a ) have been receiving increasing attention owing to their potential applications in photosciences, such as three-dimensional (3D) optical data storage [1-4]. The achievable process of 3D high precision spatial control is that the 2PA is confined to the focus volume (voxel) in the TPA material, resulting in 2PA induced modulation of opt ical properties that is hi ghly localized within the focal volume. Secondly, the premise of the 3D optical data storage is that 2PA of laser light can be used to initiate photochemical processes that alter the local optical property of a material [5]. Consequently, numerous organic materials have been investigated experimentally and theoretically to draw conclusions in the structure–property relationship of molecules with TPA materials [6]. Recently, the utility of the anthr acene as a special and efficient i -center for the two-photon chromophores has been demonstrated by several groups [7]. The anthracene unit has two different ways to link in, 9, 10- or 2, 6- linkages, and to form two different conjugation pathways with two different quinoid characters. With appropriate modifications, the electronic and photonic properties of anthracen e-centered conjugated molecules are highly dependent on both the nature of the active building blocks and the way in which they are linked. In the current work, the synthesis and characterization of a symmetric-type anthracene derivative is reported, modifying 4-methylstyrene from the 2-position and 6-position of the bila teral anthracene unit via Heck reaction. The one photon absorption (OPA) spectra, fluorescence emission spectra, and fluorescence quantum yields are determined. The TPA prop erties of this anthracene derivative are studied by measuring the two-photon excited fluorescence and calculating TPA cross-sections of PMMA sample films by the Z-scan technology. Finally, the TPA mechanism and method ar e used for writing and retrieving data on anthracene derivative films in the 800nm-fs pulsed laser optical data storage system.

Supramolecular azopolymers were prepared through strong hydrogen bonding interaction between pyridine moiety of poly (4-vinylpyridine) (P4VP) and phenol moiety of 4-nitro- 4’-hydroxyazobenzene (AzoOH). A multilayered composite film with supramolecular azopolymers as a recording layer and polyvinyl alcohol (PVA) as a spacing layer was prepared through alternately stacking. Under two-photon excitation, azobenzene chromophore can be orientated perpendicularly to the polarization direction of the writing beam via trans-cis-trans photoisomerization, yielding optical birefringence. Polarization-multiplexed and multilayered optical data storage were demonstrated by encoding two letters in the same region of each of the two layers based on the property.

Porous anodic alumina (PAA), with highly ordered microstructures, has attracted much attention due to some unique physical and optical characteristics. In recent years, PAA is also used to obtain different colors by methods such as growing nanowires, tuning pore depth, or sputtering metal on PAA surface. In this paper, we report a simple and precisely controllable method to tune color by changing the pore diameter of PAA. In order to obtain PPA with different pore diameter, we first prepare the PPA membrane by two step anodization of high purity aluminium foil in acidic solutions and then immerse the fabricated PPA membrane into phosphoric acid to enlarge pore diameter. The different pore diameters of PAA are controlled by immersed time in phosphoric acid. After sputtering metal on surface of PAA, the brilliant color can be seen on the surface of PAA. Different colors of PAA film with metal-coated are obtained using this method and colorful patterns are successfully fabricated. The physical model of the PAA is constructed and the mechanism of tuning color is analyzed. It is concluded that the color can be tuned by changing pore diameter of the PAA membrane. This method will be of potential use in decoration, color displays and anti-counterfeiting technology.

The adaptive optics system (AO) without a wavefront sensor produces an alternative tool to correct the aberrations where the wavefront distortions are hard to be measured directly. This kind of adaptive optics system optimizes an evaluation parameter directly relevant to the wavefront quality to achieve the wavefront correction, and the optimization algorithms determines the efficiency of wavefront sensor-less AO system. In this paper, several frequently-used algorithms covering hill climbing algorithm, genetic algorithm, simulated annealing algorithm and two hybrid algorithms, known as hybrid genetic-hill climbing algorithm and hybrid simulated annealing-hill climbing algorithm (SAHC), have been investigated to improve the correction efficiency. The correction speeds and correction effects of the five kinds of algorithms have been compared in simulations and experiments for an adaptive optics system with 19-elements unimorph deformable mirror. The results show that hill climbing algorithm has the fastest correction speed, but suffered from the local optimum problem. The other four kinds of algorithms can get good correction results and have similar correction effects. Considering the correction effect and correction speed comprehensively, SAHC is the most efficient optimization algorithm in the five kinds of optimization algorithms.

Optically induced molecular orientation by photoisomerization of chromophores has been intensively researched with views of application in photonics. We report a new polarization-encoded data storage method in a diazobenzene/MMA copolymer. Two-photon absorption (TPA) of 4-{(2-methacryloyloxyethyl)oxy}-4'-(4-nitrophenylazo)azobenzene/MMA copolymer creates a regularly angle variation of molecular orientation via a trans-cis isomerization process and induces birefringence in the sample. This feature is a key for ultrahigh-density optical data storage. The experiment for two-photon recording and reading was carried out by a homemade two-photon scanning microscope developed based on a confocal laser scanning fluoresce microscope. Linearly polarized femtosecond pulsed laser beam with pulse width 80fs, repetition rate 80MHz and wavelength 800nm was used as recording beam. A polarizer and a half-wave plate were used to control the readout beam polarization state. A Ti: sapphire laser at continuous-wave mode was used for readout process. Experimental results of recording and reading data bits with size of 4 microns and interval of 8 microns were presented. An approximatively linearly relationship between excitation power and the readout signal intensity was observed. The great difference between the signals read out by different polarized laser beams provide a multiple-state way to improve storage density.