We report on experimental observation of non-laminar proton acceleration modulated by strong magnetic field in laser irradiating micron-meter Aluminum targets. The results illustrate co

We report on experimental observation of non-laminar proton acceleration modulated by strong magnetic field in laser irradiating micron-meter Aluminum targets. The results illustrate coexistence of ring-like and filamentation structures. We implement the knife edge method into the radiochromic film detector to map the accelerated beams, measuring source size of 30 ~ 110 μm for proton of > 5MeV. The diagnosis reveals that the ring-like profile originates from low energy protons far off the axis while the filamentation is from the near-axis high energy protons, exhibiting non-laminar features. Particle-in-cell simulations reproduced the experimental results, showing that the short-term magnetic turbulence via Weibel instability and the long-term quasi-static annular magnetic field by the streaming electric current account for the measured beam profile. Our work provides direct mapping of laser-driven proton sources in the space-energy domain and reveals the non-laminar beam evolution at featured time scales.show less

We report on compact and robust supercontinuum generation and post-compression using transmission of light through multiple thin solid plates at the SwissFEL x-ray free-electron laser f

We report on compact and robust supercontinuum generation and post-compression using transmission of light through multiple thin solid plates at the SwissFEL x-ray free-electron laser facility. A single stage consisting of three thin plates followed by a chirped mirror compressor achieves compression of initially 30 fs pulses with 800 nm center wavelength to sub-10 fs duration. We also demonstrate a two-stage implementation to compress the pulses further to sub-5 fs duration. With the two-stage setup, the generated supercontinuum includes wavelengths ranging from 500 nm to 1100 nm. The multi-plate setup is compact, robust, and stable which makes it ideal for applications at free-electron laser facilities such as pump-probe experiments and laser-arrival timing tools.show less

We demonstrate the stabilization of optical frequency combs (OFCs) using a segment of fiber delay line as reference. An Er-doped fiber mode-locked laser is phase locked to a kilometer-l

We demonstrate the stabilization of optical frequency combs (OFCs) using a segment of fiber delay line as reference. An Er-doped fiber mode-locked laser is phase locked to a kilometer-long fiber delay line using three different schemes. The short-term stability of the comb modes in the OFC stabilized by these schemes are obviously enhanced, down to 10^-12 level at millisecond average time. Among these three schemes, phase locking two bunches of comb modes in the OFC to the same fiber delay line exhibits the lowest residual phase noise. Fiber-delay-line-referenced optical frequency combs can provide reliable laser sources in precise metrology owing to its advances of low-cost, compactness and highly-integration.show less

Kalman filtering (KF) has good potential in fast rotation of state of polarization (RSOP) tracking. Different measurement equations cause the diverse RSOP tracking performances. We comp

Kalman filtering (KF) has good potential in fast rotation of state of polarization (RSOP) tracking. Different measurement equations cause the diverse RSOP tracking performances. We compare the conventional KF (CKF) and the modified KF (MKF)that have different measurement equations. Semi-theoretical analysis indicates the lower conditional variances of measurement residual and process noise of MKF. Compared with CKF, the MKF has > 3-dB optical signal-to-noise ratio (OSNR) improvement at the 10-MHz scrambling rate in simulation. For MKF, more significant tracking speed improvement exists in lower OSNR. MKF can be smoothly combined with adaptive algorithm, which outperforms adaptive CKF throughout the simulations.show less