Widely Tunable High-Power Two-Color VECSELs for New Wavelength Generation

Abstract

We report a collinear, two-color vertical external cavity surface emitting laser, which with minimal changes, is suitable for intracavity type I second harmonic generation (SHG), type II sum frequency generation (SFG) and type II difference frequency generation (DFG). The demonstrated two-chip cavity provides high-brightness, independently tunable two color, orthogonally polarized intracavity lasing modes. VECSEL chips with emission around 970 nm and 1185 nm allow the generation of a wide range of wavelengths in the visible and long-wavelength spectral range. The open cavity, collinear geometry, provided a platform for efficient SHG yellow output, SHG blue output, and SFG of green output in the same cavity while only changing the nonlinear crystals. In all cases for visible light generation, a lithium triborate nonlinear crystal is introduced in the cavity region where the fundamental beams are overlapped. Simultaneous SHG and SFG in the same cavity resulting in overlapped outputs consisting of two visible colors is also demonstrated. By using two VECSEL chips with similar gain peaks, intracavity THz generation by DFG is demonstrated for the first time in a T-cavity VECSEL geometry. A custom made tilted periodically-poled lithium niobate nonlinear crystal generated DFG signal around 1 THz.

High power two-color orbital angular momentum beam generation using vertical external cavity surface emitting lasers

“…Previous works have demonstrated VECSELs tunable over 30 nm. 21 The output power remained consistent and within 10% of the maximum power.…”

“…The two-color T-cavity VECSEL developed by our group is a modification of conventional VECSEL cavities, simultaneously allowing for the generation of high-power two-color coaxial emission and a broad-range of wavelength generation through intracavity nonlinear sum or difference frequency conversion. 21,22 In this paper, we report the demonstration of higher-order HG and LG modes in a two-color T-cavity VECSEL geometry. 23 By combining intracavity mode-control elements (MCEs) with external astigmatic mode converters (AMCs), a wide range of HG and LG mode pairs are demonstrated.…”

Widely Tunable Terahertz‐Generating Semiconductor Disk Laser

“…In this regard, the available high‐performance VECSELs, [ 21,22 ] also called semiconductor disk lasers (SDLs), can offer outstanding output parameters that are important for efficient intracavity‐frequency conversion in a nonlinear crystal. For instance, VECSELs can provide not only remarkably high intracavity powers in the range of a few hundred of watts, but also offer high‐power multimode [ 23 ] or single‐frequency [ 24 ] continuous‐wave (CW) operation exceeding tens of watts, as well as two‐color [ 25,26 ] and mode‐locked emission. [ 27 ]…”

Optically pumped VECSELs: review of technology and progress

“…At higher pump powers, however, the absolute intensity fluctuations are reduced to a level of 0-20% and twocolour operation is obtained. Later on, this work was extended to THz generation via intracavity DFG from a two-chip cavity [301,302]. Moreover, the potential intensity fluctuations in two-wavelength VECSELs could be addressed by using two separate gain chips in the same cavity [303] or two VECSEL gain elements in a coupled T-cavity configuration [304,305].…”