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Research Divisions Time: the 2009-07-16   source: Xi'an Institute of Optics and Precision Mechanics of CAS   【big | medium | small】  【print

State Key Laboratory of Transient Optics and Photonics

State Key Laboratory of Transient Optics and Photonics (SKLTOP) was founded in 1991 and opened to international and domestic scientists from 1993. In 1995 it was evaluated and accepted to be a State Key Lab by the authorities concerned. In 1999 the Lab entered the Knowledge Innovation Project of the Chinese Academy of Sciences (CAS).

There are Master of Science degree and PhD Degree majors: optics, physical electronics, optoelectronics, and one postdoctoral opening in optics. So far more than 200 masters and doctors have graduated from the lab.

There are 48 research staffs: 1 academician of CAS, 15 professors, 16 associate professors and senior engineers, 13 research assistants, 2 junior research assistants and 1 secretary. There are 17 PhD students, 33 MSc students studying in the Lab and 2 postdoctoral fellows working in the Lab.

The Lab has established widespread academic exchanges and cooperation with international academies (University of Marburg, Kansas State University, University of Vienna, Integrated Research Center for Photonic Networks and Technologies of ItalyLondon South Bank University, etc.) and domestic academies (Institute of Physics of CAS, Xi’an Jiaotong University, Beijing University, Institute of Electronics of CAS, Institute of Chemistry of CAS, Institute of Botany of CAS, Xidian University, Northwest University, Nankai University, Tianjin University, etc.).

 

Mission
Mainly on transient optics and photonics technology based on Ultra-fast  Photonics, Ultrafast  Photo-Electronics and  Opticsfunc-tional  Materials, including the basic study of ultrafast laser technology , ultrafast process diagnosis technology,  and transient optics and ultrafast photonics technology  applications in communication, mater-ial and high energy density physics.  
To be a lab that can play a very  important role in the field of ultrafast optics in the world, and  can make crucial contribution to the country.
To be the national research center in the field of  transient optics  and photonics technology.

Basic Photonics

Micro-structure Nonlinear Optics
It well known that totally reflected light beam is laterally shifted from position predicted by geometrical optics. This phenomenon is referred to as the Goos-H?nchen (GH) shift.
In micro-structure optics, we found a novel phenomenon of a transmitted beam though a dielectric slab in air, the negative lateral shift from position predicted by geometrical optics, according to Snell’s law of refraction. The magnitude of GH shift is very small only about the order of the wavelength. We found that the GH shift can be greatly enhanced in total internal reflection by a single dielectric thin film.

Photorefractive Nonlinear Optics
Steady-state optical spatial solitons, which are known as screening-photovoltaic solitons, are theoretically demonstrated for biased photovoltaic photorefractive crystals, which are due to both the spatially nonuniform screening of the external electric field and the photovoltaic effect. These solitons differ from screening solitons and photovoltaic solitons. Screening solitons are originated from the nonuniform screening of the external field, while photovoltaic solitons are originated from the photovoltaic effect. When photovoltaic effect is neglectable, the physical system of screening-photovoltaic solitons becomes the physical system of screening solitons, the space-charge field of screening-photovoltaic solitons becomes the space-charge field of screening solitons, the nonlinear wave equation of screening-photovoltaic solitons becomes the nonlinear wave equation of screening solitons, and screening-photovoltaic solitons becomes screening solitons. When the external field is absent, the physical system of screening-photovoltaic solitons becomes the physical system of photovoltaic solitons, the space-charge field of screening-photovoltaic solitons becomes the space-charge field of photovoltaic solitons, the nonlinear wave equation of screening-photovoltaic solitons becomes the nonlinear wave equation of photovoltaic solitons, and screening-photovoltaic solitons becomes photovoltaic solitons; and it is predicted that gray photovoltaic solitons are possible for closed-circuit conditions. Thus, the studies of screening solitons and photovoltaic solitons may be changed into ones of screening-photovoltaic solitons. We show theoretically that screening-photovoltaic solitons can be switched from bright to dark solitons by changing the polarity of the external electric field and by rotating the polarization of the light. For appropriate cases, the screening-photovoltaic nonlinearity can be switched from self-defocusing to self-focusing (or self-focusing to self-defocusing) by adding an external electric field. Under a strong bias condition, the screening-photovoltaic nonlinearity can be switched from self-defocusing to self-focusing (or self-focusing to self-defocusing) by changing the polarity of the external electric field or by rotating the polarization of the light.

Fiber Nonlinear Optics
The self-stability of multiple four-wave mixings (FWMs) in the optical fibers is proposed and proved for the first time. This effect can realize a kind of photonic Robin Hood, where power is redistributed between multiple wavelengths from those that have more to those that have less.
This photonic Robin Hood has been proved by using a dispersion-flattened high-nonlinearity photonic-crystal fiber and an erbium-doped fiber laser cavity. Therefore, during multiple four-wave mixing processes, power is distributed from the rich to the poor to ensure that they have a relatively equitable power. This function is names as the photonic Robin Hood effect.

