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We investigated room-temperature pulsed lasing in heavily doped Fe:ZnSe single crystals. The active elements were pumped by a Q-switched Cr3+:Yb3+:Ho3+:YSGG laser operating at 2.87 μm. Our results show that the generation of short laser pulses has a deep high-frequency modulation associated with relaxation dynamics in Fe:ZnSe. The lasing regime obtained in this study provides a straightforward way to generate mid-IR single nanosecond pulses at moderate pump energies. Moreover, we found a relation between the lasing pulse duration and the concentration of Fe2+ doping ions, and we experimentally demonstrated pulse shortening in heavily doped active crystals. Single-pulse lasing with an FWHM pulse duration of ~2.8 ns was achieved in ZnSe crystals doped with 2.3 · 1019 cm-3 Fe2+ ions. The demonstrated single-pulse lasing regime is applicable for seeding high-power mid-IR laser systems.

We investigated room-temperature pulsed lasing in heavily doped Fe:ZnSe single crystals. The active elements were pumped by a Q-switched Cr3+:Yb3+:Ho3+:YSGG laser operating at 2.87 μm. Our results show that the generation of short laser pulses has a deep high-frequency modulation associated with relaxation dynamics in Fe:ZnSe. The lasing regime obtained in this study provides a straightforward way to generate mid-IR single nanosecond pulses at moderate pump energies. Moreover, we found a relation between the lasing pulse duration and the concentration of Fe2+ doping ions, and we experimentally demonstrated pulse shortening in heavily doped active crystals. Single-pulse lasing with an FWHM pulse duration of ∼2.8 ns was achieved in ZnSe crystals doped with 2.3 · 1019 cm-3 Fe2+ ions. The demonstrated single-pulse lasing regime is applicable for seeding high-power mid-IR laser systems. [ABSTRACT FROM AUTHOR]

Developing a diffusion barrier layer on material interfaces has potential applications in various fields such as in packaging materials, pharmaceuticals, chemical filtration, microelectronics, and medical devices. Although numerous physical and chemical methods have been proposed to generate the diffusion barrier layer, the complexity of fabrication techniques and the high manufacturing costs limit their practical utility. Here, we propose an innovative approach to fabricate the diffusion barrier layer by irradiating poly(dimethylsiloxane) (PDMS) with a mid-infrared (λ = 10.6 μm) CO 2 laser. This process directly creates a diffusion barrier layer on the PDMS surface by forming a heavily cross-linked network in the polymer matrix. The optimal irradiation conditions were investigated by modulating the defocusing distance, laser power, and number of scanning passes. The barrier thickness can reach up to 70 μm as observed by the scanning electron microscope (SEM). The attenuated total reflectance (ATR), electron dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS) analyses collectively confirmed the formation of the SiO x structure on the modified surface based on the decreased methyl group signal and the increased oxygen/silicon ratio. The diffusion test with the model drugs (rhodamine B and donepezil) demonstrated that the modified surface exhibits effective diffusion barrier properties and the rate of drug diffusion through the modified barrier layer can be controlled by the optimization of the irradiation parameters. This novel approach provides the possibility to develop a controllable diffusion barrier layer in a biocompatible polymer with prospective applications in the fields of pharmaceuticals, packing materials, and medical devices.

The development of kW-class diode-pumped picosecond laser sources emitting at various wavelengths started at the HiLASE Center four years ago. A 500-W Perla C thin-disk laser with a diffraction limited beam and repetition rate of 50-100 kHz, a frequency conversion to mid-infrared (mid-IR), and second to fifth harmonic frequencies was demonstrated. We present an updated review on the progress in the development of compact picosecond and femtosecond high average power radiation sources covering the ultraviolet (UV) to mid-IR spectral range at the HiLASE Center. We also report on thin-disk manufacturing by atomic diffusion bonding, which is a crucial technology for future high-power laser development. [ABSTRACT FROM AUTHOR]

The development of kW-class diode-pumped picosecond laser sources emitting at various wavelengths started at the HiLASE Center four years ago. A 500-W Perla C thin-disk laser with a diffraction limited beam and repetition rate of 50–100 kHz, a frequency conversion to mid-infrared (mid-IR), and second to fifth harmonic frequencies was demonstrated. We present an updated review on the progress in the development of compact picosecond and femtosecond high average power radiation sources covering the ultraviolet (UV) to mid-IR spectral range at the HiLASE Center. We also report on thin-disk manufacturing by atomic diffusion bonding, which is a crucial technology for future high-power laser development.

In the present paper the results of the computer analysis of the GaAs-based and GaSb-based active regions that can be applied in compact semiconductor laser sources of radiation at mid-infrared wavelengths are presented. Quantum well material contents and strain dependencies on the maximal gain are investigated. It is shown that above 3 µm the maximal gain obtained for GaInNAs/AlGaInAs active region is high only for thick, highly-strained GaInNAs QWs with N concentration higher than 2%. Much higher gain in this wavelength range can be obtained for GaInAsSb/AlGaAsSb active region, which offers relatively high gain even at 4.5 µm when the Sb content in GaInAsSb and compressive strain in this layer are equal to 50% and - 2%, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Background: Attenuated total reflection–Fourier transform infrared (ATR–FTIR) spectroscopy could serve as a diagnostic tool for detecting and discriminating different diseases. The aim of this preliminary study was to distinguish malignant and nonmalignant lung tissues with ATR–FTIR spectroscopy. Methods: Sixty lung tissue samples were obtained from 30 patients who underwent pulmonary lobectomy. Samples were examined with ATR–FTIR spectroscopy before histologic diagnosis. Peak positions, intensities, and full width at half maximum of each absorbent band were measured, and the relative intensity ratios were calculated. Canonical discriminant analysis was performed to discriminate malignant and nonmalignant groups. Results: Twenty-two parameters were significantly different between malignant and nonmalignant groups. Peak intensity at 1546/cm, intensity ratio at 1120/cm, and full width at half maximum at 1303 and 1240/cm were selected as independent factors to form discriminant functions. The sensitivity and specificity of the discriminants were all 96.7%. Conclusions: ATR–FTIR spectroscopy is a promising method for the detection of malignant lung tissue and could be proved useful in lung tumor surgery. [Copyright &y& Elsevier]

We present results on the responsivity of YBCO thin-film devices to mid-infrared (25 /spl mu/m) radiation. Light is generated by pulsed diode-laser sources monitored by a calibrated HgCdTe detector. For the sample geometry studied here, we estimate an upper limit to the low-frequency responsivity, R of /spl sim/1000 V/W. [ABSTRACT FROM PUBLISHER]

Semiconductor lasers and detectors based on intersubband electron transitions are used to generate and measure high-speed pulses of mid-infrared radiation. In particular, we use a commercial comb generator to gain-switch a state-of-the-art 8-μm quantum cascade laser mounted in a high-speed package. The output pulses of this device are then detected with a small-area quantum-well infrared photodetector, also packaged for high-speed operation. Pulse widths shorter than 90 ps are directly measured with this system. Accounting for the finite response time of the detection electronics, a deconvolved duration of approximately 45 ps is extrapolated [ABSTRACT FROM PUBLISHER]