Nonequilibrium and thermal effects in mode-locked VECSELs

Moloney, Jerome V.; Kilen, I.; Bäumner, Ada; Scheller, Maik; Koch, S. W.

doi:10.1364/oe.22.006422

Cited by 32 publications

(13 citation statements)

References 12 publications

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“…Significant attention has also been devoted to the so-called 'self-mode-locking' that was first reported by Chen et al in 2011 [375]. In these cases, the physical mechanism for the saturable absorption has been credited to a possible Kerr effect in the VECSEL gain material [376], but several reports have been published on the topic that both support and contradict self-mode-locking [207,211,307,[377][378][379][380][381]. Most notably, Quarterman et al [207] measured a sufficiently large Kerr effect in a VECSEL structure to support Kerr-lens mode locking.…”

Section: Mode-locking Mechanismmentioning

confidence: 99%

“…Again, it was found that measurable nonlinear lensing exists in VECSELs. However, whether this nonlinear lensing is strong enough to cause stable mode-locking is still under consideration [208,210,211].…”

Section: Optical Propertiesmentioning

confidence: 99%

“…Most notably, Quarterman et al [207] measured a sufficiently large Kerr effect in a VECSEL structure to support Kerr-lens mode locking. On the other hand, the long-term stability of self-mode-locking is still not unanimously resolved [211]. A review of the reported self-mode-locking results can be found in [382].…”

Section: Mode-locking Mechanismmentioning

confidence: 99%

See 2 more Smart Citations

Optically pumped VECSELs: review of technology and progress

Guina

Rantamäki

Härkönen

2017

J. Phys. D: Appl. Phys.

205

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Section: Mode-locking Mechanismmentioning

confidence: 99%

Section: Optical Propertiesmentioning

confidence: 99%

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Optically pumped VECSELs: review of technology and progress

Guina

Rantamäki

Härkönen

2017

J. Phys. D: Appl. Phys.

205

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“…Another modelocking mechanism reported recently is the so-called self-mode-locked VECSEL or the KLM-VECSEL [103][104][105][106] . No apparent saturable absorber is used in these laser cavities, and a hard aperture is inserted in front of the OC or highly reflective end mirror.…”

Section: Device Principle Vertical External-cavity Surface-emitting Lmentioning

confidence: 99%

Recent advances in ultrafast semiconductor disk lasers

et al. 2015

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The performance of ultrafast semiconductor disk lasers has rapidly advanced in recent decades. The strong interest from industry for inexpensive, compact, and reliable ultrafast laser sources in the picosecond and femtosecond domains has driven this technology toward commercial products. Frequency metrology and biomedical applications would benefit from sub-200-femtosecond pulse durations with peak powers in the kilowatt range. The aim of this review is to briefly describe the market potential and give an overview of the current status of mode-locked semiconductor disk lasers. Particular focus is placed on the ongoing efforts to achieve shorter pulses with higher peak powers.

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“…4,5 Recently, there have been reports of SDLs operating in a pulsed regime without a saturable absorber in the cavity, so called self-mode-locking (SML). [6][7][8][9][10][11][12][13][14][15] It has been suggested that Kerr lensing in the gain medium 7,8 or saturable absorption in unpumped quantum wells (QWs) causes the observed pulsation. 6 However, there has not yet been sufficient characterisation or modelling to determine what the causal effect is.…”

mentioning

confidence: 99%

Reflection z-scan measurements of the non-linear lens in VECSEL gain structures

et al. 2016

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We present reflection z-scan measurements of a quantum well VECSEL gain structure under pumped and unpumped conditions. The implications for the design of mode-locked cavities will be discussed; both in relation to SESAM mode-locked lasers and the possibility of self-mode-locking.Semiconductor disk lasers (SDLs), also known as vertical-external-cavity surface-emitting lasers (VECSELs), have been the subject of considerable interest in recent years due to flexibility in their design and low cost. This has led to steady improvements in power up to 106 W 1 in continuous wave (CW) operation and kilowatt peak powers in mode-locked (ML) operation with sub-picosecond pulse durations typically at gigaHertz repetition frequencies. 2, 3Most ML-SDLs have used semiconductor saturable absorber mirrors (SESAMs) to initiate mode-locking. 4, 5 Recently, there have been reports of SDLs operating in a pulsed regime without a saturable absorber in the cavity, so called self-mode-locking (SML). 6-15 It has been suggested that Kerr lensing in the gain medium 7, 8 or saturable absorption in unpumped quantum wells (QWs) causes the observed pulsation. 6 However, there has not yet been sufficient characterisation or modelling to determine what the causal effect is.To understand the observed lasing behavior of self-mode-locked SDLs it is important to characterize nonlinear lensing in a SDL gain structure. The magnitude of the non-linear lensing would influence the cavity design of SML-SDLs. Non-linear lensing may also need to be considered when designing SESAM ML-SDLs. SDL gain chips are multilayer structures with scope for large variation in composition, thickness and number of layers. The complexity of their design makes modeling the non-linear response challenging. The non-linear response of semiconductors is highly dependent on the photon energy of the incident light as compared to the band gap energy of the semiconductor. 16 There are many different physical mechanisms that could affect lensing in the gain chip, including carrier and thermal effects, the strength of which are not well known and may occur on very different time scales. 17, 18 In order to obtain representative values of the lensing it is essential to replicate laser operating conditions when characterising the non-linear lens. The structure must be probed at a wavelength on resonance with the quantum well emission, where the SDL gain chip would naturally lase, and with a pulse duration that is comparable to reported self mode-locking (<1 ps).Previous measurements of non-linear lensing in a SDL gain structure indicate that there is a non-linear lens large enough to perturb a SDL cavity. 19 However, the probe laser used in Ref. 19 had long pulses compared to observed sub-picosecond SDL performance, and probed the sample below the band gap energy of the quantum wells.In this letter we present the first measurements of the non-linear lens in a SDL gain structure probing on resonance with the QW emission, with pulse durations typical of ML-SDLs. We observe a self-defocussin...

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Nonequilibrium and thermal effects in mode-locked VECSELs

Cited by 32 publications

References 12 publications

Optically pumped VECSELs: review of technology and progress

Optically pumped VECSELs: review of technology and progress

Recent advances in ultrafast semiconductor disk lasers

Reflection z-scan measurements of the non-linear lens in VECSEL gain structures

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