Upconversion-pumped femtosecond thulium laser at 2309 nm mode-locked by a GaSb-based SESAM.

We report on a femtosecond thulium laser operating on the H → H transition with upconversion pumping around 1 µm and passively mode-locked by a GaSb-based SEmiconductor Saturable Absorber Mirror (SESAM). This laser employs a 6 at.% Tm:LiYF laser crystal and a polarization maintaining Yb-fiber master oscillator power amplifier at 1043 nm as a pump source addressing the F → F excited-state absorption transition of Tm ions.

Gigahertz semiconductor laser at a center wavelength of 2 µm in single and dual-comb operation.

Dual-comb lasers are a new class of ultrafast lasers that enable fast, accurate and sensitive measurements without any mechanical delay lines. Here, we demonstrate a 2-µm laser called MIXSEL (Modelocked Integrated eXternal-cavity Surface Emitting Laser), based on an optically pumped passively modelocked semiconductor thin disk laser. Using III-V semiconductor molecular beam epitaxy, we achieve a center wavelength in the shortwave infrared (SWIR) range by integrating InGaSb quantum well gain and saturable absorber layers onto a highly reflective mirror.

Single-cavity dual-modelocked 2.36-µm laser.

We present the first dual-modelocked femtosecond oscillator operating beyond 2 µm wavelength. This new class of laser is based on a Cr:ZnS gain medium, an InGaSb SESAM for modelocking, and a two-surface reflective device for spatial duplexing of the two modelocked pulse trains (combs). The laser operates at 2.

Cryptic extinction risk in a western Pacific lizard radiation.

Unlabelled: Cryptic ecologies, the Wallacean Shortfall of undocumented species' geographical ranges and the Linnaean Shortfall of undescribed diversity, are all major barriers to conservation assessment. When these factors overlap with drivers of extinction risk, such as insular distributions, the number of threatened species in a region or clade may be underestimated, a situation we term 'cryptic extinction risk'. The genus is a diverse radiation of insular and arboreal geckos that occurs across the western Pacific.

High-power low-noise 2-GHz femtosecond laser oscillator at 2.4 µm.

Femtosecond lasers with high repetition rates are attractive for spectroscopic applications with high sampling rates, high power per comb line, and resolvable lines. However, at long wavelengths beyond 2 µm, current laser sources are either limited to low output power or repetition rates below 1 GHz. Here we present an ultrafast laser oscillator operating with high output power at multi-GHz repetition rate.