We report on mode-locked thulium-doped fiber lasers with high-energy nanosecond pulses, relying on the transmission in a semiconductor saturable absorber (SESA) and a carbon nanotube (CNTs-PVA) film separately. A section of an SMF–MMF–SMF structure multim
The excitation of high-order Laguerre–Gaussian (LG) modes in a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser resonator was presented by applying the diffraction of a second-order circular Dammann grating (CDG) for annular pumping. In the study, t
The characteristics of terahertz radiation from an n-type InN excited by femtosecond laser pulses tunable from 750 to 840 nm are experimentally studied. Terahertz emission from InN is closely bound up with the Dember effect. Terahertz emission can be inte
A slanted columnar TiO2 sculptured anisotropic thin film is prepared using the glancing angle deposition (GLAD) technique. We extend the inference regarding the optical properties of a uniaxial birefringent film based on theoretical analysis to include th
Excess frequency noise induced by mechanical vibration is the dominant noise source at low Fourier frequencies in fiber-delay-line stabilized lasers. To resolve this problem, a double-winding fiber spool is designed and implemented that has ultralow accel
We present a novel and simple method to obtain an ultrawide free spectral range (FSR) silicon ring resonator together with a tuning range covering the entire spectrum from 1500 to 1600 nm. A ring resonator with a large FSR together with a high Q factor, h