Pulse shaping in a midwave-IR OPCPA for multi-µJ few-cycle pulse generation at 12 µm via DFG.

We report on dispersion management in mid-IR optical parametric chirped pulse amplifiers (OPCPA) aiming for high-energy few-cycle pulses beyond 4 µm. The available pulse shapers in this spectral region limit the feasibility of sufficient higher-order phase control. Intending the generation of high energy pulses at 12 µm via DFG driven by the signal and idler pulses of a midwave-IR OPCPA, we introduce alternative approaches for mid-IR pulse shaping, namely a germanium-prism pair and a sapphire-prism Martinez compressor. Furthermore, we explore the limits of bulk compression in Si and Ge for multi-mJ pulse energies.

10-µJ few-cycle 12-µm source based on difference-frequency generation driven by a 1-kHz mid-wave infrared OPCPA.

We report on high-energy, few-cycle pulse generation in the long-wave infrared spectral region via difference-frequency generation (DFG) in GaSe and AgGaSe2 nonlinear crystals. The DFG is driven by the signal at 3.5 µm and idler at 5 µm of a high-power mid-wave infrared optical parametric chirped pulse amplification (OPCPA) system operating at a 1-kHz repetition rate. The DFG pulses contain up to 17 µJ of energy and cover a spectrum from 8.5 µm to 14.5 µm. They are generated with a conversion efficiency of 2.1 %. Compression results in 10.2-µJ pulses with sub-150-fs duration, corresponding to less than four optical cycles.

Micromachining of Invar with 784 Beams Using 1.3 ps Laser Source at 515 nm.

To fulfil the requirements for high-resolution organic light-emitting diode (OLED) displays, precise and high-quality micrometer-scale patterns have to be fabricated inside metal shadow masks. Invar has been selected for this application due to its unique properties, especially a low coefficient of thermal expansion. In this study, a novel cost-efficient method of multi-beam micromachining of invar will be introduced. The combination of a Meopta beam splitting, focusing and monitoring module with a galvanometer scanner and HiLASE high-energy pulse laser system emitting ultrashort pulses at 515 nm allows drilling and cutting of invar foil with 784 beams at once with high precision and almost no thermal effects and heat-affected zone, thus significantly improving the throughput and efficiency.

Verdet constant of potassium terbium fluoride crystal as a function of wavelength and temperature.

Potassium terbium fluoride KTb3F10 (KTF) crystal is a promising magneto-active material for creating multi-kilowatt average-power Faraday isolators operating at the visible and near-infrared wavelengths. Nevertheless, the key material's parameter needed for the design of any Faraday isolator-the Verdet constant, has not been comprehensively investigated yet. In this Letter, we report on measurement of the Verdet constant of the KTF crystal for wavelengths between 600 and 1500 nm and for temperatures ranging from 15 to 295 K. A suitable model for the Verdet constant as a function of wavelength and temperature has been developed and may be conveniently used for optimal design of KTF-based high-average-power Faraday isolators.

Single-Shot near Edge X-ray Fine Structure (NEXAFS) Spectroscopy Using a Laboratory Laser-Plasma Light Source.

We present a proof of principle experiment on single-shot near edge soft X-ray fine structure (NEXAFS) spectroscopy with the use of a laboratory laser-plasma light source. The source is based on a plasma created as a result of the interaction of a nanosecond laser pulse with a double stream gas puff target. The laser-plasma source was optimized for efficient soft X-ray (SXR) emission from the krypton/helium target in the wavelength range from 2 nm to 5 nm. This emission was used to acquire simultaneously emission and absorption spectra of soft X-ray light from the source and from the investigated sample using a grazing incidence grating spectrometer. NEXAFS measurements in a transmission mode revealed the spectral features near the carbon K-α absorption edge of thin polyethylene terephthalate (PET) film and L-ascorbic acid in a single-shot. From these features, the composition of the PET sample was successfully obtained. The NEXAFS spectrum of the L-ascorbic acid obtained in a single-shot exposure was also compared to the spectrum obtained a multi-shot exposure and to numerical simulations showing good agreement. In the paper, the detailed information about the source, the spectroscopy system, the absorption spectra measurements and the results of the studies are presented and discussed.

Compact system for near edge X-ray fine structure (NEXAFS) spectroscopy using a laser-plasma light source.

We present a compact laboratory system for near edge soft X-ray fine structure (NEXAFS) spectroscopy that was developed using a laser-plasma light source. The source is based on a double stream gas puff target. The plasma is formed by the interaction of a laser beam with the double stream gas puff target approach. The laser plasma source was optimized for efficient soft X-ray emission from a krypton/helium target in the range of 1.5 to 5 nm wavelength. This emission is used to acquire simultaneously the emission and absorption spectra of soft X-ray light from the source and from the investigated sample using a grazing incidence spectrometer. The measurements in the transmission mode reveal the features near the carbon K-α absorption edge of thin PET film. From those features, the composition of the sample was successfully obtained. The data are in agreement with synchrotron measurements. In the paper, the detailed information about the source, its optimization, the system, spectral measurements and the results are presented and discussed.