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In this Letter, we investigate the resolution of two-photon polymerization (2PP) with an amplified mode-locked external cavity diode laser with adjustable pulse length and a high repetition rate. The experimental results are analyzed with a newly developed 2PP model. Even with low pulse peak intensity, the produced structural dimensions are comparable to those generated by traditional 2PP laser sources. Thus, we show that a compact monolithic picosecond laser diode without amplification and with a repetition rate in the GHz regime can also be applied for 2PP. These results show the high application potential of compact mode-locked diode lasers for low-cost and compact 2PP systems.

We present a femtosecond laser diode system that is capable of autonomously adjusting itself to compensate for the external dispersion in an arbitrary application. The laser system contains a spatial light modulator inside the cavity which is controlled by an evolutionary algorithm in order to allow for phase and amplitude shaping of the laser emission. The cavity-internal dispersion control is shown to be much more efficient than an external control with a pulse shaper.

A self-optimizing approach to intra-cavity spectral shaping of external cavity mode-locked semiconductor lasers using edge-emitting multi-section diodes is presented. An evolutionary algorithm generates spectrally resolved phase- and amplitude masks that lead to the utilization of a large part of the net gain spectrum for mode-locked operation. Using these masks as a spectral amplitude and phase filter, a bandwidth of the optical intensity spectrum of 3.7 THz is achieved and Fourier-limited pulses of 216 fs duration are generated after further external compression.

A spectrally tunable, narrow linewidth master oscillator power amplifier system emitting ns pulses with high peak power is presented. The master oscillator is a distributed feedback ridge waveguide (DFB-RW) laser, which is operated in continuous wave (CW) mode and emits at about 975 nm with a spectral line width below 10 pm. The oscillator can be tuned over a range of 0.9 nm by varying the injection current. The tapered amplifier (TA) consists of an RW section and a flared gain-guided section. The RW section of the amplifier acts as an optical gate and converts the CW input beam emitted by the DFB-RW laser into a train of short optical pulses, which are subsequently amplified by the tapered section. The width of the pulses is 8 ns at a repetition rate of 25 kHz. The peak power is 16.3 W. The TA preserves the spectral properties of the emission of the DBR-RW laser. The amplified spontaneous emission is suppressed by about 40 dB.

We analyze the influence of second and third order intracavity dispersion on a passively mode-locked diode laser by introducing a spatial light modulator (SLM) into the external cavity. The dispersion is optimized for chirped pulses with highest possible spectral bandwidth that can be externally compressed to the sub picosecond range. We demonstrate that the highest spectral bandwidth is achieved for a combination of second and third order dispersion. With subsequent external compression pulses with a duration of 437 fs are generated.

We present a method of the generation of sub-100 ps pulses with an all-semiconductor master oscillator-power amplifier (MOPA) system, consisting of a three section distributed Bragg reflector (DBR) laser as MO and a two section tapered PA. The pulses generated by the gain-switched DBR laser are first shortened by the ridge-waveguide input section of the PA acting as a saturable absorber and then amplified by the tapered gain region section. We generate laser pulses with a minimum duration of 35 ps and a peak power of more than 65 W. The spectral width is less than 0.25 nm around a center wavelength of 1063 nm.

We present results on a monolithic semiconductor-based master-oscillator power amplifier (MOPA) combining a distributed-feedback (DFB) laser and a tapered amplifier on a single chip. The MOPA reaches an output power of almost 12 W at an emission wavelength around 1064 nm in continuous-wave operation. Pulses with a length of around 100 ps can be obtained either by injecting nanosecond current pulses into the tapered amplifier alone or into both the DFB laser and the tapered amplifier. In the latter case, pulses with a width of 84 ps, a peak power of 42 W, and a spectral width of 160 pm are generated.

We present a multimodal diode-laser-based terahertz (THz) spectroscopy system. In contrast to other laser-based THz setups that provide either cw or broadband THz generation, our configuration combines the advantages of both approaches. Our low complexity setup enables fast switching from cw difference frequency generation to broadband THz emission, enabling sophisticated data analysis like much more complex time domain spectroscopy systems.

We report on the generation of ultrashort pulses by dispersion management of a passively modelocked external cavity diode laser. Pulse widths down to 200 fs are obtained at 830 nm emission wavelength. We use intracavity dispersion management to increase the spectral bandwidth and compress the strongly chirped pulses externally with a grating compressor.

Almost chirp-free pulses with a duration of 190 fs were achieved from a mode-locked semiconductor disk laser (SDL) emitting at approximately 1045 nm. Pulse shaping was different from the soliton-like mode-locking process known from lasers using dielectric gain media; passive amplitude modulation provided by a fast saturable absorber was essential. The spectrum of the absorber had to be matched to the gain spectrum within a few nm. A tapered diode amplifier was demonstrated to be a device for both picking and amplifying SDL pulses. The pulse repetition rate of the SDL output was reduced from 3 GHz to 47 MHz.

Passive mode-locked laser operation based on an Yb-doped lanthanum scandium borate crystal is demonstrated. Pulse durations as short as 58 fs and 67 fs were achieved applying a Ti:sapphire- and a diode-laser pump source, respectively. The average output powers were 73 mW and 39 mW at a repetition rate of 90 MHz. The laser was broadly tunable from 1028 to 1057 nm in the sub-200 fs pulse regime.