We present a mode−locked GaSb−based optically pumped semiconductor disk laser operating at 2 µm based on the self−mode−locked mechanism. Using the delay differential equation model, we discuss the influence of cavity length on the stability of self−mode−locking and design a Z−shaped long cavity for self−mode−locking. Employing an aperture and an F−P etalon in the cavity length of ~365 mm, we obtain stable self−mode−locking at a center wavelength of 2034.5 nm, with a pulse duration of 255.48 ps and average output power of 173 mW at a repetition rate of 404 MHz.

In this paper, we have demonstrated a 1.3 W green laser using a V-shaped intracavity frequency doubling 1036 nm semiconductor disk laser. The beam quality of the fundamental and second harmonic generation (SHG) laser is investigated. It has been found that the output lasers at the fundamental and SHG wavelength both suffer from reduced beam quality along with power scaling. The measured beam profile is elliptical under high power operation. In order to improve the SHG laser beam, an intracavity aperture is employed to control the mode characteristics of fundamental frequency light. By fine-tuning the aperture, a nearly circular beam profile with improving beam quality and brightness is realized.

We present an 850 nm vertical-cavity surface-emitting laser (VCSEL) featuring enhanced thermal stability and >30 GHz modulation bandwidth. The device maintains stable performance with bandwidths of 30.30 GHz at 25°C and 30.54 GHz at 55°C under 5 mA bias, showing minimal change. Notably, the bandwidth remains nearly constant across a wide current range (3-7 mA). The VCSEL exhibits excellent signal integrity, with relative intensity noise (RIN) consistently below -140 dB/Hz even at elevated temperatures. Advanced thermal management techniques, including polyimide integration and a double-mesa structure, effectively mitigate thermal impedance increase and carrier dynamics degradation. Furthermore, the device successfully achieves 106 Gbit/s PAM4 transmission, as evidenced by clear eye diagrams. These results demonstrate that our co-optimized thermal and carrier design represents a promising approach for developing robust optoelectronic devices capable of reliable high-temperature operation.

A beam combining method to improve the brightness of diode lasers is proposed based on a V-shaped external cavity spectral beam and beam-waist splitting polarization combination. This design has the outstanding advantages of improving the beam quality, brightness, and versatility of the diode laser. Specifically, an output power over 16W with M² factors of 1.79 × 3.92 (Beam Parameter Product BPP = 0.55 × 1.22 mm mrad) at 40 A in the fast and slow axis is demonstrated for a commercial standard cm-bar. Furthermore, the slow axis M² of the combined laser is improved by 56% compared with that of a single emitter. Additionally, the brightness of 262 MW·cm⁻²·sr⁻¹, 136% higher than that of spectral beam combining without using beam-waist splitting polarization, was realized.

Structural colors from the interaction of light with well-designed nanostructures are highly promising for achieving long-term colors with high purity and brightness compared with traditional dyes and pigments. However, further improvement of the brightness and purity of colors originating from optical interference or nanophotonic resonances remains challenging due to inevitable losses and sidebands in such a design. Here, we show that in-band gap topologically protected state colors (TPSCs) that reside at the interface between layered thin films in the extended model with different Zak phases are ideal candidates for high-brightness transmissive colors due to the low loss characteristic from topology. At the same time, by applying several degrees of freedom to tune the narrow resonant linewidths (FWHM down to ?12 nm in simulation, with further improvement possibility) of TPSCs within the band gap, we can realize a color gamut of 156% sRGB color space. The design is verified by sputtering TiO₂/SiO₂ layers on a glass substrate, with FWHM ?20 nm and a transmission above 94.5% realized. The exact TPSCs resonance at the physical interface of different units presented here may guarantee further color brightness and purity improvement with the cooperation of active materials in layered thin film structures, which are highly promising for large-scale and high-performance transmissive structural colors.