Fig. 1. Structure and characterization of Te nanoflakes. (a)-(c) Atomic structural model of Te viewed in different directions; (d) OM (optical microscopy) image of Te nanoflakes; (e) AFM (atomic force microscopy) image of Te nanoflake; (f) Raman spectrum of Te nanoflake; (g) XRD (X-ray diffraction) spectra of Te nanoflake

Fig. 2. Fine structure and component analysis of Te nanoflake. (a) Low-magnification bright-field image; (b) high resolution image, where the insert shows selected area electron diffraction (SAED) pattern; (c) energy dispersive X-ray spectroscopy (EDS) spectrum

Fig. 3. Nonlinear saturation absorption characterization of Te nanoflake. (a) Two-arm detection experimental device, where LD represents laser diode, WDM represents wavelength division multiplexing, EDF represents erbium-doped optical fiber, ISO represents isolator, OC represents optical coupler, and SA represents saturable absorber; (b) optical fiber end face; (c) saturable absorption curve

Fig. 4. Schematic of pulse fiber laser based on Te saturable absorber, where PI-ISO represents polarization-insensitive isolator and PC represents polarization controller

Fig. 5. Output characteristics of Te saturable absorber based pulse laser. (a) Pulse sequence at different values of pump power; (b) spectra at different values of pump power; (c) frequency spectrum at a particular pump power, where the insert is radio frequency spectrum in the frequency of 0-600 kHz; (d) fitting curve at single pulse

Fig. 6. Variation of pulse single. (a) Pulse duration or repetition rate versus pump power; (b) central wavelength versus pump power