Spectroscopy and Kerr-lens mode-locked operation of Yb:GdScO3 crystal.

A Kerr-lens mode-locked laser based on a Yb3+-doped disordered gadolinium scandate (Yb:GdScO3) crystal is reported for the first time, to the best of our knowledge. The crystal with the perovskite structure was grown using the Czochralski method, and its room temperature (RT) and low temperature (LT) spectra were also investigated. Due to the crystal's multisite structure (Gd3+/Sc3+ site), Yb:GdScO3 offers broad and intense polarized emission spectra in the near-infrared range (975-1075 nm). The stimulated emission cross section σSE is 0.46 × 10-20 cm2 at 1000 nm with an emission band width of 75.7 nm for E // b polarization. The continuous wave (CW) laser was operated pumped by a 976 nm fiber-coupled LD laser, resulting in a maximum output power of 8.74 W with a slope efficiency of 76.1% was obtained. Additionally, a pulses as short as 74 fs are generated at ∼1061.7 nm via Kerr-lens mode-locking. The average output power amounts to 32 mW at a pulse repetition rate of 101.4 MHz. All results indicate Yb:GdScO3 a promising candidate for 1 µm ultrashort laser.

A storage mechanism of data access record on consortium chain based on master-slave blocks.

Although data on the blockchain cannot be tampered with, malicious access by insiders can also lead to data leakage. Access records of block are an important basis for tracing the source of data breaches; however, access records themselves may be tampered with. Therefore, it is important to study how to protect the block access records. So far, the protection of block access records has not received much attention. To make block access records a protected data resource as well, this paper proposes a storage mechanism of data access record on consortium chain based on master-slave blocks. In this mechanism, the master block is used to store data resources, and the slave block of the master block is used to store access records of the master block. This method ensures that the slave block has the security characteristics of the single chain block, making the access record traceable and immutable. The storage mechanism's viability is confirmed by real-world experimentation. The proposed mechanism outperforms the single chain in terms of data query performance, according to the testing results on public data sets.