Operation of an optical in-well-pumped vertical-external-cavity surface-emitting laser

Abstract

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Femtosecond synchronously in-well pumped vertical-external-cavity surface-emitting laser

“…Threshold was reached at an unreflected pump power of 69 mW. The corresponding slope efficiency of 5.8% is in good agreement with the 6% observed under CW operation of a gain element from the same wafer [15]. It is worth noting that the CW experiment used a gain element, that was capillary bonded to a single-crystal diamond heat spreader to enable high-power (~1W) operation.…”

“…Higher pump powers would be expected to result in a higher output power in line with the observations on CW systems [15,16]. An optimization of the gain element structure for in-well pumping would allow for a further increase.…”

“…These systems are characterized by a large amount of chirp while the carrier capture time of ~20 ps [13,14] limits the speed of gain dynamics. For an optical in-well pumped system [15,16], where the carriers are generated directly in the QWs, the carrier transportation time is eliminated. The faster build-up of the gain will affect the pulse shape and potentially lead to a reduction of the chirp.…”

VECSEL Semiconductor Lasers: A Path to High‐Power, Quality Beam and UV to IR Wavelength by Design

“…In an attempt to reduce quantum defect and improve efficiency in VECSEL lasers, in-well, rather than barrier, optical pumping has also been used for these devices [44][45][46][47][48]. Another important advantage of optically pumped semiconductor gain medium is its spectrally broad absorption and hence tolerance of broad pump wavelength variation.…”

“…Thus, for passive mode locking in Ref. [62], pump beam was injected at 45 to the chip with incident beam direction in the plane perpendicular to the plane of the picture in Figure 1.6c. This pump flexibility is enabled by the thin disk nature of the laser gain medium with pump absorption length of the order of only 1 mm.…”