本實驗採用 c-cut 雙折射晶體 Nd:GdVO₄，架設單晶體單光軸的共振腔架構，並於同一光軸上加入兩個輸出耦合鏡，實現1064 nm與1342 nm的雙波長雷射輸出。由於雙折射晶體中尋常光(o-ray)與非尋常光(e-ray)具有不同的折射率，導致其在共振腔內所對應的有效腔長不同，針對兩種折射率情況進行穩定區模擬，並依據模擬結果完成腔體設計。由於兩者穩定區相互分離，使得腔內可以同時產生徑向偏振與方位角偏振的圓柱向量光束。並上述基礎上加入飽和吸收體Cr:YAG實施被動Q開關的操作，成功產生脈衝式的圓柱向量光輸出。
隨後，為了評估光束的偏振品質以及空間特性，透過狹縫以及偏振片量測其偏振度，再經由CCD映像測量法量測其M²光束品質因子。此外，利用示波器擷取脈衝訊號以分析其單脈衝能量、重複頻率與脈衝寬度(FWHM)，表示系統的輸出性能。

In this work, we demonstrate the generation of a dual-wavelength cylindrical vector pulsed laser based on a c-cut Nd:GdVO₄ gain medium using passive Q-switching. A compact four-mirror resonator incorporating two output couplers designed for 1064 nm and 1342 nm is employed to realize simultaneous dual-wavelength operation within a single cavity. Owing to the intrinsic birefringence of the Nd:GdVO₄ crystal, the ordinary- and extraordinary-polarized components experience different refractive indices, resulting in distinct effective optical path lengths and separated resonator stability regions. Such a cavity configuration enables the direct generation of cylindrical vector beams, including radially polarized (RP) and azimuthally polarized (AP) modes, at both wavelengths. By inserting a Cr⁴⁺:YAG saturable absorber, stable passively Q-switched dual-wavelength cylindrical vector pulses are obtained. The polarization characteristics of the generated CVBs are evaluated using a slit and a rotating polarizer to determine the degree of polarization (DOP), while the beam quality factor M² is characterized using a CCD based beam profiling method. The temporal behaviors of the Q-switched pulses are further investigated with an oscilloscope. The proposed system provides an effective approach for realizing dual-wavelength cylindrical vector pulsed Nd:GdVO₄ lasers, which may facilitate advanced applications requiring structured light and multi-wavelength pulsed operation.

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