Single-Mode Lasing:
In certain supermode microcavities, stimulated scattering can lead to the preferential amplification of a single cavity mode, resulting in single-mode lasing. This typically occurs when the cavity is designed to have a high quality factor (Q) for a specific mode, while suppressing other modes. The high Q-factor ensures that the single mode has a lower threshold for lasing, allowing it to dominate over other modes.
By carefully engineering the cavity geometry, material composition, and doping profile, it is possible to achieve strong optical confinement and minimize scattering losses for the desired mode. This enables efficient single-mode lasing with high output power and good beam quality.
Dual-Mode Lasing:
In other cases, stimulated scattering in supermode microcavities can result in dual-mode lasing, where two cavity modes oscillate simultaneously. This occurs when the cavity supports multiple modes with similar Q-factors and gain conditions. Due to the competitive nature of lasing, both modes can reach the lasing threshold and coexist in the cavity.
Dual-mode lasing can be advantageous in certain applications, such as wavelength-division multiplexing (WDM) systems or the generation of entangled photon pairs for quantum information processing. By carefully controlling the cavity design and excitation conditions, it is possible to achieve stable dual-mode operation with specific wavelength separation and controlled mode coupling.
The transition from single-mode to dual-mode lasing, or vice versa, can be influenced by various factors such as the excitation power, temperature, and cavity detuning. By manipulating these parameters, it is possible to selectively excite or suppress specific modes and achieve the desired lasing behavior in supermode microcavities.
In summary, stimulated scattering in supermode microcavities can lead to either single- or dual-mode lasing, depending on the cavity design, material properties, and excitation conditions. By carefully engineering these factors, it is possible to tailor the lasing behavior for specific applications and achieve desired optical characteristics.
