Generation of 84-fs pulses from a mode-locked Tm:CNNGG disordered garnet crystal laser

Abstract

A mode-locked laser based on a Tm:CNNGG disordered crystal as an active medium and a single-walled carbon nanotube saturable absorber is demonstrated, operating at a central wavelength of 2018 nm. Transformlimited 84 fs pulses are generated with an average output power of 22 mW at a repetition rate of ∼90 MHz. A maximum output power of 98 mW is obtained at a slightly longer pulse duration of 114 fs.

Power-scalable sub-100-fs Tm laser at 2.08 μm

“…An average power of 210 mW was demonstrated in 2019 with an SWCNT-SA ML Tm:LuYO 3 ceramic laser [16] . In 2020, a slightly higher power of 222 mW was obtained from a Tm:Sc 2 O 3 laser using the KLM technique [21] , which represents the highest power ever reported Tm:(Lu,Y)2O3-SWCNT [16] Tm:(Lu,Y)2O3-SESAM [17] Tm:MgWO4-GSA [18] Tm:MgWO4-SWCNT [19] Tm:CLNGG-SWCNT [20] Tm:Sc2O3-KLM [21] Tm:CNNGG-SWCNT [22] This Work from such sub-100-fs ML solid-state Tm lasers. One can recognize that all the average powers higher than 100 mW were obtained by using the above-mentioned sesquioxide materials [16,17,21] , and an obvious trade-off between average power and pulse duration can be seen from all these reported results.…”

“…Subsequently, shorter pulse durations of 57 fs at 2045 nm and 54 fs at 2048 nm were reported using a single-walled carbon nanotube (SWCNT)-based SA and a SESAM, respectively, with average output power still below 100 mW [16,17] . Figure 1 summarizes the state of the art of sub-100-fs ML solid-state Tm lasers emitting in the 2-µm spectral range [16][17][18][19][20][21][22] . An average power of 210 mW was demonstrated in 2019 with an SWCNT-SA ML Tm:LuYO 3 ceramic laser [16] .…”

Mid-Infrared Laser Emissions of Tm3+-doped Garnets: The Case Study of Disordered Tm:CNGG Crystal

“…Recently, disordered garnets such as CNGG (calcium niobium gallium garnet) doped with Tm 3+ and codoped with Tm 3+ and Ho 3+ ions have attracted a lot of attention for generation of ultrashort pulses at ~2 µm [1]. Pan et al reported on a Tm oscillator operating on the 3 F4 → 3 H6 transition and delivering 84 fs pulses at 2018 nm (emission bandwidth: >50 nm) and demonstrated continuous wavelength tuning between 1879-2086 nm [1]. It is interesting to extend the emission range of such crystals further into mid-IR.…”

The interferometric measurement of thermal lens effect in an LD pumped Tm-doped bulk laser

“…Further designing a few-cycle mode-locking oscillator requires a strong pumping intensity inside the laser crystal for achieving a high conversion efficiency and simultaneously enhancing the optical Kerr effect. 13) Such a long-folded laser cavity usually possesses a narrow stable operation region, which makes it very sensitive to the variation of the thermal focal length. 14) So accurate measuring the thermal focal length is significant for designing and optimizing the 2 μm mode-locking oscillator.…”