It is accidental, but interesting to celebrate the 10th anniversary of Chinese Optics Letters (COL)after revival from the “most important” day in 2012, December 21, which is closely related to Mayancalendar. The last decade sees the development of optics in China and around the world, and NobelPrize awarded to scientists for their excellent work in fiber optics, quantum optics, etc. Up to now,most research results are still published in journals, and COL has been trying to publish the mostexcellent papers for authors and readers.Here, we would like to share with you some milestones in the 10 years’ development of COL,and what we have been pursuing is to build a distinguished journal. The first issue of COL wasco-published by Shanghai Institute of Optics and Fine Mechanics, Chinese Optical Society, and theOptical Society (OSA) in January 2003; COL has been archived in Optics InfoBase of OSA since2005, and now it has been traced back to the first issue; COL has been collected by Science CitationIndex-Expended since 2007, and the latest impact factor is 0.967; topical editors were introduced tomanage the peer review process of manuscripts in 2010; the first joint issue by COL and AppliedOptics was published in 2011; COL received the first 1000 submissions in 2011; ScholarOne systemwas introduced to promote the peer review in 2012; the style of cover page of COL is renewed anda cover picture is introduced to promote excellent papers in 2013.With your continuous support, COL has a healthy growth over the past 10 years. In 2012, COLreceived 1016 submissions and published 277 papers after strict selection. Meanwhile, COL has alwaysbeen trying to give authors timely, constructive and valuable responses for their submissions,and now an average acceptance period of 50 days (from submission to acceptance) has been achieved.You can frequently see must-read achievements reported in COL, e.g., the former OSA president ProfessorJoseph Eberly, Professor See-Leang Chin of Laval University, Canada, and other top scientists’papers in this 10th anniversary issue. You could feel that COL is getting better and better, and it isbecoming more and more important not to miss the cutting-edge publications in COL.Last but not least, we would like to show our sincere appreciation to authors who submit theirexcellent research results to COL, scientists who do volunteer peer review for COL, and readers whoread and cite articles in COL.We hope you will always be happy to read COL in the next 10 years.Thank you!ZhizhanXu, Editor-in-ChiefChanghe Zhou, Executive Editor-in-Chief

Efforts in realizing all-optical packet switching are overwhelming in the past decade. While optical packet switching remains an attractive switching paradigm in the long run, technical challenges prohibit it from becoming a practical solution for the ever-growing bandwidth hunger during the next few years. Finding a technically viable way to meet the increasing capacity requirement with good scalability and flexibility becomes a clear pursue for the community. Hybrid packet and circuit switching is considered to be one promising technique in realizing high performance switching at low cost and less energy consumption, by taking the advantage of both packet switching and circuit switching. In this paper, we review existing work in hybrid optical packet and circuit switching. We discuss the key technical challenges in realizing hybrid optical packet and circuit switching. We further introduce our ongoing efforts in building a seamlessly transformable packet/circuit-switching node with hybrid optical and electronic components. We show that in a hybrid node, the scheduling complexity with typical scheduling algorithms may be reduced to half of a node running in full packet switching mode.

Broadband and energetic terahertz (THz) pulses can be remotely generated in air through filamentation. We review such THz generation and detection in femtosecond Ti-sapphire laser induced remote filaments. New results are presented on the direct relationship between THz generation in a two color filament and induced N2 fluorescence through population trapping during molecular alignment and revival in air. This further supports the new technique of remote THz detection in air through the sensitive measurement of N2 fluorescence.

Both polymer stabilization and bent-shaped molecule doping strategies are utilized to widen the blue phase range of liquid crystals. The molecular structures of compositions are optimized for high thermooptical and electro-optical performances. A low temperature applicable blue phase liquid crystal with suppressed hysteresis is achieved. The bistability of one blue phase liquid crystal is investigated. Based on these materials, fast tunable devices such as gratings with polarization insensitivity are designed and fabricated. The materials and device designs demonstrated here are suitable in wide applications requiring fast response time.

