Two-colour high-speed asynchronous optical sampling based on offset-stabilized Yb:KYW and Ti:sapphire oscillators.

We present a high-speed asynchronous optical sampling system, based on two different Kerr-lens mode-locked lasers with a GHz repetition rate: An Yb:KYW oscillator and a Ti:sapphire oscillator are synchronized in a master-slave configuration at a repetition rate offset of a few kHz. This system enables two-colour pump-probe measurements with resulting noise floors below 10⁻6 at a data aquisition time of 5 seconds. The measured temporal resolution within the 1 ns time window is below 350 fs, including a timing jitter of less than 50 fs. The system is applied to investigate zone-folded coherent acoustic phonons in two different semiconductor superlattices in transmission geometry at a probe wavelength far below the bandgap of the superlattice constituents. The lifetime of the phonon modes with a zero wave vector and frequencies in the range from 100 GHz to 500 GHz are measured at room temperature and compared with previous work.

Fiber-coupled high-speed asynchronous optical sampling with sub-50 fs time resolution.

We present a fiber-coupled pump-probe system with a sub-50 fs time resolution and a nanosecond time window, based on high-speed asynchronous optical sampling. By use of a transmission grism pulse compressor, we achieve pump pulses with a pulse duration of 42 fs, an average power of 300 mW and a peak power exceeding 5 kW at a pulse repetition rate of 1 GHz after 6 m of optical fiber. With this system we demonstrate thickness mapping of soft X-ray mirrors at a sub-nm thickness resolution on a cm(2) scan area. In addition, terahertz field generation with resolved spectral components of up to 3.5 THz at a GHz frequency resolution is demonstrated.

Mode-locked Tm,Ho:YAP laser around 2.1 µm.

A passively mode-locked Tm,Ho:YAP laser around 2.1 µm wavelength employing a semiconductor saturable absorber mirror is demonstrated. Stable continuous wave mode-locking operation was achieved at variable center wavelengths of 2036.5 nm, 2064.5 nm, 2095.5 nm, 2103.5 nm, and 2130 nm, respectively. Pulses as short as 40.4 ps were obtained at 2064.5 nm with a spectral FWHM of 0.5 nm at output powers of 132 mW and a repetition rate around 107 MHz. A maximum output power of 238 mW was obtained at 2130 nm with a pulse duration of 66 ps.

Efficient continuous wave and passively mode-locked Tm-doped crystalline silicate laser.

An efficient continuous wave and passively mode-locked thulium-doped oxyorthosilicate Tm:LuYSiO5 laser is demonstrated. A maximum slope efficiency of 56.3% is obtained at 2057.4 nm in continuous wave operation regime. With an InGaAs quantum well SESAM, self-starting passively mode-locked Tm:LuYSiO5 laser is realized in the 1929 nm to 2065 nm spectral region. A maximum average output power of 130.2 mW with a pulse duration of 33.1 ps and a repetition rate of about 100 MHz is generated at 1984.1 nm. Pulses as short as 24.2 ps with an average output power of 100 mW are obtained with silicon prisms where used to manage the intracavity dispersion. The shortest pulse duration of about 19.6 ps is obtained with an average output power of 64.5 mW at 1944.3 nm.

Comparative investigations on continuous wave operation of a-cut and b-cut Tm,Ho:YAlO3 lasers at room temperature.

The Tm,Ho:YAlO3 laser performance for two crystal orientations pumped by a wavelength tunable Ti:Sapphire laser is presented in this paper. An experimental investigation comparing a- and b-oriented Tm,Ho:YAlO3 crystals laser performance is demonstrated and discussed. Single- and multi-wavelength operations of Tm,Ho:YAlO3 lasers have been investigated in detail. The maximum output powers of 890 mW at 2119 nm for a-oriented Tm,Ho:YAlO3 crystal and 946 mW at 2103 nm for b-oriented Tm,Ho:YAlO3 crystal have been obtained, respectively. The two crystals show very similar performance in terms of output power and conversion efficiency, only that the b-cut Tm,Ho:YAP crystal demonstrates more regimes of multi-wavelength operations.

Passively mode-locked 10 GHz femtosecond Ti:sapphire laser.

We report a mode-locked Ti:sapphire femtosecond laser emitting 42 fs pulses at a 10 GHz repetition rate. When operated with a spectrally integrated average power greater than 1 W, the associated femtosecond laser frequency comb contains approximately 500 modes, each with power exceeding 1 mW. Spectral broadening in nonlinear microstructured fiber yields comb elements with individual powers greater than 1 nW over approximately 250 nm of spectral bandwidth. The modes of the emitted comb are resolved and imaged with a simple grating spectrometer and digital camera. Combined with absorption spectroscopy of rubidium vapor, this approach permits identification of the mode index and measurement of the carrier envelope offset frequency of the comb.