Search

Communication industry has developed relying on technological advancement in microelectronics and large-scale integrated circuits. Modified polyimide (MPI) materials with low dielectric loss, relatively simple fabrication process, and cost-effectiveness have significant social and economic benefits. In this work, 6FAPB and 6FDA were used to polymerize fluorinated PI films by thermal imidization, and SiO2 was used to modify PI films for further obtaining low dielectric constant (ε)/loss (tanδ) and enhance mechanical properties. The values of dielectric constant (ε) and tan δ were 2.75 and 0.00491, respectively, under 10 GHz. Meanwhile, the elastic modulus of MPI films was enhanced by the SiO2 adding process, with a maximum tensile modulus of 2.42 GPa. The results indicate that low polarity Si–O–Si bonds lead to a decrease in overall polarity of PI films and lead to tan decrease. This work provides a simple method to increase mechanical properties and reduce the dielectric constant/loss (at 10 GHz high frequency) of PI film by introducing trifluoromethyl and SiO2. [ABSTRACT FROM AUTHOR]

In this paper, we report a 946nm double Q-switched laser side pumped by an 808-nm pulse laser diode (LD). A layered tungsten diselenide (WSe 2 ) saturable absorber (SA) together with an MgO doped LiNbO 3 electro-optic (EO) modulator is applied to double Q-switch the Nd: YAG laser, producing trains of nanosecond-duration pulses with 500 Hz repetition rate. Such WSe 2 saturable absorbers are fabricated by chemical vapor deposition (CVD) in a hot wall chamber and then embedded into a resonant mirror. The achieved pulse energy of double Q-switched laser at 946 nm is approximately 2.63 mJ with 10.8 ns pulse width and the peak power is round 244 kW, corresponding to the beam quality factors of M 2 x = 3.846,M 2 y = 3.861. Monolayer WSe 2 nanosheets applied in the experiment would be a promising SA for passive Q-switching operation.