We present a review of terahertz plasmonic metamaterial devices that have functionalities and applications ranging from sensing, enhanced electromagnetic fields, and near field manipulation. Metamaterials allow the properties of light propagation to be manipulated at will by using a combination of appropriately designed geometry and suitable materials at the unit cell level. In this review, we first discuss the sensing aspect of a planar plasmonic metamaterial and how to overcome its limitations. Conventional symmetric metamaterials are limited by their low Q factor, thus we probed the symmetry broken plasmonic metamaterial structures in which the interference between a broad continuum mode and a narrow localized mode leads to the excitation of the sharp Fano resonances. We also discuss the near field mediated excitation of dark plasmonic modes in metamaterials that is caused by a strong coupling from the bright mode resonator. The near field coupling between the dark and bright mode resonances leads to classical analogue of electromagnetically induced transparency in plasmonic systems. Finally, we discuss active switching in terahertz metamaterials based on high temperature superconductors that holds the promise of reducing the resistive losses in these systems, though it fails to suppress the radiation loss in plasmonic metamaterial at terahertz frequencies.

We demonstrate Fourier domain optical coherenc tomography (FDOCT) monitoring and guiding of quantum cascade laser (QCL) therapy. The laser therapy is performed with a 6.1-μm mid-IR QCL and it involves both tissue coagulation or ablation. FDOCT allows real-time monitoring that minimize unnecessary damage to the surrounding tissues. We perform lipid phantom tissue ablation, chicken egg yolk coagulation, and tissue and blood vessel coagulation on chicken embryo to validate the FDOCT guiding quantum cascade laser therapy.

We review the principle and some recent applications of Doppler optical coherence tomography (OCT). The advances of the phase-resolved Doppler OCT method are described. Functional OCT algorithms which are based on an extension of the phase-resolved scheme are also introduced. Recent applications of Doppler OCT for quantification of flow, imaging of microvasculature and vocal fold vibration, and optical coherence elastography are briefly discussed.

In the past two decades, two-photon microscopy (TPM) transforms biomedical research, allowing nondestructive high-resolution fluorescent molecular imaging and label-free imaging in vivo and in real time. Here we review the recent advances of TPM technology including novel laser sources, new image acquisition paradigms, and microendoscopic imaging systems. Then, we survey the capabilities of TPM imaging of biological relevant molecules such as nicotinamide adenine dinucleotide (NADH), flavin adenine dinucleotide (FAD), and reactive oxygen species (ROS). Biomedical applications of TPM in neuroscience and cancer detection are demonstrated.

The recent progress on Raman scattering in GaN single crystals and GaN/AlN heterostructures is reviewed. Anti-Stokes Raman scattering is used to determine electron-phonon scattering time and decay time constant for longitudinal-optical phonons. In a typical high electron mobility transistor based on GaN/AlN heterostructures, strong resonances are reached for the first-order and second-order Raman scattering processes. Therefore, both Stokes and anti-Stokes Raman intensities are dramatically enhanced. The feasibility for laser cooling of a nitride structure is studied. A further optimization will enable us to reach the threshold for laser cooling. Raman scattering have potential applications in up-conversion lasers and laser cooling of nitride ultrafast electronic and optoelectronic devices.

Silicon photonics has become one of the major technologies in this very information age. It has been intensively pursued by researchers and entrepreneurs all over the world in recent years. Achieving the large scale silicon photonic integration, particularly monolithic integration, is the final goal so that high density data communication will become much cheaper, more reliable, and less energy consuming. Comparing with the developed countries, China may need to invest more to develop top down nanoscale integration capability (more on processing technology) to sustain the development in silicon photonics and to elevate its own industry structure.

In this letter, we solve three-dimensional time-dependent Newton equations for atoms interacting with a ten-cycle elliptically polarized laser pulse. The ionized electron momentum distributions show a tilt angle between the distribution density peak and the main polarization axis. The tilt angle’s behavior changes with an increasing laser intensity. We show that this behavior change is directly related to the release time of the electron from the atom.