Ultrahigh Speed Photonic Communication Networks

With the rapid growth of Internet traffic, there is an increasing demand on system bandwidth and transmission speed, which becomes a main driving force to develop ultrahigh-speed, high-capacity optical fiber networks. Ultrahigh-speed photonic communication networks technology will be the key technology in next generation networks.
Ultrahigh-speed pulse generation techniques
Ultrashort optical pulse source are very important for optical time-division multiplexing communication systems. Gain-switched DFB Semiconductor lasers and Electro-absorption modulated lasers have becoming the focuses of attentions, because of their advantages, compacts, stability, high repetition frequency and short pulse width etc.
Ultrahigh-Speed Optical Packet Compression
Through time-division arrayed optical delay and useful signal packet selection, low-speed pulses, for example 1Gb/s or other speed, can be compressed to some ultrahigh-speed optical packets with repetition frequency of 100Gb/s, or higher. Then low-speed pulses code stream with a long occupying time will become discrete high dense optical packet, which can shorten the occupy time and improve the transmitting capacity greatly. The key technology in this subsystem includes two field, message speed up-conversion technology and identification technology of useful message using Optical gate. 
All-Optical Packet Decompression Subsystem
After ultrahigh-speed optical packet arrived at the destination, we must decompress them into original low-speed code stream for compatible low-speed terminal equipments. To this aim, several techniques have been proposed, for example nonlinear optical loop mirror (NOLM), TOAD and so on. In these decompression technologies, the use of semiconductor-based devices is a promising choice to implement this function because of their compactness and integratability. Highly detuned four-wave mixing (FWM) in semiconductor optical amplifiers (SOAs) takes advantage from ultra-fast intra-band phenomena like spectral hole burning and carrier heating whose characteristic response times are less than hundreds of femtoseconds.

 

 

Photonic Materials and Devices

Photonic Crystal Polymer Materials
Light interacting with a band-gap (photonic) material would be totally reflected at a certain selected wavelength. The wavelength at which the stop-band would occur depends on the dimension and spacing of the crystals forming the material. The extension of the concept of photonic crystals from crystal lattices to fibers resulted in the design of glass hollow fibers that could trap light inside, making it a perfect device for wave-guiding, in which the reproduction of the crystal lattice would be given by a periodic array of microscopic air holes that run along the entire fiber length. If polymers are used instead of glass the advantage of a more flexible fiber which would allow easier and less expensive installation is achieved. The cost of glass photonic crystal fibers is expensive and these materials can be bought at costs between $50 -$800 per meter. Direct spun polymeric versions could be produced at a fraction of that cost.
This research project ultimately will produce photonic crystal fibers and bandgap fibers from polymer based systems.

Advanced Optical Materials and Specialty Optical Fibers
Our research primarily concerns with advanced optical materials for photonics applications, high power laser glasses and laser ceramics, and the development of specialty high performance optical fibers. Glass fibers doped with various rare-earth ions and transition metal ions are being developed for photonic devices such as fiber lasers, optical amplifier with wide bandwidth, wavelength converter, fiber gratings, fiber isolator, all-optical fiber switch, and so on. And we are using innovative Rare-Earth-Doped glass and fiber technology to design, produce and deliver a new class of advanced optical light sources for a number of applications in the  oil, gas, utilities, and R&D markets. Now we can offer customized RE-Doped glass optical fiber preforms, special glass melting, and fiber pulling services.

Ultrafast Diagnosis

High-speed photography & diagnosis Lab is specializing in design and production of this technology products based on opto-electronic process are developed to make measurements of ultrafast phenomena which happens in very short period with very tiny size.
1. Design and manufacture of every our streak tube and camera, frame tube and frame camera. Spectral sensitivity of streak and frame cameras is spreading from hard X-rays to near infrared range.
2. Design and manufacture of MCP gated frame camera. The temporal resolution of our single MCP gated frame camera can reach to 60ps, and that of the two MCP (0.5mm thick) gated frame camera can reach to 35ps,
3. Design and manufacture of femosecond electron diffraction device to study solid phase transitions, determine the structures of transient species in gas phase, and follow surface dynamics et al.

 

Ultrafast Phenomena and Nanophotonics

1 Energy transfer between pigments in photosynthesis
(1) Time-resolved fluorescence spectroscopy
(2) Time-resolved different absorption spectroscopy
(3) Theory models on energy transfer
2 Optical Properties and Applications of Biological and Organic Photon-functional Materials
Optical materials are the constructive blocks of optical science, technology and engineering. Among the broad photon-functional materials, we are interested in the multi-functional biological molecule -- bacteriorhodopsin (BR), as well as the organic photochromic compounds -- fulgide and diarylethene, because of their specially optical features and potential applications in optical memories, optical switches, optical information processing and sensing.

Ultrafast Photonics and Applications

1 Self-starting femtosecond Ti:sapphire laser based on Saturable Bragg ReflectorSBR

2 High repetition rate femtosecond Ti:sapphire amplifiers

3 Femtosecond Erbium-doped fiber lasers and amplifiers

4 Ultrashort ytterbium-doped fiber lasers and amplifiers

5 The Optical Parametric Chirped Pulse Amplification (OPCPA)

6 Fs laser ultra-precision lithography and Three-dimensional data storage.

 

Mailing Address:

State Key Laboratory of Transient Optics and Photonics Xi’an Institute of Optics and recision Mechanics, CAS No.322 West Friendship Road Xi’an 710068 China
Phone: 0086-29-88887615   Fax: 0086-29-88887603   E-mail: liping@opt.ac.cn
Website: http://www.tot.labs.gov.cn

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XIOPM (Xi’an Institute of Optics and Precision Mechanics) won the National Science and Technology Advancement Special Award
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