Efficient Mode-Locking of Sub-70-fs Ti:Sapphire Laser by Graphene Saturable Absorber

Baek, In Hyung; Lee, Hwang Woon; Bae, Sukang; Hong, Byung Hee; Ahn, Y. H.; Yeom, Dong‐Il; Rotermund, Fabıan

doi:10.1143/apex.5.032701

Cited by 152 publications

(96 citation statements)

References 22 publications

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“…This, along with the ultrafast recovery time [28], low saturation fluence [16,26], and ease of fabrication [29] and integration [30], makes graphene an excellent broadband SA [27]. Consequently, mode-locked lasers using graphene SAs (GSAs) have been demonstrated from∼800nm [31] to ∼970nm [32], ∼1µm [33], ∼1.5µm [26] and ∼2µm [34] up to ∼2,4µm [35]. Therefore, experimental setups that combine the unique optical properties and simple fabrication of graphene, with fiber lasers, are attractive prospects for few-cycle generation.…”

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confidence: 99%

Few-cycle pulses from a graphene mode-locked all-fiber laser

Purdie

Popa

Wittwer

et al. 2015

Applied Physics Letters

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We combine a graphene mode-locked oscillator with an external compressor and achieve∼29fs pulses with∼52mW average power. This is a simple, low-cost, and robust setup, entirely fiber based, with no free-space optics, for applications requiring high temporal resolution.Ultrafast light pulses in the femtosecond range are needed for advanced photonics applications. E.g. in pump-probe spectroscopy, photophysical and photochemical relaxation processes are monitored by exciting a sample with an ultrashort light pulse. The maximum temporal resolution is determined by the duration, ∆τ , of the pulse. This is usually defined as the full width at half maximum (FWHM) of its intensity profile in the time domain, I(t) [1]. Alternatively ∆τ may be defined by the number of oscillation periods of the electric field carrier wave (optical cycles) within the pulse[2] N = ∆τ T0 = ν 0 ∆τ , where T 0 is the optical cycle of frequency ν 0 . The ultimate pulse duration is set by a single cycle of light, i.e. T 0 , given by[2] λ c , where λ is the wavelength and c is the speed of light. Finally, the uncertainty relation ∆ν∆τ ≃ 1 π provides a measure of the minimum frequency bandwidth ∆ν required for an ultrashort pulse formation[2], i.e. the broader the bandwidth, the shorter the supported pulse. In the visible and near infrared (NIR), T 0 lies, e.g, between 2fs at λ ∼600nm and 5fs at λ ∼1.5µm, which set the ultimate speed limit for devices operating in this wavelength range. Achieving shorter pulses therefore requires moving to shorter wavelengths.Pulses as short as 2-cycles can be generated directly from laser cavities using passive mode-locking [1][2][3]. Ti:Saphire lasers have become established tools for few-cycle generation [2], with the shortest pulses produced to date having ∆τ ∼5fs[4] at a centre wavelength, λ 0 ∼800nm, corresponding to less than 2-cycles, with spectral width ∆λ ∼600nm [4]. Ti:Saphire lasers able to generate few-cycle durations are typically optimized to make use of the maximum ∆λ gain available[2], consequently they have no wavelength tunability[2]. Tunable Ti:Saphire operate with a much longer pulse duration, e.g. ∆τ ∼150fs in a typical∼680-1080nm commercially available spectral range [5]. Tunable few-cycle pulses can be achieved by exploiting nonlinear optical effects in optical parametric amplifiers (OPAs). These can be described by expressing the polarization (P ) as a power series in the applied optical field (E) [6,7]:, where ǫ 0 is the free space permittivity, χ (1) is the linear and χ (2) and χ (3) are the second-and third-order nonlinear susceptibilities. OPAs are optical amplifiers based on the χ (2) nonlinearity of a crystal [6][7][8], in a process, called parametric [6,7], where there is no net transfer of energy and momentum between E and the crystal [6,7]. This can be visualized, by considering energy transfer from a pump pulse of frequency ω p to two pulses of lower frequencies ω s and ω i , called signal and idler [6,7], with the requirement ω p = ω s + ω i [6,7]. Under this condition, OPAs can...

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confidence: 99%

Few-cycle pulses from a graphene mode-locked all-fiber laser

Purdie

Popa

Wittwer

et al. 2015

Applied Physics Letters

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“…This is especially true for the chirped-pulse operation mode, when the pulse duration is significantly longer than the short decay time (100-200 fs) and comparable to the longer decay time of the graphene (1.5 ps) [1], meaning that a large part of the absorption cannot be saturated and that the absorber is subject to much higher thermal load as compared to the short-pulse system [3]. The cavity mode size has to be strictly controlled and scaled with increasing of the pulse energy.…”

Section: Graphene Damagementioning

confidence: 99%

“…Successful implementations range from 800 [1] to 2500 nm [2] on the wavelength scale. Pulses with durations down to 41 fs [3] have been obtained.…”

Section: Introductionmentioning

confidence: 99%

Graphene mode-locked Cr:ZnS chirped-pulse oscillator

et al. 2014

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“…The length of the multipass amplifier for the eigenmode propagation depending on the average pump power was described [17]. The reduction in the thermal lensing effect and thermal distortion in the Ti:sapphire based laser system has been maintained by employing the water cooling [18,19] and cryogenically cooled [20]. Along with the thermal compensation, the phase fluctuations and pulse duration required to be measured accurately.…”

Section: Introductionmentioning

confidence: 99%

Thermal Lensing Compensation in the Development of 30 fs Pulse Duration Chirped Pulse Amplification Laser System and Single-Shot Intensity-Phase Measurement

Imran

Hussain

2018

Acta Phys. Pol. A

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We present 30 fs pulse duration home-made chirped pulse amplification Ti:sapphire laser system operating at a repetition rate of 1 kHz with 4.0 mJ pulse energy. The Ti:sapphire laser system with ∼ 819 nm center wavelength has a long-cavity oscillator, four pass grating stretcher, 8-pass pre-amplifier, 4-pass post-amplifier and a double pass grating compressor. The Peltier coolers and thermal eigenmode post-amplifier are introduced to compensate the thermal lensing of the crystal in the amplifiers and to enhance the beam focusability on the crystal. The Strehl ratio and M 2 value measured by employing the Shack-Hartman wavefront sensor HASO4 to observe the spatial profile and beam quality. The most sensitive single-shot second harmonic generation frequency-resolved optical gating diagnostic technique is employed to characterize intensity and phase of the output compressed laser pulses.

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Efficient Mode-Locking of Sub-70-fs Ti:Sapphire Laser by Graphene Saturable Absorber

Cited by 152 publications

References 22 publications

Few-cycle pulses from a graphene mode-locked all-fiber laser

Few-cycle pulses from a graphene mode-locked all-fiber laser

Graphene mode-locked Cr:ZnS chirped-pulse oscillator

Thermal Lensing Compensation in the Development of 30 fs Pulse Duration Chirped Pulse Amplification Laser System and Single-Shot Intensity-Phase Measurement

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