As the flat panel displays (Liquid Crystal Displays, AMOLED, etc.) reach near perfection in their viewing qualities and display areas, it is natural to seek the next level of displays, including 3D displays. There is a strong surge in 3D liquid crystal displays as a result of the successful movie Avatar. Most of these 3D displays involve the employment of special glasses that allow one view perspective for each of the eyes to achieve a depth perception. Such displays are not real 3D displays. In fact, these displays can only provide one viewing perspective for all viewers, regardless of the viewer’s position. In addition, a fundamental viewing problem of focusing and accommodation exist that can lead to discomfort and fatigue for many viewers. In this paper, the authors review the current status of stereoscopic 3D displays and their problems. The authors will also discuss the possibility of using flat panels for the display of both phase and intensity of video image information, leading to the ultimate display of 3D holographic video images. Many of the fundamental issues and limitations will be presented and discussed.

The wavefront recording plane (WRP), subsequently generalized to be known as the virtual diffraction plane (VDP), is a recent concept that has been successfully deployed in fast generation and processing of digital holograms. In brief, the WRP and its extension, the VDP, is a hypothetical plane that is located between the hologram and the object scene, and which is at close proximity to the latter. As such, the fringe patterns on the hypothetical plane are carrying the holistic information of the hologram, as well as the local optical properties of the object scene. This important property enables a hologram to be processed with classical image processing techniques that are normally unsuitable for handling holographic information. In this paper we shall review a number of works, that have been developed based on the framework of the WRP and the VDP.

We investigate the propagation of intense probe pulses in a lifetime broadened \Lambda-type three-level atomic system with a configuration of electromagnetically induced transparency. We find that ultraslow optical solitons formed by a balance between dispersion and nonlinearity can be stored and retrieved in the system by switching off and on a control field. Such pulses are robust during storage and retrieval, and hence may have potential applications in optical and quantum information processing.

We propose a new mechanism/scheme to explain the ultrafast population inversion of molecular ions which takes place in a time scale comparable to the femtosecond laser pulse. The nonlinear pumping process including the pump photons and the self-generated harmonic photons of the pump laser would be responsible for building up population inversion to realize remote molecule lasers in femtosecond laser filaments in gases. It is shown that the remote laser emissions in molecular ions of gases may be a universal process in the femtosecond laser filament.

Progresses on the development of a high repetition rate mid-IR laser source suitable for the next generation of high-field physics experiments are reported. The presented optical parametric chirped pulse amplification (OPCPA) source currently delivers carrier-envelope phase (CEP)-stable 67-fs duration optical pulses with up to 18- \mu J output energy at 160-kHz repetition rate. The focusability of the output beam (M2~2) enables peak intensities exceeding 1014 W/cm2 and the record output energy stability-below 1% power fluctuation over 4.5 h makes this source a key enabler for the strong field physics community.

We present three possible design options of laser plasma acceleration (LPA) for reaching a 100-GeV level energy by means of a multi-petawatt laser such as the 3.5-kJ, 500-fs PETawatt Aquitane Laser (PETAL) at French Alternative Energies and Atomic Energy Commission (CEA). Based on scaling of laser wakefield acceleration in the quasi-linear regime with the normalized vector potential a0 = 1.4(1.6), acceleration to 100 (130) GeV requires a 30-m-long plasma waveguide operated at the plasma density ne \approx 7 \times 10^{15} cm^{ 3} with a channel depth \Delta n/ne=20%, while a nonlinear laser wakefield accelerator in the bubble regime with a0 \geq 2 can reach 100 GeV approximately in a 36/a0-m-long plasma through self-guiding. The third option is a hybrid concept that employs a ponderomotive channel created by a long leading pulse for guiding a short trailing driving laser pulse. The detail parameters for three options are evaluated, optimizing the operating plasma density at which a given energy gain is obtained over the dephasing length and the matched conditions for propagation of relativistic laser pulses in plasma channels, including the self-guiding. For the production of high-quality beams with 1%-level energy spread and a 1\pi-mm-mradlevel transverse normalized emittance at 100-MeV energy, a simple scheme based on the ionization-induced injection mechanism may be conceived. We investigate electron beam dynamics and effects of synchrotron radiation due to betatron motion by solving the beam dynamics equations on energy and beam radius numerically. For the bubble regime case with a0=4, radiative energy loss becomes 10% at the maximum energy of 90 GeV.